/**
 * TraceStudio API 通讯层
 * 统一管理所有后端请求，处理 CORS 和错误
 */

import { API_BASE_URL, WS_BASE_URL } from './base'

if (import.meta.env.DEV) {
  console.log('🔗 API Base URL:', API_BASE_URL)
}

interface ApiResponse<T = any> {
  data?: T
  error?: string
}

/**
 * 通用请求方法
 */
export async function request<T = any>(
  endpoint: string,
  options: RequestInit = {}
): Promise<ApiResponse<T>> {
  try {
    const url = `${API_BASE_URL}${endpoint}`
    const response = await fetch(url, {
      ...options,
      headers: {
        'Content-Type': 'application/json',
        ...options.headers,
      },
    })

    if (!response.ok) {
      // Try to include response body (JSON or text) to aid debugging (eg. 422 validation errors)
      let bodyText = ''
      try {
        bodyText = await response.text()
      } catch (e) {
        bodyText = ''
      }
      throw new Error(`HTTP ${response.status}: ${response.statusText} ${bodyText}`)
    }

    const data = await response.json()
    return { data }
  } catch (error) {
    console.error(`API 请求失败 [${endpoint}]:`, error)
    return { error: error instanceof Error ? error.message : String(error) }
  }
}

/**
 * GET /api/plugins - 获取所有可用的算子
 */
export async function getPlugins(): Promise<ApiResponse<{
  plugins: Record<string, any>
}>> {
  return request('/api/plugins', { method: 'GET' })
}

/**
 * POST /api/node/preview - 预览节点输出
 */
export async function previewNode(payload: {
  node: any
  limit?: number
}): Promise<ApiResponse<{
  columns?: string[]
  preview?: any[]
  error?: string
}>> {
  return request('/api/node/preview', {
    method: 'POST',
    body: JSON.stringify(payload),
  })
}

/**
 * POST /api/graph/execute - 执行完整的计算图
 */
export async function executeGraph(payload: {
  nodes: any[]
  edges: any[]
  settings?: any
  global_context?: any
}): Promise<ApiResponse<{
  status: string
  message?: string
  execution_time?: number
  error?: string
}>> {
  return request('/api/graph/execute', {
    method: 'POST',
    body: JSON.stringify(payload),
  })
}

/**
 * WS /ws/graph/execute - 流式执行图
 * 返回 WebSocket 实例，调用方负责监听 message/close/error。
 */
export function executeGraphWS(payload: {
  nodes: any[]
  edges: any[]
  settings?: any
}): WebSocket {
  const url = `${WS_BASE_URL}/api/ws/graph/execute`
  const ws = new WebSocket(url)
  ws.onopen = () => {
    try {
      ws.send(JSON.stringify(payload))
    } catch (e) {
      console.error('WS 发送初始化消息失败:', e)
    }
  }
  return ws
}

/**
 * 健康检查
 */
export async function healthCheck(): Promise<ApiResponse<{
  status: string
  service: string
  version: string
}>> {
  return request('/', { method: 'GET' })
}

/**
 * 用户列表
 */
export async function listUsers(): Promise<ApiResponse<{
  users: string[]
}>> {
  return request('/api/users/list', { method: 'GET' })
}