package businessapi

import (
	"bytes"
	"context"
	"encoding/json"
	"fmt"
	"io"
	"net/http"
	"strings"
	"sync"
	"time"

	"git.warky.dev/wdevs/whatshooked/pkg/config"
	"git.warky.dev/wdevs/whatshooked/pkg/events"
	"git.warky.dev/wdevs/whatshooked/pkg/logging"

	"go.mau.fi/whatsmeow/types"
)

// Client represents a WhatsApp Business API client
type Client struct {
	id          string
	phoneNumber string
	config      config.BusinessAPIConfig
	httpClient  *http.Client
	eventBus    *events.EventBus
	mediaConfig config.MediaConfig
	connected   bool
	mu          sync.RWMutex
}

// NewClient creates a new Business API client
func NewClient(cfg config.WhatsAppConfig, eventBus *events.EventBus, mediaConfig config.MediaConfig) (*Client, error) {
	if cfg.Type != "business-api" {
		return nil, fmt.Errorf("invalid client type for business-api: %s", cfg.Type)
	}

	if cfg.BusinessAPI == nil {
		return nil, fmt.Errorf("business_api configuration is required for business-api type")
	}

	// Validate required fields
	if cfg.BusinessAPI.PhoneNumberID == "" {
		return nil, fmt.Errorf("phone_number_id is required")
	}
	if cfg.BusinessAPI.AccessToken == "" {
		return nil, fmt.Errorf("access_token is required")
	}

	// Set default API version
	if cfg.BusinessAPI.APIVersion == "" {
		cfg.BusinessAPI.APIVersion = "v21.0"
	}

	return &Client{
		id:          cfg.ID,
		phoneNumber: cfg.PhoneNumber,
		config:      *cfg.BusinessAPI,
		httpClient: &http.Client{
			Timeout: 30 * time.Second,
		},
		eventBus:    eventBus,
		mediaConfig: mediaConfig,
		connected:   false,
	}, nil
}

// Connect validates the Business API credentials
func (c *Client) Connect(ctx context.Context) error {
	// Validate credentials by making a test request to get phone number details
	url := fmt.Sprintf("https://graph.facebook.com/%s/%s",
		c.config.APIVersion,
		c.config.PhoneNumberID)

	req, err := http.NewRequestWithContext(ctx, "GET", url, nil)
	if err != nil {
		return fmt.Errorf("failed to create request: %w", err)
	}

	req.Header.Set("Authorization", "Bearer "+c.config.AccessToken)

	resp, err := c.httpClient.Do(req)
	if err != nil {
		c.eventBus.Publish(events.WhatsAppPairFailedEvent(ctx, c.id, err))
		return fmt.Errorf("failed to validate credentials: %w", err)
	}
	defer resp.Body.Close()

	if resp.StatusCode != http.StatusOK {
		body, _ := io.ReadAll(resp.Body)
		err := fmt.Errorf("API returned status %d: %s", resp.StatusCode, string(body))
		c.eventBus.Publish(events.WhatsAppPairFailedEvent(ctx, c.id, err))
		return err
	}

	c.mu.Lock()
	c.connected = true
	c.mu.Unlock()

	logging.Info("Business API client connected", "account_id", c.id, "phone", c.phoneNumber)
	c.eventBus.Publish(events.WhatsAppConnectedEvent(ctx, c.id, c.phoneNumber))
	return nil
}

// Disconnect closes the Business API client
func (c *Client) Disconnect() error {
	c.mu.Lock()
	c.connected = false
	c.mu.Unlock()

	logging.Info("Business API client disconnected", "account_id", c.id)
	return nil
}

// IsConnected returns whether the client is connected
func (c *Client) IsConnected() bool {
	c.mu.RLock()
	defer c.mu.RUnlock()
	return c.connected
}

// GetID returns the client ID
func (c *Client) GetID() string {
	return c.id
}

// GetPhoneNumber returns the phone number
func (c *Client) GetPhoneNumber() string {
	return c.phoneNumber
}

// GetType returns the client type
func (c *Client) GetType() string {
	return "business-api"
}

// SendTextMessage sends a text message via Business API
func (c *Client) SendTextMessage(ctx context.Context, jid types.JID, text string) (string, error) {
	if ctx == nil {
		ctx = context.Background()
	}

	// Convert JID to phone number
	phoneNumber := jidToPhoneNumber(jid)

	// Create request
	reqBody := SendMessageRequest{
		MessagingProduct: "whatsapp",
		To:               phoneNumber,
		Type:             "text",
		Text: &TextObject{
			Body: text,
		},
	}

	messageID, err := c.sendMessage(ctx, reqBody)
	if err != nil {
		c.eventBus.Publish(events.MessageFailedEvent(ctx, c.id, phoneNumber, text, err))
		return "", err
	}

	logging.Debug("Message sent via Business API", "account_id", c.id, "to", phoneNumber)
	c.eventBus.Publish(events.MessageSentEvent(ctx, c.id, messageID, phoneNumber, text))
	return messageID, nil
}

// SendImage sends an image message via Business API
func (c *Client) SendImage(ctx context.Context, jid types.JID, imageData []byte, mimeType string, caption string) (string, error) {
	if ctx == nil {
		ctx = context.Background()
	}

	phoneNumber := jidToPhoneNumber(jid)

	// Upload media first
	mediaID, err := c.uploadMedia(ctx, imageData, mimeType)
	if err != nil {
		c.eventBus.Publish(events.MessageFailedEvent(ctx, c.id, phoneNumber, caption, err))
		return "", fmt.Errorf("failed to upload image: %w", err)
	}

