package spa_handler

import (
	"bytes"
	"fmt"
	"io"
	"io/fs"
	"net/http"
	"strings"
	"time"
)

func tryToDeliverFile(file fs.File, path string, w http.ResponseWriter, r *http.Request, appender ...string) {
	content, err := io.ReadAll(file)
	if err != nil {
		file.Close()
		http.Error(w, "can not read file", http.StatusInternalServerError)
		return
	}
	merge := bytes.NewBuffer([]byte{})
	for _, a := range appender {
		merge.WriteString(a)
	}
	newContent := strings.Replace(string(content), "</html>", fmt.Sprintf("%s\n</html>", merge.String()), 1)

	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)

	fileSeeker := bytes.NewReader([]byte(newContent))
	w.Header().Set("Content-Type", contentType)
	http.ServeContent(w, r, path, time.Now(), 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
}