export const WECHAT_OPEN_LOCATION_PAGE_PATH = '/pages/open-location/index'

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

export interface WechatOpenLocationPageOptions {
  latitude?: unknown
  longitude?: unknown
  name?: unknown
  address?: unknown
}

export type WechatOpenLocationValidationResult =
  | { ok: true; value: WechatOpenLocationTarget }
  | { ok: false; message: string }

const MAX_NAME_LENGTH = 100
const MAX_ADDRESS_LENGTH = 300

const firstValue = (value: unknown) => (
  Array.isArray(value) ? value[0] : value
)

const normalizeText = (value: unknown) => {
  const first = firstValue(value)
  return typeof first === 'string' ? first.trim() : ''
}

const normalizeCoordinate = (value: unknown) => {
  const first = firstValue(value)
  if (typeof first === 'string' && !first.trim()) return null
  if (typeof first !== 'string' && typeof first !== 'number') return null

  const coordinate = Number(first)
  return Number.isFinite(coordinate) ? coordinate : null
}

export const validateWechatOpenLocationTarget = (
  target: WechatOpenLocationPageOptions
): WechatOpenLocationValidationResult => {
  const latitude = normalizeCoordinate(target.latitude)
  const longitude = normalizeCoordinate(target.longitude)
  const name = normalizeText(target.name)
  const address = normalizeText(target.address)

  if (latitude === null || longitude === null) {
    return { ok: false, message: '地图坐标缺失或格式错误' }
  }
  if (latitude < -90 || latitude > 90 || longitude < -180 || longitude > 180) {
    return { ok: false, message: '地图坐标超出有效范围' }
  }
  if (!name) {
    return { ok: false, message: '目的地名称不能为空' }
  }
  if (name.length > MAX_NAME_LENGTH || address.length > MAX_ADDRESS_LENGTH) {
    return { ok: false, message: '目的地名称或地址过长' }
  }

  return {
    ok: true,
    value: {
      latitude,
      longitude,
      name,
      address
    }
  }
}

export const buildWechatOpenLocationPageUrl = (
  target: WechatOpenLocationPageOptions
) => {
  const result = validateWechatOpenLocationTarget(target)
  if (!result.ok) throw new TypeError(result.message)

  const params = new URLSearchParams()
  params.set('latitude', String(result.value.latitude))
  params.set('longitude', String(result.value.longitude))
  params.set('name', result.value.name)
  params.set('address', result.value.address || '')

  // 微信页面路由对加号的解码行为不统一，空格固定使用百分号编码。
  const query = params.toString().replace(/\+/g, '%20')
  return `${WECHAT_OPEN_LOCATION_PAGE_PATH}?${query}`
}

export const parseWechatOpenLocationPageOptions = (
  options: WechatOpenLocationPageOptions = {}
) => validateWechatOpenLocationTarget(options)