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[chirp] / src / main.zig
diff --git a/src/main.zig b/src/main.zig
index f5e66ea54fc0d264251b26eba1081b92bf26a959..f8113dc108ae1f5f1474f3b0bd02bc85033cd022 100644 (file)
--- a/src/main.zig
+++ b/src/main.zig
@@ -1,189 +1,22 @@
 const std = @import("std");
 const lmdb = @import("lmdb");
 const std = @import("std");
 const lmdb = @import("lmdb");
+const db = @import("db");
 const http = @import("http");
 
 // db {{{
 
 const http = @import("http");
 
 // db {{{
 
-const Prng = struct {
-    var prng: std.Random.DefaultPrng = std.Random.DefaultPrng.init(0);
-
-    fn IdType(comptime T: type) type {
-        const ti = @typeInfo(@TypeOf(T.get));
-        return ti.Fn.params[1].type.?;
-    }
-
-    pub fn gen_id(dbi: anytype) IdType(@TypeOf(dbi)) {
-        var id: IdType(@TypeOf(dbi)) = @enumFromInt(Prng.prng.next());
-
-        while (dbi.has(id)) {
-            id = @enumFromInt(Prng.prng.next());
-        }
-
-        return id;
-    }
-
-    pub fn gen_str(dbi: anytype, comptime len: usize) [len]u8 {
-        var buf: [len / 2]u8 = undefined;
-        var res: [len]u8 = undefined;
-        Prng.prng.fill(&buf);
-        for (0..len / 2) |i| {
-            res[i * 2 + 0] = 'a' + (buf[i] % 16);
-            res[i * 2 + 1] = 'a' + (buf[i] >> 4 % 16);
-        }
-
-        while (dbi.has(res)) {
-            Prng.prng.fill(&buf);
-            for (0..len / 2) |i| {
-                res[i * 2 + 0] = 'a' + (buf[i] % 16);
-                res[i * 2 + 1] = 'a' + (buf[i] >> 4 % 16);
-            }
-        }
-
-        return res;
-    }
-};
-
 const Db = struct {
 const Db = struct {
-    fn Key(types: anytype) type {
-        return std.meta.Tuple(&types);
+    fn users(txn: lmdb.Txn) !db.Db(UserId, User) {
+        return try db.Db(UserId, User).init(txn, "users");
     }
     }
-    fn users(txn: *const lmdb.Txn) !lmdb.Dbi(UserId, User) {
-        return try txn.dbi("users", UserId, User);
+    fn user_ids(txn: lmdb.Txn) !db.Db(Username, UserId) {
+        return try db.Db(Username, UserId).init(txn, "user_ids");
     }
     }
-    fn user_ids(txn: *const lmdb.Txn) !lmdb.Dbi(Username, UserId) {
-        return try txn.dbi("user_ids", Username, UserId);
+    fn sessions(txn: lmdb.Txn) !db.Db(SessionToken, UserId) {
+        return try db.Db(SessionToken, UserId).init(txn, "sessions");
     }
     }
-    fn sessions(txn: *const lmdb.Txn) !lmdb.Dbi(SessionToken, UserId) {
-        return try txn.dbi("sessions", SessionToken, UserId);
-    }
-    fn posts(txn: *const lmdb.Txn) !lmdb.Dbi(PostId, Post) {
-        return try txn.dbi("posts", PostId, Post);
-    }
-    fn lists(txn: *const lmdb.Txn, comptime T: type) !lmdb.Dbi(ListId, ListNode(T)) {
-        return try txn.dbi("lists", ListId, ListNode(T));
-    }
-    fn sets(txn: *const lmdb.Txn, comptime T: type) !lmdb.Dbi(Key(.{ SetId, T }), u0) {
-        return try txn.dbi("sets", Key(.{ SetId, T }), u0);
-    }
-
-    const ListId = enum(u64) { _ };
-
-    pub fn ListNode(comptime T: type) type {
-        return struct {
-            next: ?ListId,
-            prev: ?ListId,
-            data: T,
-        };
-    }
-
-    pub fn List(comptime T: type) type {
-        return struct {
-            const Self = @This();
-
-            first: ListId = undefined,
-            last: ListId = undefined,
-            len: usize = 0,
-
-            pub const Iterator = struct {
-                dbi: lmdb.Dbi(ListId, ListNode(T)),
-                id_maybe: ?ListId,
-
-                pub fn next(self: *Iterator) ?T {
-                    const id = self.id_maybe orelse return null;
-
-                    // TODO: how to handle this?
-                    const ln = self.dbi.get(id) orelse return null;
-                    self.id_maybe = ln.next;
-                    return ln.data;
-                }
-            };
-            pub fn it(self: *const Self, txn: *const lmdb.Txn) !Iterator {
-                const list = try Db.lists(txn, T);
-                return .{ .dbi = list, .id_maybe = if (self.len > 0) self.first else null };
-            }
-            pub fn append(self: *Self, txn: *const lmdb.Txn, t: T) !void {
-                const list = try Db.lists(txn, T);
-                const new_id = Prng.gen_id(list);
-
-                if (self.len == 0) {
-                    self.first = new_id;
-                    self.last = new_id;
-                    self.len = 1;
-                    list.put(new_id, .{
-                        .next = null,
-                        .prev = null,
-                        .data = t,
-                    });
-                } else {
-                    const prev_id = self.last;
-                    var last = list.get(prev_id).?;
-                    last.next = new_id;
-                    list.put(prev_id, last);
-
-                    list.put(new_id, .{
-                        .next = null,
-                        .prev = prev_id,
-                        .data = t,
-                    });
-
-                    self.last = new_id;
-                    self.len += 1;
-                }
-            }
-        };
-    }
-
-    const SetId = enum(u64) { _ };
-
-    pub fn Set(comptime T: type) type {
-        return struct {
-            const Self = @This();
-            const SetKey = Key(.{ SetId, T });
-
-            len: usize = 0,
-            set_id: ?SetId = null,
-
-            pub fn init(self: *Self) void {
-                self.set_id = @enumFromInt(Prng.prng.next());
-            }
-
-            pub fn has(self: Self, txn: *const lmdb.Txn, t: T) !bool {
-                if (self.set_id == null) return false;
-
-                const set = try Db.sets(txn, T);
-                const key = SetKey{ self.set_id.?, t };
-
-                return set.has(key);
-            }
-
-            pub fn add(self: *Self, txn: *const lmdb.Txn, t: T) !void {
-                if (self.set_id == null) self.init();
-
-                const set = try Db.sets(txn, T);
-                const key = SetKey{ self.set_id.?, t };
-
-                if (!set.has(key)) {
-                    set.put(key, 0);
-                    if (set.has(key)) {
-                        self.len += 1;
-                    }
-                }
-            }
-
-            pub fn del(self: *Self, txn: *const lmdb.Txn, t: T) !void {
-                if (self.set_id == null) self.init();
-
-                const set = try Db.sets(txn, T);
-                const key = SetKey{ self.set_id.?, t };
-
-                if (set.has(key)) {
-                    set.del(key);
-                    if (!set.has(key)) {
-                        self.len -= 1;
-                    }
-                }
-            }
-        };
+    fn posts(txn: lmdb.Txn) !db.Db(PostId, Post) {
+        return try db.Db(PostId, Post).init(txn, "posts");
     }
 };
 
     }
 };
 
@@ -194,236 +27,396 @@ const Db = struct {
 const User = struct {
     // TODO: choose sizes
     id: UserId,
 const User = struct {
     // TODO: choose sizes
     id: UserId,
-    username: Username,
+    name: Username,
+    display_name: DisplayName,
     password_hash: PasswordHash,
     password_hash: PasswordHash,
-    posts: PostList = PostList{},
+    posts: PostList,
+    following: UserList,
+    followers: UserList,
 };
 
 const Post = struct {
     id: PostId,
 };
 
 const Post = struct {
     id: PostId,
+    parent_id: ?PostId,
+    quote_id: ?PostId,
 
     user_id: UserId,
     time: Timestamp,
 
 
     user_id: UserId,
     time: Timestamp,
 
-    upvotes: UserList = UserList{},
-    downvotes: UserList = UserList{},
-    comments: PostList = PostList{},
-    // reposts
+    upvotes: u64 = 0,
+    downvotes: u64 = 0,
+    votes: VoteList,
+    comments: PostList,
+    quotes: PostList,
 
     text: PostText,
 };
 
 
     text: PostText,
 };
 
