const BASE_URL = ''

class ApiClient {
  async request<T>(url: string, options: RequestInit = {}): Promise<T> {
    const headers = new Headers(options.headers || {})
    const isFormData = options.body instanceof FormData
    if (!isFormData && !headers.has('Content-Type')) {
      headers.set('Content-Type', 'application/json')
    }

    const response = await fetch(`${BASE_URL}${url}`, {
      ...options,
      credentials: 'include',
      headers,
    })

    if (!response.ok) {
      const error = await response.json().catch(() => ({ detail: '请求失败' }))
      throw new Error(error.detail || '请求失败')
    }

    if (response.status === 204 || response.status === 205) {
      return undefined as T
    }

    const contentType = response.headers.get('content-type') || ''
    if (!contentType.includes('application/json')) {
      return undefined as T
    }

    return response.json()
  }

  get<T>(url: string): Promise<T> {
    return this.request<T>(url)
  }

  post<T>(url: string, data?: unknown): Promise<T> {
    return this.request<T>(url, {
      method: 'POST',
      body: data ? JSON.stringify(data) : undefined,
    })
  }

  put<T>(url: string, data?: unknown): Promise<T> {
    return this.request<T>(url, {
      method: 'PUT',
      body: data ? JSON.stringify(data) : undefined,
    })
  }

  delete<T>(url: string): Promise<T> {
    return this.request<T>(url, { method: 'DELETE' })
  }
}

export const api = new ApiClient()