	// Send message with media ID
	reqBody := SendMessageRequest{
		MessagingProduct: "whatsapp",
		To:               phoneNumber,
		Type:             "image",
		Image: &MediaObject{
			ID:      mediaID,
			Caption: caption,
		},
	}

	messageID, err := c.sendMessage(ctx, reqBody)
	if err != nil {
		c.eventBus.Publish(events.MessageFailedEvent(ctx, c.id, phoneNumber, caption, err))
		return "", err
	}

	logging.Debug("Image sent via Business API", "account_id", c.id, "to", phoneNumber)
	c.eventBus.Publish(events.MessageSentEvent(ctx, c.id, messageID, phoneNumber, caption))
	return messageID, nil
}

// SendVideo sends a video message via Business API
func (c *Client) SendVideo(ctx context.Context, jid types.JID, videoData []byte, mimeType string, caption string) (string, error) {
	if ctx == nil {
		ctx = context.Background()
	}

	phoneNumber := jidToPhoneNumber(jid)

	// Upload media first
	mediaID, err := c.uploadMedia(ctx, videoData, mimeType)
	if err != nil {
		c.eventBus.Publish(events.MessageFailedEvent(ctx, c.id, phoneNumber, caption, err))
		return "", fmt.Errorf("failed to upload video: %w", err)
	}

	// Send message with media ID
	reqBody := SendMessageRequest{
		MessagingProduct: "whatsapp",
		To:               phoneNumber,
		Type:             "video",
		Video: &MediaObject{
			ID:      mediaID,
			Caption: caption,
		},
	}

	messageID, err := c.sendMessage(ctx, reqBody)
	if err != nil {
		c.eventBus.Publish(events.MessageFailedEvent(ctx, c.id, phoneNumber, caption, err))
		return "", err
	}

	logging.Debug("Video sent via Business API", "account_id", c.id, "to", phoneNumber)
	c.eventBus.Publish(events.MessageSentEvent(ctx, c.id, messageID, phoneNumber, caption))
	return messageID, nil
}

// SendDocument sends a document message via Business API
func (c *Client) SendDocument(ctx context.Context, jid types.JID, documentData []byte, mimeType string, filename string, caption string) (string, error) {
	if ctx == nil {
		ctx = context.Background()
	}

	phoneNumber := jidToPhoneNumber(jid)

	// Upload media first
	mediaID, err := c.uploadMedia(ctx, documentData, mimeType)
	if err != nil {
		c.eventBus.Publish(events.MessageFailedEvent(ctx, c.id, phoneNumber, caption, err))
		return "", fmt.Errorf("failed to upload document: %w", err)
	}

	// Send message with media ID
	reqBody := SendMessageRequest{
		MessagingProduct: "whatsapp",
		To:               phoneNumber,
		Type:             "document",
		Document: &DocumentObject{
			ID:       mediaID,
			Caption:  caption,
			Filename: filename,
		},
	}

	messageID, err := c.sendMessage(ctx, reqBody)
	if err != nil {
		c.eventBus.Publish(events.MessageFailedEvent(ctx, c.id, phoneNumber, caption, err))
		return "", err
	}

	logging.Debug("Document sent via Business API", "account_id", c.id, "to", phoneNumber, "filename", filename)
	c.eventBus.Publish(events.MessageSentEvent(ctx, c.id, messageID, phoneNumber, caption))
	return messageID, nil
}

// sendMessage sends a message request to the Business API
func (c *Client) sendMessage(ctx context.Context, reqBody SendMessageRequest) (string, error) {
	url := fmt.Sprintf("https://graph.facebook.com/%s/%s/messages",
		c.config.APIVersion,
		c.config.PhoneNumberID)

	jsonData, err := json.Marshal(reqBody)
	if err != nil {
		return "", fmt.Errorf("failed to marshal request: %w", err)
	}

	req, err := http.NewRequestWithContext(ctx, "POST", url, bytes.NewBuffer(jsonData))
	if err != nil {
		return "", fmt.Errorf("failed to create request: %w", err)
	}

	req.Header.Set("Authorization", "Bearer "+c.config.AccessToken)
	req.Header.Set("Content-Type", "application/json")

	resp, err := c.httpClient.Do(req)
	if err != nil {
		return "", fmt.Errorf("failed to send request: %w", err)
	}
	defer resp.Body.Close()

	body, err := io.ReadAll(resp.Body)
	if err != nil {
		return "", fmt.Errorf("failed to read response: %w", err)
	}

	if resp.StatusCode != http.StatusOK {
		var errResp ErrorResponse
		if err := json.Unmarshal(body, &errResp); err == nil {
			return "", fmt.Errorf("API error: %s (code: %d)", errResp.Error.Message, errResp.Error.Code)
		}
		return "", fmt.Errorf("API returned status %d: %s", resp.StatusCode, string(body))
	}

	var sendResp SendMessageResponse
	if err := json.Unmarshal(body, &sendResp); err != nil {
		return "", fmt.Errorf("failed to parse response: %w", err)
	}

	if len(sendResp.Messages) == 0 {
		return "", fmt.Errorf("no message ID in response")
	}

	return sendResp.Messages[0].ID, nil
}

// jidToPhoneNumber converts a WhatsApp JID to E.164 phone number format
func jidToPhoneNumber(jid types.JID) string {
	// JID format is like "27123456789@s.whatsapp.net"
	// Extract the phone number part before @
	phone := jid.User

	// Ensure it starts with + for E.164
	if !strings.HasPrefix(phone, "+") {
		phone = "+" + phone
	}

	return phone
}