package webhook

// TwilioWebhookHandler processes incoming Twilio SMS webhook HTTP requests via Gin.
// Reference: Facebook webhook adapter pattern (facebook_webhook.go)
//
// URL patterns:
//   /webhooks/sms/:phone_number              — Chatwoot-compatible inbound SMS/MMS
//   /webhooks/twilio/sms/:phone_number       — legacy inbound SMS/MMS
//   /webhooks/twilio/status/:phone_number    — delivery status callbacks
//
// Method: POST (Twilio sends form-encoded data, not JSON)

import (
	"fmt"
	"net/http"
	"net/url"
	"strings"

	"github.com/gochat/gochat/internal/channel"
	twiliochannel "github.com/gochat/gochat/internal/channel/twilio"
	"github.com/gochat/gochat/internal/model"
	channelmodel "github.com/gochat/gochat/internal/model/channel"
	"github.com/gochat/gochat/internal/worker"
	applogger "github.com/gochat/gochat/pkg/logger"

	"github.com/gin-gonic/gin"
	"gorm.io/gorm"
)

// TwilioWebhookHandler processes Twilio SMS webhook requests via Gin.
type TwilioWebhookHandler struct {
	twilioWebhook *twiliochannel.WebhookHandler
	db            *gorm.DB
	persister     *IncomingPersister
}

func (h *TwilioWebhookHandler) WithWorkerPool(wp *worker.WorkerPool) *TwilioWebhookHandler {
	if h != nil && h.persister != nil {
		h.persister.SetWorkerPool(wp)
	}
	return h
}

// NewTwilioWebhookHandler creates a Twilio SMS webhook handler for Gin integration.
func NewTwilioWebhookHandler(twilioWebhook *twiliochannel.WebhookHandler, db *gorm.DB, dispatcher ...*channel.Dispatcher) *TwilioWebhookHandler {
	return &TwilioWebhookHandler{
		twilioWebhook: twilioWebhook,
		db:            db,
		persister:     NewIncomingPersister(db, dispatcher...),
	}
}

// HandleTwilioInboundSMS processes an incoming Twilio SMS webhook Gin request.
func (h *TwilioWebhookHandler) HandleTwilioInboundSMS(c *gin.Context) {
	phoneNumber := c.Param("phone_number")
	if phoneNumber == "" {
		applogger.L().Warn("Twilio webhook: missing phone_number in path")
		c.Data(http.StatusOK, "application/xml", []byte("<Response></Response>"))
		return
	}

	// Lookup inbox from database
	inbox, err := h.lookupInboxByPhoneNumber(phoneNumber)
	if err != nil {
		applogger.L().Warnf("Twilio webhook: inbox lookup failed for phone_number %s: %v", phoneNumber, err)
		c.Data(http.StatusOK, "application/xml", []byte("<Response></Response>"))
		return
	}

	incomingMsg, err := h.twilioWebhook.ProcessInboundSMS(c.Request, inbox)
	if err != nil {
		applogger.L().Errorf("Twilio webhook: process inbound SMS failed for inbox %d: %v", inbox.ID, err)
		c.Data(http.StatusOK, "application/xml", []byte("<Response></Response>"))
		return
	}
	if incomingMsg != nil {
		if _, persistErr := h.persister.PersistIncoming(c.Request.Context(), inbox, incomingMsg); persistErr != nil {
			applogger.L().Errorf("Twilio webhook: persist inbound SMS failed for inbox %d source_id=%s: %v", inbox.ID, incomingMsg.SourceID, persistErr)
		}
	}
	c.Data(http.StatusOK, "application/xml", []byte("<Response></Response>"))
}

