package handlers

import (
	"io"
	"net/http"

	"github.com/go-chi/chi/v5"

	"sneak.berlin/go/upaas/internal/models"
	"sneak.berlin/go/upaas/internal/service/audit"
)

// maxWebhookBodySize is the maximum allowed size of a webhook request body (1MB).
const maxWebhookBodySize = 1 << 20

// HandleWebhook handles incoming Gitea webhooks.
func (h *Handlers) HandleWebhook() http.HandlerFunc { //nolint:funlen // audit logging adds necessary length
	return func(writer http.ResponseWriter, request *http.Request) {
		secret := chi.URLParam(request, "secret")
		if secret == "" {
			http.NotFound(writer, request)

			return
		}

		// Find app by webhook secret
		application, findErr := models.FindAppByWebhookSecret(
			request.Context(),
			h.db,
			secret,
		)
		if findErr != nil {
			h.log.Error("failed to find app by webhook secret", "error", findErr)
			http.Error(writer, "Internal Server Error", http.StatusInternalServerError)

			return
		}

		if application == nil {
			http.NotFound(writer, request)

			return
		}

		// Read request body with size limit to prevent memory exhaustion
		body, readErr := io.ReadAll(io.LimitReader(request.Body, maxWebhookBodySize))
		if readErr != nil {
			h.log.Error("failed to read webhook body", "error", readErr)
			http.Error(writer, "Bad Request", http.StatusBadRequest)

			return
		}

		// Get event type from header
		eventType := request.Header.Get("X-Gitea-Event")
		if eventType == "" {
			eventType = "push"
		}

		// Log webhook receipt
		h.audit.LogFromRequest(request.Context(), request, audit.LogEntry{
			Username:     "webhook",
			Action:       models.AuditActionWebhookReceive,
			ResourceType: models.AuditResourceWebhook,
			ResourceID:   application.ID,
			Detail:       "webhook from app: " + application.Name + ", event: " + eventType,
		})

		// Process webhook
		webhookErr := h.webhook.HandleWebhook(
			request.Context(),
			application,
			eventType,
			body,
		)
		if webhookErr != nil {
			h.log.Error("failed to process webhook", "error", webhookErr)
			http.Error(writer, "Internal Server Error", http.StatusInternalServerError)

			return
		}

		writer.WriteHeader(http.StatusOK)
	}
}