using UnityEngine;
using UnityEngine.UI;

namespace GameFramework
{
    /// <summary>
    /// 暂停菜单控制器。
    /// 按 ESC 切换暂停/继续。
    /// 暂停时显示菜单 Canvas，提供继续/设置/返回主菜单三个按钮。
    /// 使用 old Input Manager（Input.GetKeyDown）。
    /// </summary>
    public class PauseMenu : MonoBehaviour
    {
        [Header("Input")]
        [SerializeField] KeyCode pauseKey = KeyCode.Escape;

        [Header("Canvas")]
        [SerializeField] Canvas hudCanvas;
        [SerializeField] Canvas pauseMenuCanvas;

        [Header("Buttons")]
        [SerializeField] Button resumeButton;
        [SerializeField] Button settingsButton;
        [SerializeField] Button mainMenuButton;

        [Header("Settings Panel (placeholder)")]
        [SerializeField] GameObject settingsPanel;
        [SerializeField] Button settingsBackButton;

        [Header("Audio")]
        [SerializeField] AudioData pauseSFX;
        [SerializeField] AudioData unpauseSFX;

        bool isPaused = false;

        void Start()
        {
            // 绑定按钮
            if (resumeButton != null)
                resumeButton.onClick.AddListener(OnResumeClick);
            if (settingsButton != null)
                settingsButton.onClick.AddListener(OnSettingsClick);
            if (mainMenuButton != null)
                mainMenuButton.onClick.AddListener(OnMainMenuClick);
            if (settingsBackButton != null)
                settingsBackButton.onClick.AddListener(OnSettingsBackClick);

            // 初始状态
            if (pauseMenuCanvas != null)
                pauseMenuCanvas.enabled = false;
            if (settingsPanel != null)
                settingsPanel.SetActive(false);

            // 确保游戏开始时是运行状态
            if (TimeController.Instance != null)
                TimeController.Instance.Unpause();
            if (GameManager.Instance != null)
                GameManager.GameState = GameState.Playing;
        }

        void Update()
        {
            // 游戏结束时不允许暂停
            if (GameManager.Instance != null && GameManager.GameState == GameState.GameOver)
                return;

            if (Input.GetKeyDown(pauseKey))
            {
                if (isPaused)
                    Resume();
                else
                    Pause();
            }
        }

        void Pause()
        {
            isPaused = true;

            if (TimeController.Instance != null)
                TimeController.Instance.Pause();

            if (GameManager.Instance != null)
                GameManager.GameState = GameState.Paused;

            if (hudCanvas != null)
                hudCanvas.enabled = false;
            if (pauseMenuCanvas != null)
                pauseMenuCanvas.enabled = true;

            // 显示鼠标
            Cursor.visible = true;
            Cursor.lockState = CursorLockMode.None;

            // 选中继续按钮（手柄/键盘导航用）
            if (resumeButton != null)
                resumeButton.Select();

            if (AudioManager.Instance != null && pauseSFX != null)
                AudioManager.Instance.PlaySFX(pauseSFX);
        }

        void Resume()
        {
            isPaused = false;

            if (TimeController.Instance != null)
                TimeController.Instance.Unpause();

            if (GameManager.Instance != null)
                GameManager.GameState = GameState.Playing;

            if (hudCanvas != null)
                hudCanvas.enabled = true;
            if (pauseMenuCanvas != null)
                pauseMenuCanvas.enabled = false;

            // 隐藏鼠标
            Cursor.visible = false;
            Cursor.lockState = CursorLockMode.Locked;

            if (AudioManager.Instance != null && unpauseSFX != null)
                AudioManager.Instance.PlaySFX(unpauseSFX);
        }

        // 只在 Pause 状态下才响应按钮
        // Resume 是公开方法因为按钮 onClick 需要调用
        public void OnResumeClick()
        {
            if (isPaused)
                Resume();
        }

        void OnSettingsClick()
        {
            if (settingsPanel != null)
                settingsPanel.SetActive(true);
        }

        void OnSettingsBackClick()
        {
            if (settingsPanel != null)
                settingsPanel.SetActive(false);
        }

        void OnMainMenuClick()
        {
            // 先解除暂停，再加载主菜单
            isPaused = false;
            if (TimeController.Instance != null)
                TimeController.Instance.Unpause();

            if (pauseMenuCanvas != null)
                pauseMenuCanvas.enabled = false;

            if (SceneLoader.Instance != null)
                SceneLoader.Instance.LoadMainMenuScene();
        }
    }
}