feat: implement automatic update check

Author: yplog

internal/update/update.go

@@ -1,11 +1,82 @@
 package update
 
 import (
+	"encoding/json"
+	"fmt"
+	"io"
+	"net/http"
 	"os"
 	"os/exec"
+	"strings"
+
+	"github.com/yplog/memotty/internal/ui"
 )
 
+type GitHubRelease struct {
+	TagName string `json:"tag_name"`
+}
+
+func getLatestVersion() (string, error) {
+	resp, err := http.Get("https://api.github.com/repos/yplog/memotty/releases/latest")
+	if err != nil {
+		return "", fmt.Errorf("failed to fetch latest release: %w", err)
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode != http.StatusOK {
+		return "", fmt.Errorf("GitHub API returned status: %d", resp.StatusCode)
+	}
+
+	body, err := io.ReadAll(resp.Body)
+	if err != nil {
+		return "", fmt.Errorf("failed to read response: %w", err)
+	}
+
+	var release GitHubRelease
+	if err := json.Unmarshal(body, &release); err != nil {
+		return "", fmt.Errorf("failed to parse JSON: %w", err)
+	}
+
+	return release.TagName, nil
+}
+
+func normalizeVersion(version string) string {
+	return strings.TrimPrefix(version, "v")
+}
+
 func Run() error {
+	fmt.Println("🔍 Checking for updates...")
+
+	currentVersion := ui.GetVersionInfo()
+	currentVersionClean := normalizeVersion(strings.TrimPrefix(currentVersion, "memotty "))
+
+	if currentVersionClean == "dev" {
+		fmt.Println("Development version detected, proceeding with update...")
+		return runInstallScript()
+	}
+
+	latestVersion, err := getLatestVersion()
+	if err != nil {
+		fmt.Printf("Could not check latest version: %v\n", err)
+		fmt.Println("Proceeding with update anyway...")
+		return runInstallScript()
+	}
+
+	latestVersionClean := normalizeVersion(latestVersion)
+
+	fmt.Printf("Current version: %s\n", currentVersionClean)
+	fmt.Printf("Latest version: %s\n", latestVersionClean)
+
+	if currentVersionClean >= latestVersionClean {
+		fmt.Println("Already up to date! No update needed.")
+		return nil
+	}
+
+	fmt.Printf("Updating from %s to %s...\n", currentVersionClean, latestVersionClean)
+	return runInstallScript()
+}
+
+func runInstallScript() error {
 	cmd := exec.Command("bash", "-c", "curl -fsSL https://raw.githubusercontent.com/yplog/memotty/main/scripts/install.sh | bash")
 	cmd.Stdout = os.Stdout
 	cmd.Stderr = os.Stderr