-const SessionTokenLen = 16;
+const Vote = struct {
+    const Kind = enum { Up, Down };
+
+    kind: Kind,
+    time: Timestamp,
+};
 
 const Id = u64;
 const Login = struct {
     user: User,
 
 const Id = u64;
 const Login = struct {
     user: User,
-    user_id: UserId,
     session_token: SessionToken,
 };
 const UserId = enum(u64) { _ };
 const PostId = enum(u64) { _ };
 const Timestamp = i64;
 const Username = std.BoundedArray(u8, 16);
     session_token: SessionToken,
 };
 const UserId = enum(u64) { _ };
 const PostId = enum(u64) { _ };
 const Timestamp = i64;
 const Username = std.BoundedArray(u8, 16);
+const DisplayName = std.BoundedArray(u8, 64);
 const PasswordHash = std.BoundedArray(u8, 128);
 const PasswordHash = std.BoundedArray(u8, 128);
-const SessionToken = [SessionTokenLen]u8;
+const SessionToken = u64;
 const CookieValue = std.BoundedArray(u8, 128);
 const PostText = std.BoundedArray(u8, 1024);
 const CookieValue = std.BoundedArray(u8, 128);
 const PostText = std.BoundedArray(u8, 1024);
-const PostList = Db.List(PostId);
-const UserList = Db.Set(UserId);
+const PostList = db.Set(PostId);
+const UserList = db.Set(UserId);
+const VoteList = db.SetList(UserId, Vote);
 
 
-pub fn hash_password(password: []const u8) !PasswordHash {
-    var hash_buffer = try PasswordHash.init(128);
+fn parse_enum(comptime E: type, buf: []const u8, base: u8) !E {
+    return @enumFromInt(try std.fmt.parseUnsigned(@typeInfo(E).Enum.tag_type, buf, base));
+}
 
 
-    // TODO: choose buffer size
-    // TODO: dont allocate on stack, maybe zero memory?
-    var buffer: [1024 * 10]u8 = undefined;
-    var alloc = std.heap.FixedBufferAllocator.init(&buffer);
+// https://developer.mozilla.org/en-US/docs/Glossary/Percent-encoding
+fn reencode(text: []const u8) !PostText {
+    var result = try PostText.init(0);
+
+    const len = @min(text.len, 1024); // TODO: PostText length
+
+    var idx: usize = 0;
+    while (idx < len) : (idx += 1) {
+        const c = text[idx];
+        if (c == '+') {
+            try result.append(' ');
+        } else if (c == '%') {
+            // special case of &#...
+            // assume only &#, no &#x
+            if (idx + 6 < text.len and std.mem.eql(u8, text[idx .. idx + 6], "%26%23")) {
+                const num_start = idx + 6;
+                var num_end = num_start;
+                while (num_end < text.len and std.ascii.isDigit(text[num_end])) {
+                    num_end += 1;
+                }
 
 
-    // TODO: choose limits
-    const result = try std.crypto.pwhash.argon2.strHash(password, .{
-        .allocator = alloc.allocator(),
-        .params = std.crypto.pwhash.argon2.Params.fromLimits(1000, 1024),
-    }, hash_buffer.slice());
+                if (num_end + 2 < text.len and
+                    text[num_end] == '%' and
+                    text[num_end + 1] == '3' and
+                    std.ascii.toLower(text[num_end + 2]) == 'b')
+                {
+                    try std.fmt.format(result.writer(), "&#{s};", .{text[num_start..num_end]});
+                    idx = num_end + 2;
+                    continue;
+                }
+            }
 
 
-    try hash_buffer.resize(result.len);
+            try std.fmt.format(result.writer(), "&#x{s};", .{text[idx + 1 .. idx + 3]});
+            idx += 2;
+        } else {
+            try result.append(c);
+        }
+    }
 
 
-    return hash_buffer;
+    return result;
 }
 
 }
 
-pub fn verify_password(password: []const u8, hash: PasswordHash) bool {
-    var buffer: [1024 * 10]u8 = undefined;
-    var alloc = std.heap.FixedBufferAllocator.init(&buffer);
-
-    if (std.crypto.pwhash.argon2.strVerify(hash.constSlice(), password, .{
-        .allocator = alloc.allocator(),
-    })) {
-        return true;
-    } else |err| {
-        std.debug.print("verify error: {}\n", .{err});
-        return false;
+fn decode(text: []const u8) !std.BoundedArray(u8, 32) {
+    var result = try std.BoundedArray(u8, 32).init(0);
+
+    const max_len = @min(text.len, 1024); // TODO: PostText length
+
+    var idx: usize = 0;
+    var len: usize = 0;
+    while (len < max_len and idx < text.len) : ({
+        idx += 1;
+        len += 1;
+    }) {
+        const c = text[idx];
+        if (c == '+') {
+            try result.append(' ');
+        } else if (c == '%') {
+            if (idx + 2 < text.len) {
+                try std.fmt.format(result.writer(), "{c}", .{try std.fmt.parseUnsigned(u8, text[idx + 1 .. idx + 3], 16)});
+            }
+            idx += 2;
+        } else {
+            try result.append(c);
+        }
     }
     }
+
+    return result;
 }
 
 }
 
-pub fn register_user(env: *lmdb.Env, username: []const u8, password: []const u8) !bool {
-    const username_array = try Username.fromSlice(username);
+const Chirp = struct {
+    pub fn hash_password(password: []const u8) !PasswordHash {
+        var hash_buffer = try PasswordHash.init(128);
 
 
-    const txn = try env.txn();
-    defer {
-        txn.commit();
-        env.sync();
-    }
+        // TODO: choose buffer size
+        // TODO: dont allocate on stack, maybe zero memory?
+        var buffer: [1024 * 10]u8 = undefined;
+        var alloc = std.heap.FixedBufferAllocator.init(&buffer);
 
 
-    const users = try Db.users(&txn);
-    const user_ids = try Db.user_ids(&txn);
+        // TODO: choose limits
+        const result = try std.crypto.pwhash.argon2.strHash(password, .{
+            .allocator = alloc.allocator(),
+            .params = std.crypto.pwhash.argon2.Params.fromLimits(1000, 1024),
+        }, hash_buffer.slice());
 
 
-    if (user_ids.has(username_array)) {
-        return false;
-    } else {
-        const user_id = Prng.gen_id(users);
-        users.put(user_id, User{
-            .id = user_id,
-            .username = username_array,
-            .password_hash = try hash_password(password),
-        });
+        try hash_buffer.resize(result.len);
 
 
-        user_ids.put(username_array, user_id);
+        return hash_buffer;
+    }
 
 
-        return true;
+    pub fn verify_password(password: []const u8, hash: PasswordHash) bool {
+        var buffer: [1024 * 10]u8 = undefined;
+        var alloc = std.heap.FixedBufferAllocator.init(&buffer);
+
+        if (std.crypto.pwhash.argon2.strVerify(hash.constSlice(), password, .{
+            .allocator = alloc.allocator(),
+        })) {
+            return true;
+        } else |err| {
+            std.debug.print("verify error: {}\n", .{err});
+            return false;
+        }
     }
     }
-}
 
 
-pub fn login_user(env: *lmdb.Env, username: []const u8, password: []const u8) !SessionToken {
-    const username_array = try Username.fromSlice(username);
+    pub fn register_user(env: *lmdb.Env, username: []const u8, password: []const u8) !bool {
+        const username_array = try Username.fromSlice(username);
+        const display_name = try DisplayName.fromSlice(username);
 
 
-    const txn = try env.txn();
-    defer {
-        txn.commit();
-        env.sync();
+        const txn = try env.txn();
+        defer txn.commit() catch {};
+
+        const users = try Db.users(txn);
+        const user_ids = try Db.user_ids(txn);
+
+        if (try user_ids.has(username_array)) {
+            return false;
+        } else {
+            const user_id = try db.Prng.gen(users.dbi, UserId);
+
+            try users.put(user_id, User{
+                .id = user_id,
+                .name = username_array,
+                .display_name = display_name,
+                .password_hash = try hash_password(password),
+                .posts = try PostList.init(txn),
+                .following = try UserList.init(txn),
+                .followers = try UserList.init(txn),
+            });
+
+            try user_ids.put(username_array, user_id);
+
+            return true;
+        }
     }
 
