#include "alfpriv.h"

/* LABEL */

typedef struct {
    DWORD    style;
    HFONT    font;
    ALFColor bgcolor;
    ALFColor textcolor;
    int      dpi;
} ALFLabelPriv;

static int
ALF__LabelTopPadding(HWND hwnd, ALFLabelPriv *priv)
{
    (void)hwnd;

    // some pixels on top to align with the edit control
    // see also: alfedit.cpp
    return ALF_Compat_GetSystemMetricsForDpi(
                SM_CYEDGE, (UINT)priv->dpi)
            + (!ALF_Compat_IsMinWindowsVersion(4, 0) ? 2 : 1) /* internal padding in edit control */;
}

static int
ALF__LabelLeftPadding(HWND hwnd, HDC hdc, ALFLabelPriv *priv)
{
    (void)hwnd;

    // some pixels on the left to align with the edit control
    // see also: alfedit.cpp
    int p = ALF_Compat_GetSystemMetricsForDpi(
                SM_CXEDGE, (UINT)priv->dpi);

    p += 1;

    TEXTMETRIC tm;
    ZeroMemory(&tm, sizeof(tm));
    if (GetTextMetrics(hdc, &tm)) {
        if (tm.tmPitchAndFamily & (TMPF_VECTOR | TMPF_TRUETYPE))
            p += ALF_GetAveCharWidth(hdc) / 2;
    }

    return p;
}

static void
ALF_Label_Paint(HWND hwnd, ALFLabelPriv *priv, HDC hdc, RECT *r)
{
    if (priv->bgcolor == ALF_COLOR_TRANSPARENT) {
        ALF_Compat_DrawThemeParentBackground(hwnd, hdc, r);
        SetBkMode(hdc, TRANSPARENT);
    } else {
        ALF_FillRect(hdc, r, priv->bgcolor);
        SetBkMode(hdc, OPAQUE);
        SetBkColor(hdc, ALF_ColorToGdi(priv->bgcolor));
    }

    HFONT oldFont = SelectFont(hdc, priv->font);
    SetTextColor(hdc, ALF_ColorToGdi(priv->textcolor));

    TCHAR *text = ALF_Text(hwnd);

    // calc drawtext style
    UINT format = DT_EXPANDTABS | DT_NOCLIP;

    LRESULT uiState = SendMessage(hwnd, WM_QUERYUISTATE, 0, 0);
    if (uiState & UISF_HIDEACCEL)
        format |= DT_HIDEPREFIX;

    // calculate text position
    RECT rcClient = { 0, 0, 0, 0 };
    GetClientRect(hwnd, &rcClient);

    RECT rcText = { 0, 0, 0, 0 };
    DrawText(hdc, text, -1, &rcText, DT_EXPANDTABS | DT_CALCRECT);

    RECT rcTarget = { 0, 0, 0, 0 };

    switch (priv->style & ALF_LABEL_HALIGN_MASK) {
        case ALF_LABEL_ALIGN_LEFT:
            format |= DT_LEFT;
            rcTarget.left = 0;
            rcTarget.right = rcText.right - rcText.left;
            break;
        case ALF_LABEL_ALIGN_LEFT_LIKE_EDIT:
            format |= DT_LEFT;
            rcTarget.left  = ALF__LabelLeftPadding(hwnd, hdc, priv);
            rcTarget.right = rcTarget.left + rcText.right - rcText.left;
            break;
        case ALF_LABEL_ALIGN_HCENTER:
            format |= DT_CENTER;
            rcTarget.left  = (rcClient.right - rcClient.left - rcText.right + rcText.left)/2;
            rcTarget.right = rcTarget.left + rcText.right - rcText.left;
            break;
        case ALF_LABEL_ALIGN_RIGHT:
            format |= DT_RIGHT;
            rcTarget.right = rcClient.right - rcClient.left;
            rcTarget.left  = rcTarget.right - rcText.right + rcText.left;
            break;
    }
    switch (priv->style & ALF_LABEL_VALIGN_MASK) {
        case ALF_LABEL_ALIGN_TOP:
            format |= DT_TOP;
            rcTarget.top    = 0;
            rcTarget.bottom = rcText.bottom - rcText.top;
            break;
        case ALF_LABEL_ALIGN_TOP_LIKE_EDIT:
            format |= DT_TOP;
            rcTarget.top    = ALF__LabelTopPadding(hwnd, priv);
            rcTarget.bottom = rcTarget.top + rcText.bottom - rcText.top;
            break;
        case ALF_LABEL_ALIGN_BOTTOM:
            format |= DT_BOTTOM;
            rcTarget.bottom = rcClient.bottom - rcClient.top;
            rcTarget.top    = rcTarget.bottom - rcText.bottom + rcText.top;
            break;
        case ALF_LABEL_ALIGN_VCENTER:
            format |= DT_VCENTER;
            rcTarget.top    = (rcClient.bottom - rcClient.top - rcText.bottom + rcText.top) / 2;
            rcTarget.bottom = rcTarget.top + rcText.bottom - rcText.top;
            break;
    }

    if (!IsWindowEnabled(hwnd)) {
        ALF_Compat_DrawDisabledText(hdc, text, -1, &rcTarget, format);
    } else {
        DrawText(hdc, text, -1, &rcTarget, format);
    }

