// server/skland/http.js — the /skland/* HTTP surface (JSON). Wired into the main request listener by routes.js when
// (i18n-ignore-file: the answers are bilingual by design, 中文 · English, the same convention as server/http/*
// — docs/I18N.md; the panel renders its own labels and shows these strings verbatim as the diagnostic)
// the skland module is enabled (opts.skland / env SP_SKLAND=1). **Every** answer of this surface is JSON, including
// the errors: a JSON client must never be handed the module-level HTML error page (http/common.js sendError), so a
// local `fail()` writes { ok: false, error } with the status instead. POST bodies are read with a size cap; the
// security headers come from the outer listener.
//
// Endpoints (docs/skland.md):
//   GET  /skland/status?player=…            the player's binding state
//   POST /skland/scan/start    {player}     start a scan session → { scanId, scanUrl }
//   POST /skland/scan/poll     {player}     one poll; finishes the login when the phone confirmed
//   POST /skland/phone/send    {player, phone, captcha?}     send the SMS code
//   POST /skland/phone/login   {player, phone, code}         验证码 login → bind
//   POST /skland/password/login {player, phone, password}    密码 login → bind
//   POST /skland/unbind        {player}     forget the credentials
//   GET  /skland/roles?player=…&refresh=1  the bound arknights roles (cached)

import { sendJson } from '../http/common.js';
import { SESSION_BINDING_PREFIX } from './session.js';

/** The cap on a POST body (a phone + code + player id is small). */
const MAX_BODY = 64 * 1024;

/** Read the request body as JSON (async iterable; node:http IncomingMessage supports it). */
export async function readJsonBody(req) {
  let size = 0;
  const chunks = [];
  for await (const chunk of req) {
    size += chunk.length;
    if (size > MAX_BODY) throw new Error('body too large');
    chunks.push(chunk);
  }
  if (!chunks.length) return {};
  return JSON.parse(Buffer.concat(chunks).toString('utf8'));
}

/**
 * @param {{ service: ReturnType<typeof import('./service.js').createSklandService>, sessionPlayer?: Function }} deps
 * @returns {(req: import('node:http').IncomingMessage, res: import('node:http').ServerResponse,
 *            parts: { rawPath: string, query: string }) => Promise<boolean>}
 *   resolves true when the request was a /skland/* route (handled here).
 */
export function createSklandHttp({ service, sessionPlayer }) {
  const queryParam = (parts, name) => {
    for (const pair of parts.query.split('&')) {
      const [k, v] = pair.split('=');
      if (decodeURIComponent(k || '') === name) return decodeURIComponent(v || '');
    }
    return '';
  };

  /** Every failure of this surface is JSON — never the module-level HTML error page. */
  const fail = (req, res, status, error) => sendJson(req, res, status, { ok: false, error });

  async function handle(req, res, parts) {
    if (parts.rawPath !== '/skland' && !parts.rawPath.startsWith('/skland/')) return false;
    const scoped = parts.rawPath.startsWith('/skland/session/');
    const path = scoped ? parts.rawPath.replace('/skland/session/', '/skland/') : parts.rawPath;
    const ownedPlayer = scoped ? sessionPlayer?.(req) : null;
    if (scoped && !ownedPlayer) {
      fail(req, res, 401, '游戏会话已失效，请重新连接 · Game session expired'); return true;
    }
    const allowed = (player) => scoped || (!player.startsWith(SESSION_BINDING_PREFIX) && !player.startsWith('@account/'));
    try {
      if (req.method === 'GET' && path === '/skland/status') {
        const player = ownedPlayer || queryParam(parts, 'player') || '';
        if (!allowed(player)) { fail(req, res, 403, '需要游戏会话 · Game session required'); return true; }
        if (!player) { fail(req, res, 400, '缺少 player 参数 · Missing player'); return true; }
        sendJson(req, res, 200, service.status(player));
        return true;
      }
      if (req.method === 'GET' && path === '/skland/roles') {
        const player = ownedPlayer || queryParam(parts, 'player') || '';
        if (!allowed(player)) { fail(req, res, 403, '需要游戏会话 · Game session required'); return true; }
        const refresh = queryParam(parts, 'refresh') === '1';
        if (!player) { fail(req, res, 400, '缺少 player 参数 · Missing player'); return true; }
        try {
          sendJson(req, res, 200, { ok: true, roles: await service.roles(player, refresh) });
        } catch (e) {
          sendJson(req, res, 200, { ok: false, error: e.message });
        }
        return true;
      }
      if (req.method !== 'POST') { fail(req, res, 405, '不支持的请求方法 · Method not allowed'); return true; }