     }
 
-    const user_ids = try Db.user_ids(&txn);
-    const user_id = user_ids.get(username_array) orelse return error.UnknownUsername;
-    std.debug.print("id: {}\n", .{user_id});
+    pub fn login_user(
+        env: *lmdb.Env,
+        username: []const u8,
+        password: []const u8,
+    ) !SessionToken {
+        const username_array = try Username.fromSlice(username);
+
+        const txn = try env.txn();
+        defer txn.commit() catch {};
+
+        const user_ids = try Db.user_ids(txn);
+        const user_id = try user_ids.get(username_array);
+        std.debug.print("user logging in, id: {}\n", .{user_id});
+
+        const users = try Db.users(txn);
+        const user = try users.get(user_id);
 
 
-    const users = try Db.users(&txn);
-    if (users.get(user_id)) |user| {
         if (verify_password(password, user.password_hash)) {
         if (verify_password(password, user.password_hash)) {
-            const sessions = try Db.sessions(&txn);
-            const session_token = Prng.gen_str(sessions, SessionTokenLen);
-            sessions.put(session_token, user_id);
+            const sessions = try Db.sessions(txn);
+            const session_token = try db.Prng.gen(sessions.dbi, SessionToken);
+            try sessions.put(session_token, user_id);
             return session_token;
         } else {
             return error.IncorrectPassword;
         }
             return session_token;
         } else {
             return error.IncorrectPassword;
         }
-    } else {
-        return error.UserNotFound;
     }
     }
-}
 
 
-fn logout_user(env: *lmdb.Env, session_token: SessionToken) !void {
-    const txn = try env.txn();
-    defer {
-        txn.commit();
-        env.sync();
+    fn logout_user(env: *lmdb.Env, session_token: SessionToken) !void {
+        const txn = try env.txn();
+        defer txn.commit() catch {};
+
+        const sessions = try Db.sessions(txn);
+        try sessions.del(session_token);
     }
 
     }
 
-    const sessions = try Db.sessions(&txn);
-    sessions.del(session_token);
-}
+    fn append_post(env: *lmdb.Env, user_id: UserId, post_list: PostList, parent_id: ?PostId, quote_id: ?PostId, text: []const u8) !void {
+        var post_id: PostId = undefined;
+
+        // TODO: do this in one commit
+
+        var txn: lmdb.Txn = undefined;
+        {
+            // create post
+            txn = try env.txn();
+            defer txn.commit() catch {};
+
+            const posts = try Db.posts(txn);
+            post_id = try db.Prng.gen(posts.dbi, PostId);
+
+            const decoded_text = try reencode(text);
+            try posts.put(post_id, Post{
+                .id = post_id,
+                .parent_id = parent_id,
+                .quote_id = quote_id,
+                .user_id = user_id,
+                .time = std.time.timestamp(),
+                .votes = try VoteList.init(txn),
+                .comments = try PostList.init(txn),
+                .quotes = try PostList.init(txn),
+                .text = decoded_text,
+            });
+        }
 
 
-fn post(env: *lmdb.Env, user_id: UserId, text: []const u8) !void {
-    var post_id: PostId = undefined;
-
-    var txn = try env.txn();
-    {
-        const posts = try Db.posts(&txn);
-        post_id = Prng.gen_id(posts);
-        posts.put(post_id, Post{
-            .id = post_id,
-            .user_id = user_id,
-            .time = std.time.timestamp(),
-            .text = try PostText.fromSlice(text),
-        });
+        {
+            // append to user's posts
+            txn = try env.txn();
+            defer txn.commit() catch {};
+
+            var posts_view = try post_list.open(txn);
+            try posts_view.append(post_id, {});
+        }
+
+        if (quote_id != null) {
+            txn = try env.txn();
+            defer txn.commit() catch {};
 
 
-        txn.commit();
-        env.sync();
+            const posts = try Db.posts(txn);
+            const quote_post = try posts.get(quote_id.?);
+            var quotes = try quote_post.quotes.open(txn);
+            try quotes.append(post_id, {});
+        }
     }
 
     }
 
-    txn = try env.txn();
-    {
-        const users = try Db.users(&txn);
-        var user = users.get(user_id) orelse return error.UserNotFound;
-        try user.posts.append(&txn, post_id);
-        users.put(user_id, user);
+    fn post(env: *lmdb.Env, user_id: UserId, text: []const u8) !void {
+        const txn = try env.txn();
+
+        const users = try Db.users(txn);
+        const user = try users.get(user_id);
+
+        txn.abort();
 
 
-        txn.commit();
-        env.sync();
+        try append_post(env, user_id, user.posts, null, null, text);
     }
     }
-}
 
 
-fn vote(env: *lmdb.Env, post_id: PostId, user_id: UserId, dir: enum { Up, Down }) !void {
-    const txn = try env.txn();
-    defer {
-        txn.commit();
-        env.sync();
+    fn comment(env: *lmdb.Env, user_id: UserId, parent_post_id: PostId, text: []const u8) !void {
+        const txn = try env.txn();
+
+        const posts = try Db.posts(txn);
+        const parent_post = try posts.get(parent_post_id);
+
+        txn.abort();
+
+        try append_post(env, user_id, parent_post.comments, parent_post_id, null, text);
     }
 
     }
 
-    const posts = try Db.posts(&txn);
+    fn quote(env: *lmdb.Env, user_id: UserId, quote_post_id: PostId, text: []const u8) !void {
+        const txn = try env.txn();
 
 
-    var p = posts.get(post_id) orelse return error.PostNotFound;
-    if (dir == .Up) {
-        try p.upvotes.add(&txn, user_id);
-    } else {
-        try p.downvotes.add(&txn, user_id);
+        const users = try Db.users(txn);
+        const user = try users.get(user_id);
+
+        txn.abort();
+
+        try append_post(env, user_id, user.posts, null, quote_post_id, text);
     }
     }
-    posts.put(post_id, p);
-}
 
 
-fn unvote(env: *lmdb.Env, post_id: PostId, user_id: UserId, dir: enum { Up, Down }) !void {
-    const txn = try env.txn();
-    defer {
-        txn.commit();
-        env.sync();
+    fn vote(env: *lmdb.Env, post_id: PostId, user_id: UserId, kind: Vote.Kind) !void {
+        const txn = try env.txn();
+        defer txn.commit() catch {};
+
+        const posts = try Db.posts(txn);
+
+        var p = try posts.get(post_id);
+        var votes_view = try p.votes.open(txn);
+
+        var add_vote = true;
+
+        if (try votes_view.has(user_id)) {
+            const old_vote = try votes_view.get(user_id);
+
+            add_vote = old_vote.kind != kind;
+
+            try votes_view.del(user_id);
+
+            switch (old_vote.kind) {
+                .Up => p.upvotes -= 1,
+                .Down => p.downvotes -= 1,
+            }
+            try posts.put(post_id, p);
+        }
+
+        if (add_vote) {
+            try votes_view.append(user_id, Vote{
+                .kind = kind,
+                .time = std.time.timestamp(),
+            });
+
+            if (kind == .Up) {
+                p.upvotes += 1;
+            } else {
+                p.downvotes += 1;
+            }
+            try posts.put(post_id, p);
+        }
     }
 
     }
 
-    const posts = try Db.posts(&txn);
+    fn follow(env: *lmdb.Env, user_id: UserId, user_id_to_follow: UserId) !void {
+        const txn = try env.txn();
+        defer txn.commit() catch {};
 
 
-    var p = posts.get(post_id) orelse return error.PostNotFound;
-    if (dir == .Up) {
-        try p.upvotes.del(&txn, user_id);
-    } else {
-        try p.downvotes.del(&txn, user_id);
+        const users = try Db.users(txn);
+
+        const user = try users.get(user_id);
+        const user_to_follow = try users.get(user_id_to_follow);
+
+        var user_following = try user.following.open(txn);
+        var user_to_follow_followers = try user_to_follow.followers.open(txn);
+
+        if ((user_following.has(user_id_to_follow) catch false) and (user_to_follow_followers.has(user_id) catch false)) {
+            try user_following.del(user_id_to_follow);
+            try user_to_follow_followers.del(user_id);
+        } else if (!(user_following.has(user_id_to_follow) catch true) and !(user_to_follow_followers.has(user_id) catch true)) {
+            try user_following.append(user_id_to_follow, {});
+            try user_to_follow_followers.append(user_id, {});
+        } else {
+            std.debug.print("Something went wrong when trying to unfollow\n", .{});
+        }
     }
     }
-    posts.put(post_id, p);
-}
 
