import { clearToken, getToken } from '@/lib/auth'

export class ApiError extends Error {
  status: number
  code: string

  constructor(status: number, code: string, message: string) {
    super(message)
    this.status = status
    this.code = code
  }
}

async function request<T>(
  method: string,
  path: string,
  body?: unknown,
): Promise<T> {
  const headers: Record<string, string> = {
    Accept: 'application/json',
  }
  const token = getToken()
  if (token) headers.Authorization = `Bearer ${token}`
  if (body !== undefined) headers['Content-Type'] = 'application/json'

  const res = await fetch(path, {
    method,
    headers,
    credentials: 'include',
    body: body === undefined ? undefined : JSON.stringify(body),
  })

  if (res.status === 204) return undefined as T

  const text = await res.text()
  let data: unknown = null
  if (text) {
    try {
      data = JSON.parse(text)
    } catch {
      data = { error: { code: 'PARSE_ERROR', message: text } }
    }
  }

  if (!res.ok) {
    if (res.status === 401) clearToken()
    const err = data as { error?: { code?: string; message?: string } } | null
    throw new ApiError(
      res.status,
      err?.error?.code ?? 'ERROR',
      err?.error?.message ?? res.statusText,
    )
  }

  return data as T
}

export const api = {
  get: <T>(path: string) => request<T>('GET', path),
  post: <T>(path: string, body?: unknown) => request<T>('POST', path, body),
  patch: <T>(path: string, body?: unknown) => request<T>('PATCH', path, body),
  put: <T>(path: string, body?: unknown) => request<T>('PUT', path, body),
  delete: <T>(path: string) => request<T>('DELETE', path),
}