/** HTTP API (docs/05 §6, docs/06). */
import { Hono, type Context } from 'hono';
import { deleteCookie, getCookie, setCookie } from 'hono/cookie';
import { z } from 'zod';
import { nicknameError, normalizeNickname, normalizeRoomCode, formatRoomCode } from '@bg/shared';
import type { Config } from '../config';
import { authorizeUrl, avatarUrl, exchangeCode, safeNext, type DiscordUser } from '../auth/discord';
import { SESSION_COOKIE, SESSION_TTL, randomToken, signValue, unsignValue, type Sessions } from '../auth/sessions';
import { toPublicUser, type Users } from '../auth/users';
import type { RoomManager } from '../rooms/manager';
import { WindowLimiter } from '../ws/rate-limit';
import { createAdminApp, type AdminDeps } from './admin';
import type { Roles } from '../admin/roles';
import type { SettingsStore } from '../admin/settings';

export interface HttpDeps {
  config: Config;
  users: Users;
  sessions: Sessions;
  rooms: RoomManager;
  /** Injected for tests. */
  discordExchange?: (code: string, redirectUri: string) => Promise<DiscordUser>;
  ipOf: (req: Request) => string;
  health: () => { ok: boolean; [k: string]: unknown };
  roles: Roles;
  settings: SettingsStore;
  admin: Omit<AdminDeps, 'users' | 'sessions' | 'rooms' | 'roles' | 'settings'>;
}

type Env = { Variables: { userId: string | null } };

const OAUTH_COOKIE = 'oauth';

export function createHttpApp(d: HttpDeps) {
  const app = new Hono<Env>();
  const createLimiter = new WindowLimiter(10, 60_000);
  const lookupLimiter = new WindowLimiter(30, 60_000);
  const guestLimiter = new WindowLimiter(20, 60_000);
  const redirectUri = `${d.config.publicOrigin}/api/auth/discord/callback`;

  const cookieOpts = (maxAgeMs: number) => ({
    httpOnly: true,
    secure: d.config.secureCookies,
    sameSite: 'Lax' as const,
    path: '/',
    maxAge: Math.floor(maxAgeMs / 1000),
  });

  // Session resolution.
  app.use('/api/*', async (c, next) => {
    const token = getCookie(c, SESSION_COOKIE);
    c.set('userId', token ? d.sessions.resolve(token) : null);
    await next();
  });

  // CSRF: state-changing requests must come from our origin (docs/04 §7).
  app.use('/api/*', async (c, next) => {
    if (c.req.method !== 'GET' && c.req.method !== 'HEAD') {
      const origin = c.req.header('origin');
      if (!origin || !d.config.allowedOrigins.includes(origin)) return c.json({ error: '잘못된 요청이에요.' }, 403);
    }
    await next();
  });

  const requireUser = (c: Context<Env>) => c.get('userId');

  const startSession = (c: Context<Env>, userId: string, kind: 'guest' | 'member') => {
    const { token } = d.sessions.create(userId, kind, c.req.header('user-agent') ?? null);
    setCookie(c, SESSION_COOKIE, token, cookieOpts(SESSION_TTL[kind]));
  };

  app.get('/healthz', (c) => {
    const h = d.health();
    return c.json(h, h.ok ? 200 : 503);
  });

  app.get('/api/config', (c) => {
    const site = d.settings.getSite();
    return c.json({
      discord: d.config.discord !== null,
      catalog: d.settings.catalog(),
      siteName: site.siteName,
      announcement: site.announcement,
      maintenance: site.maintenance,
    });
  });

  app.post('/api/auth/guest', async (c) => {
    if (!guestLimiter.allow(d.ipOf(c.req.raw))) return c.json({ error: '잠시 후 다시 시도해 주세요.' }, 429);
    const body = z.object({ nickname: z.string().max(100) }).safeParse(await c.req.json().catch(() => null));
    if (!body.success) return c.json({ error: '닉네임을 입력해 주세요.' }, 400);
    const nick = normalizeNickname(body.data.nickname);
    const e = nicknameError(nick, d.settings.getSite().bannedWords);
    if (e) return c.json({ error: e }, 400);
    const current = requireUser(c);
    if (current) {
      // Already signed in: treat as a nickname change instead of creating another account.
      const err = d.users.changeNickname(current, nick);
      if (err) return c.json({ error: err }, 400);
      return c.json({ me: toPublicUser(d.users.get(current)!) });
    }
    const u = d.users.createGuest(nick);
    startSession(c, u.id, 'guest');
    return c.json({ me: toPublicUser(u) });
  });

