import { AsyncLocalStorage } from 'node:async_hooks';
import { createHash, createHmac, timingSafeEqual } from 'node:crypto';
import { promises as fs } from 'node:fs';
import path from 'node:path';
import type { MiddlewareHandler } from 'hono';

// Telegram/HF replacement for the Devvit runtime services (redis, context, reddit, realtime).
// State lives as JSON files under DATA_DIR (an HF Storage Bucket mount in production,
// ./data in local dev). Identity comes from Telegram WebApp initData instead of Reddit.

export type RuntimeIdentity = { postId: string; username: string };
export type TelegramUser = { id: number; username?: string; first_name?: string };

export const DATA_DIR = process.env.WEEDSIM_DATA_DIR ?? path.resolve('data');
export const WORLD_ID = process.env.WEEDSIM_WORLD_ID ?? 'world-1';
export const BOT_TOKEN = process.env.BOT_TOKEN ?? '';
export const WEBAPP_URL = (process.env.WEBAPP_URL ?? '').replace(/\/$/, '');
export const PASS_PRICE_STARS = Math.max(1, Number(process.env.PASS_PRICE_STARS ?? 420) || 420);
export const PASS_PAYLOAD = 'breeders-pass';
export const FREE_BREED_LIMIT = Math.max(0, Number(process.env.FREE_BREED_LIMIT ?? 25) || 25);
const INIT_DATA_MAX_AGE_SECONDS = Math.max(300, Number(process.env.INIT_DATA_MAX_AGE_SECONDS ?? 86_400) || 86_400);

// Dev mode: no bot token means no Telegram to verify against — run open, as the
// Devvit build did with context.postId/user absent ('local-post'/'anonymous').
export const DEV_MODE = !BOT_TOKEN;

type RequestAuth = { identity: RuntimeIdentity; tgUser: TelegramUser | null };
const authStore = new AsyncLocalStorage<RequestAuth>();

const ANONYMOUS: RequestAuth = { identity: { postId: WORLD_ID, username: 'anonymous' }, tgUser: null };

/** Drop-in for the old per-route identity() helpers. */
export async function identity(): Promise<RuntimeIdentity> {
  return (authStore.getStore() ?? ANONYMOUS).identity;
}

export function currentTgUser(): TelegramUser | null {
  return (authStore.getStore() ?? ANONYMOUS).tgUser;
}

// ---------------------------------------------------------------------------
// File-backed KV with the same contract the routes used from Devvit redis:
// string values, get/set/del, last-write-wins on whole values.
// ---------------------------------------------------------------------------

function kvPath(key: string): string {
  const safe = key.replace(/[^A-Za-z0-9._-]/g, '_').slice(0, 120);
  const digest = createHash('sha1').update(key).digest('hex').slice(0, 10);
  return path.join(DATA_DIR, 'kv', `${safe}.${digest}.json`);
}

const writeQueues = new Map<string, Promise<void>>();

function enqueue(key: string, work: () => Promise<void>): Promise<void> {
  const next = (writeQueues.get(key) ?? Promise.resolve()).then(work, work);
  writeQueues.set(key, next);
  void next.finally(() => {
    if (writeQueues.get(key) === next) writeQueues.delete(key);
  });
  return next;
}

async function writeFileAtomic(file: string, value: string): Promise<void> {
  await fs.mkdir(path.dirname(file), { recursive: true });
  const temp = `${file}.${process.pid}.${Math.random().toString(36).slice(2, 8)}.tmp`;
  await fs.writeFile(temp, value, 'utf8');
  await fs.rename(temp, file);
}

export const redis = {
  async get(key: string): Promise<string | undefined> {
    try {
      return await fs.readFile(kvPath(key), 'utf8');
    } catch {
      return undefined;
    }
  },
  async set(key: string, value: string): Promise<void> {
    await enqueue(key, () => writeFileAtomic(kvPath(key), value));
  },
  async del(key: string): Promise<void> {
    await enqueue(key, async () => {
      await fs.rm(kvPath(key), { force: true });
    });
  },
};

// ---------------------------------------------------------------------------
// Realtime: the Devvit push channel was a fail-open convenience; the client
// already polls /api/agent-link/events, so push is intentionally a no-op here.
// ---------------------------------------------------------------------------

export const realtime = {
  async send(_channel: string, _message: unknown): Promise<void> {},
};

