using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using Avalonia.Controls;
using Avalonia.Input;
using Avalonia.Interactivity;
using Avalonia.Platform.Storage;
using ClaudeDo.Ui.Services;
using ClaudeDo.Ui.ViewModels;

namespace ClaudeDo.Ui.Views;

public partial class InteractiveTerminalView : UserControl
{
    public InteractiveTerminalView()
    {
        InitializeComponent();
        TerminalHost.Loaded += OnTerminalHostLoaded;
        DataContextChanged += OnDataContextChanged;

        // Tunnel: TerminalControl handles KeyDown itself and forwards Ctrl+V to the child as a raw
        // control byte, where nothing acts on it — paste has to be intercepted before it gets there.
        AddHandler(KeyDownEvent, OnPreviewKeyDown, RoutingStrategies.Tunnel);
        AddHandler(DragDrop.DragOverEvent, OnDragOver);
        AddHandler(DragDrop.DropEvent, OnDrop);
    }

    private void OnDataContextChanged(object? sender, EventArgs e)
    {
        if (DataContext is InteractiveTerminalViewModel vm && TerminalHost.IsLoaded)
            vm.AttachControl(TerminalHost);
    }

    private void OnTerminalHostLoaded(object? sender, RoutedEventArgs e)
    {
        if (DataContext is InteractiveTerminalViewModel vm)
            vm.AttachControl(TerminalHost);
    }

    private void OnPreviewKeyDown(object? sender, KeyEventArgs e)
    {
        // AltGr arrives as Ctrl+Alt; the library would turn it into a control sequence (and mark it handled).
        if (IsAltGrText(e.KeyModifiers, e.KeySymbol))
        {
            if (DataContext is not InteractiveTerminalViewModel altGrVm) return;
            e.Handled = true;
            _ = SendTextAndReportAsync(altGrVm, e.KeySymbol!);
            return;
        }

        if (e.Key != Key.V || !e.KeyModifiers.HasFlag(KeyModifiers.Control) || e.KeyModifiers.HasFlag(KeyModifiers.Alt))
            return;
        if (DataContext is not InteractiveTerminalViewModel vm) return;

        e.Handled = true;
        _ = PasteAndReportAsync(this, vm);
    }

    // A clipboard image (e.g. a screenshot) can't be typed into the child process, so it's written
    // to a temp PNG and its path is inserted the same way a dropped file is — Claude reads the file
    // itself. Plain-text clipboard content keeps going through the existing bracketed-paste flow.
    // Once a bitmap is confirmed present, any failure (dir/file write, send) is a real paste
    // failure — never silently fall back to a text paste of the same clipboard.
    private static async System.Threading.Tasks.Task PasteAndReportAsync(InteractiveTerminalView view, InteractiveTerminalViewModel vm)
    {
        Avalonia.Media.Imaging.Bitmap? bitmap = null;
        try
        {
            bitmap = await TryGetClipboardBitmapAsync(TopLevel.GetTopLevel(view));
            if (bitmap is null)
            {
                if (!await vm.PasteAsync()) vm.ReportSendFailed();
                return;
            }

            var path = ClipboardImageTempStore.NewPngPath(DateTime.UtcNow);
            Directory.CreateDirectory(ClipboardImageTempStore.Directory);
            bitmap.Save(path);
            if (!await vm.SendTextAsync(FormatDroppedPaths(new[] { path })))
                vm.ReportSendFailed();
        }
        catch (Exception)
        {
            vm.ReportSendFailed();
        }
        finally
        {
            bitmap?.Dispose();
        }
    }

    private static async System.Threading.Tasks.Task<Avalonia.Media.Imaging.Bitmap?> TryGetClipboardBitmapAsync(TopLevel? topLevel)
    {
        if (topLevel?.Clipboard is not { } clipboard) return null;
        try
        {
            using var data = await clipboard.TryGetDataAsync();
            return data is null ? null : await Avalonia.Input.AsyncDataTransferExtensions.TryGetBitmapAsync(data);
        }
        catch (Exception)
        {
            return null;
        }
    }

    private static bool IsFilesDrop(DragEventArgs e) => e.DataTransfer?.Contains(DataFormat.File) == true;

    private void OnDragOver(object? sender, DragEventArgs e)
    {
        e.DragEffects = IsFilesDrop(e) ? DragDropEffects.Copy : DragDropEffects.None;
        e.Handled = true;
    }

    // Dropping files types their paths into the session's composer (no Enter) — the common case is
    // "look at this file", not "run something".
    private void OnDrop(object? sender, DragEventArgs e)
    {
        if (DataContext is not InteractiveTerminalViewModel vm || !IsFilesDrop(e)) return;
        e.Handled = true;

        var text = FormatDroppedPaths(e.DataTransfer!.TryGetFiles()?.Select(i => i.TryGetLocalPath()));
        if (text.Length > 0) _ = SendTextAndReportAsync(vm, text);
    }

    private static async System.Threading.Tasks.Task SendTextAndReportAsync(InteractiveTerminalViewModel vm, string text)
    {
        if (!await vm.SendTextAsync(text))
            vm.ReportSendFailed();
    }

    /// <summary>True for an AltGr keystroke (Windows reports it as Ctrl+Alt) whose
    /// <paramref name="keySymbol"/> is already a single printable character, e.g. "@" or "\".</summary>
    internal static bool IsAltGrText(KeyModifiers modifiers, string? keySymbol) =>
        modifiers.HasFlag(KeyModifiers.Control) && modifiers.HasFlag(KeyModifiers.Alt)
        && keySymbol is { Length: 1 } && !char.IsControl(keySymbol[0]);

    /// <summary>Joins dropped file paths into one insertable chunk: quoted when they contain a
    /// space, space-separated, with a trailing space so the user can keep typing.</summary>
    internal static string FormatDroppedPaths(IEnumerable<string?>? paths)
    {
        var usable = (paths ?? Enumerable.Empty<string?>())
            .Where(p => !string.IsNullOrWhiteSpace(p))
            .Select(p => p!.Contains(' ') ? $"\"{p}\"" : p)
            .ToList();
        return usable.Count == 0 ? string.Empty : string.Join(" ", usable) + " ";
    }
}