  app.get('/api/auth/discord/start', async (c) => {
    if (!d.config.discord) return c.text('디스코드 로그인이 설정되지 않았어요.', 404);
    const state = randomToken(24);
    const next = safeNext(c.req.query('next'));
    setCookie(c, OAUTH_COOKIE, await signValue(d.config.sessionSecret, JSON.stringify({ state, next, at: Date.now() })), {
      ...cookieOpts(10 * 60_000),
      path: '/api/auth/discord',
    });
    return c.redirect(authorizeUrl(d.config.discord.clientId, redirectUri, state));
  });

  app.get('/api/auth/discord/callback', async (c) => {
    const discord = d.config.discord;
    if (!discord) return c.text('디스코드 로그인이 설정되지 않았어요.', 404);
    const raw = getCookie(c, OAUTH_COOKIE);
    deleteCookie(c, OAUTH_COOKIE, { path: '/api/auth/discord' });
    const payload = raw ? await unsignValue(d.config.sessionSecret, raw) : null;
    const parsed = payload ? (JSON.parse(payload) as { state: string; next: string; at: number }) : null;
    const code = c.req.query('code');
    if (!parsed || !code || parsed.state !== c.req.query('state') || Date.now() - parsed.at > 10 * 60_000) {
      return c.redirect('/?login=failed');
    }
    let du: DiscordUser;
    try {
      du = d.discordExchange ? await d.discordExchange(code, redirectUri) : await exchangeCode(discord, code, redirectUri);
    } catch {
      return c.redirect('/?login=failed');
    }
    const avatar = avatarUrl(du);
    const existing = d.users.findByOauth('discord', du.id);
    if (existing?.banned_at) return c.redirect('/?login=banned');
    const current = requireUser(c) ? d.users.get(requireUser(c)!) : null;
    let userId: string;
    let merged = false;
    if (existing) {
      userId = existing.id;
      d.users.setAvatar(userId, avatar);
      if (current && current.kind === 'guest' && current.id !== existing.id) {
        d.users.mergeGuestInto(current.id, existing.id);
        merged = true;
      }
    } else if (current && current.kind === 'guest') {
      d.users.linkOauth(current.id, 'discord', du.id, du.username);
      d.users.promoteToMember(current.id, avatar);
      userId = current.id;
      merged = true;
    } else {
      const nick = normalizeNickname(du.global_name ?? du.username).slice(0, 12);
      const u = d.users.createMember(nicknameError(nick) ? '디스코드 사용자' : nick, avatar);
      d.users.linkOauth(u.id, 'discord', du.id, du.username);
      userId = u.id;
    }
    const old = getCookie(c, SESSION_COOKIE);
    if (old) d.sessions.revoke(old);
    startSession(c, userId, 'member');
    const next = safeNext(parsed.next);
    return c.redirect(merged ? `${next}${next.includes('?') ? '&' : '?'}linked=1` : next);
  });

  app.post('/api/auth/logout', (c) => {
    const token = getCookie(c, SESSION_COOKIE);
    if (token) d.sessions.revoke(token);
    deleteCookie(c, SESSION_COOKIE, { path: '/' });
    return c.json({ ok: true });
  });

  app.post('/api/auth/logout-all', (c) => {
    const u = requireUser(c);
    if (!u) return c.json({ error: '로그인이 필요해요.' }, 401);
    d.sessions.revokeAll(u);
    deleteCookie(c, SESSION_COOKIE, { path: '/' });
    return c.json({ ok: true });
  });

  app.get('/api/me', (c) => {
    const u = requireUser(c);
    const row = u ? d.users.get(u) : null;
    if (!row) return c.json({ me: null });
    return c.json({
      me: toPublicUser(row),
      settings: JSON.parse(row.settings_json),
      useAvatar: !!row.use_avatar,
      role: d.roles.roleOf(row.id),
      hasDiscordAvatar: !!row.avatar_url,
      activeRoom: d.rooms.activeRoomFor(row.id),
    });
  });

