package telegram

import (
	"bytes"
	"encoding/json"
	"errors"
	"fmt"
	"io"
	"log/slog"
	"net/http"
	"os"
	"strconv"
	"time"

	"git.nakama.town/fmartingr/butterrobot/internal/config"
	"git.nakama.town/fmartingr/butterrobot/internal/model"
)

// TelegramPlatform implements the Platform interface for Telegram
type TelegramPlatform struct {
	config *config.TelegramConfig
	apiURL string
	log    *slog.Logger
}

// New creates a new TelegramPlatform instance
func New(cfg *config.TelegramConfig) *TelegramPlatform {
	return &TelegramPlatform{
		config: cfg,
		apiURL: "https://api.telegram.org/bot" + cfg.Token,
		log:    slog.New(slog.NewTextHandler(os.Stdout, &slog.HandlerOptions{Level: slog.LevelDebug})).With(slog.String("platform", "telegram")),
	}
}

// Init initializes the Telegram platform
func (t *TelegramPlatform) Init(cfg *config.Config) error {
	if t.config.Token == "" {
		t.log.Error("Missing Telegram token")
		return model.ErrPlatformInit
	}

	// Set webhook URL based on hostname
	webhookURL := fmt.Sprintf("https://%s/telegram/incoming/%s", cfg.Hostname, t.config.Token)
	t.log.Info("Setting Telegram webhook", "url", webhookURL)

	// Create webhook setup request
	url := fmt.Sprintf("%s/setWebhook", t.apiURL)
	payload := map[string]interface{}{
		"url":             webhookURL,
		"max_connections": 40,
		"allowed_updates": []string{"message"},
	}

	data, err := json.Marshal(payload)
	if err != nil {
		t.log.Error("Failed to marshal webhook payload", "error", err)
		return fmt.Errorf("failed to marshal webhook payload: %w", err)
	}

	resp, err := http.Post(url, "application/json", bytes.NewBuffer(data))
	if err != nil {
		t.log.Error("Failed to set webhook", "error", err)
		return fmt.Errorf("failed to set webhook: %w", err)
	}
	defer resp.Body.Close()

	if resp.StatusCode != http.StatusOK {
		bodyBytes, _ := io.ReadAll(resp.Body)
		errMsg := string(bodyBytes)
		t.log.Error("Telegram API error", "status", resp.StatusCode, "response", errMsg)
		return fmt.Errorf("telegram API error: %d - %s", resp.StatusCode, errMsg)
	}

	t.log.Info("Telegram webhook successfully set")
	return nil
}

// ParseIncomingMessage parses an incoming Telegram message
func (t *TelegramPlatform) ParseIncomingMessage(r *http.Request) (*model.Message, error) {
	t.log.Debug("Parsing incoming Telegram message")

	// Read request body
	body, err := io.ReadAll(r.Body)
	if err != nil {
		t.log.Error("Failed to read request body", "error", err)
		return nil, err
	}
	defer r.Body.Close()

	// Parse JSON
	var update struct {
		Message struct {
			MessageID int `json:"message_id"`
			From      struct {
				ID        int    `json:"id"`
				IsBot     bool   `json:"is_bot"`
				Username  string `json:"username"`
				FirstName string `json:"first_name"`
			} `json:"from"`
			Chat struct {
				ID       int64  `json:"id"`
				Type     string `json:"type"`
				Title    string `json:"title,omitempty"`
				Username string `json:"username,omitempty"`
			} `json:"chat"`
			Date int    `json:"date"`
			Text string `json:"text"`
		} `json:"message"`
	}

	if err := json.Unmarshal(body, &update); err != nil {
		t.log.Error("Failed to unmarshal update", "error", err)
		return nil, err
	}

	// Convert to raw map for storage
	var raw map[string]interface{}
	if err := json.Unmarshal(body, &raw); err != nil {
		t.log.Error("Failed to unmarshal raw data", "error", err)
		return nil, err
	}

