import { getRuntimePlatform, isIosDevice, isWechatDevTools } from './env';
import {
  ensureJssdkReady,
  getJssdkSignUrl,
  initWechatJssdk,
  normalizeJssdkPageUrl,
  resetJssdkConfig,
} from './jssdk';
import type { WeixinSdkConfig } from './types';

export type ChooseWechatImageOptions = {
  count?: number;
  sourceType?: Array<'album' | 'camera'>;
};

function delay(ms: number): Promise<void> {
  return new Promise((resolve) => window.setTimeout(resolve, ms));
}

function isChooseImageCancelMessage(msg: string): boolean {
  return /cancel|取消/i.test(msg.trim());
}

/** 将微信 chooseImage / getLocalImgData fail 的 errMsg 转为用户可读文案 */
export function formatChooseImageFailMessage(errMsg: string): string {
  const msg = errMsg.trim() || '无法打开相册';
  if (isChooseImageCancelMessage(msg)) return '';

  if (/offline verifying|permission value is offline/i.test(msg)) {
    return '微信权限验证中，请稍候再试或刷新页面后重新选择图片';
  }

  if (/invalid signature|config:fail|signature/i.test(msg)) {
    return '微信 JSSDK 签名校验失败，请刷新页面后重试';
  }

  if (/photo.*denied|photos.*denied|相册.*权限|无法访问相册|无相册权限/i.test(msg)) {
    return '相册权限未开启，请在 iPhone「设置 → 隐私与安全性 → 照片」中允许微信访问相册';
  }

  if (/system.*camera|camera.*not.*allowed|无法访问相机|无相机权限/i.test(msg)) {
    return '相机权限未开启，请在 iPhone「设置 → 隐私与安全性 → 相机」中允许微信使用摄像头';
  }

  if (/permission|auth|denied|授权|拒绝/i.test(msg)) {
    return `微信选图接口未就绪（${msg}），请刷新页面后重试`;
  }

  return msg;
}

async function reportChooseImageEvent(
  config: WeixinSdkConfig,
  payload: {
    status: 'fail';
    errMsg: string;
    sourceType?: string;
    stage: 'jssdk' | 'choose' | 'read' | 'empty';
  },
) {
  if (isChooseImageCancelMessage(payload.errMsg)) return;
  try {
    const headers: Record<string, string> = {
      'Content-Type': 'application/json',
      'X-Client-App': config.clientApp,
    };
    const token = config.getAccessToken?.();
    if (token) headers.Authorization = `Bearer ${token}`;
    await fetch(`${config.apiBase ?? '/api/v1'}/common/wechat/choose-image`, {
      method: 'POST',
      headers,
      body: JSON.stringify({
        status: 'fail',
        errMsg: payload.errMsg,
        sourceType: payload.sourceType,
        stage: payload.stage,
        pageUrl: typeof window !== 'undefined' ? normalizeJssdkPageUrl(window.location.href) : undefined,
        signUrl: typeof window !== 'undefined' ? getJssdkSignUrl() : undefined,
      }),
    });
  } catch {
    /* 上报失败不影响主流程 */
  }
}

function base64ToFile(base64: string, fileName: string): File {
  const normalized = base64.startsWith('data:')
    ? base64
    : `data:image/jpeg;base64,${base64.replace(/\s/g, '')}`;
  const [header, body] = normalized.split(',');
  const mime = header.match(/:(.*?);/)?.[1] ?? 'image/jpeg';
  const binary = atob(body);
  const bytes = new Uint8Array(binary.length);
  for (let i = 0; i < binary.length; i++) bytes[i] = binary.charCodeAt(i);
  return new File([bytes], fileName, { type: mime });
}

function localIdToFile(localId: string): Promise<File> {
  return new Promise((resolve, reject) => {
    if (!window.wx?.getLocalImgData) {
      reject(new Error('微信 getLocalImgData 不可用'));
      return;
    }
    window.wx.getLocalImgData({
      localId,
      success: (res) => {
        try {
          resolve(base64ToFile(res.localData, `wx-${Date.now()}.jpg`));
        } catch (e) {
          reject(e instanceof Error ? e : new Error('图片解析失败'));
        }
      },
      fail: (err) => {
        const raw = err.errMsg || '读取图片失败';
        const formatted = formatChooseImageFailMessage(raw);
        reject(new Error(formatted || raw));
      },
    });
  });
}

function checkJsApi(apiName: string): Promise<boolean> {
  return new Promise((resolve) => {
    if (!window.wx?.checkJsApi) {
      resolve(!!window.wx?.chooseImage);
      return;
    }
    window.wx.checkJsApi({
      jsApiList: [apiName],
      success: (res) => resolve(!!res.checkResult?.[apiName]),
      fail: () => resolve(false),
    });
  });
}

async function ensureChooseImageJssdk(config: WeixinSdkConfig): Promise<void> {
  const jssdkOptions = {
    apiBase: config.apiBase ?? '/api/v1',
    clientApp: config.clientApp,
    getAccessToken: config.getAccessToken,
    jsApiList: ['chooseImage', 'getLocalImgData'],
  };

