using System.Collections.ObjectModel;
using System.ComponentModel;
using ClaudeDo.Data;
using ClaudeDo.Ui.Localization;
using CommunityToolkit.Mvvm.ComponentModel;
using CommunityToolkit.Mvvm.Input;
using Microsoft.EntityFrameworkCore;
using TaskStatus = ClaudeDo.Data.Models.TaskStatus;

namespace ClaudeDo.Ui.ViewModels.Modals;

public sealed partial class MergeHelperTaskRowViewModel : ViewModelBase
{
    public required string Id { get; init; }
    public required string Title { get; init; }
    public required string StatusText { get; init; }

    [ObservableProperty] private bool _isSelected;
}

/// <summary>
/// "Let Claude handle it" task picker: lists the non-terminal tasks of a list (or all lists),
/// pre-ticks the actionable ones, and resolves <see cref="Result"/> with the ordered selected
/// task ids (null on cancel).
/// </summary>
public sealed partial class MergeHelperSelectionModalViewModel : ViewModelBase
{
    private readonly IDbContextFactory<ClaudeDoDbContext> _dbFactory;
    private string _listId = "";

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

    [ObservableProperty] private string _scopeLabel = "";

    public bool HasTasks => Tasks.Count > 0;
    public bool CanConfirm => Tasks.Any(t => t.IsSelected);

    public TaskCompletionSource<IReadOnlyList<string>?> Result { get; } = new();
    public Action? CloseAction { get; set; }

    public MergeHelperSelectionModalViewModel(IDbContextFactory<ClaudeDoDbContext> dbFactory)
        => _dbFactory = dbFactory;

    public void Configure(string listId, string listName)
    {
        _listId = listId;
        ScopeLabel = Loc.T("modals.mergeHelper.scopeList", listName);
    }

    public async Task LoadAsync(CancellationToken ct = default)
    {
        foreach (var row in Tasks) row.PropertyChanged -= OnRowChanged;
        Tasks.Clear();

        await using var ctx = await _dbFactory.CreateDbContextAsync(ct);
        var candidates = await ctx.Tasks.AsNoTracking()
            .Where(t => t.Status != TaskStatus.Done && t.Status != TaskStatus.Cancelled)
            .Where(t => t.ListId == _listId)
            .OrderBy(t => t.SortOrder).ThenBy(t => t.CreatedAt)
            .Select(t => new { t.Id, t.Title, t.Status })
            .ToListAsync(ct);

        foreach (var c in candidates)
        {
            var row = new MergeHelperTaskRowViewModel
            {
                Id = c.Id,
                Title = c.Title,
                StatusText = c.Status.ToString(),
                IsSelected = IsTickedByDefault(c.Status),
            };
            row.PropertyChanged += OnRowChanged;
            Tasks.Add(row);
        }
        OnPropertyChanged(nameof(HasTasks));
        OnPropertyChanged(nameof(CanConfirm));
    }

    // Actionable statuses are pre-ticked; Running/WaitingForChildren are listed but unticked
    // (the helper would only poll them). Done/Cancelled never make it into the list.
    internal static bool IsTickedByDefault(TaskStatus status) => status
        is TaskStatus.Idle or TaskStatus.Queued or TaskStatus.WaitingForReview or TaskStatus.Failed;

    private void OnRowChanged(object? sender, PropertyChangedEventArgs e)
    {
        if (e.PropertyName == nameof(MergeHelperTaskRowViewModel.IsSelected))
            OnPropertyChanged(nameof(CanConfirm));
    }

    [RelayCommand]
    private void SelectAll()
    {
        foreach (var t in Tasks) t.IsSelected = true;
    }

    [RelayCommand]
    private void SelectNone()
    {
        foreach (var t in Tasks) t.IsSelected = false;
    }

    [RelayCommand]
    private void Confirm()
    {
        Result.TrySetResult(Tasks.Where(t => t.IsSelected).Select(t => t.Id).ToList());
        CloseAction?.Invoke();
    }

    [RelayCommand]
    private void Cancel()
    {
        Result.TrySetResult(null);
        CloseAction?.Invoke();
    }
}