using System.Collections.ObjectModel;
using Avalonia;
using Avalonia.Controls;
using Avalonia.Controls.ApplicationLifetimes;
using ClaudeDo.Data;
using ClaudeDo.Data.Models;
using ClaudeDo.Data.Repositories;
using ClaudeDo.Ui.Services;
using ClaudeDo.Ui.Views;
using CommunityToolkit.Mvvm.ComponentModel;
using CommunityToolkit.Mvvm.Input;
using Microsoft.EntityFrameworkCore;
using TaskStatus = ClaudeDo.Data.Models.TaskStatus;

namespace ClaudeDo.Ui.ViewModels;

public partial class TaskListViewModel : ViewModelBase
{
    private readonly IDbContextFactory<ClaudeDoDbContext> _dbFactory;
    private readonly WorkerClient _worker;
    private readonly Func<TaskEditorViewModel> _editorFactory;
    private readonly Action<string> _showMessage;

    public ObservableCollection<TaskItemViewModel> Tasks { get; } = new();

    [ObservableProperty] private TaskItemViewModel? _selectedTask;
    [ObservableProperty, NotifyCanExecuteChangedFor(nameof(AddTaskCommand))] private string? _currentListId;
    [ObservableProperty] private string _listName = "Tasks";
    [ObservableProperty] private string _inlineAddTitle = "";

    public event Action<TaskItemViewModel?>? SelectedTaskChanged;

    partial void OnSelectedTaskChanged(TaskItemViewModel? value) =>
        SelectedTaskChanged?.Invoke(value);

    public TaskListViewModel(IDbContextFactory<ClaudeDoDbContext> dbFactory, WorkerClient worker,
        Func<TaskEditorViewModel> editorFactory, Action<string> showMessage)
    {
        _dbFactory = dbFactory;
        _worker = worker;
        _editorFactory = editorFactory;
        _showMessage = showMessage;

        worker.TaskUpdatedEvent += OnTaskUpdated;
        worker.TaskFinishedEvent += (_, taskId, _, _) => OnTaskUpdated(taskId);
        worker.PropertyChanged += (_, e) =>
        {
            if (e.PropertyName == nameof(WorkerClient.IsConnected))
                Avalonia.Threading.Dispatcher.UIThread.Post(() =>
                {
                    foreach (var t in Tasks)
                        t.RunNowCommand.NotifyCanExecuteChanged();
                });
        };

        worker.RunNowRequestedEvent += taskId =>
        {
            var item = Tasks.FirstOrDefault(t => t.Id == taskId);
            item?.SetStarting();
        };

        worker.TaskStartedEvent += (_, taskId, _) =>
        {
            var item = Tasks.FirstOrDefault(t => t.Id == taskId);
            item?.ClearStarting();
        };
    }

    public async Task LoadAsync(string? listId)
    {
        CurrentListId = listId;
        Tasks.Clear();
        SelectedTask = null;

        if (listId is not null)
        {
            using var context = _dbFactory.CreateDbContext();
            var listRepo = new ListRepository(context);
            var list = await listRepo.GetByIdAsync(listId);
            ListName = list?.Name ?? "Tasks";
        }
        else
        {
            ListName = "Tasks";
        }

        if (listId is null) return;

        try
        {
            using var context = _dbFactory.CreateDbContext();
            var taskRepo = new TaskRepository(context);
            var entities = await taskRepo.GetByListIdAsync(listId);
            var taskIds = entities.Select(e => e.Id).ToList();
            var subtaskCounts = await context.Subtasks
                .Where(s => taskIds.Contains(s.TaskId))
                .GroupBy(s => s.TaskId)
                .ToDictionaryAsync(g => g.Key, g => g.Count());
            foreach (var e in entities)
            {
                var tags = await taskRepo.GetEffectiveTagsAsync(e.Id);
                subtaskCounts.TryGetValue(e.Id, out var count);
                Tasks.Add(new TaskItemViewModel(e, tags, RunNowAsync, () => _worker.IsConnected,
                    _dbFactory, count, ToggleDoneAsync));
            }
        }
        catch (Exception ex)
        {
            _showMessage($"Error loading tasks: {ex.Message}");
        }
    }

    private bool CanAddTask() => CurrentListId is not null;

