#include "alfpriv.h"

typedef struct {
    ALFAPP app;
    DWORD  comboStyle;
} ALFComboCreateParams;

static int
ALF__ComboItemHeight(HWND hwnd)
{
    int height = 0;
    HDC hDc = GetDC(hwnd);
    HFONT font = (HFONT)SendMessage(hwnd, WM_GETFONT, 0, 0);
    if (font) {
        HFONT oldfont = SelectFont(hDc, font);

        TEXTMETRIC tm;
        ZeroMemory(&tm, sizeof(tm));

        if (GetTextMetrics(hDc, &tm)) {
            height = tm.tmHeight;
        }

        SelectFont(hDc, oldfont);
    }

    ReleaseDC(hwnd, hDc);
    return height;
}

static LRESULT CALLBACK
ALF__ComboWindowProc(HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
{
    if (uMsg == WM_NCCREATE) {
        ALFComboCreateParams *params = (ALFComboCreateParams*)((CREATESTRUCT*)lParam)->lpCreateParams;

        SetWindowLongPtr(hwnd, 0, (LONG_PTR)params->app);
    }

    ALFAPP app = (ALFAPP)GetWindowLongPtr(hwnd, 0);
    HWND   hwndChild = (HWND)GetWindowLongPtr(hwnd, sizeof(void*));

    if (uMsg == WM_CREATE) {
        ALFComboCreateParams *params = (ALFComboCreateParams*)((CREATESTRUCT*)lParam)->lpCreateParams;
        HWND hwndCombo = CreateWindowEx(0,
                                        TEXT("COMBOBOX"),
                                        TEXT(""),
                                        WS_CHILD | WS_VISIBLE | WS_TABSTOP | CBS_OWNERDRAWFIXED | CBS_HASSTRINGS | params->comboStyle,
                                        0, 0, 0, 200 /* FIXME needed for commctl32 v5, what is the best value here? */,
                                        hwnd,
                                        (HMENU) GetWindowLongPtrW(hwnd, GWLP_ID),
                                        ((CREATESTRUCT*)lParam)->hInstance,
                                        NULL);

        SetWindowLongPtr(hwnd, sizeof(void*), (LONG_PTR)hwndCombo);
    }
    if (uMsg == WM_ENABLE && hwndChild) {
        EnableWindow(hwndChild, (BOOL)wParam);
        return 0;
    }
    if (uMsg == WM_SETTEXT && hwndChild) {
        LRESULT index = SendMessage(hwndChild, CB_FINDSTRINGEXACT, (WPARAM)-1, lParam);
        if (index >= 0) {
            SendMessage(hwnd, CB_SETCURSEL, (WPARAM)index, 0);
        } else {
            return SendMessage(hwndChild, WM_SETTEXT, wParam, lParam);
        }
    }
    if (uMsg == WM_GETTEXTLENGTH && hwndChild) {
        if ((GetWindowLong(hwndChild, GWL_STYLE) & CBS_DROPDOWNLIST) == CBS_DROPDOWNLIST) {
            int index = SendMessage(hwndChild, CB_GETCURSEL, 0, 0);
            if (index != CB_ERR) {
                return SendMessage(hwndChild, CB_GETLBTEXTLEN, (WPARAM)index, 0);
            }
        }
        return SendMessage(hwndChild, WM_GETTEXTLENGTH, wParam, lParam);
    }
    if (uMsg == WM_GETTEXT && hwndChild) {
        if ((GetWindowLong(hwndChild, GWL_STYLE) & CBS_DROPDOWNLIST) == CBS_DROPDOWNLIST) {
            int index = SendMessage(hwndChild, CB_GETCURSEL, 0, 0);
            if (index != CB_ERR) {
                return SendMessage(hwndChild, CB_GETLBTEXT, (WPARAM)index, lParam);
            }
        }
        return SendMessage(hwndChild, WM_GETTEXT, wParam, lParam);
    }
    if (uMsg == WM_SETFONT && hwndChild) {
        SendMessage(hwndChild, WM_SETFONT, wParam, lParam);

        int h = ALF__ComboItemHeight(hwnd);
        if (h)
            SendMessage(hwndChild, CB_SETITEMHEIGHT, (WPARAM)0, h);

