1200 try out.appendSlice(alloc, ">");
1201 },
1202 .plain => {
1203 try out.appendSlice(alloc, "<span");
1204 try out.appendSlice(alloc, style_attr);
1205 try out.appendSlice(alloc, ">");
1206 },
1207 }
1208 }
1209
1210 fn closeTag(self: @This()) []const u8 {
1211 return switch (self) {
1212 .span, .plain => "</span>",
1213 .a => "</a>",
1214 };
1215 }
1216 };
1217
1218 // emit this panel's grid as rows of text, coalescing adjacent cells that
1219 // share a focus id and colors into one tag (a clickable span, a link, or a
1220 // plain colored span). cells under a child scroll keep only their background.
1221 for (0..grid.size.height) |y| {
1222 var cur_id: ?usize = null;
1223 var cur_fg: ?Grid.Color = null;
1224 var cur_bg: ?Grid.Color = null;
1225 var open_tag: ?CellTag = null;
1226 var first = true;
1227 for (0..grid.size.width) |x| {
1228 const cell = grid.cells.items[try grid.cells.at(.{ y, x })];
1229 // a cell covered by a child scroll's viewport is drawn by that scroll's
1230 // own div, so blank its glyph and make it non-clickable here — but keep
1231 // its background, so the backdrop still shows through the scroll's
1232 // transparent div instead of a bare hole.
1233 const covered_by_scroll = blk: {
1234 for (direct.items) |id| {
1235 const r = (focus.children.get(id) orelse continue).rect;
1236 if (x >= r.x and y >= r.y and x < r.x + r.size.width and y < r.y + r.size.height) break :blk true;
1237 }
1238 break :blk false;
1239 };
1240 // the focusable cell at (x, y) among this panel's own focusables (skipping
1241 // any that belong to a child scroll, whose cells are drawn in their own
1242 // panel); none for a covered cell.
1243 const cell_id = if (covered_by_scroll) null else blk: {
1244 var iter = focus.children.iterator();
1245 while (iter.next()) |entry| {
1246 const child = entry.value_ptr.*;
1247 if (!child.focus.focusable) continue;
1248 if (excluded.contains(entry.key_ptr.*)) continue;
1249 const r = child.rect;
1250 if (x >= r.x and y >= r.y and x < r.x + r.size.width and y < r.y + r.size.height) {
1251 break :blk entry.key_ptr.*;
1252 }
1253 }
1254 break :blk null;
1255 };
1256 const fg = if (covered_by_scroll) null else cell.style.fg;
1257 const bg = cell.style.bg;
1258
1259 if (first or cell_id != cur_id or !colorEql(fg, cur_fg) or !colorEql(bg, cur_bg)) {
1260 if (open_tag) |t| try output.appendSlice(allocator, t.closeTag());
1261
1262 var new_tag: ?CellTag = null;
1263 if (cell_id) |id| {
1264 if (focus.children.get(id)) |child| {
1265 new_tag = switch (child.focus.kind) {
1266 .custom => |custom| CellTag.init(custom),
1267 else => .span,
1268 };
1269 }
1270 }
1271 if (new_tag == null and (fg != null or bg != null)) new_tag = .plain;
1272
1273 if (new_tag) |t| {
1274 var style_buf: [64]u8 = undefined;
1275 try t.writeOpenTag(allocator, output, cell_id orelse 0, styleAttr(&style_buf, fg, bg));
1276 }
1277
1278 open_tag = new_tag;
1279 cur_id = cell_id;
1280 cur_fg = fg;
1281 cur_bg = bg;
1282 first = false;
1283 }
1284
1285 if (covered_by_scroll) {
1286 try appendEscapedHtml(allocator, output, " ");
1287 } else if (cell.continuation) {
1288 // the wide rune to the left was emitted 2ch wide, covering this column
1289 } else if (cell.rune) |rune| {
1290 // a double-width rune is pinned inside a 2ch span so the
1291 // fallback glyph's advance width can't shift the rest of the row
1292 const wide = x + 1 < grid.size.width and grid.cells.items[try grid.cells.at(.{ y, x + 1 })].continuation;
1293 if (wide) {
1294 try output.appendSlice(allocator, "<span class=\"w2\">");
1295 try appendEscapedHtml(allocator, output, rune);
1296 try output.appendSlice(allocator, "</span>");
1297 } else {
1298 try appendEscapedHtml(allocator, output, rune);
1299 }
1300 } else {
1301 try appendEscapedHtml(allocator, output, " ");
1302 }
1303 }
1304 if (open_tag) |t| try output.appendSlice(allocator, t.closeTag());
1305 try output.append(allocator, '\n');
1306 }
1307
1308 // each child scroll becomes a natively-scrollable div positioned over its
1309 // viewport, holding its full content rendered recursively.