 
-fn get_session_user_id(env: *lmdb.Env, session_token: SessionToken) !UserId {
-    const txn = try env.txn();
-    defer txn.abort();
+    fn get_session_user_id(env: *lmdb.Env, session_token: SessionToken) !UserId {
+        const txn = try env.txn();
+        defer txn.abort();
 
 
-    const sessions = try Db.sessions(&txn);
+        const sessions = try Db.sessions(txn);
 
 
-    if (sessions.get(session_token)) |user_id| {
-        return user_id;
-    } else {
-        return error.SessionNotFound;
+        return try sessions.get(session_token);
     }
     }
-}
 
 
-fn get_user(env: *lmdb.Env, user_id: UserId) !?User {
-    const txn = try env.txn();
-    defer txn.abort();
+    fn get_user(env: *lmdb.Env, user_id: UserId) !User {
+        const txn = try env.txn();
+        defer txn.abort();
 
 
-    const users = try Db.users(&txn);
-    return users.get(user_id);
-}
+        const users = try Db.users(txn);
+        return try users.get(user_id);
+    }
+};
 
 // }}}
 
 // html {{{
 fn html_form(res: *http.Response, comptime fmt_action: []const u8, args_action: anytype, inputs: anytype) !void {
 
 // }}}
 
 // html {{{
 fn html_form(res: *http.Response, comptime fmt_action: []const u8, args_action: anytype, inputs: anytype) !void {
-    try res.write("<form style=\"display: inline-block!important;\" action=\"", .{});
+    try res.write("<form action=\"", .{});
     try res.write(fmt_action, args_action);
     try res.write("\" method=\"post\">", .{});
 
     try res.write(fmt_action, args_action);
     try res.write("\" method=\"post\">", .{});
 
@@ -447,65 +440,295 @@ fn html_form(res: *http.Response, comptime fmt_action: []const u8, args_action:
 // }}}
 
