package proxy

import (
	"encoding/json"
	"fmt"
	"net/http"
	"time"

	"gpt-plus/config"
)

// b2proxyResponse represents the JSON response from the B2Proxy API.
type b2proxyResponse struct {
	Code int `json:"code"`
	Data []struct {
		IP   string `json:"ip"`
		Port int    `json:"port"`
	} `json:"data"`
}

// FetchB2Proxy calls the B2Proxy API to get a proxy IP for the given country.
// Returns a proxy URL like "socks5://1.2.3.4:10000" or "http://1.2.3.4:10000".
// Uses a direct HTTP client (no proxy) with a 10-second timeout.
func FetchB2Proxy(cfg config.B2ProxyConfig, countryCode string) (string, error) {
	// Build the API URL
	url := fmt.Sprintf("%s/gen?zone=%s&ptype=%d&count=1&proto=%s&stype=json&sessType=sticky&sessTime=%d&sessAuto=1&region=%s",
		cfg.APIBase, cfg.Zone, cfg.PType, cfg.Proto, cfg.SessTime, countryCode)

	// Use a direct HTTP client (must not go through proxy to fetch proxy)
	directClient := &http.Client{Timeout: 10 * time.Second}

	resp, err := directClient.Get(url)
	if err != nil {
		return "", fmt.Errorf("b2proxy API request failed: %w", err)
	}
	defer resp.Body.Close()

	if resp.StatusCode != http.StatusOK {
		return "", fmt.Errorf("b2proxy API returned status %d", resp.StatusCode)
	}

	var result b2proxyResponse
	if err := json.NewDecoder(resp.Body).Decode(&result); err != nil {
		return "", fmt.Errorf("b2proxy API decode failed: %w", err)
	}

	if result.Code != 200 {
		return "", fmt.Errorf("b2proxy API error code: %d", result.Code)
	}

	if len(result.Data) == 0 {
		return "", fmt.Errorf("b2proxy API returned no proxy for region %s", countryCode)
	}

	entry := result.Data[0]
	proxyURL := fmt.Sprintf("%s://%s:%d", cfg.Proto, entry.IP, entry.Port)
	return proxyURL, nil
}