    [RelayCommand(CanExecute = nameof(CanAddTask))]
    private async Task InlineAdd()
    {
        var title = InlineAddTitle.Trim();
        if (string.IsNullOrEmpty(title) || CurrentListId is null) return;

        string defaultCommitType;
        using (var context = _dbFactory.CreateDbContext())
        {
            var listRepo = new ListRepository(context);
            var list = await listRepo.GetByIdAsync(CurrentListId);
            defaultCommitType = list?.DefaultCommitType ?? "chore";
        }

        var entity = new TaskEntity
        {
            Id = Guid.NewGuid().ToString(),
            ListId = CurrentListId,
            Title = title,
            Status = TaskStatus.Manual,
            CommitType = defaultCommitType,
            CreatedAt = DateTime.UtcNow,
        };

        try
        {
            using var context = _dbFactory.CreateDbContext();
            var taskRepo = new TaskRepository(context);
            await taskRepo.AddAsync(entity);
            var tags = await taskRepo.GetEffectiveTagsAsync(entity.Id);
            var vm = new TaskItemViewModel(entity, tags, RunNowAsync, () => _worker.IsConnected,
                _dbFactory, 0, ToggleDoneAsync);
            Tasks.Add(vm);
            SelectedTask = vm;
            InlineAddTitle = "";
        }
        catch (Exception ex)
        {
            _showMessage($"Error creating task: {ex.Message}");
        }
    }

    [RelayCommand(CanExecute = nameof(CanAddTask))]
    private async Task AddTask()
    {
        string defaultCommitType;
        using (var context = _dbFactory.CreateDbContext())
        {
            var listRepo = new ListRepository(context);
            var list = await listRepo.GetByIdAsync(CurrentListId);
            defaultCommitType = list?.DefaultCommitType ?? "chore";
        }

        var editor = _editorFactory();
        await editor.LoadAgentsAsync(_worker);
        editor.InitForCreate(CurrentListId, defaultCommitType);

        var window = new TaskEditorView { DataContext = editor };
        editor.RequestClose += () => window.Close();
        window.Closed += (_, _) => editor.OnWindowClosed();
        _ = ShowDialogAsync(window);

        var saved = await editor.ShowAndWaitAsync();
        if (saved is null) return;

        try
        {
            using var context = _dbFactory.CreateDbContext();
            var taskRepo = new TaskRepository(context);
            var tagRepo = new TagRepository(context);
            await taskRepo.AddAsync(saved);

            foreach (var tagName in editor.SelectedTagNames)
            {
                var tagId = await tagRepo.GetOrCreateAsync(tagName);
                await taskRepo.AddTagAsync(saved.Id, tagId);
            }

            var tags = await taskRepo.GetEffectiveTagsAsync(saved.Id);
            Tasks.Add(new TaskItemViewModel(saved, tags, RunNowAsync, () => _worker.IsConnected,
                _dbFactory, 0, ToggleDoneAsync));

            // Auto wake-queue if agent+queued
            if (saved.Status == TaskStatus.Queued &&
                tags.Any(t => t.Name == "agent"))
            {
                try { await _worker.WakeQueueAsync(); }
                catch { /* worker offline is fine */ }
            }
        }
        catch (Exception ex)
        {
            _showMessage($"Error creating task: {ex.Message}");
        }
    }

    [RelayCommand]
    private async Task EditTask()
    {
        if (SelectedTask is null || CurrentListId is null) return;