 // write {{{
 // }}}
 
 // write {{{
+const TimeStr = std.BoundedArray(u8, 256);
+// fn time_str(_t: i64) TimeStr {
+//     var result = TimeStr.init(0) catch unreachable;
+
+//     const nthSecond: u64 = @intCast(_t);
+//     const nthDay = nthSecond / std.time.s_per_day;
+//     const secondInDay = nthSecond - nthDay * std.time.s_per_day;
+//     const hourInDay = secondInDay / std.time.s_per_hour;
+//     const secondInHour = secondInDay % std.time.s_per_hour;
+//     const minuteInHour = secondInHour / 60;
+//     const secondInMinute = secondInDay % std.time.s_per_min;
+
+//     const nthYear = nthDay / 365; // maybe check
+//     const year = 1970 + nthYear;
+//     const leapdays = year / 4 - year / 100 + year / 400;
+//     const secondInYear = nthSecond - (nthYear * 365 + leapdays) * std.time.s_per_day;
+//     const dayInYear = secondInYear / std.time.s_per_day;
+
+//     std.fmt.format(result.writer(), "<time>{:0>2}:{:0>2}:{:0>2} {:0>2}.{:0>2}.{:0>4} UTC</time>", .{
+//         hourInDay,
+//         minuteInHour,
+//         secondInMinute,
+//         dayInYear,
+//         0,
+//         year,
+//     }) catch unreachable;
+
+//     return result;
+// }
+// http://howardhinnant.github.io/date_algorithms.html
+fn time_str(_t: i64) TimeStr {
+    const t: u64 = @intCast(_t);
+    var result = TimeStr.init(0) catch unreachable;
+
+    const nD = @divFloor(t, std.time.s_per_day);
+    const z: u64 = nD + 719468;
+    const era: u64 = (if (z >= 0) z else z - 146096) / 146097;
+    const doe: u64 = z - era * 146097; // [0, 146096]
+    const yoe: u64 = (doe - doe / 1460 + doe / 36524 - doe / 146096) / 365; // [0, 399]
+    const Y: u64 = yoe + era * 400;
+    const doy: u64 = doe - (365 * yoe + yoe / 4 - yoe / 100); // [0, 365]
+    const mp: u64 = (5 * doy + 2) / 153; // [0, 11]
+    const D: u64 = doy - (153 * mp + 2) / 5 + 1; // [1, 31]
+    const M: u64 = if (mp < 10) mp + 3 else mp - 9;
+
+    const h: u64 = @divFloor(t - nD * std.time.s_per_day, std.time.s_per_hour);
+    const m: u64 = @divFloor(t - nD * std.time.s_per_day - h * std.time.s_per_hour, std.time.s_per_min);
+    const s: u64 = t - nD * std.time.s_per_day - h * std.time.s_per_hour - m * std.time.s_per_min;
+
+    std.fmt.format(result.writer(), "<time><span>{:0>4}-{:0>2}-{:0>2} {:0>2}:{:0>2}:{:0>2} UTC</span><script>document.currentScript.parentElement.innerHTML=new Date({}).toLocaleString()</script></time>", .{ Y, M, D, h, m, s, t * 1000 }) catch unreachable;
+
+    return result;
+}
 fn write_header(res: *http.Response, logged_in: ?Login) !void {
     if (logged_in) |login| {
         try res.write(
 fn write_header(res: *http.Response, logged_in: ?Login) !void {
     if (logged_in) |login| {
         try res.write(
-            \\<a href="/user/{s}">Home</a><br />
-        , .{login.user.username.constSlice()});
+            \\<a href="/">Home</a><br />
+        , .{});
+        try res.write(
+            \\<a href="/user/{s}">Profile</a><br />
+        , .{login.user.name.constSlice()});
+        try res.write(
+            \\<a href="/post">Post</a><br />
+        , .{});
+        try res.write(
+            \\<a href="/edit">Edit</a><br />
+        , .{});
         try html_form(res, "/logout", .{}, .{
             \\type="submit" value="Logout"
         });
         try html_form(res, "/quit", .{}, .{
             \\type="submit" value="Quit"
         });
         try html_form(res, "/logout", .{}, .{
             \\type="submit" value="Logout"
         });
         try html_form(res, "/quit", .{}, .{
             \\type="submit" value="Quit"
         });
-        try res.write("<br />", .{});
-        try html_form(res, "/post", .{}, .{
-            \\type="text" name="text"
-            ,
-            \\type="submit" value="Post"
-        });
+        try res.write("<br /><br />", .{});
     } else {
         try res.write(
             \\<a href="/">Home</a><br />
     } else {
         try res.write(
             \\<a href="/">Home</a><br />
-            \\<a href="/register">Register</a>
-            \\<a href="/login">Login</a><br />
+            \\<form action="/register" method="post">
+            \\<input type="text" name="username" />
+            \\<input type="password" name="password" />
+            \\<input type="submit" value="Register" />
+            \\</form>
+            \\<form action="/login" method="post">
+            \\<input type="text" name="username" />
+            \\<input type="password" name="password" />
+            \\<input type="submit" value="Login" />
+            \\</form>
         , .{});
         try html_form(res, "/quit", .{}, .{
             \\type="submit" value="Quit"
         });
         , .{});
         try html_form(res, "/quit", .{}, .{
             \\type="submit" value="Quit"
         });
+        try res.write("<br /><br />", .{});
     }
 }
     }
 }
-fn write_posts(res: *http.Response, txn: *const lmdb.Txn, user: User, login: ?Login) !void {
+fn write_start(res: *http.Response) !void {
+    try res.write(
+        \\<!doctype html>
+        \\<html>
+        \\<head>
+        \\<link rel="icon" href="data:image/svg+xml,<svg xmlns=%22http://www.w3.org/2000/svg%22 viewBox=%220 0 100 100%22><text y=%22.9em%22 font-size=%2290%22>&#128035;</text></svg>">
+        \\<style>
+        \\  form {
+        \\    display: inline-block;
+        \\  }
+        \\  .toggle > form > input:placeholder-shown {
+        \\    display: none;
+        \\  }
+        \\  .toggle:hover > form > input {
+        \\    display: inline-block;
+        \\  }
+        \\  .toggle > form > input:placeholder-shown + input {
+        \\    display: none;
+        \\  }
+        \\  .toggle:hover > form > input + input {
+        \\    display: inline-block;
+        \\  }
+        \\</style>
+        \\</head>
+        \\<body>
+    , .{});
+}
+fn write_end(res: *http.Response) !void {
+    try res.write("</body></html>", .{});
+}
+fn write_post(res: *http.Response, txn: lmdb.Txn, logged_in: ?Login, post_id: PostId, recurse: enum { No, Once, Yes }) !void {
     const posts = try Db.posts(txn);
     const posts = try Db.posts(txn);
-    var it = try user.posts.it(txn);
-    while (it.next()) |post_id| {
-        const p = posts.get(post_id) orelse break;
+    const post = posts.get(post_id) catch {
+        res.redirect("/") catch {};
+        return;
+    };
+    const users = try Db.users(txn);
+    const user = try users.get(post.user_id);
+
+    try res.write(
+        \\<div>
+        \\<span><a href="/user/{s}">{s}</a> {s}</span><br />
+        \\<span>{s}</span><br />
+    , .{ user.name.constSlice(), user.display_name.constSlice(), time_str(post.time).constSlice(), post.text.constSlice() });
+
+    if (recurse != .No and post.quote_id != null) {
+        try res.write("<div style=\"border: 1px solid black;\">", .{});
+        try write_post(res, txn, logged_in, post.quote_id.?, .No);
+        try res.write("</div>", .{});
+    }
+
+    const comments_view = try post.comments.open(txn);
+    const quotes_view = try post.quotes.open(txn);
+    const votes_view = try post.votes.open(txn);
+
+    // Votes
+    const vote: ?Vote = if (logged_in != null and try votes_view.has(logged_in.?.user.id)) try votes_view.get(logged_in.?.user.id) else null;
+
+    if (vote != null and vote.?.kind == .Up) {
+        try html_form(res, "/upvote", .{}, .{
+            .{ "type=\"hidden\" value=\"{x}\" name=\"post_id\"", .{@intFromEnum(post.id)} },
+            .{ "type=\"submit\" value=\"&#x2B06; {}\"", .{post.upvotes} },
+        });
+    } else {
+        try html_form(res, "/upvote", .{}, .{
+            .{ "type=\"hidden\" value=\"{x}\" name=\"post_id\"", .{@intFromEnum(post.id)} },
+            .{ "type=\"submit\" value=\"&#x21E7; {}\"", .{post.upvotes} },
+        });
+    }
+    if (vote != null and vote.?.kind == .Down) {
+        try html_form(res, "/downvote", .{}, .{
+            .{ "type=\"hidden\" value=\"{x}\" name=\"post_id\"", .{@intFromEnum(post.id)} },
+            .{ "type=\"submit\" value=\"&#x2B07; {}\"", .{post.downvotes} },
+        });
+    } else {
+        try html_form(res, "/downvote", .{}, .{
+            .{ "type=\"hidden\" value=\"{x}\" name=\"post_id\"", .{@intFromEnum(post.id)} },
+            .{ "type=\"submit\" value=\"&#x21E9; {}\"", .{post.downvotes} },
+        });
+    }
+
+    // Comment Count
+    try res.write(
+        \\<span class="toggle">
+        \\<a href="/post/{x}">&#x1F4AD; {}</a> 
+    , .{ @intFromEnum(post.id), comments_view.len() });
+    if (logged_in != null) {
+        try html_form(res, "/comment", .{}, .{
+            .{ "type=\"hidden\" value=\"{x}\" name=\"post_id\"", .{@intFromEnum(post.id)} },
+            "type=\"text\" name=\"text\" placeholder=\"Text\"",
+            "type=\"submit\" value=\"Comment\"",
+        });
+    }
+    try res.write(
+        \\</span>
+    , .{});
+
+    // Quote
+    try res.write(
+        \\<span class="toggle">
+        \\<a href="/quotes/{x}">&#x1F501; {}</a> 
+    , .{ @intFromEnum(post.id), quotes_view.len() });
+    try html_form(res, "/quote", .{}, .{
+        .{ "type=\"hidden\" value=\"{x}\" name=\"post_id\"", .{@intFromEnum(post.id)} },
+        "type=\"text\" name=\"text\" placeholder=\"Text\"",
+        "type=\"submit\" value=\"Quote\"",
+    });
+    try res.write(
+        \\</span>
+        \\<br />
+    , .{});
+
+    // Comments
+    if (recurse != .No and comments_view.len() > 0) {
         try res.write(
         try res.write(
-            \\<div>
-            \\<p>{s}</p>
-        , .{p.text.constSlice()});
-        if (login != null and try p.upvotes.has(txn, login.?.user_id)) {
-            try html_form(res, "/unupvote/{}", .{@intFromEnum(post_id)}, .{
-                .{ "type=\"submit\" value=\"&#x2B06; {}\"", .{p.upvotes.len} },
-            });
-        } else {
-            try html_form(res, "/upvote/{}", .{@intFromEnum(post_id)}, .{
-                .{ "type=\"submit\" value=\"&#x2B06; {}\"", .{p.upvotes.len} },
-            });
-        }
-        if (login != null and try p.downvotes.has(txn, login.?.user_id)) {
-            try html_form(res, "/undownvote/{}", .{@intFromEnum(post_id)}, .{
-                .{ "type=\"submit\" value=\"&#x2B07; {}\"", .{p.downvotes.len} },
-            });
-        } else {
-            try html_form(res, "/downvote/{}", .{@intFromEnum(post_id)}, .{
-                .{ "type=\"submit\" value=\"&#x2B07; {}\"", .{p.downvotes.len} },
+            \\<details>
+            \\<summary>Comments</summary>
+        , .{});
+        try res.write("<div style=\"margin: 10px;\">", .{});
+        var it = comments_view.iterator();
+        var count: u8 = 0;
+        while (it.next()) |kv| {
+            try write_post(res, txn, logged_in, kv.key, switch (recurse) {
+                .Yes => .Yes,
+                .Once => .No,
+                else => unreachable,
             });
             });
+            try res.write("<br />", .{});
+            if (recurse == .Once) {
+                count += 1;
+                if (count >= 3) break;
+            }
         }
         try res.write(
         }
         try res.write(
-            \\<span>&#x1F4AD; {}</span>
             \\</div>
             \\</div>
-        , .{p.comments.len});
+            \\</details>
+        , .{});
+    }
+
+    try res.write(
+        \\</div>
+    , .{});
+}
+fn write_posts(res: *http.Response, txn: lmdb.Txn, logged_in: ?Login, user: User) !void {
+    const posts_view = try user.posts.open(txn);
+
+    var it = posts_view.reverse_iterator();
+    while (it.next()) |kv| {
+        const post_id = kv.key;
+
+        try write_post(res, txn, logged_in, post_id, .Once);
+        try res.write("<br />", .{});
+    }
+}
+fn write_timeline(res: *http.Response, txn: lmdb.Txn, logged_in: ?Login, user: User) !void {
+    const users = try Db.users(txn);
+    const posts = try Db.posts(txn);
+
+    var newest_post_ids = try std.BoundedArray(PostId, 10).init(0); // TODO: TimelinePostsCount
+    var prev_newest_post: ?Post = null;
+
+    const following = try user.following.open(txn);
+
+    while (true) {
+        var newest_post: ?Post = null;
+
+        var it = following.iterator();
+        while (it.next()) |kv| {
+            const followed_user = try users.get(kv.key);
+            const followed_posts = try followed_user.posts.open(txn);
+
+            if (followed_posts.len() == 0) {
+                continue;
+            }
+
+            var followed_posts_it = followed_posts.reverse_iterator();
+            while (followed_posts_it.next()) |followed_post_kv| {
+                const last_post = try posts.get(followed_post_kv.key);
+
+                if ((prev_newest_post == null or last_post.time < prev_newest_post.?.time) and (newest_post == null or newest_post.?.time < last_post.time)) {
+                    newest_post = last_post;
+                }
+            }
+        }
+        if (newest_post) |post| {
+            newest_post_ids.append(post.id) catch break;
+            prev_newest_post = post;
+        } else {
+            break;
+        }
+    }
+
+    for (newest_post_ids.constSlice()) |post_id| {
+        try write_post(res, txn, logged_in, post_id, .Once);
+        try res.write("<br />", .{});
     }
 }
 // }}}
     }
 }
 // }}}
@@ -514,33 +737,26 @@ fn list_users(env: lmdb.Env) !void {
     const txn = try env.txn();
     defer txn.abort();
 
     const txn = try env.txn();
     defer txn.abort();
 
-    // const users = try Db.users(&txn);
-    const users = try txn.dbi("users", UserId, User);
-    var cursor = try users.cursor();
-
-    var key: UserId = undefined;
-    var user_maybe = cursor.get(&key, .First);
+    const users = try Db.users(txn);
+    var it = try users.iterator();
 