// ---------------------------------------------------------------------------
// Telegram initData verification (https://core.telegram.org/bots/webapps).
// ---------------------------------------------------------------------------

export function verifyInitData(raw: string): TelegramUser | null {
  if (!raw || !BOT_TOKEN) return null;
  const params = new URLSearchParams(raw);
  const hash = params.get('hash');
  if (!hash) return null;
  params.delete('hash');
  const dataCheckString = [...params.entries()]
    .sort(([a], [b]) => (a < b ? -1 : a > b ? 1 : 0))
    .map(([key, value]) => `${key}=${value}`)
    .join('\n');
  const secret = createHmac('sha256', 'WebAppData').update(BOT_TOKEN).digest();
  const expected = createHmac('sha256', secret).update(dataCheckString).digest('hex');
  const expectedBuffer = Buffer.from(expected, 'hex');
  let providedBuffer: Buffer;
  try {
    providedBuffer = Buffer.from(hash, 'hex');
  } catch {
    return null;
  }
  if (expectedBuffer.length !== providedBuffer.length || !timingSafeEqual(expectedBuffer, providedBuffer)) return null;
  const authDate = Number(params.get('auth_date') ?? 0);
  if (!authDate || Date.now() / 1000 - authDate > INIT_DATA_MAX_AGE_SECONDS) return null;
  try {
    const user = JSON.parse(params.get('user') ?? '') as TelegramUser;
    return typeof user?.id === 'number' ? user : null;
  } catch {
    return null;
  }
}

// ---------------------------------------------------------------------------
// Stable player names. Telegram handles can change; state keys must not.
// First visit persists a name for the numeric user id and keeps it forever.
// ---------------------------------------------------------------------------

function userNamePath(userId: number): string {
  return path.join(DATA_DIR, 'users', `user-${userId}.json`);
}

const NAME_INDEX_KEY = 'weedsim:v1:users:name-index';

function sanitizeName(name: string | undefined): string {
  return (name ?? '').replace(/[^A-Za-z0-9_]/g, '').slice(0, 24);
}

async function usernameFor(tgUser: TelegramUser): Promise<string> {
  try {
    const stored = JSON.parse(await fs.readFile(userNamePath(tgUser.id), 'utf8')) as { username?: string };
    if (typeof stored.username === 'string' && stored.username) return stored.username;
  } catch {
    // first visit
  }
  const index = JSON.parse((await redis.get(NAME_INDEX_KEY)) ?? '{}') as Record<string, number>;
  const base = sanitizeName(tgUser.username) || sanitizeName(tgUser.first_name) || `grower_${String(tgUser.id).slice(-6)}`;
  let candidate = base;
  for (let suffix = 2; index[candidate.toLowerCase()] !== undefined && index[candidate.toLowerCase()] !== tgUser.id; suffix += 1) {
    candidate = `${base}_${suffix}`;
  }
  index[candidate.toLowerCase()] = tgUser.id;
  await redis.set(NAME_INDEX_KEY, JSON.stringify(index));
  await writeFileAtomic(userNamePath(tgUser.id), JSON.stringify({ username: candidate, tgUserId: tgUser.id, createdAt: new Date().toISOString() }));
  return candidate;
}

// ---------------------------------------------------------------------------
// Breeder's Pass entitlements, keyed by the stable Telegram user id.
// ---------------------------------------------------------------------------

function passPath(userId: number): string {
  return path.join(DATA_DIR, 'passes', `pass-${userId}.json`);
}

// Comma-separated Telegram user ids that enter without buying (operator/testers).
const FREE_PASS_IDS = new Set(
  (process.env.PASS_FREE_USER_IDS ?? '')
    .split(',')
    .map((value) => Number(value.trim()))
    .filter((value) => Number.isFinite(value) && value > 0)
);

export async function hasPass(userId: number): Promise<boolean> {
  if (FREE_PASS_IDS.has(userId)) return true;
  try {
    await fs.access(passPath(userId));
    return true;
  } catch {
    return false;
  }
}

export async function grantPass(userId: number, details: Record<string, unknown>): Promise<void> {
  await writeFileAtomic(passPath(userId), JSON.stringify({ userId, grantedAt: new Date().toISOString(), ...details }, null, 2));
}

// ---------------------------------------------------------------------------
// Free tier: lifetime breed counter per Telegram user id.
// ---------------------------------------------------------------------------

function freeBreedPath(userId: number): string {
  return path.join(DATA_DIR, 'trials', `breeds-${userId}.json`);
}

export async function freeBreedsUsed(userId: number): Promise<number> {
  try {
    const stored = JSON.parse(await fs.readFile(freeBreedPath(userId), 'utf8')) as { used?: number };
    return typeof stored.used === 'number' && stored.used >= 0 ? stored.used : 0;
  } catch {
    return 0;
  }
}

export async function recordFreeBreed(userId: number): Promise<void> {
  const used = await freeBreedsUsed(userId);
  await writeFileAtomic(freeBreedPath(userId), JSON.stringify({ used: used + 1, updatedAt: new Date().toISOString() }));
}

