import Taro from '@tarojs/taro'

export interface Location {
  latitude: number
  longitude: number
  speed?: number
  accuracy?: number
}

export interface LocationInfo {
  latitude: number
  longitude: number
  address: string
  name?: string
}

// 获取当前位置
export const getCurrentLocation = (): Promise<LocationInfo> => {
  return new Promise((resolve, reject) => {
    Taro.getLocation({
      type: 'wgs84',
      success: (res) => {
        console.log('===获取地理位置', res)
        // 使用逆地理编码获取地址信息
        reverseGeocode(res.latitude, res.longitude)
          .then(address => {
            resolve({
              latitude: res.latitude,
              longitude: res.longitude,
              address
            })
          })
          .catch(() => {
            resolve({
              latitude: res.latitude,
              longitude: res.longitude,
              address: `${res.latitude.toFixed(6)}, ${res.longitude.toFixed(6)}`
            })
          })
      },
      fail: (error) => {
        reject(error)
      }
    })
  })
}

// 选择地图位置
export const chooseLocation = (): Promise<LocationInfo> => {
  return new Promise((resolve, reject) => {
    Taro.chooseLocation({
      success: (res) => {
        resolve({
          latitude: res.latitude,
          longitude: res.longitude,
          address: res.address,
          name: res.name
        })
      },
      fail: (error) => {
        reject(error)
      }
    })
  })
}

export const getLocation = (): Promise<Location> => {
  return new Promise((resolve, reject) => {
    Taro.getLocation({
      success: (res) => {
        resolve({
          latitude: res.latitude,
          longitude: res.longitude,
          speed: res.speed,
          accuracy: res.accuracy
        })
      },
      fail: (error) => {
        reject(error)
      }
    })
  })
}

// 逆地理编码（简化版本，实际项目中应该调用真实的地图服务API）
export const reverseGeocode = (latitude: number, longitude: number): Promise<string> => {
  return new Promise((resolve) => {
    // 这里应该调用真实的地图服务API，比如腾讯地图、高德地图等
    // 暂时返回坐标字符串
    setTimeout(() => {
      resolve(`纬度:${latitude.toFixed(6)}, 经度:${longitude.toFixed(6)}`)
    }, 500)
  })
}

// 计算两点间距离（单位：米）
export const calculateDistance = (
  lat1: number, 
  lng1: number, 
  lat2: number, 
  lng2: number
): number => {
  const radLat1 = lat1 * Math.PI / 180.0
  const radLat2 = lat2 * Math.PI / 180.0
  const a = radLat1 - radLat2
  const b = lng1 * Math.PI / 180.0 - lng2 * Math.PI / 180.0
  
  let s = 2 * Math.asin(Math.sqrt(
    Math.pow(Math.sin(a/2), 2) + 
    Math.cos(radLat1) * Math.cos(radLat2) * 
    Math.pow(Math.sin(b/2), 2)
  ))
  
  s = s * 6378.137 // 地球半径
  s = Math.round(s * 10000) / 10000
  
  return s * 1000 // 转换为米
}