 
-    while (user_maybe) |*user| {
-        std.debug.print("[{}] {s}\n", .{ key, user.username.constSlice() });
-
-        user_maybe = cursor.get(&key, .Next);
+    while (it.next()) |kv| {
+        const key = kv.key;
+        const user = kv.val;
+        std.debug.print("[{}] {s}\n", .{ key, user.name.constSlice() });
     }
 }
 fn list_user_ids(env: lmdb.Env) !void {
     const txn = try env.txn();
     defer txn.abort();
 
     }
 }
 fn list_user_ids(env: lmdb.Env) !void {
     const txn = try env.txn();
     defer txn.abort();
 
-    const user_ids = try Db.user_ids(&txn);
-    var cursor = try user_ids.cursor();
-
-    var key: Username = undefined;
-    var user_id_maybe = cursor.get(&key, .First);
+    const user_ids = try Db.user_ids(txn);
+    var it = try user_ids.iterator();
 
 
-    while (user_id_maybe) |user_id| {
+    while (it.next()) |kv| {
+        const key = kv.key;
+        const user_id = kv.val;
         std.debug.print("[{s}] {}\n", .{ key.constSlice(), user_id });
         std.debug.print("[{s}] {}\n", .{ key.constSlice(), user_id });
-
-        user_id_maybe = cursor.get(&key, .Next);
     }
 }
 
     }
 }
 
@@ -548,16 +764,13 @@ fn list_sessions(env: lmdb.Env) !void {
     const txn = try env.txn();
     defer txn.abort();
 
     const txn = try env.txn();
     defer txn.abort();
 
-    const sessions = try Db.sessions(&txn);
-    var cursor = try sessions.cursor();
+    const sessions = try Db.sessions(txn);
+    var it = try sessions.iterator();
 
 
-    var key: SessionToken = undefined;
-    var user_id_maybe = cursor.get(&key, .First);
-
-    while (user_id_maybe) |user_id| {
-        std.debug.print("[{s}] {}\n", .{ key, user_id });
-
-        user_id_maybe = cursor.get(&key, .Next);
+    while (it.next()) |kv| {
+        const key = kv.key;
+        const user_id = kv.val;
+        std.debug.print("[{x}] {}\n", .{ key, user_id });
     }
 }
 
     }
 }
 
@@ -565,22 +778,19 @@ fn list_posts(env: lmdb.Env) !void {
     const txn = try env.txn();
     defer txn.abort();
 
     const txn = try env.txn();
     defer txn.abort();
 
-    const posts = try Db.posts(&txn);
-    var cursor = try posts.cursor();
-
-    var key: PostId = undefined;
-    var post_maybe = cursor.get(&key, .First);
-
-    while (post_maybe) |p| {
-        std.debug.print("[{}] {s}\n", .{ key, p.text.constSlice() });
+    const posts = try Db.posts(txn);
+    var it = try posts.iterator();
 
 
-        post_maybe = cursor.get(&key, .Next);
+    while (it.next()) |kv| {
+        const key = kv.key;
+        const post = kv.val;
+        std.debug.print("[{}] {s}\n", .{ key, post.text.constSlice() });
     }
 }
 
 const ReqBufferSize = 4096;
     }
 }
 
 const ReqBufferSize = 4096;
-const ResHeadBufferSize = 1024 * 16;
-const ResBodyBufferSize = 1024 * 16;
+const ResHeadBufferSize = 1024 * 64;
+const ResBodyBufferSize = 1024 * 64;
 
 pub fn main() !void {
     // server
 
 pub fn main() !void {
     // server
@@ -623,7 +833,8 @@ fn handle_connection(server: *http.Server, env: *lmdb.Env) !void {
     accept: while (true) {
         server.wait();
 
     accept: while (true) {
         server.wait();
 
-        while (try server.next_request(&req_buffer)) |req| {
+        while (try server.next_request(&req_buffer)) |*_req| {
+            var req: *http.Request = @constCast(_req);
             // std.debug.print("[{}]: {s}\n", .{ req.method, req.target });
 
             // reponse
             // std.debug.print("[{}]: {s}\n", .{ req.method, req.target });
 
             // reponse
@@ -633,23 +844,26 @@ fn handle_connection(server: *http.Server, env: *lmdb.Env) !void {
             var logged_in: ?Login = null;
 
             if (req.get_cookie("session_token")) |session_token_str| {
             var logged_in: ?Login = null;
 
             if (req.get_cookie("session_token")) |session_token_str| {
-                var session_token: SessionToken = undefined;
-                std.mem.copyForwards(u8, &session_token, session_token_str);
-                // const session_token = try std.fmt.parseUnsigned(SessionToken, session_token_str, 10);
-                // const session_token = std.mem.bytesToValue(SessionToken, session_token_str);
-                if (get_session_user_id(env, session_token)) |user_id| {
-                    const txn = try env.txn();
-                    defer txn.abort();
-                    const users = try Db.users(&txn);
+                var remove_session_token = true;
 
 
-                    logged_in = .{
-                        .user = users.get(user_id) orelse return error.UserNotFound,
-                        .user_id = user_id,
-                        .session_token = session_token,
-                    };
-                } else |err| {
-                    std.debug.print("get_session_user err: {}\n", .{err});
+                if (std.fmt.parseUnsigned(SessionToken, session_token_str, 16) catch null) |session_token| {
+                    // const session_token = try std.fmt.parseUnsigned(SessionToken, session_token_str, 10);
+                    // const session_token = std.mem.bytesToValue(SessionToken, session_token_str);
+                    if (Chirp.get_session_user_id(env, session_token) catch null) |user_id| {
+                        const txn = try env.txn();
+                        defer txn.abort();
+                        const users = try Db.users(txn);
 
 
+                        logged_in = .{
+                            .user = try users.get(user_id),
+                            .session_token = session_token,
+                        };
+
+                        remove_session_token = false;
+                    }
+                }
+
+                if (remove_session_token) {
                     try res.add_header(
                         "Set-Cookie",
                         .{"session_token=deleted; Expires=Thu, 01 Jan 1970 00:00:00 GMT"},
                     try res.add_header(
                         "Set-Cookie",
                         .{"session_token=deleted; Expires=Thu, 01 Jan 1970 00:00:00 GMT"},
@@ -657,60 +871,177 @@ fn handle_connection(server: *http.Server, env: *lmdb.Env) !void {
                 }
             }
 
                 }
             }
 
+            // TODO: refactor into functions
+            // TODO: make sure we send a reply
+
             // html
             if (req.method == .GET) {
             // html
             if (req.method == .GET) {
+                try write_start(&res);
                 try write_header(&res, logged_in);
 
                 try write_header(&res, logged_in);
 
-                if (std.mem.eql(u8, req.target, "/register")) {
-                    try res.write(
-                        \\<form action="/register" method="post">
-                        \\<input type="text" name="username" />
-                        \\<input type="password" name="password" />
-                        \\<input type="submit" value="Register" />
-                        \\</form>
-                    , .{});
-                    try res.send();
-                } else if (std.mem.eql(u8, req.target, "/login")) {
-                    try res.write(
-                        \\<form action="/login" method="post">
-                        \\<input type="text" name="username" />
-                        \\<input type="password" name="password" />
-                        \\<input type="submit" value="Login" />
-                        \\</form>
-                    , .{});
-                    try res.send();
-                } else if (std.mem.startsWith(u8, req.target, "/user/")) {
+                const txn = try env.txn();
+                defer txn.abort();
+
+                if (std.mem.startsWith(u8, req.target, "/user/")) {
                     const username = req.target[6..req.target.len];
 
                     const username = req.target[6..req.target.len];
 