// ---------------------------------------------------------------------------
// Hono middleware: establish identity, then gate game routes on the pass.
// ---------------------------------------------------------------------------

export const identityMiddleware: MiddlewareHandler = async (c, next) => {
  if (DEV_MODE) {
    return authStore.run(ANONYMOUS, next);
  }
  const raw = c.req.header('x-telegram-init-data') ?? '';
  const tgUser = verifyInitData(raw);
  if (!tgUser) {
    return c.json({ ok: false, status: 'error', message: 'Open WEED-SIM inside Telegram to play.' }, 401);
  }
  const username = await usernameFor(tgUser);
  return authStore.run({ identity: { postId: WORLD_ID, username }, tgUser }, next);
};

// Free model: entry is free; the pass unlocks trading, cloning, Agent Control,
// and breeding beyond the lifetime free-cross limit. Reads are never gated.
const PASS_ONLY_POSTS: RegExp[] = [/^\/api\/clone$/, /^\/api\/market\//, /^\/api\/agent-link\/session$/];

export const paywallGate: MiddlewareHandler = async (c, next) => {
  if (DEV_MODE) return next();
  const tgUser = currentTgUser();
  if (tgUser && (await hasPass(tgUser.id))) return next();
  if (c.req.method.toUpperCase() !== 'POST') return next();
  const requestPath = c.req.path;
  if (PASS_ONLY_POSTS.some((pattern) => pattern.test(requestPath))) {
    return c.json({ ok: false, status: 'error', message: "Breeder's Pass required: trading, cloning, and Agent Control unlock with the pass." }, 402);
  }
  if (requestPath === '/api/breed') {
    if (!tgUser) return c.json({ ok: false, status: 'error', message: 'Open WEED-SIM inside Telegram to play.' }, 401);
    const used = await freeBreedsUsed(tgUser.id);
    if (used >= FREE_BREED_LIMIT) {
      return c.json({ ok: false, status: 'error', message: `Your ${FREE_BREED_LIMIT} free crosses are used up. The Breeder's Pass unlocks unlimited breeding - your garden is waiting.` }, 402);
    }
    await next();
    if (c.res.status === 200) await recordFreeBreed(tgUser.id);
    return;
  }
  return next();
};

// ---------------------------------------------------------------------------
// Telegram Bot API client + one-time webhook self-configuration at boot.
// ---------------------------------------------------------------------------

// HF Spaces block direct egress to api.telegram.org; point TELEGRAM_API_BASE at a
// relay (see tools/telegram-relay.ts) to route Bot API calls through a reachable host.
const TELEGRAM_API_BASE = (process.env.TELEGRAM_API_BASE ?? 'https://api.telegram.org').replace(/\/$/, '');
const TELEGRAM_RELAY_KEY = process.env.TELEGRAM_RELAY_KEY ?? '';

export async function tgApi<T = unknown>(method: string, payload: Record<string, unknown>): Promise<T> {
  const response = await fetch(`${TELEGRAM_API_BASE}/bot${BOT_TOKEN}/${method}`, {
    method: 'POST',
    headers: { 'Content-Type': 'application/json', ...(TELEGRAM_RELAY_KEY ? { 'X-Relay-Key': TELEGRAM_RELAY_KEY } : {}) },
    body: JSON.stringify(payload),
  });
  const body = (await response.json()) as { ok: boolean; result?: T; description?: string };
  if (!body.ok) throw new Error(`Telegram ${method} failed: ${body.description ?? response.status}`);
  return body.result as T;
}

/** Shared secret Telegram echoes back on webhook calls; derived so it needs no extra config. */
export function webhookSecret(): string {
  return createHash('sha256').update(`weedsim-webhook:${BOT_TOKEN}`).digest('hex').slice(0, 40);
}

export async function configureTelegramWebhook(): Promise<void> {
  if (DEV_MODE || !WEBAPP_URL) {
    console.log('WEED-SIM: webhook setup skipped', DEV_MODE ? '(dev mode, no BOT_TOKEN)' : '(WEBAPP_URL unset)');
    return;
  }
  // Boot-time networking can be flaky and Telegram is unreachable until this
  // succeeds, so retry forever; persistent failure in the logs = egress problem.
  for (let attempt = 1; ; attempt += 1) {
    try {
      await tgApi('setWebhook', {
        url: `${WEBAPP_URL}/telegram/webhook`,
        secret_token: webhookSecret(),
        allowed_updates: ['message', 'pre_checkout_query'],
      });
      console.log(`WEED-SIM: Telegram webhook configured for ${WEBAPP_URL} (attempt ${attempt})`);
      return;
    } catch (error) {
      const message = error instanceof Error ? error.message : String(error);
      if (attempt <= 5 || attempt % 10 === 0) {
        console.error(`WEED-SIM: webhook setup attempt ${attempt} failed (${message}); retrying`);
      }
      await new Promise((resolve) => setTimeout(resolve, attempt <= 5 ? 15_000 : 60_000));
    }
  }
}