using Core.TaskSystem;
using TMPro;
using UnityEngine;

namespace UI.Tasks
{
    public class TaskPanelController : MonoBehaviour
    {
        [Header("System")]
        [SerializeField] private TaskService taskService;

        [Header("List")]
        [SerializeField] private RectTransform listContent;
        [SerializeField] private TaskListItemView taskItemPrefab;

        [Header("Details")]
        [SerializeField] private TMP_Text detailText;
        [SerializeField] private TMP_Text titleText;

        [Header("Selection")]
        [SerializeField] private bool autoSelectFirstTask = true;

        TaskService boundService;
        string selectedTaskId;

        void OnEnable()
        {
            BindService();
            RefreshAll();
        }

        void OnDisable()
        {
            UnbindService();
        }

        void BindService()
        {
            TaskService service = taskService != null ? taskService : TaskService.Instance;
            if (service == null)
            {
                Debug.LogError($"{nameof(TaskPanelController)} requires a TaskService reference.", this);
                return;
            }

            if (boundService == service) { return; }
            UnbindService();

            boundService = service;
            boundService.Changed += RefreshAll;
        }

        void UnbindService()
        {
            if (boundService == null) { return; }
            boundService.Changed -= RefreshAll;
            boundService = null;
        }

        void RefreshAll()
        {
            if (boundService == null) { return; }
            if (listContent == null || taskItemPrefab == null) { return; }

            for (int i = listContent.childCount - 1; i >= 0; i--)
            {
                Destroy(listContent.GetChild(i).gameObject);
            }

            for (int i = 0; i < boundService.Tasks.Count; i++)
            {
                TaskEntry task = boundService.Tasks[i];
                TaskListItemView view = Instantiate(taskItemPrefab, listContent);
                view.Bind(task, OnTaskClicked);
            }

            if (!string.IsNullOrWhiteSpace(selectedTaskId) && boundService.TryGetTask(selectedTaskId, out TaskEntry selected))
            {
                ShowDetails(selected);
                return;
            }

            if (autoSelectFirstTask && boundService.Tasks.Count > 0)
            {
                Select(boundService.Tasks[0]);
                return;
            }

            ClearDetails();
        }

        void OnTaskClicked(TaskEntry task)
        {
            Select(task);
        }

        void Select(TaskEntry task)
        {
            if (task == null)
            {
                selectedTaskId = null;
                ClearDetails();
                return;
            }

            selectedTaskId = task.id;
            ShowDetails(task);
        }

        void ShowDetails(TaskEntry task)
        {
            if (titleText != null) { titleText.text = task.ShortName; }

            if (detailText != null)
            {
                string statusLabel = task.status switch
                {
                    TaskStatus.Completed => "完成",
                    TaskStatus.Expired => "超时",
                    _ => "待做"
                };

                detailText.text = $"{statusLabel}\n\n{task.Description}";
            }
        }

        void ClearDetails()
        {
            if (titleText != null) { titleText.text = string.Empty; }
            if (detailText != null) { detailText.text = string.Empty; }
        }
    }
}