-                    const txn = try env.txn();
-                    defer txn.abort();
+                    const user_ids = try Db.user_ids(txn);
+                    if (user_ids.get(try Username.fromSlice(username))) |user_id| {
+                        const users = try Db.users(txn);
+                        const user = try users.get(user_id);
+
+                        const following = try user.following.open(txn);
+                        const followers = try user.followers.open(txn);
+
+                        try res.write(
+                            \\<a href="/user/{s}">{s}</a>
+                        , .{
+                            user.name.constSlice(), user.display_name.constSlice(),
+                        });
+                        if (logged_in != null and user_id != logged_in.?.user.id) {
+                            if (try followers.has(logged_in.?.user.id)) {
+                                try html_form(&res, "/follow", .{}, .{
+                                    .{ "type=\"hidden\" name=\"user_id\" value=\"{x}\"", .{@intFromEnum(user_id)} },
+                                    \\type="submit" value="Unfollow"
+                                });
+                            } else {
+                                try html_form(&res, "/follow", .{}, .{
+                                    .{ "type=\"hidden\" name=\"user_id\" value=\"{x}\"", .{@intFromEnum(user_id)} },
+                                    \\type="submit" value="Follow"
+                                });
+                            }
+                        }
+                        try res.write(
+                            \\ <a href="/following/{s}">{} following</a>
+                            \\ <a href="/followers/{s}">{} followers</a>
+                        , .{
+                            user.name.constSlice(), following.len(),
+                            user.name.constSlice(), followers.len(),
+                        });
+
+                        try write_posts(&res, txn, logged_in, user);
+                    } else |err| {
+                        try res.write(
+                            \\<p>User not found [{}]</p>
+                        , .{err});
+                    }
+                } else if (std.mem.startsWith(u8, req.target, "/following/")) {
+                    const username = req.target[11..req.target.len];
 
 
-                    const user_ids = try Db.user_ids(&txn);
+                    const user_ids = try Db.user_ids(txn);
                     if (user_ids.get(try Username.fromSlice(username))) |user_id| {
                     if (user_ids.get(try Username.fromSlice(username))) |user_id| {
-                        const users = try Db.users(&txn);
-                        const user = users.get(user_id).?;
-                        try write_posts(&res, &txn, user, logged_in);
-                    } else {
+                        const users = try Db.users(txn);
+                        const user = try users.get(user_id);
+
+                        const following = try user.following.open(txn);
+                        var it = following.iterator();
+
+                        try res.write(
+                            \\<h2><a href="/user/{s}">{s}</a> follows:</h2>
+                        , .{ user.name.constSlice(), user.display_name.constSlice() });
+
+                        while (it.next()) |kv| {
+                            const following_user = try users.get(kv.key);
+
+                            try res.write(
+                                \\<a href="/user/{s}">{s}</a><br />
+                            , .{ following_user.name.constSlice(), following_user.display_name.constSlice() });
+                        }
+                    } else |err| {
                         try res.write(
                         try res.write(
-                            \\<p>User not found</pvo>
-                        , .{});
+                            \\<p>User not found [{}]</p>
+                        , .{err});
                     }
                     }
-                    try res.send();
-                } else {
-                    if (logged_in) |login| {
-                        const user = (try get_user(env, login.user_id)).?;
+                } else if (std.mem.startsWith(u8, req.target, "/followers/")) {
+                    const username = req.target[11..req.target.len];
 
 
-                        const txn = try env.txn();
-                        defer txn.abort();
+                    const user_ids = try Db.user_ids(txn);
+                    if (user_ids.get(try Username.fromSlice(username))) |user_id| {
+                        const users = try Db.users(txn);
+                        const user = try users.get(user_id);
+
+                        const followers = try user.followers.open(txn);
+                        var it = followers.iterator();
+
+                        try res.write(
+                            \\<h2><a href="/user/{s}">{s}</a> followers:</h2>
+                        , .{ user.name.constSlice(), user.display_name.constSlice() });
+
+                        while (it.next()) |kv| {
+                            const follower_user = try users.get(kv.key);
 
 
-                        try write_posts(&res, &txn, user, logged_in);
+                            try res.write(
+                                \\<a href="/user/{s}">{s}</a><br />
+                            , .{ follower_user.name.constSlice(), follower_user.display_name.constSlice() });
+                        }
+                    } else |err| {
+                        try res.write(
+                            \\<p>User not found [{}]</p>
+                        , .{err});
+                    }
+                } else if (std.mem.startsWith(u8, req.target, "/post/")) {
+                    const post_id_str = req.target[6..req.target.len];
+                    const post_id = try parse_enum(PostId, post_id_str, 16);
+
+                    try write_post(&res, txn, logged_in, post_id, .Yes);
+                } else if (std.mem.startsWith(u8, req.target, "/quotes/")) {
+                    const post_id_str = req.target[8..req.target.len];
+                    const post_id = try parse_enum(PostId, post_id_str, 16);
 
 
-                        try res.send();
+                    const posts = try Db.posts(txn);
+                    const post = try posts.get(post_id);
+
+                    const quotes_view = try post.quotes.open(txn);
+                    var it = quotes_view.iterator();
+                    while (it.next()) |kv| {
+                        try write_post(&res, txn, logged_in, kv.key, .Once);
+                        try res.write("<br />", .{});
+                    }
+                } else if (std.mem.eql(u8, req.target, "/post")) {
+                    if (logged_in) |login| {
+                        _ = login;
+                        const referer = if (req.get_header("Referer")) |ref| ref else "/post";
+
+                        try html_form(&res, "/post", .{}, .{
+                            .{ "type=\"hidden\" name=\"referer\" value=\"{s}\"", .{referer} },
+                            "type=\"text\" name=\"text\"",
+                            "type=\"submit\" value=\"Post\"",
+                        });
+                    } else {
+                        try res.write("not logged in", .{});
+                    }
+                } else if (std.mem.eql(u8, req.target, "/edit")) {
+                    if (logged_in) |login| {
+                        try res.write("<br />Username: ", .{});
+                        try html_form(&res, "/set_username", .{}, .{
+                            .{ "type=\"text\" name=\"username\" placeholder=\"{s}\"", .{login.user.name.constSlice()} },
+                            "type=\"submit\" value=\"Change\"",
+                        });
+                        try res.write("<br />Display Name: ", .{});
+                        try html_form(&res, "/set_display_name", .{}, .{
+                            .{ "type=\"text\" name=\"display_name\" placeholder=\"{s}\"", .{login.user.display_name.constSlice()} },
+                            "type=\"submit\" value=\"Change\"",
+                        });
+                        try res.write("<br />Password: ", .{});
+                        try html_form(&res, "/set_password", .{}, .{
+                            "type=\"text\" name=\"password\"",
+                            "type=\"submit\" value=\"Change\"",
+                        });
+                    } else {
+                        try res.write("not logged in", .{});
+                    }
+                } else if (std.mem.eql(u8, req.target, "/")) {
+                    if (logged_in) |login| {
+                        try write_timeline(&res, txn, logged_in, login.user);
                     } else {
                     } else {
-                        try res.write("[GET] {s}", .{req.target});
-                        try res.send();
+                        // TODO: generic home
+                        try res.write("Homepage", .{});
                     }
                     }
+                } else {
+                    try res.redirect("/");
                 }
                 }
+                try write_end(&res);
+                try res.send();
             }
             // api
             else {
             }
             // api
             else {
@@ -720,116 +1051,140 @@ fn handle_connection(server: *http.Server, env: *lmdb.Env) !void {
                     const password = req.get_value("password").?;
 
                     std.debug.print("New user: {s} {s}\n", .{ username, password });
                     const password = req.get_value("password").?;
 
                     std.debug.print("New user: {s} {s}\n", .{ username, password });
-                    if (try register_user(env, username, password)) {
-                        try res.redirect("/login");
-                    } else {
-                        try res.redirect("/register");
-                    }
-                    try res.send();
+                    _ = try Chirp.register_user(env, username, password);
                 } else if (std.mem.eql(u8, req.target, "/login")) {
                     // TODO: handle args not supplied
                     const username = req.get_value("username").?;
                     const password = req.get_value("password").?;
 
                     std.debug.print("New login: {s} {s}\n", .{ username, password });
                 } else if (std.mem.eql(u8, req.target, "/login")) {
                     // TODO: handle args not supplied
                     const username = req.get_value("username").?;
                     const password = req.get_value("password").?;
 
                     std.debug.print("New login: {s} {s}\n", .{ username, password });
-                    if (login_user(env, username, password)) |session_token| {
+                    if (Chirp.login_user(env, username, password)) |session_token| {
                         res.status = .see_other;
                         res.status = .see_other;
-                        try res.add_header(
-                            "Location",
-                            .{ "/user/{s}", .{username} },
-                        );
                         try res.add_header(
                             "Set-Cookie",
                         try res.add_header(
                             "Set-Cookie",
-                            .{ "session_token={s}; Secure; HttpOnly", .{session_token} },
+                            .{ "session_token={x}; HttpOnly", .{session_token} },
                         );
                         );
-
-                        try res.send();
                     } else |err| {
                         std.debug.print("login_user err: {}\n", .{err});
                     } else |err| {
                         std.debug.print("login_user err: {}\n", .{err});
-                        try res.redirect("/login");
-                        try res.send();
                     }
                 } else if (std.mem.eql(u8, req.target, "/logout")) {
                     if (logged_in) |login| {
                     }
                 } else if (std.mem.eql(u8, req.target, "/logout")) {
                     if (logged_in) |login| {
-                        try logout_user(env, login.session_token);
+                        try Chirp.logout_user(env, login.session_token);
 
