import type { Env } from '../types';

export const CN_OFFSET_MS = 8 * 60 * 60 * 1000;

/** 毫秒时间戳 → "YYYY-MM-DD HH:mm:ss"（Asia/Shanghai，中国无夏令时） */
export function formatDateCN(ms: number): string {
  const d = new Date((ms || 0) + CN_OFFSET_MS);
  const p = (n: number, len = 2) => String(n).padStart(len, '0');
  return (
    `${d.getUTCFullYear()}-${p(d.getUTCMonth() + 1)}-${p(d.getUTCDate())} ` +
    `${p(d.getUTCHours())}:${p(d.getUTCMinutes())}:${p(d.getUTCSeconds())}`
  );
}

export function now(): number {
  return Date.now();
}

// ------------------------------------------------------------------ 响应封装

export function json(data: unknown, init: ResponseInit = {}): Response {
  const headers = new Headers(init.headers);
  headers.set('Content-Type', 'application/json; charset=utf-8');
  return new Response(JSON.stringify(data ?? {}), { ...init, headers });
}

/** Artalk 成功响应：RespData 是「裸数据」，RespSuccess 是 {"msg":"Success"} */
export function ok(data: unknown): Response {
  return json(data);
}

export function okMsg(msg = 'Success', extra: Record<string, unknown> = {}): Response {
  return json({ msg, ...extra });
}

/** Artalk 错误响应：{"msg": "..."} + 非 200 状态码 */
export function fail(status: number, msg: string, extra: Record<string, unknown> = {}): Response {
  return json({ msg, ...extra }, { status });
}

// ------------------------------------------------------------------ 请求解析

export function getClientIP(req: Request): string {
  return (
    req.headers.get('CF-Connecting-IP') ||
    (req.headers.get('X-Forwarded-For') || '').split(',')[0].trim() ||
    '127.0.0.1'
  );
}

export function getUserAgent(req: Request): string {
  return req.headers.get('User-Agent') || '';
}

export async function readBody(req: Request): Promise<Record<string, any>> {
  const ct = req.headers.get('Content-Type') || '';
  try {
    if (ct.includes('application/json')) {
      const v = await req.json();
      return v && typeof v === 'object' ? (v as Record<string, any>) : {};
    }
    if (ct.includes('form-urlencoded')) {
      const text = await req.text();
      const out: Record<string, any> = {};
      for (const [k, v] of new URLSearchParams(text)) out[k] = v;
      return out;
    }
    const text = await req.text();
    if (!text) return {};
    try {
      const v = JSON.parse(text);
      return v && typeof v === 'object' ? v : {};
    } catch {
      const out: Record<string, any> = {};
      for (const [k, v] of new URLSearchParams(text)) out[k] = v;
      return out;
    }
  } catch {
    return {};
  }
}

export function qp(url: URL, key: string): string {
  return url.searchParams.get(key) ?? '';
}

export function qInt(url: URL, key: string, dft = 0): number {
  const v = parseInt(url.searchParams.get(key) ?? '', 10);
  return Number.isFinite(v) ? v : dft;
}

export function qBool(url: URL, key: string): boolean {
  const v = (url.searchParams.get(key) ?? '').toLowerCase();
  return v === '1' || v === 'true' || v === 'yes';
}

// ------------------------------------------------------------------ 校验

export function isEmail(s: string): boolean {
  return /^[^\s@]+@[^\s@]+\.[^\s@]+$/.test((s || '').trim());
}

export function isUrl(s: string): boolean {
  try {
    const u = new URL(s);
    return u.protocol === 'http:' || u.protocol === 'https:';
  } catch {
    return false;
  }
}

export function trimTo(s: string, max: number): string {
  const v = String(s ?? '');
  return v.length > max ? v.slice(0, max) : v;
}

// ------------------------------------------------------------------ CORS

export function corsHeaders(req: Request, env: Env): Headers {
  const headers = new Headers();
  const origin = req.headers.get('Origin') || '';
  const allow = (env.ALLOWED_ORIGINS || '')
    .split(',')
    .map((s) => s.trim())
    .filter(Boolean);

  if (origin && (allow.includes(origin) || allow.includes('*'))) {
    headers.set('Access-Control-Allow-Origin', origin);
  } else if (!origin) {
    headers.set('Access-Control-Allow-Origin', '*');
  }
  headers.set('Vary', 'Origin');
  headers.set('Access-Control-Allow-Methods', 'GET,POST,PUT,DELETE,OPTIONS');
  headers.set(
    'Access-Control-Allow-Headers',
    'Content-Type,Authorization,X-Requested-With,X-Api-Version',
  );
  headers.set('Access-Control-Max-Age', '86400');
  return headers;
}