        return 0;
    }
    if (uMsg == WM_GETFONT && hwndChild) {
        return SendMessage(hwndChild, WM_GETFONT, wParam, lParam);
    }
    if (uMsg == CB_ADDSTRING && hwndChild) {
        return SendMessage(hwndChild, CB_ADDSTRING, wParam, lParam);
    }
    if (uMsg == CB_INSERTSTRING && hwndChild) {
        return SendMessage(hwndChild, CB_INSERTSTRING, wParam, lParam);
    }
    if (uMsg == CB_GETCURSEL && hwndChild) {
        return SendMessage(hwndChild, CB_GETCURSEL, wParam, lParam);
    }
    if (uMsg == CB_SETCURSEL && hwndChild) {
        LRESULT curSel = SendMessage(hwndChild, CB_GETCURSEL, wParam, lParam);
        if ((WPARAM)curSel != wParam) {
            LRESULT newSel = SendMessage(hwndChild, CB_SETCURSEL, wParam, lParam);
            SendMessage(hwnd, WM_COMMAND, MAKEWPARAM(GetWindowLong(hwndChild, GWL_ID), CBN_SELCHANGE), (LPARAM)hwndChild);
            return newSel;
        }
    }
    if (uMsg == CB_GETLBTEXTLEN && hwndChild) {
        return SendMessage(hwndChild, CB_GETLBTEXTLEN, wParam, lParam);
    }
    if (uMsg == CB_GETLBTEXT && hwndChild) {
        return SendMessage(hwndChild, CB_GETLBTEXT, wParam, lParam);
    }

    if (uMsg == WM_COMMAND && (HWND)lParam == hwndChild) {
        return SendMessage(GetParent(hwnd), WM_COMMAND, wParam, (LPARAM)hwnd);
    }

    if (uMsg == ALF_WM_QUERYSIZE) {
        HDC hDc = GetDC(hwnd);
        HFONT font = (HFONT)SendMessage(hwnd, WM_GETFONT, 0, 0);

        if (font) {
            HFONT oldfont = SelectFont(hDc, font);

            TEXTMETRIC tm;
            ZeroMemory(&tm, sizeof(tm));

            if (GetTextMetrics(hDc, &tm)) {
                SIZE *ps = (SIZE*)lParam;
                if (!ps->cx) {
                    ps->cx = ALF_CentipointsToPixels(GetParent(hwnd), 12000);
                }

                if (!ps->cy) {
                    ps->cy = tm.tmHeight + 2*app->compatFn->GetSystemMetricsForDpi(
                            SM_CYEDGE, ALF_CentipointsToPixels(GetParent(hwnd), 7200))
                        + 4 /* padding internal to the edit control */
                        + 2 /* external padding to line up with themed button */;
                }
            }

            SelectFont(hDc, oldfont);
        }

        ReleaseDC(hwnd, hDc);
        return 0;
    }

    if (uMsg == WM_MEASUREITEM) {
        PMEASUREITEMSTRUCT lpmis = (LPMEASUREITEMSTRUCT) lParam;

        int h = ALF__ComboItemHeight(hwnd);
        if (h)
            lpmis->itemHeight = h;

        return TRUE;
    }

    if (uMsg == WM_DRAWITEM) {
        LPDRAWITEMSTRUCT lpdis = (LPDRAWITEMSTRUCT) lParam;

        if (lpdis->itemID != (UINT)-1) { // Empty item
            DWORD clrForeground = SetTextColor(lpdis->hDC,
                GetSysColor(lpdis->itemState & (ODS_SELECTED | ODS_FOCUS) ?
                COLOR_HIGHLIGHTTEXT : COLOR_WINDOWTEXT));

            DWORD clrBackground = SetBkColor(lpdis->hDC,
                GetSysColor(lpdis->itemState & (ODS_SELECTED | ODS_FOCUS) ?
                COLOR_HIGHLIGHT : COLOR_WINDOW));

            LONG y = lpdis->rcItem.top;
            LONG x = lpdis->rcItem.left;

            // add left padding like an edit control
            TEXTMETRIC tm;
            ZeroMemory(&tm, sizeof(tm));
            if (GetTextMetrics(lpdis->hDC, &tm)) {
                if (tm.tmPitchAndFamily & (TMPF_VECTOR | TMPF_TRUETYPE))
                    x += ALF_GetAveCharWidth(lpdis->hDC) / 2;
            }

