const API_BASE = 'https://api.dongfeng-systems.org'

export interface WeatherLocation {
  city: string
  latitude: number
  longitude: number
}

export interface CurrentWeather {
  city: string
  temperatureF: number
  humidityPercent: number
  windSpeedMph: number
  weatherCode: number
  description: string
}

const LOCATION_SET_KEY = 'weatherLocationSet'
const TEMP_UNIT_KEY = 'weatherTempUnit'
const TIME_FORMAT_KEY = 'timeFormat'

export type TempUnit = 'C' | 'F'
export type TimeFormat = '12h' | '24h'

/**
 * Check if location has been set (localStorage hint)
 */
export function hasLocationHint(): boolean {
  if (typeof window === 'undefined') return false
  return localStorage.getItem(LOCATION_SET_KEY) === 'true'
}

/**
 * Get temperature unit preference from localStorage
 */
export function getTempUnit(): TempUnit {
  if (typeof window === 'undefined') return 'F'
  const stored = localStorage.getItem(TEMP_UNIT_KEY)
  return stored === 'C' ? 'C' : 'F'
}

/**
 * Set temperature unit preference in localStorage
 */
export function setTempUnit(unit: TempUnit): void {
  if (typeof window === 'undefined') return
  localStorage.setItem(TEMP_UNIT_KEY, unit)
}

/**
 * Convert Fahrenheit to Celsius
 */
export function fahrenheitToCelsius(f: number): number {
  return (f - 32) * (5 / 9)
}

/**
 * Format temperature with unit
 */
export function formatTemperature(tempF: number, unit: TempUnit): string {
  if (unit === 'C') {
    return `${Math.round(fahrenheitToCelsius(tempF))}°C`
  }
  return `${Math.round(tempF)}°F`
}

/**
 * Get time format preference from localStorage
 */
export function getTimeFormat(): TimeFormat {
  if (typeof window === 'undefined') return '12h'
  const stored = localStorage.getItem(TIME_FORMAT_KEY)
  return stored === '24h' ? '24h' : '12h'
}

/**
 * Set time format preference in localStorage
 */
export function setTimeFormat(format: TimeFormat): void {
  if (typeof window === 'undefined') return
  localStorage.setItem(TIME_FORMAT_KEY, format)
}

/**
 * Mark location as set in localStorage
 */
export function setLocationHint(value: boolean): void {
  if (typeof window === 'undefined') return
  if (value) {
    localStorage.setItem(LOCATION_SET_KEY, 'true')
  } else {
    localStorage.removeItem(LOCATION_SET_KEY)
  }
}

/**
 * Set user's weather location by city name
 */
export async function setWeatherLocation(city: string, user: string = 'frontend'): Promise<WeatherLocation> {
  const res = await fetch(
    `${API_BASE}/api/weather/set-location?user=${encodeURIComponent(user)}&city=${encodeURIComponent(city)}`,
    { cache: 'no-store' }
  )
  if (!res.ok) {
    const text = await res.text()
    throw new Error(text || 'Failed to set location')
  }
  return res.json()
}

/**
 * Get current weather for user
 * Returns null if no location is set (instead of throwing)
 */
export async function getCurrentWeather(user: string = 'frontend'): Promise<CurrentWeather | null> {
  try {
    const res = await fetch(
      `${API_BASE}/api/weather/current?user=${encodeURIComponent(user)}`,
      { cache: 'no-store' }
    )
    if (!res.ok) {
      const text = await res.text()
      // Check if it's a "no location set" error - treat 404 and location-related errors as needing location
      if (
        text.toLowerCase().includes('no location') ||
        text.toLowerCase().includes('location not set') ||
        text.toLowerCase().includes('not found') ||
        res.status === 404 ||
        res.status === 400
      ) {
        return null
      }
      throw new Error(text || 'Failed to fetch weather')
    }
    return res.json()
  } catch (err) {
    // Network errors or other fetch failures - treat as needing location setup
    if (err instanceof TypeError && err.message.includes('fetch')) {
      return null
    }
    // Re-throw actual errors
    throw err
  }
}