package devices

import (
	"fmt"
	"os"
	"os/exec"
	"strings"
	"sync"
)

// TODO: A command device
// You will be able to use shell commands to push the power button and get the status.
//
// Status will give an env variable: WOLBODGE_STATUS_FILE, you will be expected to write a "0" or a "1" there, depending on the state.

func NewCommand(shell []string, statusCmd string, toggleStatusCmd string) Device {
	device := &command{
		shell:           shell,
		statusCmd:       statusCmd,
		toggleStatusCmd: toggleStatusCmd,
		lock:            sync.Mutex{},
	}
	return device
}

type command struct {
	shell           []string
	statusCmd       string
	toggleStatusCmd string
	lock            sync.Mutex
}

func (d *command) Status() (bool, error) {
	d.lock.Lock()
	defer d.lock.Unlock()

	file, err := os.CreateTemp("", "wolbodge-status-*")
	if err != nil {
		return false, fmt.Errorf("failed to create temporary status file: %w", err)
	}
	defer os.Remove(file.Name())

	cmd := d.makeCommand(d.statusCmd)
	cmd.Env = append(
		cmd.Environ(),
		fmt.Sprintf("WOLBODGE_STATUS_FILE=%s", file.Name()),
	)

	err = cmd.Run()
	if err != nil {
		return false, fmt.Errorf("failed to run command: %w", err)
	}

	data, err := os.ReadFile(file.Name())
	if err != nil {
		return false, fmt.Errorf("failed to read status file: %w", err)
	}

	content := string(data)
	content = strings.TrimSpace(content)

	switch content {
	case "0":
		return false, nil
	case "1":
		return true, nil
	default:
		return false, fmt.Errorf("invalid status file content, expected \"0\" or \"1\", got \"%s\"", content)
	}
}

func (d *command) ToggleStatus() error {
	d.lock.Lock()
	defer d.lock.Unlock()

	cmd := d.makeCommand(d.toggleStatusCmd)
	err := cmd.Run()
	if err != nil {
		return fmt.Errorf("failed to run command: %w", err)
	}

	return nil
}

func (d *command) makeCommand(command string) *exec.Cmd {
	args := make([]string, len(d.shell))
	copy(args, d.shell)

	for i := range args {
		args[i] = strings.ReplaceAll(args[i], "$COMMAND", command)
	}

	return exec.Command(args[0], args[1:]...)
}

func (d *command) String() string {
	return "command"
}