import axios, { type AxiosInstance, type AxiosRequestConfig, type AxiosResponse } from "axios"

/**
 * Token management utilities
 */
const getTokenFromCookie = (name: string): string | null => {
  if (typeof document === "undefined") return null
  const value = `; ${document.cookie}`
  const parts = value.split(`; ${name}=`)
  if (parts.length === 2) return parts.pop()?.split(";").shift() || null
  return null
}

const setTokenInCookie = (name: string, token: string): void => {
  if (typeof document === "undefined") return
  document.cookie = `${name}=${token}; path=/; secure; SameSite=Strict; max-age=2592000`
}

const removeTokenFromCookie = (name: string): void => {
  if (typeof document === "undefined") return
  document.cookie = `${name}=; path=/; expires=Thu, 01 Jan 1970 00:00:00 UTC;`
}

const getToken = (): string | null => {
  // Check cookies first (more secure)
  const authToken = getTokenFromCookie("authToken")
  if (authToken) return authToken
  
  const guestToken = getTokenFromCookie("guestToken")
  if (guestToken) return guestToken
  
  return null
}

/**
 * Centralized API client with interceptors
 */
class APIClient {
  private client: AxiosInstance
  private baseUrl: string
  private isRefreshing = false
  private failedQueue: Array<{
    resolve: (value?: unknown) => void
    reject: (reason?: unknown) => void
  }> = []

  constructor() {
    this.baseUrl = process.env.NEXT_PUBLIC_API_URL || "https://api.example.com"

    this.client = axios.create({
      baseURL: `${this.baseUrl}/api/v1`,
      timeout: 15000,
      headers: {
        "Content-Type": "application/json",
        "Api-Token": process.env.NEXT_PUBLIC_API_TOKEN || "123",
      },
    })

    this.setupInterceptors()
  }

  private setupInterceptors(): void {
    // Request interceptor
    this.client.interceptors.request.use(
      (config) => {
        const token = getToken()
        if (token) {
          config.headers.Authorization = `Bearer ${token}`
        }

        // Add language parameter if i18n is available
        if (typeof window !== "undefined" && (window as any).i18n) {
          const lang = (window as any).i18n.language || "tm"
          const url = config.url || ""
          config.url = `${url}${url.includes("?") ? "&" : "?"}lang=${lang}`
        }

        return config
      },
      (error) => Promise.reject(error)
    )

    // Response interceptor
    this.client.interceptors.response.use(
      (response) => response,
      async (error) => {
        const originalRequest = error.config

        // Handle 401 errors
        if (error.response?.status === 401 && !originalRequest._retry) {
          if (this.isRefreshing) {
            // Queue requests while refreshing
            return new Promise((resolve, reject) => {
              this.failedQueue.push({ resolve, reject })
            })
              .then(() => this.client(originalRequest))
              .catch((err) => Promise.reject(err))
          }

          originalRequest._retry = true
          this.isRefreshing = true

          try {
            // Attempt to get guest token
            const guestTokenResponse = await axios.post(
              `${this.baseUrl}/api/v1/auth/guest-token`,
              {},
              {
                headers: {
                  "Content-Type": "application/json",
                  "Api-Token": process.env.NEXT_PUBLIC_API_TOKEN || "123",
                },
              }
            )

            const newToken = guestTokenResponse.data?.token || guestTokenResponse.data?.data
            
            if (newToken) {
              setTokenInCookie("guestToken", newToken)
              this.processQueue(null)
              return this.client(originalRequest)
            }
          } catch (refreshError) {
            this.processQueue(refreshError)
            this.clearAuthToken()
            
            if (typeof window !== "undefined") {
              window.location.href = "/login"
            }
            
            return Promise.reject(refreshError)
          } finally {
            this.isRefreshing = false
          }
        }

        // Handle HTML error responses
        if (
          error.response?.data &&
          typeof error.response.data === "string" &&
          error.response.data.includes("<!DOCTYPE html>")
        ) {
          return Promise.reject({
            ...error,
            response: {
              ...error.response,
              data: { message: "Server returned HTML instead of JSON" },
            },
          })
        }

        return Promise.reject(error)
      }
    )
  }

  private processQueue(error: any): void {
    this.failedQueue.forEach((promise) => {
      if (error) {
        promise.reject(error)
      } else {
        promise.resolve()
      }
    })
    this.failedQueue = []
  }

  get<T = any>(url: string, config?: AxiosRequestConfig): Promise<AxiosResponse<T>> {
    return this.client.get<T>(url, config)
  }

  post<T = any>(url: string, data?: any, config?: AxiosRequestConfig): Promise<AxiosResponse<T>> {
    return this.client.post<T>(url, data, config)
  }

  put<T = any>(url: string, data?: any, config?: AxiosRequestConfig): Promise<AxiosResponse<T>> {
    return this.client.put<T>(url, data, config)
  }

  patch<T = any>(url: string, data?: any, config?: AxiosRequestConfig): Promise<AxiosResponse<T>> {
    return this.client.patch<T>(url, data, config)
  }

  delete<T = any>(url: string, config?: AxiosRequestConfig): Promise<AxiosResponse<T>> {
    return this.client.delete<T>(url, config)
  }

  setAuthToken(token: string): void {
    removeTokenFromCookie("guestToken")
    setTokenInCookie("authToken", token)
    this.client.defaults.headers.common["Authorization"] = `Bearer ${token}`
  }

  setGuestToken(token: string): void {
    setTokenInCookie("guestToken", token)
    this.client.defaults.headers.common["Authorization"] = `Bearer ${token}`
  }

  clearAuthToken(): void {
    removeTokenFromCookie("authToken")
    removeTokenFromCookie("guestToken")
    delete this.client.defaults.headers.common["Authorization"]
  }
}

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

// Export helper functions
export const setAuthToken = (token: string) => apiClient.setAuthToken(token)
export const setGuestToken = (token: string) => apiClient.setGuestToken(token)
export const clearAuthToken = () => apiClient.clearAuthToken()