1310 for (direct.items) |id| {
1311 const child = focus.children.get(id) orelse continue;
1312 const info = child.focus.scroll orelse continue;
1313 const r = child.rect;
1314 // overflow only on the axes the widget scrolls; `auto` shows a bar only
1315 // when that axis actually overflows. the other axis is clipped (hidden),
1316 // matching how the terminal Scroll handles its non-scrolling axis.
1317 const overflow = switch (info.direction) {
1318 .vert => "overflow-x:hidden;overflow-y:auto",
1319 .horiz => "overflow-x:auto;overflow-y:hidden",
1320 .both => "overflow:auto",
1321 };
1322 // the id carries a content version so JS preserves the native scroll
1323 // position across re-renders of the same content but resets it when the
1324 // content is replaced — e.g. selecting a different commit. the widget's
1325 // scroll offset (in cells) rides along so JS can apply it when it has no
1326 // preserved position, letting a wasm-side scrollToRect (the files list
1327 // scrolling to its selected row on page load) reach the browser.
1328 var buf: [224]u8 = undefined;
1329 try output.appendSlice(allocator, try std.fmt.bufPrint(&buf, "<div class=\"scroll\" data-scroll-id=\"{d}-{d}\" data-scroll-x=\"{d}\" data-scroll-y=\"{d}\" style=\"left:{d}ch;top:{d}em;width:{d}ch;height:{d}em;{s}\">", .{ id, child.focus.version, info.offset_x, info.offset_y, r.x, r.y, r.size.width, r.size.height, overflow }));
1330 try renderPanel(allocator, output, child.focus, info.content);
1331 try output.appendSlice(allocator, "</div>");
1332 }
1333 }
1334
1335 // emits the form overlay — one <form> per "form:<url>" focus subtree in the
1336 // widget tree, each wrapping the text inputs and submit button inside it,
1337 // positioned absolutely over the matching grid cells.
1338 pub fn generateOverlay(allocator: std.mem.Allocator, root: *ui.Widget, session: *ui.Session) ![]const u8 {
1339 const root_focus = root.getFocus();
1340
1341 var out: std.ArrayList(u8) = .empty;
1342 errdefer out.deinit(allocator);
1343
1344 const form_prefix = "form:";
1345
1346 // Focus.children is an AutoArrayHashMap that preserves insertion order,
1347 // which matches the order widgets were added in code
1348 var iter = root_focus.children.iterator();
1349 while (iter.next()) |entry| {
1350 const child = entry.value_ptr.*;
1351 const action_url = switch (child.focus.kind) {
1352 .custom => |custom| if (std.mem.startsWith(u8, custom, form_prefix))
1353 custom[form_prefix.len..]
1354 else
1355 continue,
1356 else => continue,
1357 };
1358
1359 try out.appendSlice(allocator, "<form action=\"");
1360 try appendEscapedHtml(allocator, &out, action_url);
1361 try out.appendSlice(allocator, "\" method=\"post\"");
1362 // an empty action must not POST — block it and send the input to the TUI instead
1363 if (action_url.len == 0) try out.appendSlice(allocator, " onsubmit=\"event.preventDefault();sendEnter(this);\"");
1364 try out.appendSlice(allocator, ">");
1365
1366 // form.focus.children was populated by addChild, which flattens the
1367 // whole subtree into one map — so descendants (inputs + the submit
1368 // button) all appear here. positions on form.focus are relative to
1369 // the form, so we look up absolute rects via root_focus for layout.
