package commands

import (
	"fmt"
	"os"
	"os/exec"
	"path/filepath"
	"strconv"
	"syscall"

	"git.dws.rip/DWS/onyx/internal/core"
	"github.com/spf13/cobra"
)

// NewDaemonCmd creates the daemon command with start, stop, and status subcommands
func NewDaemonCmd() *cobra.Command {
	cmd := &cobra.Command{
		Use:   "daemon",
		Short: "Manage the Onyx daemon for transparent versioning",
		Long: `The daemon command controls the Onyx background daemon that monitors
your repository for changes and automatically creates snapshots.`,
	}

	cmd.AddCommand(newDaemonStartCmd())
	cmd.AddCommand(newDaemonStopCmd())
	cmd.AddCommand(newDaemonStatusCmd())

	return cmd
}

// newDaemonStartCmd creates the daemon start subcommand
func newDaemonStartCmd() *cobra.Command {
	return &cobra.Command{
		Use:   "start",
		Short: "Start the Onyx daemon",
		Long:  `Starts the Onyx daemon in the background to monitor the repository.`,
		RunE:  runDaemonStart,
	}
}

// newDaemonStopCmd creates the daemon stop subcommand
func newDaemonStopCmd() *cobra.Command {
	return &cobra.Command{
		Use:   "stop",
		Short: "Stop the Onyx daemon",
		Long:  `Gracefully stops the running Onyx daemon.`,
		RunE:  runDaemonStop,
	}
}

// newDaemonStatusCmd creates the daemon status subcommand
func newDaemonStatusCmd() *cobra.Command {
	return &cobra.Command{
		Use:   "status",
		Short: "Check the Onyx daemon status",
		Long:  `Checks if the Onyx daemon is running and displays its status.`,
		RunE:  runDaemonStatus,
	}
}

// runDaemonStart starts the daemon in the background
func runDaemonStart(cmd *cobra.Command, args []string) error {
	// Get current directory
	cwd, err := os.Getwd()
	if err != nil {
		return fmt.Errorf("failed to get current directory: %w", err)
	}

	// Check if this is an Onyx repository
	if !core.IsOnyxRepo(cwd) {
		return fmt.Errorf("not an Onyx repository")
	}

	// Open repository to get .onx path
	repo, err := core.Open(cwd)
	if err != nil {
		return fmt.Errorf("failed to open repository: %w", err)
	}
	defer repo.Close()

	pidFile := filepath.Join(repo.GetOnyxPath(), "daemon.pid")

	// Check if daemon is already running
	if isDaemonRunning(pidFile) {
		return fmt.Errorf("daemon is already running")
	}

	// Find the onxd binary
	onxdPath, err := exec.LookPath("onxd")
	if err != nil {
		// Try to find it in the same directory as onx
		onxPath, err := os.Executable()
		if err != nil {
			return fmt.Errorf("failed to locate onxd binary: %w", err)
		}
		onxdPath = filepath.Join(filepath.Dir(onxPath), "onxd")
		if _, err := os.Stat(onxdPath); err != nil {
			return fmt.Errorf("onxd binary not found. Please ensure it's installed")
		}
	}

	// Start the daemon in the background
	daemonCmd := exec.Command(onxdPath, "--repo", cwd)
	daemonCmd.Stdout = nil
	daemonCmd.Stderr = nil
	daemonCmd.SysProcAttr = &syscall.SysProcAttr{
		Setsid: true, // Create new session
	}

	if err := daemonCmd.Start(); err != nil {
		return fmt.Errorf("failed to start daemon: %w", err)
	}

	// Detach the process
	if err := daemonCmd.Process.Release(); err != nil {
		return fmt.Errorf("failed to release daemon process: %w", err)
	}

	fmt.Println("Onyx daemon started successfully")
	return nil
}

// runDaemonStop stops the running daemon
func runDaemonStop(cmd *cobra.Command, args []string) error {
	// Get current directory
	cwd, err := os.Getwd()
	if err != nil {
		return fmt.Errorf("failed to get current directory: %w", err)
	}

	// Check if this is an Onyx repository
	if !core.IsOnyxRepo(cwd) {
		return fmt.Errorf("not an Onyx repository")
	}

	// Open repository to get .onx path
	repo, err := core.Open(cwd)
	if err != nil {
		return fmt.Errorf("failed to open repository: %w", err)
	}
	defer repo.Close()

	pidFile := filepath.Join(repo.GetOnyxPath(), "daemon.pid")

	// Read PID from file
	pid, err := readPIDFile(pidFile)
	if err != nil {
		if os.IsNotExist(err) {
			return fmt.Errorf("daemon is not running (no PID file found)")
		}
		return fmt.Errorf("failed to read PID file: %w", err)
	}

	// Check if process exists
	process, err := os.FindProcess(pid)
	if err != nil {
		return fmt.Errorf("failed to find daemon process: %w", err)
	}

	// Send SIGTERM to gracefully stop the daemon
	if err := process.Signal(syscall.SIGTERM); err != nil {
		return fmt.Errorf("failed to stop daemon: %w", err)
	}

	fmt.Println("Onyx daemon stopped successfully")
	return nil
}

// runDaemonStatus checks the daemon status
func runDaemonStatus(cmd *cobra.Command, args []string) error {
	// Get current directory
	cwd, err := os.Getwd()
	if err != nil {
		return fmt.Errorf("failed to get current directory: %w", err)
	}

	// Check if this is an Onyx repository
	if !core.IsOnyxRepo(cwd) {
		return fmt.Errorf("not an Onyx repository")
	}

	// Open repository to get .onx path
	repo, err := core.Open(cwd)
	if err != nil {
		return fmt.Errorf("failed to open repository: %w", err)
	}
	defer repo.Close()

	pidFile := filepath.Join(repo.GetOnyxPath(), "daemon.pid")

	if isDaemonRunning(pidFile) {
		pid, _ := readPIDFile(pidFile)
		fmt.Printf("Onyx daemon is running (PID: %d)\n", pid)
	} else {
		fmt.Println("Onyx daemon is not running")
	}

	return nil
}

// isDaemonRunning checks if the daemon is running based on the PID file
func isDaemonRunning(pidFile string) bool {
	pid, err := readPIDFile(pidFile)
	if err != nil {
		return false
	}

	// Check if process exists
	process, err := os.FindProcess(pid)
	if err != nil {
		return false
	}

	// Send signal 0 to check if process is alive
	err = process.Signal(syscall.Signal(0))
	return err == nil
}

// readPIDFile reads the PID from a file
func readPIDFile(path string) (int, error) {
	data, err := os.ReadFile(path)
	if err != nil {
		return 0, err
	}

	pid, err := strconv.Atoi(string(data[:len(data)-1])) // Remove trailing newline
	if err != nil {
		return 0, fmt.Errorf("invalid PID file: %w", err)
	}

	return pid, nil
}