package main

import (
	"fmt"
	"io"
	"net/http"
	"os"
	"strings"
	"time"
)

func parseVersion(v string) [3]int {
	var t [3]int
	for i, p := range strings.SplitN(strings.TrimSpace(v), ".", 3) {
		fmt.Sscanf(p, "%d", &t[i])
	}
	return t
}

func versionGreater(remote, local string) bool {
	r, l := parseVersion(remote), parseVersion(local)
	for i := 0; i < 3; i++ {
		if r[i] > l[i] {
			return true
		}
		if r[i] < l[i] {
			return false
		}
	}
	return false
}

func checkSelfUpdate(cfg SelfUpdateConfig) (needsUpdate bool, info string, err error) {
	if cfg.URL == "" {
		return false, "", nil
	}
	url := fmt.Sprintf("%s/raw/branch/%s/version.txt", cfg.URL, cfg.Branch)
	client := &http.Client{Timeout: 10 * time.Second}
	resp, err := client.Get(url)
	if err != nil {
		return false, "", err
	}
	defer resp.Body.Close()
	data, _ := io.ReadAll(resp.Body)
	remote := strings.TrimSpace(string(data))
	if !versionGreater(remote, VERSION) {
		return false, "", nil
	}
	return true, fmt.Sprintf("Version actuelle : %s\nVersion disponible : %s", VERSION, remote), nil
}

func doSelfUpdate(cfg SelfUpdateConfig) error {
	exePath, err := os.Executable()
	if err != nil {
		return err
	}
	newPath := exePath + ".new"
	oldPath := exePath + ".old"

	url := fmt.Sprintf("%s/raw/branch/%s/%s", cfg.URL, cfg.Branch, cfg.ExeName)
	client := &http.Client{Timeout: 120 * time.Second}
	resp, err := client.Get(url)
	if err != nil {
		return err
	}
	defer resp.Body.Close()

	f, err := os.Create(newPath)
	if err != nil {
		return err
	}
	n, copyErr := io.Copy(f, resp.Body)
	f.Close()
	if copyErr != nil {
		os.Remove(newPath)
		return copyErr
	}
	if n < 1000 {
		os.Remove(newPath)
		return fmt.Errorf("fichier telecharge invalide (%d octets)", n)
	}

	// Supprimer le Mark of the Web (Zone.Identifier)
	os.Remove(newPath + ":Zone.Identifier")

	if err := os.Rename(exePath, oldPath); err != nil {
		os.Remove(newPath)
		return err
	}
	if err := os.Rename(newPath, exePath); err != nil {
		os.Rename(oldPath, exePath) // restaurer
		return err
	}
	return nil
}