1370 var inner_iter = child.focus.children.iterator();
1371 while (inner_iter.next()) |inner_entry| {
1372 const inner_id = inner_entry.key_ptr.*;
1373 const root_child = root_focus.children.get(inner_id) orelse continue;
1374 const r = root_child.rect;
1375 switch (root_child.focus.kind) {
1376 .text_input, .text_input_password => {
1377 const ti = session.text_inputs.get(inner_id) orelse continue;
1378 const inner_left = r.x + 1;
1379 const inner_top = r.y + 1;
1380 const inner_width = if (r.size.width > 2) r.size.width - 2 else 0;
1381
1382 try out.appendSlice(allocator, "<input type=\"");
1383 try out.appendSlice(allocator, if (root_child.focus.kind == .text_input_password) "password" else "text");
1384 try out.appendSlice(allocator, "\" data-focus-id=\"");
1385 var id_buf: [32]u8 = undefined;
1386 try out.appendSlice(allocator, try std.fmt.bufPrint(&id_buf, "{d}", .{inner_id}));
1387 if (ti.options.name.len > 0) {
1388 try out.appendSlice(allocator, "\" name=\"");
1389 try appendEscapedHtml(allocator, &out, ti.options.name);
1390 }
1391 // never the live content as the `value`: the browser tracks user
1392 // input natively, and including the wasm-side value here would make
1393 // the overlay HTML differ on every keystroke — that would trip the
1394 // diff in _setOverlay and rebuild the <input>, eating the user's
1395 // caret. a page-constant initial value is safe.
1396 if (session.input_values.get(inner_id)) |value| {
1397 try out.appendSlice(allocator, "\" value=\"");
1398 try appendEscapedHtml(allocator, &out, value);
1399 }
1400 try out.appendSlice(allocator, "\" style=\"left:");
1401 var pos_buf: [64]u8 = undefined;
1402 try out.appendSlice(allocator, try std.fmt.bufPrint(&pos_buf, "{d}ch;top:{d}em;width:{d}ch;height:1em", .{ inner_left, inner_top, inner_width }));
1403 try out.appendSlice(allocator, "\">");
1404 },
1405 .text_area => {
1406 const ti = session.text_inputs.get(inner_id) orelse continue;
1407 const inner_left = r.x + 1;
1408 const inner_top = r.y + 1;
1409 const inner_width = if (r.size.width > 2) r.size.width - 2 else 0;
1410 const inner_height = if (r.size.height > 2) r.size.height - 2 else 0;
1411
1412 try out.appendSlice(allocator, "<textarea data-focus-id=\"");
1413 var id_buf: [32]u8 = undefined;
1414 try out.appendSlice(allocator, try std.fmt.bufPrint(&id_buf, "{d}", .{inner_id}));
1415 if (ti.options.name.len > 0) {
1416 try out.appendSlice(allocator, "\" name=\"");
1417 try appendEscapedHtml(allocator, &out, ti.options.name);
1418 }
1419 // like the input above, only a page-constant initial value
1420 // inside: the browser tracks the live value and the
1421 // overlay diff must stay stable across keystrokes
1422 try out.appendSlice(allocator, "\" style=\"left:");
1423 var pos_buf: [128]u8 = undefined;
1424 try out.appendSlice(allocator, try std.fmt.bufPrint(&pos_buf, "{d}ch;top:{d}em;width:{d}ch;height:{d}em", .{ inner_left, inner_top, inner_width, inner_height }));
1425 // textarea discards the first newline immediately following
1426 // its start tag, so add one of our own so text that begins
1427 // with a newline doesn't lose it
1428 try out.appendSlice(allocator, "\">\n");
1429 if (session.input_values.get(inner_id)) |value| try appendEscapedHtml(allocator, &out, value);
1430 try out.appendSlice(allocator, "</textarea>");
1431 },
1432 .custom => |custom| {
1433 if (std.mem.eql(u8, "submit", custom)) {
1434 try out.appendSlice(allocator, "<button type=\"submit\" data-focus-id=\"");
1435 var id_buf: [32]u8 = undefined;
1436 try out.appendSlice(allocator, try std.fmt.bufPrint(&id_buf, "{d}", .{inner_id}));
1437 try out.appendSlice(allocator, "\" style=\"left:");
1438 var pos_buf: [128]u8 = undefined;
1439 try out.appendSlice(allocator, try std.fmt.bufPrint(&pos_buf, "{d}ch;top:{d}em;width:{d}ch;height:{d}em", .{ r.x, r.y, r.size.width, r.size.height }));
1440 try out.appendSlice(allocator, "\"></button>");
1441 }
1442 },
1443 else => {},
1444 }
1445 }
1446
1447 try out.appendSlice(allocator, "</form>");
1448 }
1449
1450 return try out.toOwnedSlice(allocator);
1451 }
1452
1453 fn colorEql(a: ?Grid.Color, b: ?Grid.Color) bool {
1454 if (a) |av| return if (b) |bv| av.eql(bv) else false;
1455 return b == null;
1456 }
1457
1458 // builds an HTML ` style="color:#rrggbb;background-color:#rrggbb"` attribute
1459 // from a cell's fg/bg into `buf`, omitting whichever color is unset. returns an
1460 // empty slice when neither is set.