                         try res.add_header(
                             "Set-Cookie",
                             .{"session_token=deleted; Expires=Thu, 01 Jan 1970 00:00:00 GMT"},
                         );
 
                         try res.add_header(
                             "Set-Cookie",
                             .{"session_token=deleted; Expires=Thu, 01 Jan 1970 00:00:00 GMT"},
                         );
-
-                        try res.redirect("/");
-                        try res.send();
                     }
                     }
-                } else if (std.mem.eql(u8, req.target, "/post")) {
-                    if (logged_in) |login| {
-                        const text = req.get_value("text").?;
-                        try post(env, login.user_id, text);
-
-                        try res.redirect("/");
-                        try res.send();
-                    }
-                } else if (std.mem.eql(u8, req.target, "/quit")) {
-                    try res.redirect("/");
-                    try res.send();
-                    break :accept;
-                } else if (std.mem.startsWith(u8, req.target, "/upvote/")) {
+                } else if (std.mem.eql(u8, req.target, "/set_username")) {
                     const login = logged_in orelse return error.NotLoggedIn;
                     const login = logged_in orelse return error.NotLoggedIn;
+                    const username_str = req.get_value("username") orelse return error.NoUsername;
+                    const username = try Username.fromSlice(username_str);
 
 
-                    const post_id_str = req.target[8..req.target.len];
-                    const post_id: PostId = @enumFromInt(try std.fmt.parseUnsigned(u64, post_id_str, 10));
+                    const txn = try env.txn();
+                    defer txn.commit() catch {};
 
 
-                    try vote(env, post_id, login.user_id, .Up);
-                    try unvote(env, post_id, login.user_id, .Down);
+                    const user_ids = try Db.user_ids(txn);
 
 
-                    if (req.get_header("Referer")) |ref| {
-                        try res.redirect(ref);
+                    if (!try user_ids.has(username)) {
+                        try user_ids.del(login.user.name);
+                        try user_ids.put(username, login.user.id);
+
+                        const users = try Db.users(txn);
+                        var user = login.user;
+                        user.name = username;
+                        try users.put(login.user.id, user);
                     }
                     }
-                    try res.send();
-                } else if (std.mem.startsWith(u8, req.target, "/downvote/")) {
+                } else if (std.mem.eql(u8, req.target, "/set_display_name")) {
                     const login = logged_in orelse return error.NotLoggedIn;
                     const login = logged_in orelse return error.NotLoggedIn;
+                    const display_name_str = req.get_value("display_name") orelse return error.NoDisplayName;
+                    const display_name = try DisplayName.fromSlice(display_name_str);
 
 
-                    const post_id_str = req.target[10..req.target.len];
-                    const post_id: PostId = @enumFromInt(try std.fmt.parseUnsigned(u64, post_id_str, 10));
-
-                    try vote(env, post_id, login.user_id, .Down);
-                    try unvote(env, post_id, login.user_id, .Up);
+                    const txn = try env.txn();
+                    defer txn.commit() catch {};
 
 
-                    if (req.get_header("Referer")) |ref| {
-                        try res.redirect(ref);
-                    }
-                    try res.send();
-                } else if (std.mem.startsWith(u8, req.target, "/unupvote/")) {
+                    const users = try Db.users(txn);
+                    var user = login.user;
+                    user.display_name = display_name;
+                    try users.put(login.user.id, user);
+                } else if (std.mem.eql(u8, req.target, "/set_password")) {
                     const login = logged_in orelse return error.NotLoggedIn;
                     const login = logged_in orelse return error.NotLoggedIn;
+                    const password_str = req.get_value("password") orelse return error.NoPassword;
 
 
-                    const post_id_str = req.target[10..req.target.len];
-                    const post_id: PostId = @enumFromInt(try std.fmt.parseUnsigned(u64, post_id_str, 10));
+                    const txn = try env.txn();
+                    defer txn.commit() catch {};
 
 
-                    try unvote(env, post_id, login.user_id, .Up);
+                    const users = try Db.users(txn);
+                    var user = login.user;
+                    user.password_hash = try Chirp.hash_password(password_str);
+                    try users.put(login.user.id, user);
+                } else if (std.mem.eql(u8, req.target, "/post")) {
+                    if (logged_in) |login| {
+                        const text = req.get_value("text").?;
+                        const has_referer = req.get_value("referer");
+                        try Chirp.post(env, login.user.id, text);
+                        if (has_referer) |r| {
+                            const decoded = try decode(r);
+                            try res.redirect(decoded.constSlice());
+                        }
+                    }
+                } else if (std.mem.eql(u8, req.target, "/comment")) {
+                    if (logged_in) |login| {
+                        const text = req.get_value("text") orelse return error.NoText;
+                        const post_id_str = req.get_value("post_id") orelse return error.NoPostId;
+                        const post_id = try parse_enum(PostId, post_id_str, 16);
 
 
-                    if (req.get_header("Referer")) |ref| {
-                        try res.redirect(ref);
+                        try Chirp.comment(env, login.user.id, post_id, text);
                     }
                     }
-                    try res.send();
-                } else if (std.mem.startsWith(u8, req.target, "/undownvote/")) {
+                } else if (std.mem.eql(u8, req.target, "/quote")) {
+                    if (logged_in) |login| {
+                        const text = req.get_value("text") orelse return error.NoText;
+                        const post_id_str = req.get_value("post_id") orelse return error.NoPostId;
+                        const post_id = try parse_enum(PostId, post_id_str, 16);
+
+                        try Chirp.quote(env, login.user.id, post_id, text);
+                    }
+                } else if (std.mem.eql(u8, req.target, "/upvote")) {
+                    const login = logged_in orelse return error.NotLoggedIn;
+
+                    const post_id_str = req.get_value("post_id") orelse return error.NoPostId;
+                    const post_id: PostId = @enumFromInt(try std.fmt.parseUnsigned(u64, post_id_str, 16));
+
+                    try Chirp.vote(env, post_id, login.user.id, .Up);
+                } else if (std.mem.eql(u8, req.target, "/downvote")) {
                     const login = logged_in orelse return error.NotLoggedIn;
 
                     const login = logged_in orelse return error.NotLoggedIn;
 
-                    const post_id_str = req.target[12..req.target.len];
-                    const post_id: PostId = @enumFromInt(try std.fmt.parseUnsigned(u64, post_id_str, 10));
+                    const post_id_str = req.get_value("post_id") orelse return error.NoPostId;
+                    const post_id: PostId = @enumFromInt(try std.fmt.parseUnsigned(u64, post_id_str, 16));
+
+                    try Chirp.vote(env, post_id, login.user.id, .Down);
+                } else if (std.mem.eql(u8, req.target, "/follow")) {
+                    const login = logged_in orelse return error.NotLoggedIn;
 
 
-                    try unvote(env, post_id, login.user_id, .Down);
+                    const user_id_str = req.get_value("user_id") orelse return error.NoUserId;
+                    const user_id: UserId = @enumFromInt(try std.fmt.parseUnsigned(u64, user_id_str, 16));
 
 
+                    try Chirp.follow(env, login.user.id, user_id);
+                } else if (std.mem.eql(u8, req.target, "/quit")) {
                     if (req.get_header("Referer")) |ref| {
                         try res.redirect(ref);
                     if (req.get_header("Referer")) |ref| {
                         try res.redirect(ref);
+                    } else {
+                        try res.redirect("/");
                     }
                     try res.send();
                     }
                     try res.send();
+                    break :accept;
                 } else {
                 } else {
-                    // try req.respond(
-                    //     \\<p>POST</p>
-                    // , .{});
                     try res.write("<p>[POST] {s}</p>", .{req.target});
                     try res.write("<p>[POST] {s}</p>", .{req.target});
-                    try res.send();
                 }
                 }
+
+                if (!res.has_header("Location")) {
+                    if (req.get_header("Referer")) |ref| {
+                        try res.redirect(ref);
+                    } else {
+                        try res.redirect("/");
+                    }
+                }
+                try res.send();
             }
         }
     }
             }
         }
     }
Proof-of-concept micro-blogging platform