using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Linq;
using System.Windows.Input;
using ytLive.Helpers;
using ytLive.Services;

namespace ytLive.ViewModels;

/// <summary>One row in the hotkey config dialog — an action and its current chord.</summary>
public sealed class HotkeyBindingRow : ViewModelBase
{
    public HotkeyId Id { get; }
    public string ActionName { get; }

    private HotkeyChord? _chord;
    public HotkeyChord? Chord
    {
        get => _chord;
        set
        {
            if (SetProperty(ref _chord, value))
                OnPropertyChanged(nameof(DisplayText));
        }
    }

    private bool _isCapturing;
    public bool IsCapturing
    {
        get => _isCapturing;
        set
        {
            if (SetProperty(ref _isCapturing, value))
                OnPropertyChanged(nameof(DisplayText));
        }
    }

    public string DisplayText => IsCapturing
        ? "▶ Press a key combination..."
        : HotkeyChord.DisplayString(Chord);

    public HotkeyBindingRow(HotkeyId id, HotkeyChord? chord)
    {
        Id = id;
        ActionName = GetActionName(id);
        Chord = chord;
    }

    private static string GetActionName(HotkeyId id) => id switch
    {
        HotkeyId.SceneStarting   => "Scene: Starting",
        HotkeyId.SceneLive       => "Scene: Live",
        HotkeyId.SceneBrb        => "Scene: BRB",
        HotkeyId.SceneChat       => "Scene: Chat",
        HotkeyId.SceneEnding     => "Scene: Ending",
        HotkeyId.StartStopStream => "Start / Stop Stream",
        HotkeyId.ToggleMicMute   => "Toggle Mic Mute",
        HotkeyId.ToggleGameMute  => "Toggle Desktop Audio Mute",
        HotkeyId.TraxPlayPause   => "TRAX Play / Pause",
        _ => id.ToString(),
    };
}

/// <summary>
/// ViewModel for the hotkey config dialog. Manages the working copy of
/// bindings, capture mode, conflict detection, and save/cancel/reset.
/// </summary>
public sealed class HotkeyConfigViewModel : ViewModelBase
{
    private readonly LayoutStore _store;
    private readonly Dictionary<HotkeyId, HotkeyChord?> _original;

    public ObservableCollection<HotkeyBindingRow> Rows { get; }

    public event Action? SaveRequested;
    public event Action? CancelRequested;

    private string? _conflictMessage;
    public string? ConflictMessage
    {
        get => _conflictMessage;
        set => SetProperty(ref _conflictMessage, value);
    }

    private HotkeyBindingRow? _capturingRow;
    public HotkeyBindingRow? CapturingRow
    {
        get => _capturingRow;
        private set => SetProperty(ref _capturingRow, value);
    }

    public ICommand StartCaptureCommand { get; }
    public ICommand UnbindCommand { get; }
    public ICommand ResetToDefaultsCommand { get; }
    public ICommand SaveCommand { get; }
    public ICommand CancelCommand { get; }

    public HotkeyConfigViewModel(LayoutStore store)
    {
        _store = store;
        ConflictMessage = null;

        // Load saved bindings — keys present in DB are either custom or "none" (unbound).
        var saved = store.LoadHotkeyBindings();

        // Build working copy: start from defaults, overlay saved, fill gaps.
        _original = new Dictionary<HotkeyId, HotkeyChord?>();
        foreach (HotkeyId id in Enum.GetValues(typeof(HotkeyId)))
        {
            if (saved.TryGetValue(id, out var chord))
                _original[id] = chord; // custom or null (explicitly unbound)
            else
                _original[id] = GlobalHotkeyManager.Defaults.TryGetValue(id, out var def)
                    ? def
                    : null;
        }

        Rows = new ObservableCollection<HotkeyBindingRow>(
            _original.Select(kv => new HotkeyBindingRow(kv.Key, kv.Value)));

        StartCaptureCommand = new RelayCommand(row =>
        {
            if (row is HotkeyBindingRow r) StartCapture(r);
        });
        UnbindCommand = new RelayCommand(row =>
        {
            if (row is HotkeyBindingRow r) Unbind(r);
        });
        ResetToDefaultsCommand = new RelayCommand(_ => ResetToDefaults());
        SaveCommand = new RelayCommand(_ => Save());
        CancelCommand = new RelayCommand(_ => CancelRequested?.Invoke());
    }

    /// <summary>
    /// Called by the dialog after it captures a key combo from the user.
    /// Assigns the chord if free; shows a conflict warning otherwise.
    /// </summary>
    public void AssignCapturedChord(HotkeyChord chord)
    {
        if (CapturingRow == null) return;

        // Same chord as current — no-op
        if (CapturingRow.Chord != null && CapturingRow.Chord.Equals(chord))
        {
            CapturingRow.IsCapturing = false;
            CapturingRow = null;
            return;
        }

        // Conflict: another action already uses this chord
        var conflict = Rows.FirstOrDefault(r =>
            r.Id != CapturingRow.Id && r.Chord != null && r.Chord.Equals(chord));
        if (conflict != null)
        {
            ConflictMessage = $"{chord.ToDisplayString()} is already bound to {conflict.ActionName}. Unbind it first.";
            CapturingRow.IsCapturing = false;
            CapturingRow = null;
            return;
        }

        // Free — assign it
        ConflictMessage = null;
        CapturingRow.Chord = chord;
        CapturingRow.IsCapturing = false;
        CapturingRow = null;
    }

    /// <summary>Cancel capture mode without changing the binding.</summary>
    public void CancelCapture()
    {
        if (CapturingRow == null) return;
        CapturingRow.IsCapturing = false;
        CapturingRow = null;
        ConflictMessage = null;
    }

    private void StartCapture(HotkeyBindingRow row)
    {
        CancelCapture(); // cancel any in-progress capture first
        ConflictMessage = null;
        row.IsCapturing = true;
        CapturingRow = row;
    }

    private void Unbind(HotkeyBindingRow row)
    {
        CancelCapture();
        ConflictMessage = null;
        row.Chord = null;
    }

    private void ResetToDefaults()
    {
        CancelCapture();
        ConflictMessage = null;
        foreach (var row in Rows)
        {
            row.Chord = GlobalHotkeyManager.Defaults.TryGetValue(row.Id, out var def)
                ? def
                : null;
        }
    }

    private void Save()
    {
        CancelCapture();
        ConflictMessage = null;

        var bindings = new Dictionary<HotkeyId, HotkeyChord?>();
        foreach (var row in Rows)
            bindings[row.Id] = row.Chord;

        _store.SaveHotkeyBindings(bindings);
        SaveRequested?.Invoke();
    }
}