using System.Numerics;

namespace AcDream.App.UI;

/// <summary>
/// Per-event payload delivered to <see cref="UiElement.OnEvent"/>.
/// Mirrors the retail AC client's 24-byte event struct that is passed to
/// every widget's vtable slot +0x128 (<c>OnEvent(int* event)</c>).
///
/// Layout from decompiled <c>chunk_004A0000.c</c> paperdoll handler
/// <c>FUN_004A5FA0</c>:
/// <code>
///   int      source_id;      // param_2[0]  — e.g. 0x100001d6 (drag source)
///   void*    target_widget;  // param_2[1]
///   int      event_type;     // param_2[2]  — see UiEventType
///   int      data0;          // param_2[3]
///   int      data1;          // param_2[4]  — typically x in local coords
///   int      data2;          // param_2[5]  — typically y
///   int      data3;          // param_2[6]
/// </code>
/// </summary>
public readonly record struct UiEvent(
    uint SourceId,
    UiElement? Target,
    int Type,               // see <see cref="UiEventType"/>
    int Data0 = 0,
    int Data1 = 0,
    int Data2 = 0,
    int Data3 = 0,
    object? Payload = null);

/// <summary>
/// Retail AC UI event-type constants. Each value matches the decompiled
/// switch-case in widgets' OnEvent handlers (e.g. 0x01 click, 0x15 drag
/// begin, 0x3E drop released). Win32 WM_* numbers are reused for raw
/// button/key/mouse events (0x200 = WM_MOUSEMOVE etc.) — this matches
/// retail where internal event codes collide deliberately with WM_*.
///
/// Evidence from decompile:
/// - 0x01 click      — chunk_00470000.c ~11140, chunk_004C0000.c ~9270
/// - 0x05/0x06 hover — chunk_00460000.c ~6253
/// - 0x07 tooltip    — chunk_00460000.c ~6253 (delayed via
///                      Device::RegisterTimerEvent(7, widget, delayMs))
/// - 0x0A scroll     — chunk_00470000.c ~11210
/// - 0x0E right-click— chunk_004A0000.c ~2674
/// - 0x15 drag begin — chunk_004A0000.c ~2707
/// - 0x1C drag-over  — chunk_004A0000.c ~2723
/// - 0x21 drag-enter — chunk_004A0000.c ~2714
/// - 0x3E drop-released — chunk_004A0000.c ~2754
/// </summary>
public static class UiEventType
{
    public const int Click        = 0x01;
    public const int HoverEnter   = 0x05;
    public const int HoverLeave   = 0x06;
    public const int Tooltip      = 0x07;
    public const int DoubleClick  = 0x08;
    public const int Scroll       = 0x0A;
    public const int RightClick   = 0x0E;
    public const int DragBegin    = 0x15;
    public const int DragOver     = 0x1C;
    public const int DragEnter    = 0x21;
    public const int FocusLost    = 0x28;
    public const int FocusGained  = 0x29;
    public const int DropReleased = 0x3E;

    // Raw Win32-style event numbers (retail uses WM_* verbatim for internal dispatch).
    public const int MouseMove    = 0x200;
    public const int MouseDown    = 0x201;   // left button down
    public const int MouseUp      = 0x202;   // left button up
    public const int DoubleClickLeft = 0x203;
    public const int RightDown    = 0x204;
    public const int RightUp      = 0x205;
    public const int MiddleDown   = 0x207;
    public const int MiddleUp     = 0x208;

    public const int KeyDown      = 0x100;
    public const int KeyUp        = 0x101;
    public const int Char         = 0x102;
}

/// <summary>
/// Mouse button enum matching retail's 1/2/3 encoding.
/// </summary>
public enum UiMouseButton
{
    Left   = 1,
    Right  = 2,
    Middle = 3,
}