package main

import (
	"fmt"
	"io/fs"
	"io/ioutil"
	"log"
	"os"
	"strconv"
	"strings"
	"time"

	"github.com/codingsince1985/checksum"
)

func generate_manifest(dir string) error {
	files, err := get_files(dir)
	if err != nil {
		log.Println("Error reading Image Files in folder: ", dir)
		return err
	}
	file_struct := split_filenames(files, dir)
	build_manifest(file_struct, dir)
	return err
}

func get_files(dir string) ([]fs.FileInfo, error) {
	files, err := ioutil.ReadDir(dir)
	if err != nil {
		return nil, err
	}
	return files, nil
}

func split_filenames(files []fs.FileInfo, dir string) []Files {
	var data []Files
	for i := range files {
		current_name := files[i].Name()
		split := strings.Split(current_name, "-")
		split_name := len(split) - 1
		// Routername
		router_name := strings.Join(split[5:split_name], "-")
		//RELEASE
		router_release := strings.Join(split[3:5], "-")
		//Checksum
		sha256, _ := checksum.SHA256sum(dir + "/" + current_name)
		//FileSize
		filesize := files[i].Size()
		//Build Struct
		data = append(data, Files{Model: router_name, Name: current_name, Release: router_release, Checksum: sha256, Size: filesize})
	}
	return data
}

func build_manifest(files []Files, dir string) error {
	// Datei zum Schreiben öffnen
	release := strings.Split(files[0].Release, "-")
	file, err := os.Create(dir + release[0] + ".manifest")
	if err != nil {
		fmt.Println("error creating manifest file")
		return err
	}
	defer file.Close()

	// Aktuelles Datum und Uhrzeit abrufen
	now := time.Now()
	// Datum im gewünschten Format formatieren
	formatted := now.Format("2006-01-02 15:04:05-07:00")

	branch_line := "BRANCH=" + release[0] + "\n"
	date_line := "DATE=" + formatted + "\n"
	prio_line := "PRIORITY=0" + "\n"

	// Zeilen Schreiben
	// Header
	_, err = file.WriteString(branch_line)
	if err != nil {
		return err
	}
	_, err = file.WriteString(date_line)
	if err != nil {
		return err
	}
	_, err = file.WriteString(prio_line)
	if err != nil {
		return err
	}
	_, err = file.WriteString("\n")
	if err != nil {
		return err
	}

	// Router Lines
	for i := range files {
		size_str := strconv.Itoa(int(files[i].Size))
		line := files[i].Model + " " + files[i].Release + " " + files[i].Checksum + " " + size_str + " " + files[i].Name + "\n"
		_, err := file.WriteString(line)
		if err != nil {
			return err
		}
	}
	log.Println("Manifest file " + release[0] + ".manifest" + " generated")
	return err
}