package services

import (
	"bytes"
	"encoding/json"
	"fmt"
	"log"
	"net/http"
	"os"
	"time"
)

// TelegramBot est l'instance globale accessible depuis le package db
var TelegramBot *TelegramService

type TelegramService struct {
	botToken             string
	webhookSecret        string
	BotUsername          string
	notificationsEnabled bool
}

func NewTelegramService() *TelegramService {
	svc := &TelegramService{
		botToken:      os.Getenv("TELEGRAM_BOT_TOKEN"),
		webhookSecret: os.Getenv("TELEGRAM_WEBHOOK_SECRET"),
		BotUsername:   os.Getenv("TELEGRAM_BOT_USERNAME"),
	}
	TelegramBot = svc
	return svc
}

func (t *TelegramService) IsConfigured() bool {
	return t.botToken != ""
}

func (t *TelegramService) IsNotificationsEnabled() bool {
	return t.notificationsEnabled
}

func (t *TelegramService) SetNotificationsEnabled(enabled bool) {
	t.notificationsEnabled = enabled
}

// Reload met à jour le token et le username (appelé après UpdateSettings)
func (t *TelegramService) Reload(token, username string) {
	if token != "" {
		t.botToken = token
	}
	if username != "" {
		t.BotUsername = username
	}
}

func (t *TelegramService) ValidateWebhookSecret(header string) bool {
	if t.webhookSecret == "" {
		return true // pas de secret configuré = accepté
	}
	return header == t.webhookSecret
}

// SendMessage envoie un message texte (HTML) à un chat Telegram
func (t *TelegramService) SendMessage(chatID int64, text string) error {
	if !t.IsConfigured() {
		return fmt.Errorf("telegram non configuré")
	}

	payload := map[string]interface{}{
		"chat_id":    chatID,
		"text":       text,
		"parse_mode": "HTML",
	}

	body, err := json.Marshal(payload)
	if err != nil {
		return fmt.Errorf("marshal: %w", err)
	}

	url := fmt.Sprintf("https://api.telegram.org/bot%s/sendMessage", t.botToken)
	req, err := http.NewRequest("POST", url, bytes.NewBuffer(body))
	if err != nil {
		return fmt.Errorf("création requête: %w", err)
	}
	req.Header.Set("Content-Type", "application/json")

	client := &http.Client{Timeout: 10 * time.Second}
	resp, err := client.Do(req)
	if err != nil {
		return fmt.Errorf("envoi: %w", err)
	}
	defer resp.Body.Close()

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

// SetWebhook enregistre l'URL webhook auprès de Telegram
func (t *TelegramService) SetWebhook(webhookURL string) error {
	if !t.IsConfigured() {
		return fmt.Errorf("telegram non configuré")
	}

	payload := map[string]interface{}{
		"url":          webhookURL,
		"allowed_updates": []string{"message"},
	}
	if t.webhookSecret != "" {
		payload["secret_token"] = t.webhookSecret
	}

	body, err := json.Marshal(payload)
	if err != nil {
		return err
	}

	url := fmt.Sprintf("https://api.telegram.org/bot%s/setWebhook", t.botToken)
	req, err := http.NewRequest("POST", url, bytes.NewBuffer(body))
	if err != nil {
		return err
	}
	req.Header.Set("Content-Type", "application/json")

	client := &http.Client{Timeout: 15 * time.Second}
	resp, err := client.Do(req)
	if err != nil {
		return err
	}
	defer resp.Body.Close()

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

	log.Printf("✅ [TELEGRAM] Webhook enregistré: %s", webhookURL)
	return nil
}