package spa

import (
	"io"
	"io/fs"
	"net/http"
	"strings"
)

func tryToDeliverFile(file fs.File, path string, w http.ResponseWriter, r *http.Request) {
	fileSeeker, ok := file.(io.ReadSeeker)
	if !ok {
		file.Close()
		http.Error(w, "Index file does not implement ReadSeeker", http.StatusInternalServerError)
		return
	}
	stats, statErr := file.Stat()
	if statErr != nil {
		http.Error(w, "Cannot stat index file", http.StatusInternalServerError)
		return
	}
	contentType, contentTypeErr := detectContentType(file)
	if contentTypeErr != nil {
		contentType = "text/html"
	}
	contentType = getContentTypeDetail(contentType, stats)
	w.Header().Set("Content-Type", contentType)
	http.ServeContent(w, r, path, stats.ModTime(), fileSeeker)
}

func detectContentType(file fs.File) (string, error) {
	buffer := []byte{}
	_, err := file.Read(buffer)
	if err != nil {
		return "", err
	}
	return http.DetectContentType(buffer), nil
}

func getContentTypeDetail(contentType string, info fs.FileInfo) string {
	for ending, realContentType := range contentTypeMapping {
		if strings.HasSuffix(info.Name(), ending) {
			return realContentType
		}
	}
	return contentType
}