1461 fn styleAttr(buf: []u8, fg: ?Grid.Color, bg: ?Grid.Color) []const u8 {
1462 if (fg == null and bg == null) return buf[0..0];
1463 const prefix = " style=\"";
1464 @memcpy(buf[0..prefix.len], prefix);
1465 var i: usize = prefix.len;
1466 if (fg) |c| {
1467 const s = std.fmt.bufPrint(buf[i..], "color:#{x:0>2}{x:0>2}{x:0>2};", .{ c.r, c.g, c.b }) catch return buf[0..0];
1468 i += s.len;
1469 }
1470 if (bg) |c| {
1471 const s = std.fmt.bufPrint(buf[i..], "background-color:#{x:0>2}{x:0>2}{x:0>2};", .{ c.r, c.g, c.b }) catch return buf[0..0];
1472 i += s.len;
1473 }
1474 buf[i] = '"';
1475 i += 1;
1476 return buf[0..i];
1477 }
1478
1479 fn appendEscapedHtml(allocator: std.mem.Allocator, out: *std.ArrayList(u8), input: []const u8) !void {
1480 for (input) |ch| {
1481 switch (ch) {
1482 '&' => try out.appendSlice(allocator, "&"),
1483 '<' => try out.appendSlice(allocator, "<"),
1484 '>' => try out.appendSlice(allocator, ">"),
1485 '"' => try out.appendSlice(allocator, """),
1486 '\'' => try out.appendSlice(allocator, "'"),
1487 else => try out.append(allocator, ch),
1488 }
1489 }
1490 }
1491
1492 // --- helpers --------------------------------------------------------------
1493
1494 fn getCookieValue(request: *std.http.Server.Request, name: []const u8) ?[]const u8 {
1495 var iter = request.iterateHeaders();
1496 while (iter.next()) |header| {
1497 if (!std.ascii.eqlIgnoreCase(header.name, "cookie")) continue;
1498 var pairs = std.mem.splitScalar(u8, header.value, ';');
1499 while (pairs.next()) |pair| {
1500 const trimmed = std.mem.trim(u8, pair, " \t");
1501 const eq = std.mem.indexOfScalar(u8, trimmed, '=') orelse continue;
1502 if (std.mem.eql(u8, trimmed[0..eq], name)) {
1503 return trimmed[eq + 1 ..];
1504 }
1505 }
1506 }
1507 return null;
1508 }
1509
1510 fn parseFormField(allocator: std.mem.Allocator, body: []const u8, key: []const u8) !?[]u8 {
1511 var iter = std.mem.splitScalar(u8, body, '&');
1512 while (iter.next()) |pair| {
1513 const eq = std.mem.indexOfScalar(u8, pair, '=') orelse continue;
1514 if (std.mem.eql(u8, pair[0..eq], key)) {
1515 return try decodeFormValue(allocator, pair[eq + 1 ..]);
1516 }
1517 }
1518 return null;
1519 }
1520
1521 fn decodeFormValue(allocator: std.mem.Allocator, encoded: []const u8) ![]u8 {
1522 var out: std.ArrayList(u8) = .empty;
1523 errdefer out.deinit(allocator);
1524 var i: usize = 0;
1525 while (i < encoded.len) : (i += 1) {
1526 switch (encoded[i]) {
1527 '+' => try out.append(allocator, ' '),
1528 '%' => {
1529 if (i + 2 >= encoded.len) return error.InvalidPercentEncoding;
1530 const hi = std.fmt.charToDigit(encoded[i + 1], 16) catch return error.InvalidPercentEncoding;
1531 const lo = std.fmt.charToDigit(encoded[i + 2], 16) catch return error.InvalidPercentEncoding;
1532 try out.append(allocator, hi * 16 + lo);
1533 i += 2;
1534 },
1535 else => try out.append(allocator, encoded[i]),
1536 }
1537 }
1538 return try out.toOwnedSlice(allocator);
1539 }
1540
1541 // disk-backed web session store. each login mints a random, opaque token
1542 // (not the user's id) that is stored as a file named by the token hex, whose
1543 // contents are the raw user_id bytes. authenticating a request is a lookup of
1544 // the cookie's token; logout deletes the file, revoking the session. there is
1545 // deliberately no expiry — a session lives until logout.
