package handler

import (
	"net/http"
	"os"
	"path/filepath"
	"strings"

	"codeberg.org/VARASYS/ZDDC/zddc/internal/config"
)

// adminCustomCSSName is the on-disk filename a server operator places at
// the root to theme the admin pages. It deliberately uses the .admin.css
// suffix (not just custom.css) so it pattern-matches the .zddc / .admin
// reserved-prefix family, and so anyone scanning the root tree sees it
// is admin-related.
const adminCustomCSSName = ".admin.css"

// hasCustomAdminCSS reports whether <fsRoot>/.admin.css exists. The
// editor template uses this to conditionally inject the <link> tag.
func hasCustomAdminCSS(fsRoot string) bool {
	_, err := os.Stat(filepath.Join(fsRoot, adminCustomCSSName))
	return err == nil
}

// zddcAssetsPathPrefix is the URL prefix for admin-only static assets.
// They sit under /.admin/zddc/assets/ rather than /.admin/assets/ so
// they share the editor's broader auth gate (subtree-or-super-admin)
// instead of /.admin/'s super-admin-only gate — otherwise a subtree
// admin would 404 on the custom CSS link emitted by the editor page.
const zddcAssetsPathPrefix = ZddcAdminPathPrefix + "/assets"

// serveZddcAssets handles /.admin/zddc/assets/<file>. V1 only ships
// `custom.css` (passthrough of <root>/.admin.css when present); other
// paths return 404 so we don't accidentally expose arbitrary files.
// hasAnyAdminScope has already gated the request via ServeZddc.
func serveZddcAssets(cfg config.Config, w http.ResponseWriter, r *http.Request) {
	if r.Method != http.MethodGet {
		w.Header().Set("Allow", "GET")
		http.Error(w, "Method Not Allowed", http.StatusMethodNotAllowed)
		return
	}
	rest := strings.TrimPrefix(r.URL.Path, zddcAssetsPathPrefix+"/")
	switch rest {
	case "custom.css":
		path := filepath.Join(cfg.Root, adminCustomCSSName)
		fi, err := os.Stat(path)
		if err != nil || fi.IsDir() {
			http.NotFound(w, r)
			return
		}
		w.Header().Set("Content-Type", "text/css; charset=utf-8")
		w.Header().Set("Cache-Control", "no-cache")
		http.ServeFile(w, r, path)
	default:
		http.NotFound(w, r)
	}
}