  app.patch('/api/me', async (c) => {
    const u = requireUser(c);
    if (!u) return c.json({ error: '로그인이 필요해요.' }, 401);
    const body = z
      .object({
        nickname: z.string().max(100).optional(),
        useAvatar: z.boolean().optional(),
        settings: z
          .object({
            fontScale: z.enum(['normal', 'large', 'xlarge']).optional(),
            theme: z.enum(['auto', 'light', 'dark']).optional(),
            sound: z.boolean().optional(),
            vibrate: z.boolean().optional(),
            colorBlind: z.boolean().optional(),
            tapConfirm: z.boolean().optional(),
          })
          .optional(),
      })
      .safeParse(await c.req.json().catch(() => null));
    if (!body.success) return c.json({ error: '잘못된 요청이에요.' }, 400);
    if (body.data.nickname !== undefined) {
      const nick = normalizeNickname(body.data.nickname);
      const e = nicknameError(nick, d.settings.getSite().bannedWords) ?? d.users.changeNickname(u, nick);
      if (e) return c.json({ error: e }, 400);
    }
    d.users.updateSettings(u, { useAvatar: body.data.useAvatar, settings: body.data.settings });
    return c.json({ me: toPublicUser(d.users.get(u)!) });
  });

  app.delete('/api/me', async (c) => {
    const u = requireUser(c);
    if (!u) return c.json({ error: '로그인이 필요해요.' }, 401);
    const body = z.object({ confirm: z.literal('탈퇴') }).safeParse(await c.req.json().catch(() => null));
    if (!body.success) return c.json({ error: '확인 문구를 정확히 입력해 주세요.' }, 400);
    d.users.softDelete(u);
    deleteCookie(c, SESSION_COOKIE, { path: '/' });
    return c.json({ ok: true });
  });

  app.get('/api/me/stats', (c) => {
    const u = requireUser(c);
    if (!u) return c.json({ error: '로그인이 필요해요.' }, 401);
    return c.json({ stats: d.users.stats(u) });
  });

  app.post('/api/rooms', async (c) => {
    const u = requireUser(c);
    if (!u) return c.json({ error: '로그인이 필요해요.' }, 401);
    if (!createLimiter.allow(d.ipOf(c.req.raw))) return c.json({ error: '잠시 후 다시 시도해 주세요.' }, 429);
    const body = z
      .object({ gameId: z.string().max(40), visibility: z.enum(['private', 'public']).optional() })
      .safeParse(await c.req.json().catch(() => null));
    if (!body.success || !d.settings.game(body.data.gameId)?.enabled) return c.json({ error: '없는 게임이에요.' }, 400);
    const r = d.rooms.create(u, body.data.gameId, body.data.visibility);
    if (typeof r === 'string') return c.json({ error: r }, 429);
    return c.json({ code: r.code });
  });

  app.post('/api/quick/:gameId', (c) => {
    const u = requireUser(c);
    if (!u) return c.json({ error: '로그인이 필요해요.' }, 401);
    const gameId = c.req.param('gameId');
    if (!d.settings.game(gameId)?.enabled) return c.json({ error: '없는 게임이에요.' }, 400);
    if (!createLimiter.allow(d.ipOf(c.req.raw))) return c.json({ error: '잠시 후 다시 시도해 주세요.' }, 429);
    const r = d.rooms.quickPlay(u, gameId);
    if (typeof r === 'string') return c.json({ error: r }, 429);
    return c.json({ code: r.code });
  });

  /** Room preview for the join screen (no auth needed). */
  app.get('/api/rooms/:code', (c) => {
    if (!lookupLimiter.allow(d.ipOf(c.req.raw))) return c.json({ error: '잠시 후 다시 시도해 주세요.' }, 429);
    const code = normalizeRoomCode(c.req.param('code'));
    const r = code ? d.rooms.get(code) : undefined;
    if (!r || r.status === 'broken') return c.json({ error: '방을 찾을 수 없어요. 코드를 다시 확인해 주세요.' }, 404);
    const host = d.users.get(r.hostId);
    return c.json({
      code: r.code,
      codeLabel: formatRoomCode(r.code),
      gameId: r.config.gameId,
      host: host?.nickname ?? '',
      seated: r.seatedIds().length,
      maxPlayers: r.config.maxPlayers,
      status: r.status,
    });
  });

  app.get('/api/games/:gameId/rooms', (c) => c.json({ rooms: d.rooms.publicRooms(c.req.param('gameId')) }));
  app.get('/api/public-rooms', (c) => c.json({ rooms: d.rooms.publicRooms(null).slice(0, 50) }));

  app.route(
    '/api/admin',
    createAdminApp({ ...d.admin, users: d.users, sessions: d.sessions, rooms: d.rooms, roles: d.roles, settings: d.settings }),
  );

  return app;
}