	// Create message
	msg := &model.Message{
		Text:    update.Message.Text,
		Chat:    strconv.FormatInt(update.Message.Chat.ID, 10),
		Author:  update.Message.From.Username,
		FromBot: update.Message.From.IsBot,
		Date:    time.Unix(int64(update.Message.Date), 0),
		ID:      strconv.Itoa(update.Message.MessageID),
		Raw:     raw,
	}

	t.log.Debug("Parsed message",
		"id", msg.ID,
		"chat", msg.Chat,
		"author", msg.Author,
		"from_bot", msg.FromBot,
		"text_length", len(msg.Text))

	// Create Channel object
	channelRaw, err := t.ParseChannelFromMessage(body)
	if err != nil {
		t.log.Error("Failed to parse channel data", "error", err)
		return nil, err
	}

	msg.Channel = &model.Channel{
		Platform:          "telegram",
		PlatformChannelID: msg.Chat,
		ChannelRaw:        channelRaw,
	}

	return msg, nil
}

// ParseChannelNameFromRaw extracts a human-readable channel name from raw data
func (t *TelegramPlatform) ParseChannelNameFromRaw(channelRaw map[string]interface{}) string {
	// Try to get the title first (for groups)
	if chatInfo, ok := channelRaw["chat"].(map[string]interface{}); ok {
		if title, ok := chatInfo["title"].(string); ok && title != "" {
			return title
		}

		// For private chats, use username
		if username, ok := chatInfo["username"].(string); ok && username != "" {
			return username
		}

		// Fallback to first_name if available
		if firstName, ok := chatInfo["first_name"].(string); ok && firstName != "" {
			return firstName
		}

		// Last resort: use the ID
		if id, ok := chatInfo["id"].(float64); ok {
			return strconv.FormatInt(int64(id), 10)
		}
	}

	return "unknown"
}

// ParseChannelFromMessage extracts channel data from a message
func (t *TelegramPlatform) ParseChannelFromMessage(body []byte) (map[string]any, error) {
	// Parse JSON to extract chat info
	var update struct {
		Message struct {
			Chat map[string]any `json:"chat"`
		} `json:"message"`
	}

	if err := json.Unmarshal(body, &update); err != nil {
		return nil, err
	}

	if update.Message.Chat == nil {
		return nil, errors.New("chat information not found")
	}

	return map[string]any{
		"chat": update.Message.Chat,
	}, nil
}

// SendMessage sends a message to Telegram
func (t *TelegramPlatform) SendMessage(msg *model.Message) error {
	// Convert chat ID to int64
	chatID, err := strconv.ParseInt(msg.Chat, 10, 64)
	if err != nil {
		t.log.Error("Failed to parse chat ID", "chat", msg.Chat, "error", err)
		return err
	}

	// Prepare payload
	payload := map[string]interface{}{
		"chat_id": chatID,
		"text":    msg.Text,
	}

	// Add reply if needed
	if msg.ReplyTo != "" {
		replyToID, err := strconv.Atoi(msg.ReplyTo)
		if err == nil {
			payload["reply_to_message_id"] = replyToID
		} else {
			t.log.Warn("Failed to parse reply_to ID", "reply_to", msg.ReplyTo, "error", err)
		}
	}

	t.log.Debug("Sending message to Telegram", "chat_id", chatID, "length", len(msg.Text))

	// Convert payload to JSON
	data, err := json.Marshal(payload)
	if err != nil {
		t.log.Error("Failed to marshal message payload", "error", err)
		return err
	}

	// Send HTTP request
	resp, err := http.Post(
		t.apiURL+"/sendMessage",
		"application/json",
		bytes.NewBuffer(data),
	)
	if err != nil {
		t.log.Error("Failed to send message", "error", err)
		return err
	}
	defer resp.Body.Close()

	// Check response
	if resp.StatusCode != http.StatusOK {
		bodyBytes, _ := io.ReadAll(resp.Body)
		errMsg := string(bodyBytes)
		t.log.Error("Telegram API error", "status", resp.StatusCode, "response", errMsg)
		return fmt.Errorf("telegram API error: %d - %s", resp.StatusCode, errMsg)
	}

	t.log.Debug("Message sent successfully")
	return nil
}