    ALF_Free(text);

    SelectFont(hdc, oldFont);
}

static void
ALF_Label_CalculateSize(HWND hwnd, ALFLabelPriv *priv, SIZE *pSize)
{
    int textlen = GetWindowTextLength(hwnd);
    if (textlen) {
        HDC hdcLabel = GetDC(hwnd);
        HFONT oldFont = SelectFont(hdcLabel, priv->font);

        // calc drawtext style
        UINT format = DT_LEFT | DT_EXPANDTABS | DT_CALCRECT;

        RECT r = { 0, 0, 100, 100 };

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

        DrawText(hdcLabel, textbuf, -1, &r, format);

        ALF_Free(textbuf);

        int cx = r.right - r.left;
        if ((priv->style & ALF_LABEL_HALIGN_MASK) == ALF_LABEL_ALIGN_LEFT_LIKE_EDIT)
            cx += ALF__LabelLeftPadding(hwnd, hdcLabel, priv);

        int cy = r.bottom - r.top;
        if ((priv->style & ALF_LABEL_VALIGN_MASK) == ALF_LABEL_ALIGN_TOP_LIKE_EDIT)
            cy += ALF__LabelTopPadding(hwnd, priv);


        if (pSize->cx < cx)
            pSize->cx = cx;
        if (pSize->cy < cy)
            pSize->cy = cy;

        SelectFont(hdcLabel, oldFont);

        ReleaseDC(hwnd, hdcLabel);
    }
}

static LRESULT CALLBACK
ALF__LabelWindowProc(HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
{
    ALFLabelPriv *priv = (ALFLabelPriv*)GetWindowLongPtr(hwnd, 0);
    if (!priv)
        return DefWindowProc(hwnd, uMsg, wParam, lParam);

    if (uMsg == ALF_WM_LBL_GETSTYLE) {
        return (LRESULT)priv->style;
    } else if (uMsg == ALF_WM_LBL_SETSTYLE) {
        DWORD newStyle = (DWORD)lParam;

        // if the ALF_LABEL_ALIGN_LEFT_LIKE_EDIT or ALF_LABEL_ALIGN_TOP_LIKE_EDIT
        // styles have been toggled, a new layout calculation is necessary
        if (((newStyle & ALF_LABEL_HALIGN_MASK) != (priv->style & ALF_LABEL_HALIGN_MASK)
                && ((newStyle & ALF_LABEL_HALIGN_MASK) == ALF_LABEL_ALIGN_LEFT_LIKE_EDIT
                    || (priv->style & ALF_LABEL_HALIGN_MASK) == ALF_LABEL_ALIGN_LEFT_LIKE_EDIT))
            || ((newStyle & ALF_LABEL_VALIGN_MASK) != (priv->style & ALF_LABEL_VALIGN_MASK)
                && ((newStyle & ALF_LABEL_VALIGN_MASK) == ALF_LABEL_ALIGN_TOP_LIKE_EDIT
                    || (priv->style & ALF_LABEL_VALIGN_MASK) == ALF_LABEL_ALIGN_TOP_LIKE_EDIT))) {
            ALF_InvalidateLayout(GetParent(hwnd));
        }

        priv->style = newStyle;
        InvalidateRect(hwnd, NULL, TRUE);
        return TRUE;
    } else if (uMsg == WM_SETTEXT) {
        InvalidateRect(hwnd, NULL, TRUE);
        ALF_InvalidateLayout(GetParent(hwnd));
    } else if (uMsg == WM_GETDLGCODE) {
        return DLGC_STATIC;
    } else if (uMsg == WM_SETFONT) {
        priv->font = (HFONT)wParam;
        if (LOWORD(lParam) != 0)
            InvalidateRect(hwnd, NULL, TRUE);

        ALF_InvalidateLayout(GetParent(hwnd));

        return 0;
    } else if (uMsg == WM_GETFONT) {
        return (LRESULT)priv->font;
    } else if (uMsg == WM_UPDATEUISTATE) {
        InvalidateRect(hwnd, NULL, TRUE);
    } else if (uMsg == WM_ERASEBKGND) {
        return 1; // do it in WM_PAINT
    } else if (uMsg == WM_PAINT) {
        PAINTSTRUCT ps;
        HDC hdc = BeginPaint(hwnd, &ps);

