package api

import (
	"io/fs"
	"mime"
	"net/http"
	"os"
	"path/filepath"
	"strings"
)

// defaultFavicon is served when no favicon_path is configured.
var defaultFavicon []byte

// SetDefaultFavicon sets the fallback favicon bytes (called at startup from
// the embedded web build so the binary doesn't embed a second copy).
func SetDefaultFavicon(data []byte) {
	defaultFavicon = data
}

// InitDefaultFavicon reads the favicon from the embedded web build so it can
// be served as the fallback for /favicon without an extra embedded copy.
func InitDefaultFavicon(webFS fs.FS) error {
	sub, err := fs.Sub(webFS, "web/build")
	if err != nil {
		return nil
	}
	data, err := fs.ReadFile(sub, "favicon.svg")
	if err != nil {
		return nil
	}
	SetDefaultFavicon(data)
	return nil
}

func (a *API) HandleFavicon(w http.ResponseWriter, r *http.Request) {
	if a.Cfg.Server.FaviconPath != "" {
		serveFile(w, r, a.Cfg.Server.FaviconPath)
		return
	}
	if len(defaultFavicon) > 0 {
		w.Header().Set("Content-Type", "image/svg+xml")
		w.Header().Set("Cache-Control", "public, max-age=86400")
		w.Write(defaultFavicon)
		return
	}
	http.NotFound(w, r)
}

func (a *API) HandleLogo(w http.ResponseWriter, r *http.Request) {
	if a.Cfg.Server.LogoPath != "" {
		serveFile(w, r, a.Cfg.Server.LogoPath)
		return
	}
	http.NotFound(w, r)
}

func serveFile(w http.ResponseWriter, r *http.Request, path string) {
	ext := strings.ToLower(filepath.Ext(path))
	mimeType := mime.TypeByExtension(ext)
	if mimeType == "" {
		switch ext {
		case ".svg":
			mimeType = "image/svg+xml"
		case ".ico":
			mimeType = "image/x-icon"
		default:
			mimeType = "application/octet-stream"
		}
	}

	f, err := os.Open(path)
	if err != nil {
		if os.IsNotExist(err) {
			http.NotFound(w, r)
		} else {
			http.Error(w, "internal error", http.StatusInternalServerError)
		}
		return
	}
	defer f.Close()

	stat, err := f.Stat()
	if err != nil {
		http.Error(w, "internal error", http.StatusInternalServerError)
		return
	}

	w.Header().Set("Content-Type", mimeType)
	w.Header().Set("Cache-Control", "public, max-age=86400")
	http.ServeContent(w, r, filepath.Base(path), stat.ModTime(), f)
}