1546 pub const SessionStore = struct {
1547 io: std.Io,
1548 dir: std.Io.Dir,
1549
1550 pub const token_hex_len = evt.event_id_size * 2;
1551
1552 pub fn init(io: std.Io, data_dir: std.Io.Dir) !SessionStore {
1553 try data_dir.createDirPath(io, "sessions");
1554 const dir = try data_dir.openDir(io, "sessions", .{});
1555 return .{ .io = io, .dir = dir };
1556 }
1557
1558 pub fn deinit(self: SessionStore) void {
1559 self.dir.close(self.io);
1560 }
1561
1562 // mint a new session for user_id, returning the token hex to set as the
1563 // cookie value.
1564 pub fn create(self: SessionStore, user_id: *const [evt.event_id_size]u8) ![token_hex_len]u8 {
1565 var token: [evt.event_id_size]u8 = undefined;
1566 self.io.random(&token);
1567 const token_hex = std.fmt.bytesToHex(token, .lower);
1568 const file = try self.dir.createFile(self.io, &token_hex, .{});
1569 defer file.close(self.io);
1570 try file.writeStreamingAll(self.io, user_id);
1571 return token_hex;
1572 }
1573
1574 // resolve a cookie's token to its user_id. returns false (logged out) for a
1575 // missing, malformed, or unknown token.
1576 pub fn lookup(self: SessionStore, token_hex: []const u8, out: *[evt.event_id_size]u8) bool {
1577 if (!isToken(token_hex)) return false;
1578 const file = self.dir.openFile(self.io, token_hex, .{ .mode = .read_only }) catch return false;
1579 defer file.close(self.io);
1580 var storage: [evt.event_id_size]u8 = undefined;
1581 var file_reader = file.reader(self.io, &storage);
1582 file_reader.interface.readSliceAll(out) catch return false;
1583 return true;
1584 }
1585
1586 // revoke a session. a no-op for a missing or malformed token.
1587 pub fn remove(self: SessionStore, token_hex: []const u8) void {
1588 if (!isToken(token_hex)) return;
1589 self.dir.deleteFile(self.io, token_hex) catch {};
1590 }
1591
1592 // leave `token_hex`'s session for the next visitor arriving without one.
1593 // only the `try` fixture writes one, and only a debug build honors it. the
1594 // name isn't token-shaped, so it can't collide with a session file.
1595 pub fn offerAutoLogin(self: SessionStore, token_hex: *const [token_hex_len]u8) !void {
1596 const file = try self.dir.createFile(self.io, auto_login_name, .{});
1597 defer file.close(self.io);
1598 try file.writeStreamingAll(self.io, token_hex);
1599 }
1600
1601 // claim the offered session, if one is there. the delete picks the winner
1602 // of a race, so the offer is only ever taken once. a release build never
1603 // looks, because that would be an extra syscall for every GET request.
1604 pub fn claimAutoLogin(self: SessionStore, out: *[token_hex_len]u8) bool {
1605 if (builtin.mode != .Debug) return false;
1606 {
1607 const file = self.dir.openFile(self.io, auto_login_name, .{ .mode = .read_only }) catch return false;
1608 defer file.close(self.io);
1609 var storage: [token_hex_len]u8 = undefined;
1610 var file_reader = file.reader(self.io, &storage);
1611 file_reader.interface.readSliceAll(out) catch return false;
1612 }
1613 self.dir.deleteFile(self.io, auto_login_name) catch return false;
1614 return true;
1615 }
1616
1617 const auto_login_name = "auto-login";
1618
1619 // a token is exactly token_hex_len hex chars. validating before using the
1620 // value as a path keeps attacker-supplied cookies from escaping the
1621 // sessions dir (e.g. via "/" or ".." bytes).
1622 fn isToken(token_hex: []const u8) bool {
1623 if (token_hex.len != token_hex_len) return false;
1624 for (token_hex) |c| if (!std.ascii.isHex(c)) return false;
1625 return true;
1626 }
1627 };
1628