        ALF_Label_Paint(hwnd, priv, hdc, &ps.rcPaint);

        EndPaint(hwnd, &ps);

        return TRUE;
    } else if (uMsg == WM_PRINTCLIENT) {
        RECT rc;
        GetClientRect(hwnd, &rc);

        ALF_Label_Paint(hwnd, priv, (HDC)wParam, &rc);
    } else if (uMsg == ALF_WM_QUERYSIZE) {
        ALF_Label_CalculateSize(hwnd, priv, (SIZE*)lParam);
    } else if (uMsg == WM_WINDOWPOSCHANGED) {
        WINDOWPOS *p = (WINDOWPOS *)lParam;
        if (!(p->flags & SWP_NOSIZE)) {
            // for left-top aligned labels, no redraw is necessary
            // right/bottom/center alignment basically needs to redraw the whole thing
            DWORD halign = priv->style & ALF_LABEL_HALIGN_MASK;
            DWORD valign = priv->style & ALF_LABEL_VALIGN_MASK;

            if ((halign != ALF_LABEL_ALIGN_LEFT && halign != ALF_LABEL_ALIGN_LEFT_LIKE_EDIT)
                    || (valign != ALF_LABEL_ALIGN_TOP && valign != ALF_LABEL_ALIGN_TOP_LIKE_EDIT)) {
                InvalidateRect(hwnd, NULL, TRUE);
            }
        }
    } else if (uMsg == ALF_WM_BACKGROUNDCHANGE) {
        if (priv->bgcolor == ALF_COLOR_TRANSPARENT) {
            InvalidateRect(hwnd, NULL, TRUE);
        }
        return TRUE;
    } else if (uMsg == ALF_WM_SETBGCOLOR) {
        ALFColor newcolor = (ALFColor)lParam;
        if (priv->bgcolor == newcolor)
            return TRUE;

        priv->bgcolor = newcolor;
        InvalidateRect(hwnd, NULL, TRUE);

        return TRUE;
    } else if (uMsg == ALF_WM_GETBGCOLOR) {
        return (LRESULT)priv->bgcolor;
    } else if (uMsg == ALF_WM_SETTEXTCOLOR) {
        ALFColor newcolor = (ALFColor)lParam;
        if (priv->textcolor == newcolor)
            return TRUE;

        priv->textcolor = newcolor;
        InvalidateRect(hwnd, NULL, TRUE);

        return TRUE;
    } else if (uMsg == ALF_WM_GETTEXTCOLOR) {
        return (LRESULT)priv->textcolor;
    } else if (uMsg == ALF_WM_DPICHANGE) {
        priv->dpi = (int)lParam;
        ALF_InvalidateLayout(GetParent(hwnd));
        return TRUE;
    } else if (uMsg == WM_DESTROY) {
        ALF_Free(priv);
        SetWindowLongPtr(hwnd, 0, 0);
    }

    return DefWindowProc(hwnd, uMsg, wParam, lParam);
}

HWND
ALF_AddLabel(HWND win, WORD id, int x, int y, const TCHAR *text)
{
    HWND hwndLabel = ALF_CreateControlWindow(0,
                                             text,
                                             WS_CHILD | WS_VISIBLE,
                                             0, 0, 100, 100,
                                             win,
                                             (HMENU)(ULONG_PTR)id,
                                             ALF__LabelWindowProc,
                                             NULL);

    ALFLabelPriv *priv = ALF_New(ALFLabelPriv, 1);
    priv->style = ALF_LABEL_ALIGN_LEFT | ALF_LABEL_ALIGN_TOP_LIKE_EDIT;
    priv->bgcolor = ALF_COLOR_SYS(COLOR_BTNFACE);
    priv->textcolor = ALF_COLOR_SYS(COLOR_BTNTEXT);
    priv->dpi = 96;
    SetWindowLongPtr(hwndLabel, 0, (LONG_PTR)priv);

    ALF_AddWidget(win, x, y, hwndLabel, 0, 0, ALF_LAYOUT_SIZE_QUERY | ALF_LAYOUT_INHERITFONT | ALF_LAYOUT_INHERITBGCOLOR | ALF_LAYOUT_SENDBGCHANGE | ALF_LAYOUT_SENDDPICHANGE);

    return hwndLabel;
}

DWORD
ALF_LabelStyle(HWND hwndLabel)
{
    return (DWORD)SendMessage(hwndLabel, ALF_WM_LBL_GETSTYLE, 0, 0);
}

void
ALF_LabelSetStyle(HWND hwndLabel, DWORD style)
{
    SendMessage(hwndLabel, ALF_WM_LBL_SETSTYLE, 0, (LPARAM)style);
}