using TinyTUI.Input;
using TinyTUI.Text;

namespace TinyTUI.Components;

/// <summary>
/// 支持多行文本编辑的基础编辑器组件
/// </summary>
public sealed partial class Editor(ITextMeasurer? textMeasurer = null, KeybindingRegistry? keybindings = null) : IInputComponent, IFocusableComponent
{
    private readonly ITextMeasurer _textMeasurer = textMeasurer ?? new TerminalTextMeasurer();
    private readonly KeybindingRegistry _keybindings = keybindings ?? KeybindingRegistry.CreateDefault();
    private readonly List<string> _lines = [string.Empty];
    private readonly Stack<EditorSnapshot> _undoStack = [];
    private readonly Stack<EditorSnapshot> _redoStack = [];
    private readonly List<string> _history = [];

    private int _cursorRow;
    private int _cursorColumn;
    private int _historyIndex = -1;
    private string _historyDraft = string.Empty;
    private int _lastRenderWidth = 80;
    private int _scrollOffset;
    private int? _preferredVisualColumn;

    /// <summary>
    /// 获取或设置编辑器高度
    /// </summary>
    public int Height { get; set; } = 5;

    /// <summary>
    /// 获取或设置是否按可用宽度软换行
    /// </summary>
    public bool SoftWrap { get; set; } = true;

    /// <summary>
    /// 获取或设置空编辑器的输入提示
    /// </summary>
    public string Placeholder { get; set; } = string.Empty;

    /// <inheritdoc />
    public bool Focused { get; set; }

    /// <summary>
    /// 获取当前编辑器文本
    /// </summary>
    public string Value
    {
        get => string.Join('\n', _lines);
        set => SetValue(value);
    }

    /// <summary>
    /// 在文本变化时触发
    /// </summary>
    public Action<string>? OnChanged { get; set; }

    /// <summary>
    /// 在用户取消编辑时触发
    /// </summary>
    public Action? OnCanceled { get; set; }

    /// <summary>
    /// 在用户提交编辑内容时触发
    /// </summary>
    public Action<string>? OnSubmitted { get; set; }

    /// <inheritdoc />
    public void HandleInput(TuiInputEvent input)
    {
        switch (input)
        {
            case { Kind: TuiInputEventKind.Text }:
                Edit(() => InsertText(input.Value));
                break;
            case { Kind: TuiInputEventKind.Paste }:
                Edit(() => InsertText(input.Value.Replace("\r\n", "\n")));
                break;
            case { Kind: TuiInputEventKind.Key }:
                HandleKey(input);
                break;
        }
    }

    /// <summary>
    /// 提交当前编辑内容
    /// </summary>
    public void Submit() => OnSubmitted?.Invoke(Value);

    /// <summary>
    /// 取消当前编辑
    /// </summary>
    public void Cancel() => OnCanceled?.Invoke();

    /// <summary>
    /// 清空编辑器内容
    /// </summary>
    public void Clear() => SetValue(string.Empty);

    /// <summary>
    /// 根据动作映射处理多行编辑器快捷键
    /// </summary>
    private void HandleKey(TuiInputEvent input)
    {
        if (_keybindings.Matches(input, TuiKeybindings.EditorUndo))
        {
            Undo();
            return;
        }

        if (_keybindings.Matches(input, TuiKeybindings.EditorRedo))
        {
            Redo();
            return;
        }

        if (_keybindings.Matches(input, TuiKeybindings.EditorClear))
        {
            Edit(ClearText);
            return;
        }

        if (_keybindings.Matches(input, TuiKeybindings.EditorCursorWordLeft))
        {
            MoveWordLeft();
            return;
        }

        if (_keybindings.Matches(input, TuiKeybindings.EditorCursorWordRight))
        {
            MoveWordRight();
            return;
        }

        if (_keybindings.Matches(input, TuiKeybindings.EditorDeleteWordBackward))
        {
            Edit(DeleteWordBackward);
            return;
        }

        if (_keybindings.Matches(input, TuiKeybindings.EditorDeleteWordForward))
        {
            Edit(DeleteWordForward);
            return;
        }

        if (_keybindings.Matches(input, TuiKeybindings.EditorSubmit))
        {
            Submit();
            return;
        }

        if (_keybindings.Matches(input, TuiKeybindings.EditorNewLine))
        {
            Edit(SplitLine);
            return;
        }

        if (_keybindings.Matches(input, TuiKeybindings.EditorDeleteCharBackward))
        {
            Edit(Backspace);
            return;
        }

        if (_keybindings.Matches(input, TuiKeybindings.EditorDeleteCharForward))
        {
            Edit(Delete);
            return;
        }

        if (_keybindings.Matches(input, TuiKeybindings.EditorCursorLeft))
        {
            MoveLeft();
            return;
        }

        if (_keybindings.Matches(input, TuiKeybindings.EditorCursorRight))
        {
            MoveRight();
            return;
        }

        if (_keybindings.Matches(input, TuiKeybindings.EditorCursorUp))
        {
            if (!TryNavigateHistory(-1)) MoveVertical(-1);
            return;
        }

        if (_keybindings.Matches(input, TuiKeybindings.EditorCursorDown))
        {
            if (!TryNavigateHistory(1)) MoveVertical(1);
            return;
        }

        if (_keybindings.Matches(input, TuiKeybindings.EditorCursorLineStart))
        {
            MoveToLineStart();
            return;
        }

        if (_keybindings.Matches(input, TuiKeybindings.EditorCursorLineEnd))
        {
            MoveToLineEnd();
            return;
        }

        if (_keybindings.Matches(input, TuiKeybindings.InputCancel))
            Cancel();
    }
}