import axios, { AxiosInstance, AxiosRequestConfig } from 'axios'
import { getSession } from 'next-auth/react'

class APIClient {
  private client: AxiosInstance
  private baseURL: string

  constructor() {
    this.baseURL = process.env.NEXT_PUBLIC_API_URL || 'http://localhost:8000'
    
    this.client = axios.create({
      baseURL: this.baseURL,
      timeout: 30000,
      headers: {
        'Content-Type': 'application/json',
      },
    })

    // Request interceptor for auth
    this.client.interceptors.request.use(
      async (config) => {
        const session = await getSession()
        if (session?.accessToken) {
          config.headers.Authorization = `Bearer ${session.accessToken}`
        }
        return config
      },
      (error) => Promise.reject(error)
    )

    // Response interceptor for error handling
    this.client.interceptors.response.use(
      (response) => response,
      async (error) => {
        if (error.response?.status === 401) {
          // Handle token refresh or redirect to login
          window.location.href = '/login'
        }
        return Promise.reject(error)
      }
    )
  }

  // Generic request method
  async request<T>(config: AxiosRequestConfig): Promise<T> {
    const response = await this.client.request<T>(config)
    return response.data
  }

  // Convenience methods
  async get<T>(url: string, config?: AxiosRequestConfig): Promise<T> {
    return this.request<T>({ ...config, method: 'GET', url })
  }

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

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

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

  // File upload
  async upload<T>(
    url: string,
    file: File,
    onProgress?: (progress: number) => void
  ): Promise<T> {
    const formData = new FormData()
    formData.append('file', file)

    return this.request<T>({
      method: 'POST',
      url,
      data: formData,
      headers: {
        'Content-Type': 'multipart/form-data',
      },
      onUploadProgress: (progressEvent) => {
        if (onProgress && progressEvent.total) {
          const progress = Math.round(
            (progressEvent.loaded * 100) / progressEvent.total
          )
          onProgress(progress)
        }
      },
    })
  }

  // WebSocket connection for real-time updates
  createWebSocket(path: string): WebSocket {
    const wsURL = this.baseURL.replace(/^http/, 'ws')
    return new WebSocket(`${wsURL}${path}`)
  }
}

// Export singleton instance
export const apiClient = new APIClient()

// Export typed API methods
export const api = {
  // Auth
  auth: {
    login: (credentials: { email: string; password: string }) =>
      apiClient.post<{ token: string; user: any }>('/auth/login', credentials),
    
    register: (data: { email: string; password: string; name: string }) =>
      apiClient.post<{ token: string; user: any }>('/auth/register', data),
    
    logout: () => apiClient.post('/auth/logout'),
    
    refreshToken: () =>
      apiClient.post<{ token: string }>('/auth/refresh'),
  },

  // Processing
  processing: {
    removeBackground: (file: File, options?: any, onProgress?: (p: number) => void) =>
      apiClient.upload<{ id: string; result: string }>('/process/remove-background', file, onProgress),
    
    replaceBackground: (imageId: string, backgroundId: string) =>
      apiClient.post<{ result: string }>('/process/replace-background', {
        imageId,
        backgroundId,
      }),
    
    batchProcess: (files: File[], options?: any) => {
      const formData = new FormData()
      files.forEach((file) => formData.append('files', file))
      if (options) {
        formData.append('options', JSON.stringify(options))
      }
      return apiClient.post<{ jobId: string }>('/process/batch', formData, {
        headers: { 'Content-Type': 'multipart/form-data' },
      })
    },
    
    getJobStatus: (jobId: string) =>
      apiClient.get<{ status: string; progress: number; results?: any[] }>(
        `/process/jobs/${jobId}`
      ),
  },

  // Projects
  projects: {
    list: (params?: { page?: number; limit?: number; search?: string }) =>
      apiClient.get<{ items: any[]; total: number }>('/projects', { params }),
    
    get: (id: string) =>
      apiClient.get<any>(`/projects/${id}`),
    
    create: (data: any) =>
      apiClient.post<any>('/projects', data),
    
    update: (id: string, data: any) =>
      apiClient.put<any>(`/projects/${id}`, data),
    
    delete: (id: string) =>
      apiClient.delete(`/projects/${id}`),
  },

  // Backgrounds
  backgrounds: {
    list: (category?: string) =>
      apiClient.get<any[]>('/backgrounds', { params: { category } }),
    
    upload: (file: File) =>
      apiClient.upload<{ id: string; url: string }>('/backgrounds/upload', file),
    
    generate: (prompt: string) =>
      apiClient.post<{ id: string; url: string }>('/backgrounds/generate', { prompt }),
  },

  // User
  user: {
    profile: () =>
      apiClient.get<any>('/user/profile'),
    
    updateProfile: (data: any) =>
      apiClient.put<any>('/user/profile', data),
    
    usage: () =>
      apiClient.get<{ images: number; videos: number; storage: number }>(
        '/user/usage'
      ),
    
    billing: () =>
      apiClient.get<any>('/user/billing'),
  },
}

export default api