// HandleTwilioCallback processes Chatwoot's root Twilio callback route.
// Reference: Chatwoot Twilio::CallbackController#create enqueues the event and
// always acknowledges with 204 No Content.
func (h *TwilioWebhookHandler) HandleTwilioCallback(c *gin.Context) {
	if err := c.Request.ParseForm(); err != nil {
		applogger.L().Errorf("Twilio callback: parse form failed: %v", err)
		c.Status(http.StatusNoContent)
		return
	}

	if h.twilioWebhook == nil {
		applogger.L().Warn("Twilio callback: Twilio webhook pipeline is not configured")
		c.Status(http.StatusNoContent)
		return
	}

	inbox, err := h.lookupCallbackInbox(c.Request.Form)
	if err != nil {
		applogger.L().Warnf("Twilio callback: inbox lookup failed: %v", err)
		c.Status(http.StatusNoContent)
		return
	}

	incomingMsg, err := h.twilioWebhook.ProcessInboundSMS(c.Request, inbox)
	if err != nil {
		applogger.L().Errorf("Twilio callback: process inbound SMS failed for inbox %d: %v", inbox.ID, err)
		c.Status(http.StatusNoContent)
		return
	}
	if incomingMsg != nil {
		if _, persistErr := h.persister.PersistIncoming(c.Request.Context(), inbox, incomingMsg); persistErr != nil {
			applogger.L().Errorf("Twilio callback: persist inbound SMS failed for inbox %d source_id=%s: %v", inbox.ID, incomingMsg.SourceID, persistErr)
		}
	}
	c.Status(http.StatusNoContent)
}

// HandleTwilioDeliveryStatus processes a Twilio delivery status callback.
func (h *TwilioWebhookHandler) HandleTwilioDeliveryStatus(c *gin.Context) {
	phoneNumber := c.Param("phone_number")
	if err := c.Request.ParseForm(); err != nil {
		applogger.L().Errorf("Twilio status webhook: parse form failed: %v", err)
		c.Status(http.StatusNoContent)
		return
	}

	var inbox *model.Inbox
	var err error
	if phoneNumber != "" {
		inbox, err = h.lookupInboxByPhoneNumber(phoneNumber)
	} else {
		inbox, err = h.lookupDeliveryStatusInbox(c.Request.Form)
	}
	if err != nil {
		applogger.L().Warnf("Twilio status webhook: inbox lookup failed: %v", err)
		c.Status(http.StatusNoContent)
		return
	}
	messageSID := c.Request.FormValue("MessageSid")
	messageStatus := c.Request.FormValue("MessageStatus")
	if mapped, ok := mapTwilioMessageStatus(messageStatus); ok {
		if err := h.persister.UpdateMessageStatusWithError(c.Request.Context(), inbox, messageSID, mapped, nil, twilioExternalError(c.Request.FormValue("ErrorCode"), c.Request.FormValue("ErrorMessage"), messageStatus)); err != nil {
			applogger.L().Errorf("Twilio status webhook: status persistence failed for inbox %d sid=%s status=%s: %v", inbox.ID, messageSID, messageStatus, err)
		}
	}
	c.Status(http.StatusNoContent)
}

func twilioExternalError(errorCode, errorMessage, status string) string {
	if errorCode == "" || (status != "failed" && status != "undelivered") {
		return ""
	}
	if errorMessage != "" {
		return fmt.Sprintf("%s - %s", errorCode, errorMessage)
	}
	return fmt.Sprintf("Twilio delivery failed with error code %s", errorCode)
}

func (h *TwilioWebhookHandler) lookupDeliveryStatusInbox(params url.Values) (*model.Inbox, error) {
	if h.db == nil {
		return nil, fmt.Errorf("twilio webhook database is not configured")
	}
	var twilioChannel channelmodel.ChannelTwilioSMS
	query := h.db
	if sid := params.Get("MessagingServiceSid"); sid != "" {
		query = query.Where(&channelmodel.ChannelTwilioSMS{MessagingServiceSID: sid})
	} else if accountSID, from := params.Get("AccountSid"), params.Get("From"); accountSID != "" && from != "" {
		query = query.Where(&channelmodel.ChannelTwilioSMS{AccountSID: accountSID, PhoneNumber: from})
	} else {
		return nil, fmt.Errorf("delivery status missing MessagingServiceSid or AccountSid/From")
	}
	if err := query.First(&twilioChannel).Error; err != nil {
		return nil, err
	}
	var inbox model.Inbox
	if err := h.db.Where("id = ? AND channel_type IN ?", twilioChannel.InboxID, []string{"twilio_sms", "sms"}).First(&inbox).Error; err != nil {
		return nil, err
	}
	return &inbox, nil
}

