const API_URL = process.env['NEXT_PUBLIC_API_URL'] || 'http://localhost:3001'

export interface AuthUser {
  id: string
  email: string
  name: string
  avatarUrl: string | null
}

export interface AuthTokens {
  accessToken: string
  refreshToken: string
  expiresIn: number
  user: AuthUser
}

const ACCESS_TOKEN_KEY = 'timelapse_access_token'
const REFRESH_TOKEN_KEY = 'timelapse_refresh_token'
const USER_KEY = 'timelapse_user'

// ── Token storage ────────────────────────────────────────────────

export function getAccessToken(): string | null {
  if (typeof window === 'undefined') return null
  return localStorage.getItem(ACCESS_TOKEN_KEY)
}

export function getRefreshToken(): string | null {
  if (typeof window === 'undefined') return null
  return localStorage.getItem(REFRESH_TOKEN_KEY)
}

export function getStoredUser(): AuthUser | null {
  if (typeof window === 'undefined') return null
  const raw = localStorage.getItem(USER_KEY)
  if (!raw) return null
  try { return JSON.parse(raw) } catch { return null }
}

export function storeTokens(tokens: AuthTokens): void {
  localStorage.setItem(ACCESS_TOKEN_KEY, tokens.accessToken)
  localStorage.setItem(REFRESH_TOKEN_KEY, tokens.refreshToken)
  localStorage.setItem(USER_KEY, JSON.stringify(tokens.user))
}

export function clearAuth(): void {
  localStorage.removeItem(ACCESS_TOKEN_KEY)
  localStorage.removeItem(REFRESH_TOKEN_KEY)
  localStorage.removeItem(USER_KEY)
}

// ── API helpers ──────────────────────────────────────────────────

async function apiFetch<T>(path: string, options: RequestInit = {}): Promise<T> {
  const token = getAccessToken()
  const headers: Record<string, string> = {
    'Content-Type': 'application/json',
    ...(options.headers as Record<string, string>),
  }
  if (token) headers['Authorization'] = `Bearer ${token}`

  const res = await fetch(`${API_URL}${path}`, { ...options, headers })

  if (res.status === 401) {
    // Try refresh
    const refreshed = await tryRefresh()
    if (refreshed) {
      const retryHeaders = { ...headers, Authorization: `Bearer ${getAccessToken()}` }
      const retry = await fetch(`${API_URL}${path}`, { ...options, headers: retryHeaders })
      if (!retry.ok) throw new Error(`API error ${retry.status}`)
      return retry.json() as Promise<T>
    }
    clearAuth()
    if (typeof window !== 'undefined') window.location.href = '/login'
    throw new Error('Unauthorized')
  }

  if (!res.ok) {
    const body = await res.json().catch(() => ({ message: 'Unknown error' }))
    throw new Error(body.message || `API error ${res.status}`)
  }

  return res.json() as Promise<T>
}

export async function tryRefresh(): Promise<boolean> {
  const refreshToken = getRefreshToken()
  if (!refreshToken) return false

  try {
    const res = await fetch(`${API_URL}/v1/auth/refresh`, {
      method: 'POST',
      headers: { 'Content-Type': 'application/json' },
      body: JSON.stringify({ refreshToken }),
    })
    if (!res.ok) return false
    const tokens: AuthTokens = await res.json()
    storeTokens(tokens)
    return true
  } catch {
    return false
  }
}

// ── Auth API calls ──────────────────────────────────────────────

export const authApi = {
  login: (email: string, password: string) =>
    apiFetch<AuthTokens>('/v1/auth/login', {
      method: 'POST',
      body: JSON.stringify({ email, password }),
    }),

  register: (email: string, password: string, name: string) =>
    apiFetch<AuthTokens>('/v1/auth/register', {
      method: 'POST',
      body: JSON.stringify({ email, password, name }),
    }),

  logout: () =>
    apiFetch('/v1/auth/logout', {
      method: 'POST',
      body: JSON.stringify({ refreshToken: getRefreshToken() }),
    }).finally(() => clearAuth()),

  me: () => apiFetch<AuthUser>('/v1/auth/me'),
}

// ── Devices API (JWT-authenticated) ─────────────────────────────

export const devicesApi = {
  list: (projectId?: string) => {
    const qs = projectId ? `?projectId=${projectId}` : ''
    return apiFetch<any[]>(`/v1/devices${qs}`)
  },

  get: (id: string) => apiFetch<any>(`/v1/devices/${id}`),

  stats: () => apiFetch<{ devicesOnline: number; devicesOffline: number; capturesToday: number; devicesTotal: number }>('/v1/devices/stats'),

  heartbeats: (id: string, limit?: number) => {
    const qs = limit ? `?limit=${limit}` : ''
    return apiFetch<any[]>(`/v1/devices/${id}/heartbeats${qs}`)
  },
}