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) : IInputComponent
{
    private readonly ITextMeasurer _textMeasurer = textMeasurer ?? new TerminalTextMeasurer();
    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;

    /// <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, Value: var key } when key == KeyNames.Ctrl("z"):
                Undo();
                break;
            case { Kind: TuiInputEventKind.Key, Value: var key } when key == KeyNames.Ctrl("y"):
                Redo();
                break;
            case { Kind: TuiInputEventKind.Key, Value: var key } when key == KeyNames.Ctrl("c"):
                Edit(ClearText);
                break;
            case { Kind: TuiInputEventKind.Key, Value: var key } when key == KeyNames.Ctrl(KeyNames.Left):
                MoveWordLeft();
                break;
            case { Kind: TuiInputEventKind.Key, Value: var key } when key == KeyNames.Ctrl(KeyNames.Right):
                MoveWordRight();
                break;
            case { Kind: TuiInputEventKind.Key, Value: var key } when key == KeyNames.Ctrl(KeyNames.Backspace):
                Edit(DeleteWordBackward);
                break;
            case { Kind: TuiInputEventKind.Key, Value: var key } when key == KeyNames.Ctrl(KeyNames.Delete):
                Edit(DeleteWordForward);
                break;
            case { Kind: TuiInputEventKind.Key, Value: KeyNames.Enter }:
                Edit(SplitLine);
                break;
            case { Kind: TuiInputEventKind.Key, Value: var key } when key == KeyNames.Ctrl(KeyNames.Enter):
                Submit();
                break;
            case { Kind: TuiInputEventKind.Key, Value: var key } when key == KeyNames.Ctrl("s"):
                Submit();
                break;
            case { Kind: TuiInputEventKind.Key, Value: KeyNames.Backspace }:
                Edit(Backspace);
                break;
            case { Kind: TuiInputEventKind.Key, Value: KeyNames.Delete }:
                Edit(Delete);
                break;
            case { Kind: TuiInputEventKind.Key, Value: KeyNames.Left }:
                MoveLeft();
                break;
            case { Kind: TuiInputEventKind.Key, Value: KeyNames.Right }:
                MoveRight();
                break;
            case { Kind: TuiInputEventKind.Key, Value: KeyNames.Up }:
                if (!TryNavigateHistory(-1)) MoveVertical(-1);
                break;
            case { Kind: TuiInputEventKind.Key, Value: KeyNames.Down }:
                if (!TryNavigateHistory(1)) MoveVertical(1);
                break;
            case { Kind: TuiInputEventKind.Key, Value: KeyNames.Home }:
                MoveToLineStart();
                break;
            case { Kind: TuiInputEventKind.Key, Value: KeyNames.End }:
                MoveToLineEnd();
                break;
            case { Kind: TuiInputEventKind.Key, Value: KeyNames.Escape }:
                Cancel();
                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);
}