        TaskEntity? entity;
        List<TagEntity> taskTags;
        using (var context = _dbFactory.CreateDbContext())
        {
            var taskRepo = new TaskRepository(context);
            entity = await taskRepo.GetByIdAsync(SelectedTask.Id);
            if (entity is null) return;
            taskTags = await taskRepo.GetTagsAsync(entity.Id);
        }

        var editor = _editorFactory();
        await editor.LoadAgentsAsync(_worker);
        await editor.InitForEditAsync(entity, taskTags);

        var window = new TaskEditorView { DataContext = editor };
        editor.RequestClose += () => window.Close();
        window.Closed += (_, _) => editor.OnWindowClosed();
        _ = ShowDialogAsync(window);

        var saved = await editor.ShowAndWaitAsync();
        if (saved is null) return;

        try
        {
            using var context = _dbFactory.CreateDbContext();
            var taskRepo = new TaskRepository(context);
            var tagRepo = new TagRepository(context);
            await taskRepo.UpdateAsync(saved);

            var existingTags = await taskRepo.GetTagsAsync(saved.Id);
            foreach (var old in existingTags)
                await taskRepo.RemoveTagAsync(saved.Id, old.Id);
            foreach (var tagName in editor.SelectedTagNames)
            {
                var tagId = await tagRepo.GetOrCreateAsync(tagName);
                await taskRepo.AddTagAsync(saved.Id, tagId);
            }

            var newTags = await taskRepo.GetEffectiveTagsAsync(saved.Id);
            SelectedTask.Refresh(saved, newTags);
        }
        catch (Exception ex)
        {
            _showMessage($"Error updating task: {ex.Message}");
        }
    }

    [RelayCommand]
    private async Task DeleteTask()
    {
        if (SelectedTask is null) return;
        try
        {
            using var context = _dbFactory.CreateDbContext();
            var taskRepo = new TaskRepository(context);
            await taskRepo.DeleteAsync(SelectedTask.Id);
            Tasks.Remove(SelectedTask);
            SelectedTask = null;
        }
        catch (Exception ex)
        {
            _showMessage($"Error deleting task: {ex.Message}");
        }
    }

    public async Task RefreshSingleAsync(string taskId)
    {
        using var context = _dbFactory.CreateDbContext();
        var taskRepo = new TaskRepository(context);
        var entity = await taskRepo.GetByIdAsync(taskId);
        var existing = Tasks.FirstOrDefault(t => t.Id == taskId);
        if (entity is null)
        {
            if (existing is not null) Tasks.Remove(existing);
            return;
        }
        var tags = await taskRepo.GetEffectiveTagsAsync(taskId);
        if (existing is not null)
        {
            existing.Refresh(entity, tags);
            var subtaskCount = await context.Subtasks.CountAsync(s => s.TaskId == taskId);
            await existing.RefreshSubtasksAsync(subtaskCount);
        }
    }

    private async Task RunNowAsync(string taskId)
    {
        try
        {
            await _worker.RunNowAsync(taskId);
        }
        catch (Exception ex)
        {
            _showMessage($"RunNow failed: {ex.Message}");
        }
    }

    private async Task ToggleDoneAsync(string taskId)
    {
        using var context = _dbFactory.CreateDbContext();
        var taskRepo = new TaskRepository(context);
        var entity = await taskRepo.GetByIdAsync(taskId);
        if (entity is null) return;

        entity.Status = entity.Status == TaskStatus.Done ? TaskStatus.Manual : TaskStatus.Done;
        if (entity.Status == TaskStatus.Done)
            entity.FinishedAt = DateTime.UtcNow;

        await taskRepo.UpdateAsync(entity);
        await RefreshSingleAsync(taskId);
    }

    private async void OnTaskUpdated(string taskId)
    {
        if (CurrentListId is null) return;
        await RefreshSingleAsync(taskId);
    }

    private static async Task ShowDialogAsync(Window dialog)
    {
        if (Application.Current?.ApplicationLifetime is IClassicDesktopStyleApplicationLifetime desktop
            && desktop.MainWindow is not null)
        {
            await dialog.ShowDialog(desktop.MainWindow);
        }
        else
        {
            dialog.Show();
        }
    }
}