// src/services/request.ts
import axios, {
  AxiosError,
  type AxiosInstance,
  type AxiosRequestConfig,
  type AxiosResponse,
  type InternalAxiosRequestConfig,
  type CancelTokenSource
} from 'axios'

import { useCache } from '@/utils/useCache'
const { wsCache } = useCache()
// Response data structure
export interface ApiResponse<T = unknown> {
  code: number
  data: T
  message: string
  success: boolean
  [key: string]: any // Allow additional fields
}

// Extended request options
export interface RequestOptions {
  silent?: boolean // Silent mode (no error alerts)
  rawResponse?: boolean // Return raw Axios response
  customError?: boolean // Custom error handling
  retryCount?: number // Number of retry attempts
}

// Merged request configuration
export interface FullRequestConfig extends AxiosRequestConfig {
  requestOptions?: RequestOptions
}

// Custom error type
export interface RequestError<T = any> extends Error {
  config: FullRequestConfig
  code?: string
  request?: any
  response?: AxiosResponse<T>
  isAxiosError: boolean
}

class HttpService {
  private instance: AxiosInstance
  private cancelTokenSource: CancelTokenSource

  constructor(config?: AxiosRequestConfig) {
    this.cancelTokenSource = axios.CancelToken.source()
    this.instance = axios.create({
      baseURL: import.meta.env.VITE_API_BASE_URL,
      timeout: 15000,
      headers: {
        'Content-Type': 'application/json',
        ...config?.headers
      },
      ...config
    })

    this.setupInterceptors()
  }

  private setupInterceptors() {
    // Request interceptor
    this.instance.interceptors.request.use(
      (config: InternalAxiosRequestConfig) => {
        // Add auth token
        const token = wsCache.get('user.token')
        if (token && config.headers) {
          config.headers['X-SQLBOT-TOKEN'] = `Bearer ${token}`
        }

        // Request logging
        // console.log(`[Request] ${config.method?.toUpperCase()} ${config.url}`)
        
        return config
      },
      (error) => {
        return Promise.reject(error)
      }
    )

    // Response interceptor
    this.instance.interceptors.response.use(
      (response: AxiosResponse) => {
        // console.log(`[Response] ${response.config.url}`, response.data)
        
        // Return raw response if configured
        if ((response.config as FullRequestConfig).requestOptions?.rawResponse) {
          return response
        }

        // Handle business logic
        /* if (response.data?.success !== true) {
          return Promise.reject(response.data)
        } */
        return response.data
      },
      async (error: AxiosError) => {
        const config = error.config as FullRequestConfig & { __retryCount?: number }
        const requestOptions = config?.requestOptions || {}
        
        // Retry logic for specific status codes
        const shouldRetry = 
          error.response?.status === 502 && 
          (config.__retryCount || 0) < (requestOptions.retryCount || 3)
        
        if (shouldRetry) {
          config.__retryCount = (config.__retryCount || 0) + 1
          
          // Exponential backoff
          await new Promise(resolve => 
            setTimeout(resolve, 1000 * (config.__retryCount || 1))
          )
          
          return this.instance.request(config)
        }

        // Unified error handling
        if (!requestOptions.customError && !requestOptions.silent) {
          this.handleError(error)
        }

        return Promise.reject(error)
      }
    )
  }

  private handleError(error: AxiosError) {
    let errorMessage = 'Request error'
    
    if (error.response) {
      switch (error.response.status) {
        case 400:
          errorMessage = 'Invalid request parameters'
          break
        case 401:
          errorMessage = 'Unauthorized, please login again'
          // Redirect to login page if needed
          break
        case 403:
          errorMessage = 'Access denied'
          break
        case 404:
          errorMessage = 'Resource not found'
          break
        case 500:
          errorMessage = 'Server error'
          break
        default:
          errorMessage = `Server responded with error: ${error.response.status}`
      }
    } else if (error.request) {
      errorMessage = 'No response from server'
    } else if (axios.isCancel(error)) {
      errorMessage = 'Request canceled'
      return // Skip showing cancel messages
    } else {
      errorMessage = error['message'] || 'Unknown error'
    }

    // Show error using UI library (e.g., Element Plus, Ant Design)
    console.error(errorMessage)
    // ElMessage.error(errorMessage)
    ElMessage({
      message: errorMessage,
      type: 'error'
    })
  }

  // Cancel all pending requests
  public cancelRequests(message?: string) {
    this.cancelTokenSource.cancel(message)
    // Create new token source for future requests
    this.cancelTokenSource = axios.CancelToken.source()
  }

  // Base request method
  public request<T = any>(config: FullRequestConfig): Promise<T> {
    return this.instance.request({
      cancelToken: this.cancelTokenSource.token,
      ...config
    })
  }

  // GET request
  public get<T = any>(url: string, config?: FullRequestConfig): Promise<T> {
    return this.request({ ...config, method: 'GET', url })
  }

  // POST request
  public post<T = any>(
    url: string, 
    data?: any, 
    config?: FullRequestConfig
  ): Promise<T> {
    return this.request({ ...config, method: 'POST', url, data })
  }

  // PUT request
  public put<T = any>(
    url: string,
    data?: any,
    config?: FullRequestConfig
  ): Promise<T> {
    return this.request({ ...config, method: 'PUT', url, data })
  }

  // DELETE request
  public delete<T = any>(url: string, config?: FullRequestConfig): Promise<T> {
    return this.request({ ...config, method: 'DELETE', url })
  }

  // PATCH request
  public patch<T = any>(
    url: string,
    data?: any,
    config?: FullRequestConfig
  ): Promise<T> {
    return this.request({ ...config, method: 'PATCH', url, data })
  }

  // File upload
  public upload<T = any>(
    url: string,
    file: File,
    fieldName = 'file',
    config?: FullRequestConfig
  ): Promise<T> {
    const formData = new FormData()
    formData.append(fieldName, file)

    return this.post(url, formData, {
      headers: {
        'Content-Type': 'multipart/form-data'
      },
      ...config
    })
  }

  // Download file
  public download(
    url: string,
    config?: FullRequestConfig
  ): Promise<Blob> {
    return this.request<Blob>({
      ...config,
      method: 'GET',
      url,
      responseType: 'blob'
    })
  }
}

// Create singleton instance
export const request = new HttpService({
  baseURL: import.meta.env.VITE_API_BASE_URL
})