// Package webhook provides Gin-compatible HTTP handler adapters for external
// channel webhook endpoints. Each adapter wraps the corresponding channel
// sub-package's WebhookHandler and exposes methods that can be bound directly
// to Gin router groups.
package webhook

import (
	"context"
	"time"

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

	"github.com/gochat/gochat/internal/channel"
	"github.com/gochat/gochat/internal/channel/whatsapp"
	"github.com/gochat/gochat/internal/model"
)

// WhatsAppWebhookHandler is a Gin adapter that wraps the WhatsApp
// sub-package's WebhookHandler. It translates Gin context calls into the
// underlying handler methods so that WhatsApp webhook routes can be registered
// on a Gin engine with minimal glue code.
//
// Chatwoot-style routes:
//
//	GET  /webhooks/whatsapp/:phone_number        → HandleWhatsAppVerification
//	POST /webhooks/whatsapp/:phone_number        → HandleWhatsAppWebhook
//
// WhatsApp Cloud API webhook verification (GET):
//
//	The Meta platform sends a GET request with query parameters:
//	  - hub.mode          = "subscribe"
//	  - hub.verify_token  = the token configured in the Meta dashboard
//	  - hub.challenge     = a string the endpoint must echo back verbatim
//
//	The handler validates hub.verify_token against the stored token and
//	returns hub.challenge as the response body with HTTP 200, or returns
//	HTTP 403 on mismatch.
//
// WhatsApp Cloud API webhook events (POST):
//
//	Meta delivers event payloads as JSON with structure:
//	  {
//	    "object": "whatsapp_business_account",
//	    "entry": [ { "changes": [ ... ] } ]
//	  }
//
//	The handler parses the payload, dispatches incoming messages and status
//	updates, and must respond with HTTP 200 OK within 10 seconds to avoid
//	Meta retrying delivery.
type WhatsAppWebhookHandler struct {
	provider  *whatsapp.WhatsAppProvider
	waWebhook *whatsapp.WebhookHandler
	persister *IncomingPersister
}

// NewWhatsAppWebhookHandler creates a Gin adapter wrapping the WhatsApp
// sub-package's WebhookHandler. The provider is stored for future use (e.g.
// health checks or direct API calls) while waWebhook is the core handler that
// processes verification and event requests.
func NewWhatsAppWebhookHandler(provider *whatsapp.WhatsAppProvider, waWebhook *whatsapp.WebhookHandler, db *gorm.DB, dispatcher ...*channel.Dispatcher) *WhatsAppWebhookHandler {
	h := &WhatsAppWebhookHandler{
		provider:  provider,
		waWebhook: waWebhook,
		persister: NewIncomingPersister(db, dispatcher...),
	}
	if waWebhook != nil && h.persister != nil {
		waWebhook.SetIncomingPersister(whatsAppPersisterAdapter{persister: h.persister})
	}
	return h
}

type whatsAppPersisterAdapter struct {
	persister *IncomingPersister
}

func (a whatsAppPersisterAdapter) PersistIncoming(ctx context.Context, inbox *model.Inbox, msg *channel.IncomingMessage) (interface{}, error) {
	return a.persister.PersistIncoming(ctx, inbox, msg)
}

func (a whatsAppPersisterAdapter) UpdateMessageStatus(ctx context.Context, inbox *model.Inbox, sourceID string, status model.MessageStatus, occurredAt *time.Time) error {
	return a.persister.UpdateMessageStatus(ctx, inbox, sourceID, status, occurredAt)
}

// HandleWhatsAppVerification handles GET requests for WhatsApp Cloud API
// webhook verification. Meta sends this request during initial webhook setup
// and periodic re-verification. It delegates to the underlying
// waWebhook.HandleVerification method which validates hub.verify_token and
// echoes hub.challenge on success.
//
// Expected Gin route: GET /webhooks/whatsapp/:phone_number
func (h *WhatsAppWebhookHandler) HandleWhatsAppVerification(c *gin.Context) {
	h.waWebhook.HandleVerification(c)
}

// HandleWhatsAppWebhook handles POST requests carrying WhatsApp Cloud API
// event payloads (messages, status updates, template events, etc.). It
// delegates to the underlying waWebhook.HandleWebhookEvent method which
// parses the JSON body and dispatches events to the appropriate processor.
//
// The endpoint must respond with HTTP 200 OK within 10 seconds; Meta retries
// delivery on timeout or non-200 responses.
//
// Expected Gin route: POST /webhooks/whatsapp/:phone_number
func (h *WhatsAppWebhookHandler) HandleWhatsAppWebhook(c *gin.Context) {
	h.waWebhook.HandleWebhookEvent(c)
}