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

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

async function reportChooseImageEvent(
  config: WeixinSdkConfig,
  payload: {
    status: 'fail';
    errMsg: string;
    sourceType?: string;
    stage: 'jssdk' | 'choose' | 'read' | 'empty';
  },
) {
  if (/cancel/i.test(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,
      }),
    });
  } 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) => reject(new Error(err.errMsg || '读取图片失败')),
    });
  });
}

/** 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 pageUrl = typeof window !== 'undefined' ? getJssdkSignUrl() : '';
    const sourceTypeKey = sourceType.join(',');
    try {
      await ensureJssdkReady({
        apiBase: config.apiBase ?? '/api/v1',
        clientApp: config.clientApp,
        getAccessToken: config.getAccessToken,
        jsApiList: ['chooseImage', 'getLocalImgData'],
      });
    } 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);
    }

    let localIds: string[];
    try {
      localIds = await new Promise<string[]>((resolve, reject) => {
        window.wx!.chooseImage!({
          count,
          sizeType: ['compressed'],
          sourceType,
          success: (res) => resolve(res.localIds ?? []),
          fail: (err) => reject(new Error(err.errMsg || '无法打开相册')),
        });
      });
    } catch (e) {
      const errMsg = e instanceof Error ? e.message : '无法打开相册';
      void reportChooseImageEvent(config, { status: 'fail', errMsg, sourceType: sourceTypeKey, stage: 'choose' });
      throw e;
    }

    if (!localIds.length) {
      const errMsg = '未选择图片';
      void reportChooseImageEvent(config, { status: 'fail', errMsg, sourceType: sourceTypeKey, stage: 'empty' });
      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';
}