#include "alfpriv.h"

TCHAR *_alf_panelClass = NULL;

typedef struct {
    ALFLayout layout;
    HFONT font;
} ALFPanelPriv;

static void
ALF_Panel_IntializePriv(ALFPanelPriv *priv)
{
    ALF_Layout_Init(&priv->layout);
}

static void
ALF_Panel_ClearPriv(ALFPanelPriv *priv)
{
    ALF_Layout_Clear(&priv->layout);
}

static void
ALF_Panel_Paint(ALFPanelPriv *priv, HWND hwnd, HDC dc, RECT *r)
{
    (void)priv;
    ALF_Compat_DrawThemeParentBackground(hwnd, dc, r);

    int textlen = GetWindowTextLength(hwnd);
    if (textlen < 1)
        return;

    TCHAR *textbuf = ALF_New(TCHAR, textlen + 1);
    GetWindowText(hwnd, textbuf, textlen+1);

    HFONT oldFont = SelectFont(dc, priv->font);

    SetTextColor(dc, GetSysColor(COLOR_BTNTEXT));
    SetBkMode(dc, TRANSPARENT);

    RECT rc;
    GetClientRect(hwnd, &rc);

    DrawText(dc, textbuf, -1, &rc, DT_SINGLELINE | DT_EXPANDTABS | DT_HIDEPREFIX | DT_CENTER | DT_VCENTER);

    ALF_Free(textbuf);

    SelectFont(dc, oldFont);
}

static LRESULT WINAPI
ALF__PanelWindowProc(HWND window, UINT msg, WPARAM wparam, LPARAM lparam)
{
    if (msg == WM_NCCREATE) {
        ALFPanelPriv *p = ALF_New(ALFPanelPriv, 1);

        ALF_Panel_IntializePriv(p);

        SetWindowLongPtr(window, 0, (LONG_PTR)p);
    }

    ALFPanelPriv *priv = (ALFPanelPriv *)GetWindowLongPtr(window, 0);

    if (msg == WM_NCDESTROY) {
        ALF_Panel_ClearPriv(priv);
        ALF_Free(priv);
        SetWindowLongPtr(window, 0, 0);
    }

    if (msg == WM_ERASEBKGND) {
        return TRUE;
    }

    if (msg == WM_SETFONT) {
        priv->font = (HFONT)wparam;
        if (LOWORD(lparam) != 0)
            InvalidateRect(window, NULL, TRUE);

        // fallthrough to layout, will propagate font to children
    }

    if (msg == WM_GETFONT) {
        return (LRESULT)priv->font;
    }

    if (msg == WM_SETTEXT) {
        InvalidateRect(window, NULL, TRUE);
    }

    if (msg == WM_PRINTCLIENT) {
        RECT r = { 0, 0, 0, 0 };
        GetClientRect(window, &r);

        ALF_Panel_Paint(priv, window, (HDC)wparam, &r);
        return TRUE;
    }

    if (msg == WM_PAINT) {
        PAINTSTRUCT ps;
        HDC dc = BeginPaint(window, &ps);

        ALF_Panel_Paint(priv, window, dc, &ps.rcPaint);

        EndPaint(window, &ps);

        return 0;
    }

    if (ALF_ShouldMessageBubble(window, msg, wparam, lparam))
        return SendMessage(GetParent(window), msg, wparam, lparam);

    if (msg == WM_SIZE) {
        ALF_Layout_Apply(&priv->layout, window);
    }

    LRESULT ret = 0;
    if (ALF_Layout_HandleMessage(&priv->layout, window, msg, wparam, lparam, &ret))
        return ret;

    return DefWindowProc(window, msg, wparam, lparam);
}

void
ALF_RegisterPanelClass(void)
{
    WNDCLASS cls;
    ZeroMemory(&cls, sizeof(cls));

    TCHAR  classNameBuf[256];
    ALF_BuildUniqueName(classNameBuf, TEXT("ALFPanel."), (ULONG_PTR)&_alf_panelClass);

    cls.hInstance = ALF_HINSTANCE;
    cls.hCursor = LoadCursor(NULL, (LPTSTR)IDC_ARROW);
    cls.lpszClassName = classNameBuf;
    cls.cbWndExtra = sizeof(void*);
    cls.lpfnWndProc = ALF__PanelWindowProc;

    ATOM classatom = RegisterClass(&cls);
    if (!classatom)
        MessageBox(NULL, TEXT("FATAL: Could not register panel class"), NULL, MB_OK);

    _alf_panelClass = MAKEINTATOM(classatom);
}

HWND
ALF_CreatePanelWindow(HWND parent, WORD id)
{
    return CreateWindowEx(WS_EX_CONTROLPARENT,
                          _alf_panelClass,
                          TEXT(""),
                          WS_CHILD | WS_VISIBLE | WS_CLIPCHILDREN,
                          0, 0, 0, 0,
                          parent,
                          (HMENU)(int)id,
                          ALF_HINSTANCE,
                          NULL);
}

HWND
ALF_AddPanel(HWND parent, WORD id, int x, int y)
{
    HWND hwndPanel = ALF_CreatePanelWindow(parent, id);

    ALF_AddWidget(parent, x, y, hwndPanel, 0, 0, ALF_LAYOUT_SIZE_QUERY | ALF_LAYOUT_INHERITFONT);

    return hwndPanel;
}