func (h *TwilioWebhookHandler) lookupCallbackInbox(params url.Values) (*model.Inbox, error) {
	if h.db == nil {
		return nil, fmt.Errorf("twilio webhook database is not configured")
	}
	var twilioChannel channelmodel.ChannelTwilioSMS
	query := h.db
	if phone := normalizeTwilioPhone(params.Get("To")); phone != "" {
		if accountSID := params.Get("AccountSid"); accountSID != "" {
			query = query.Where(&channelmodel.ChannelTwilioSMS{AccountSID: accountSID, PhoneNumber: phone})
		} else {
			query = query.Where(&channelmodel.ChannelTwilioSMS{PhoneNumber: phone})
		}
	} else if sid := params.Get("MessagingServiceSid"); sid != "" {
		query = query.Where(&channelmodel.ChannelTwilioSMS{MessagingServiceSID: sid})
	} else {
		return nil, fmt.Errorf("twilio callback missing To or MessagingServiceSid")
	}
	if err := query.First(&twilioChannel).Error; err != nil {
		return nil, err
	}
	var inbox model.Inbox
	if err := h.db.Where("id = ? AND channel_type IN ?", twilioChannel.InboxID, []string{"twilio_sms", "sms"}).First(&inbox).Error; err != nil {
		return nil, err
	}
	return &inbox, nil
}

func normalizeTwilioPhone(phone string) string {
	phone = strings.TrimSpace(phone)
	if phone == "" {
		return ""
	}
	if strings.HasPrefix(phone, "+") {
		return phone
	}
	return "+" + phone
}

func mapTwilioMessageStatus(status string) (model.MessageStatus, bool) {
	switch status {
	case "sent", "queued", "accepted", "sending":
		return model.MessageStatusSent, true
	case "delivered":
		return model.MessageStatusDelivered, true
	case "read":
		return model.MessageStatusRead, true
	case "undelivered", "failed":
		return model.MessageStatusFailed, true
	default:
		return "", false
	}
}

// lookupInbox fetches an Inbox record from the database.
func (h *TwilioWebhookHandler) lookupInbox(inboxID uint) (*model.Inbox, error) {
	var inbox model.Inbox
	if err := h.db.Where("id = ?", inboxID).First(&inbox).Error; err != nil {
		return nil, err
	}
	return &inbox, nil
}

// lookupInboxByPhoneNumber fetches an Inbox through the Twilio SMS channel record.
// Chatwoot exposes /webhooks/sms/:phone_number and routes by the phone number.
func (h *TwilioWebhookHandler) lookupInboxByPhoneNumber(phoneNumber string) (*model.Inbox, error) {
	if h.db == nil {
		return nil, fmt.Errorf("twilio webhook database is not configured")
	}

	var channel channelmodel.ChannelTwilioSMS
	if err := h.db.Where("phone_number = ?", phoneNumber).First(&channel).Error; err != nil {
		return nil, fmt.Errorf("twilio sms channel not found for phone_number=%s: %w", phoneNumber, err)
	}

	var inbox model.Inbox
	if err := h.db.Where("id = ? AND channel_type IN ?", channel.InboxID, []string{"twilio_sms", "sms"}).First(&inbox).Error; err != nil {
		return nil, fmt.Errorf("twilio inbox not found for channel inbox_id=%d: %w", channel.InboxID, err)
	}
	return &inbox, nil
}