      let body;
      try { body = await readJsonBody(req); } catch {
        fail(req, res, 400, '请求体无效 · Bad request'); return true;
      }
      const player = ownedPlayer || String(body.player || '');
      if (!allowed(player)) { fail(req, res, 403, '需要游戏会话 · Game session required'); return true; }

      if (path === '/skland/scan/start') {
        if (!player) { fail(req, res, 400, '缺少 player · Missing player'); return true; }
        try {
          const qr = await service.startScan(player);
          sendJson(req, res, 200, { ok: true, ...qr });
        } catch (e) { sendJson(req, res, 200, { ok: false, error: e.message }); }
        return true;
      }
      if (path === '/skland/scan/poll') {
        if (!player) { fail(req, res, 400, '缺少 player · Missing player'); return true; }
        try {
          sendJson(req, res, 200, { ok: true, ...(await service.pollScan(player)) });
        } catch (e) {
          // A poll that fails still names a terminal state: a caller stops on anything but 'waiting', and a bare
          // { ok: false } would leave it reading `state === undefined` (the panel showed "未知状态" for that).
          sendJson(req, res, 200, { ok: false, state: 'error', error: e.message });
        }
        return true;
      }
      if (path === '/skland/phone/send') {
        if (!player || !body.phone) { fail(req, res, 400, '缺少参数 · Missing fields'); return true; }
        try {
          sendJson(req, res, 200, await service.sendPhoneCode(player, String(body.phone), body.captcha));
        } catch { fail(req, res, 500, '服务器内部错误 · Internal error'); }
        return true;
      }
      if (path === '/skland/phone/login') {
        if (!player || !body.phone || !body.code) { fail(req, res, 400, '缺少参数 · Missing fields'); return true; }
        sendJson(req, res, 200, await service.loginByPhoneCode(player, String(body.phone), String(body.code)));
        return true;
      }
      if (path === '/skland/password/login') {
        if (!player || !body.phone || !body.password) { fail(req, res, 400, '缺少参数 · Missing fields'); return true; }
        sendJson(req, res, 200, await service.loginByPhonePassword(player, String(body.phone), String(body.password),
          body.captcha, typeof body.captchaStep === 'string' ? body.captchaStep : undefined));
        return true;
      }
      if (path === '/skland/unbind') {
        if (!player) { fail(req, res, 400, '缺少 player · Missing player'); return true; }
        sendJson(req, res, 200, service.unbind(player));
        return true;
      }
      fail(req, res, 404, '未知的 /skland 接口 · Unknown endpoint');
    } catch {
      fail(req, res, 500, '服务器内部错误 · Internal error');
    }
    return true;
  }
  return handle;
}

/**
 * The handler mounted when the module is OFF. Without it the path would fall through to the static mount (a 404 for
 * GET) and to routes.js's GET/HEAD gate (a **405 HTML** for POST) — an inconsistent surface for one API. This one
 * answers every /skland/* request the same way, JSON like the enabled surface, so a client can always parse the
 * "not enabled" answer.
 * @returns {(req, res, parts: { rawPath: string }) => Promise<boolean>}
 */
export function createSklandOffHandler() {
  return async (req, res, parts) => {
    if (parts.rawPath !== '/skland' && !parts.rawPath.startsWith('/skland/')) return false;
    sendJson(req, res, 404, { ok: false, error: '未启用森空岛绑定 · the Skland module is off (set SP_SKLAND=1)' });
    return true;
  };
}