// Package api holds the sitemap plugin's HTTP handlers outside the admin:
// the IndexNow key file, the HTML sitemap API and the management API.
package api

import (
	"net/http"

	"git.golem15.com/golem15/sm-sitemap-plugin/classes"
	"git.golem15.com/golem15/summercms/modules/backpack"
	"gorm.io/gorm"
)

// KeyFilePattern is the {file} constraint of the key file route: an
// IndexNow key file name, <key>.txt.
const KeyFilePattern = `[A-Za-z0-9-]{8,128}\.txt`

// KeyFile serves GET /_sitemap/indexnow/{file}: the IndexNow key as
// text/plain when IndexNow is on and file is <key>.txt; any other name, a
// replaced key or IndexNow off answers 404 (D-31). The SEO layer serves it
// at the site root.
func KeyFile(app func() *backpack.App) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		a := app()
		if a == nil {
			http.NotFound(w, r)
			return
		}
		db, ok := a.Lookup[*gorm.DB]()
		if !ok || db == nil {
			http.Error(w, "Internal Server Error", http.StatusInternalServerError)
			return
		}
		settings, err := classes.LoadSettings(db.WithContext(r.Context()))
		if err != nil {
			http.Error(w, "Internal Server Error", http.StatusInternalServerError)
			return
		}
		key := classes.ActiveKey(settings)
		if key == "" || r.PathValue("file") != classes.KeyFileName(key) {
			http.NotFound(w, r)
			return
		}
		w.Header().Set("Content-Type", "text/plain; charset=utf-8")
		w.Header().Set("Cache-Control", "no-cache, private")
		w.Header().Set("X-Robots-Tag", "noindex")
		w.WriteHeader(http.StatusOK)
		_, _ = w.Write([]byte(key))
	}
}