package utils

import (
	"fmt"
	"os"
	"os/exec"
	"runtime/debug"
	"strings"
	"syscall"

	"github.com/spf13/cobra"
)

var (
	Version       = "dev"
	RepositoryURL = "git@45.38.20.139:repos/dborg.git"
)

func init() {
	if Version == "dev" {
		if info, ok := debug.ReadBuildInfo(); ok {
			if info.Main.Version != "" && info.Main.Version != "(devel)" {
				Version = info.Main.Version
			}
		}
	}
}

func CheckForUpdates(cmd *cobra.Command) error {
	if !isTerminal() {
		return nil
	}

	latestVersion, err := getLatestRemoteTag()
	if err != nil {
		return nil
	}

	if latestVersion == "" || latestVersion == Version {
		return nil
	}

	if isNewerVersion(latestVersion, Version) {
		promptAndUpdate(latestVersion)
	}

	return nil
}

func getLatestRemoteTag() (string, error) {
	cmd := exec.Command("git", "ls-remote", "--tags", "--refs", "--sort=-v:refname", RepositoryURL)
	output, err := cmd.Output()
	if err != nil {
		return "", err
	}

	lines := strings.Split(strings.TrimSpace(string(output)), "\n")
	if len(lines) == 0 {
		return "", fmt.Errorf("no tags found")
	}

	parts := strings.Split(lines[0], "refs/tags/")
	if len(parts) < 2 {
		return "", fmt.Errorf("invalid tag format")
	}

	return strings.TrimSpace(parts[1]), nil
}

func isNewerVersion(remote, local string) bool {
	if local == "dev" || local == "(devel)" {
		return false
	}

	remote = strings.TrimPrefix(remote, "v")
	local = strings.TrimPrefix(local, "v")

	if remote == local {
		return false
	}

	remoteParts := strings.Split(remote, ".")
	localParts := strings.Split(local, ".")

	for i := 0; i < len(remoteParts) && i < len(localParts); i++ {
		if remoteParts[i] > localParts[i] {
			return true
		}
		if remoteParts[i] < localParts[i] {
			return false
		}
	}

	return len(remoteParts) > len(localParts)
}

func promptAndUpdate(newVersion string) {
	fmt.Fprintf(os.Stderr, "\n🔔 A new version of dborg is available: %s (current: %s)\n", newVersion, Version)
	fmt.Fprintf(os.Stderr, "Would you like to update now? [Y/n]: ")

	var response string
	fmt.Scanln(&response)

	response = strings.ToLower(strings.TrimSpace(response))
	if response != "" && response != "y" && response != "yes" {
		fmt.Fprintf(os.Stderr, "Update skipped. Run 'go install git.db.org.ai/dborg@%s' to update manually.\n\n", newVersion)
		return
	}

	fmt.Fprintf(os.Stderr, "Updating to %s...\n", newVersion)

	installTarget := fmt.Sprintf("git.db.org.ai/dborg@%s", newVersion)
	installCmd := exec.Command("go", "install", installTarget)
	installCmd.Stdout = os.Stderr
	installCmd.Stderr = os.Stderr

	if err := installCmd.Run(); err != nil {
		fmt.Fprintf(os.Stderr, "Failed to update: %v\n", err)
		fmt.Fprintf(os.Stderr, "Please update manually: go install git.db.org.ai/dborg@%s\n\n", newVersion)
		return
	}

	fmt.Fprintf(os.Stderr, "✓ Update successful! Restarting...\n\n")

	restartSelf()
}

func restartSelf() {
	executable, err := os.Executable()
	if err != nil {
		fmt.Fprintf(os.Stderr, "Failed to get executable path: %v\n", err)
		os.Exit(1)
	}

	args := os.Args[1:]

	err = syscall.Exec(executable, append([]string{executable}, args...), os.Environ())
	if err != nil {
		fmt.Fprintf(os.Stderr, "Failed to restart: %v\n", err)
		os.Exit(1)
	}
}

func isTerminal() bool {
	fileInfo, err := os.Stdout.Stat()
	if err != nil {
		return false
	}
	return (fileInfo.Mode() & os.ModeCharDevice) != 0
}