using System;
using Avalonia;
using Avalonia.Controls;
using Avalonia.Input;
using Avalonia.Interactivity;
using Avalonia.VisualTree;
using AdvancedCalculator.ViewModels;
using AdvancedCalculator.Models;
using Avalonia.Controls.Presenters;

namespace AdvancedCalculator.Views;

public partial class MainView : UserControl
{
    public MainView()
    {
        InitializeComponent();
        this.AttachedToVisualTree += OnAttachedToVisualTree;
        this.DetachedFromVisualTree += OnDetachedFromVisualTree;
    }

    private MainViewModel? _vm;
    private ListBox? _historyList;
    // Functions flyout is handled via per-item Tapped in XAML

    private void OnAttachedToVisualTree(object? sender, VisualTreeAttachmentEventArgs e)
    {
        _vm = DataContext as MainViewModel;
        if (_vm is not null)
        {
            _vm.CopyRequested += OnCopyRequested;
        }

        _historyList = this.FindControl<ListBox>("HistoryList");
        if (_historyList is not null)
        {
            // Handle taps anywhere in a history row to copy output text
            _historyList.AddHandler(InputElement.TappedEvent, OnHistoryTapped,
                RoutingStrategies.Tunnel | RoutingStrategies.Bubble);
        }

        // Functions flyout wiring is done via Opened/Closed events
    }

    private void OnDetachedFromVisualTree(object? sender, VisualTreeAttachmentEventArgs e)
    {
        if (_vm is not null)
        {
            _vm.CopyRequested -= OnCopyRequested;
        }
        if (_historyList is not null)
        {
            _historyList.RemoveHandler(InputElement.TappedEvent, OnHistoryTapped);
            _historyList = null;
        }
        _vm = null;
    }

    private async void OnCopyRequested(object? sender, string text)
    {
        var top = TopLevel.GetTopLevel(this);
        if (top?.Clipboard is null) return;
        try
        {
            await top.Clipboard.SetTextAsync(text);
        }
        catch
        {
            // Ignore clipboard errors; e.g., browser permission or missing gesture context
        }
    }

    private void OnHistoryTapped(object? sender, TappedEventArgs e)
    {
        // Find the ListBoxItem the tap originated from
        var source = e.Source as ContentPresenter;
        var container = source?.FindAncestorOfType<ListBoxItem>();
        if (container?.DataContext is not HistoryItem item)
            return;

        var vm = DataContext as MainViewModel;
        if (vm?.CopyHistoryOutputCommand.CanExecute(item) == true)
        {
            vm.CopyHistoryOutputCommand.Execute(item);
            // Mark handled to avoid unintended selection change on tap
            e.Handled = true;
        }
    }

    private void OnFunctionsItemTapped(object? sender, TappedEventArgs e)
    {
        var lbi = (e.Source as Control)?.FindAncestorOfType<ListBoxItem>();
        if (lbi?.DataContext is FunctionDefinitionItem item &&
            _vm?.InsertFunctionCommand.CanExecute(item) == true)
        {
            _vm.InsertFunctionCommand.Execute(item);
            // Return focus to the input box so the caret is active
            var input = this.FindControl<TextBox>("InputBox");
            input?.Focus();
            e.Handled = true;
        }
    }

    // Removed Opened/Closed dynamic wiring; handled directly in XAML.
}