  await ensureJssdkReady(jssdkOptions);

  let ready = await checkJsApi('chooseImage');
  if (!ready) {
    resetJssdkConfig();
    await initWechatJssdk({ ...jssdkOptions, url: getJssdkSignUrl() });
    ready = await checkJsApi('chooseImage');
  }
  if (!ready) {
    throw new Error('微信选图接口未授权，请刷新页面后重试');
  }
}

function isPermissionDeniedError(msg: string): boolean {
  return /permission|denied|invalid signature|config:fail|signature|接口未就绪|offline verifying/i.test(msg);
}

function invokeChooseImage(
  count: number,
  sourceType: Array<'album' | 'camera'>,
): Promise<string[]> {
  return new Promise((resolve, reject) => {
    let settled = false;
    const finish = (fn: () => void) => {
      if (settled) return;
      settled = true;
      window.clearTimeout(hangTimer);
      fn();
    };

    // 极端机型取消后无回调：最长等待后按取消解锁，避免业务侧 uploading 永久卡住
    const hangTimer = window.setTimeout(() => {
      finish(() => resolve([]));
    }, 180_000);

    window.wx!.chooseImage!({
      count,
      sizeType: ['compressed'],
      sourceType,
      success: (res) => finish(() => resolve(res.localIds ?? [])),
      fail: (err) => {
        const raw = err.errMsg || '无法打开相册';
        if (isChooseImageCancelMessage(raw)) {
          finish(() => resolve([]));
          return;
        }
        const formatted = formatChooseImageFailMessage(raw);
        finish(() => reject(new Error(formatted || raw)));
      },
      // 部分微信版本取消只走 complete
      complete: () => {
        window.setTimeout(() => {
          finish(() => resolve([]));
        }, 300);
      },
    });
  });
}

/** 微信内选图（相册/拍照），返回 File 列表；非微信环境返回 null */
export async function chooseWechatImages(
  config: WeixinSdkConfig,
  options: ChooseWechatImageOptions = {},
): Promise<File[] | null> {
  const platform = getRuntimePlatform();
  if (platform === 'browser') return null;

  const count = options.count ?? 1;
  const sourceType = options.sourceType ?? ['album', 'camera'];

  if (platform === 'wechat-h5') {
    const sourceTypeKey = sourceType.join(',');
    const jssdkOptions = {
      apiBase: config.apiBase ?? '/api/v1',
      clientApp: config.clientApp,
      getAccessToken: config.getAccessToken,
      jsApiList: ['chooseImage', 'getLocalImgData'],
    };
    try {
      await ensureChooseImageJssdk(config);
    } catch (e) {
      const errMsg = e instanceof Error ? e.message : 'JSSDK 初始化失败';
      void reportChooseImageEvent(config, { status: 'fail', errMsg, sourceType: sourceTypeKey, stage: 'jssdk' });
      throw e;
    }
    if (!window.wx?.chooseImage) {
      const errMsg = '微信选图接口不可用，请刷新页面后重试';
      void reportChooseImageEvent(config, { status: 'fail', errMsg, sourceType: sourceTypeKey, stage: 'jssdk' });
      throw new Error(errMsg);
    }

    if (isIosDevice() && !isWechatDevTools()) {
      await delay(500);
    }

    let localIds: string[] = [];
    const maxAttempts = 2;
    let lastError: Error | null = null;
    for (let attempt = 0; attempt < maxAttempts; attempt++) {
      if (attempt > 0) {
        if (lastError && isPermissionDeniedError(lastError.message)) {
          resetJssdkConfig();
          await initWechatJssdk({ ...jssdkOptions, url: getJssdkSignUrl() });
        }
        await delay(800);
      }
      try {
        localIds = await invokeChooseImage(count, sourceType);
        lastError = null;
        break;
      } catch (e) {
        lastError = e instanceof Error ? e : new Error('无法打开相册');
        const raw = lastError.message;
        const retryable = /offline verifying|权限验证中|接口未就绪/i.test(raw) || isPermissionDeniedError(raw);
        if (attempt < maxAttempts - 1 && retryable) continue;
        void reportChooseImageEvent(config, {
          status: 'fail',
          errMsg: raw,
          sourceType: sourceTypeKey,
          stage: 'choose',
        });
        throw lastError;
      }
    }
    if (lastError) throw lastError;

    if (!localIds.length) {
      return [];
    }

    const files: File[] = [];
    for (const localId of localIds) {
      try {
        files.push(await localIdToFile(localId));
      } catch (e) {
        const errMsg = e instanceof Error ? e.message : '读取图片失败';
        void reportChooseImageEvent(config, { status: 'fail', errMsg, sourceType: sourceTypeKey, stage: 'read' });
        throw e;
      }
    }
    return files;
  }

  return null;
}

export function canUseWechatChooseImage(): boolean {
  return getRuntimePlatform() !== 'browser';
}