/**
 * 高德地图微信小程序SDK - 纯定位版
 * 只负责GPS定位，地址解析由后端处理
 */

class AMapWX {
  constructor(options = {}) {
    this.key = options.key || '';
    this.version = '1.5.0';
    
    console.log(`高德地图定位SDK初始化成功 [v${this.version}]`);
    if (this.key) {
      console.log(`API Key: ${this.key.substring(0, 8)}...`);
    }
  }

  /**
   * 获取微信定位 - 主要功能
   * @param {function} callback - 定位回调函数 callback(location, error)
   * @param {object} options - 定位选项
   */
  getWxLocation(callback, options = {}) {
    const defaultOptions = {
      type: 'gcj02',
      isHighAccuracy: true,
      highAccuracyExpireTime: 4000,
      ...options
    };

    console.log('[AMapWX] 开始获取微信定位');

    wx.getLocation({
      ...defaultOptions,
      success: (res) => {
        console.log('[AMapWX] 微信定位成功:', res);
        
        const location = {
          longitude: res.longitude,
          latitude: res.latitude,
          accuracy: res.accuracy || 0,
          altitude: res.altitude || 0,
          speed: res.speed || 0,
          horizontalAccuracy: res.horizontalAccuracy || 0,
          verticalAccuracy: res.verticalAccuracy || 0
        };

        if (typeof callback === 'function') {
          callback(location, null);
        }
      },
      fail: (err) => {
        console.error('[AMapWX] 微信定位失败:', err);
        
        if (typeof callback === 'function') {
          callback(null, err);
        }
      }
    });
  }

  /**
   * 计算两点间距离
   * @param {object} point1 - 起点 {longitude, latitude}
   * @param {object} point2 - 终点 {longitude, latitude}
   * @returns {number} 距离（米）
   */
  calculateDistance(point1, point2) {
    const R = 6371000; // 地球半径（米）
    const lat1 = point1.latitude * Math.PI / 180;
    const lat2 = point2.latitude * Math.PI / 180;
    const deltaLat = (point2.latitude - point1.latitude) * Math.PI / 180;
    const deltaLng = (point2.longitude - point1.longitude) * Math.PI / 180;

    const a = Math.sin(deltaLat / 2) * Math.sin(deltaLat / 2) +
              Math.cos(lat1) * Math.cos(lat2) *
              Math.sin(deltaLng / 2) * Math.sin(deltaLng / 2);
    const c = 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1 - a));

    return R * c;
  }
}

// 创建单例实例
let amapInstance = null;

const AmapWX = {
  /**
   * 获取SDK实例
   * @param {object} options - 配置选项
   * @returns {AMapWX}
   */
  getInstance(options = {}) {
    if (!amapInstance) {
      amapInstance = new AMapWX(options);
    }
    return amapInstance;
  },

  /**
   * 重置SDK实例
   * @param {object} options - 配置选项
   * @returns {AMapWX}
   */
  resetInstance(options = {}) {
    amapInstance = new AMapWX(options);
    return amapInstance;
  }
};

// 导出模块
module.exports = {
  AMapWX,
  AmapWX
};