package sync

import (
	"bufio"
	"encoding/base32"
	"os"
	"path"
	"regexp"
	"strings"

	"srs.epita.fr/fic-server/libfic"

	"golang.org/x/crypto/blake2b"
	"gopkg.in/russross/blackfriday.v2"
)

func ProcessMarkdown(i Importer, input string, rootDir string) (output string, err error) {
	// Define the path where save linked files
	hash := blake2b.Sum512([]byte(rootDir))
	absPath := "$FILES$/" + strings.ToLower(base32.StdEncoding.WithPadding(base32.NoPadding).EncodeToString(hash[:]))

	// Process md
	output = string(blackfriday.Run(
		[]byte(input),
		blackfriday.WithRenderer(blackfriday.NewHTMLRenderer(
			blackfriday.HTMLRendererParameters{
				AbsolutePrefix: absPath,
				Flags: blackfriday.CommonHTMLFlags,
			},
		)),
	))

	// Import files
	var re *regexp.Regexp
	re, err = regexp.Compile(strings.Replace(absPath, "$", "\\$", -1) + "/[^\"]+")
	if err != nil {
		return
	}
	files := re.FindAllString(output, -1)

	for _, filePath := range files {
		iPath := strings.TrimPrefix(filePath, absPath)
		dPath := path.Join(fic.FilesDir, strings.ToLower(base32.StdEncoding.WithPadding(base32.NoPadding).EncodeToString(hash[:])), iPath)

		if err = os.MkdirAll(path.Dir(dPath), 0755); err != nil {
			return
		}

		var fdto *os.File
		if fdto, err = os.Create(dPath); err != nil {
			return
		} else {
			defer fdto.Close()
			writer := bufio.NewWriter(fdto)
			if err = getFile(i, rootDir + iPath, writer); err != nil {
				os.Remove(dPath)
				return
			}
		}
	}

	// Trim output
	output = strings.TrimSpace(output)

	return
}