            // Get and display the text for the list item.
            int len = (int)SendMessage(lpdis->hwndItem, CB_GETLBTEXTLEN, (WPARAM)lpdis->itemID, 0);
            if (len != CB_ERR) {
                TCHAR *buf = (TCHAR*)LocalAlloc(LPTR, (len+1) * sizeof(TCHAR));

                SendMessage(lpdis->hwndItem, CB_GETLBTEXT,
                    lpdis->itemID, (LPARAM)buf);

                ExtTextOut(lpdis->hDC, x, y,
                    ETO_CLIPPED | ETO_OPAQUE, &lpdis->rcItem,
                    buf, lstrlen(buf), NULL);

                LocalFree(buf);
            }

            // Restore the previous colors.
            SetTextColor(lpdis->hDC, clrForeground);
            SetBkColor(lpdis->hDC, clrBackground);
        }

        // If the item has the focus, draw the focus rectangle.
        if ((lpdis->itemState & ODS_FOCUS) && !(lpdis->itemState & ODS_NOFOCUSRECT))
            DrawFocusRect(lpdis->hDC, &lpdis->rcItem);

        return TRUE;
    }

    if (uMsg == WM_WINDOWPOSCHANGED && hwndChild) {
        WINDOWPOS *pos = (WINDOWPOS *)lParam;
        if (!(pos->flags & SWP_NOSIZE)) {
            RECT r;
            GetWindowRect(hwndChild, &r);
            SetWindowPos(hwndChild, NULL, 0, 1, pos->cx, r.bottom - r.top, SWP_NOZORDER|SWP_NOACTIVATE);

            SendMessage(hwndChild, CB_SETITEMHEIGHT, (WPARAM)-1, pos->cy - 8);

            int h = ALF__ComboItemHeight(hwnd);
            if (h)
                SendMessage(hwndChild, CB_SETITEMHEIGHT, (WPARAM)0, h);
        }
    }

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


void
ALF_RegisterComboClass(ALFAPP app)
{
    WNDCLASS cls;
    ZeroMemory(&cls, sizeof(cls));

    TCHAR  classNameBuf[256];
    ALF_BuildRandomClassName(TEXT("ALFComboBox."), classNameBuf);

    cls.hInstance = app->hInstance;
    cls.hCursor = LoadCursor(NULL, (LPTSTR)IDC_ARROW);
    cls.hbrBackground = (HBRUSH)(COLOR_BTNFACE+1);
    cls.lpszClassName = classNameBuf;
    cls.cbWndExtra = sizeof(void*)*2;
    cls.lpfnWndProc = ALF__ComboWindowProc;

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

    app->comboClass = MAKEINTATOM(classatom);
}

static HWND
ALF_InternalAddComboBox(HWND win, WORD id, UINT x, UINT y, DWORD style, const TCHAR *defaultText)
{
    ALFComboCreateParams cp;
    cp.app = ALF_ApplicationFromWindow(win);
    cp.comboStyle = style;

    HWND hwndCombo = CreateWindowEx(WS_EX_CONTROLPARENT,
                                    cp.app->comboClass,
                                    TEXT(""),
                                    WS_CHILD | WS_VISIBLE | WS_CLIPCHILDREN,
                                    0, 0, 0, 0,
                                    win,
                                    (HMENU)(int)id,
                                    (HINSTANCE)GetWindowLongPtr(win, GWLP_HINSTANCE),
                                    &cp);

    if (defaultText)
        SetWindowText(hwndCombo, defaultText);

    ALFAddWidgetParams p;
    ZeroMemory(&p, sizeof(p));
    p.hwnd = hwndCombo;
    p.x = x;
    p.y = y;
    p.width = 0;
    p.height = 0;
    p.flags = ALF_QUERYSIZE | ALF_MESSAGEFONT;

    ALF_AddWidgetEx(win, &p);

    return hwndCombo;
}

HWND
ALF_AddEditableComboBox(HWND win, WORD id, UINT x, UINT y, const TCHAR *defaultText)
{
    return ALF_InternalAddComboBox(win, id, x, y, CBS_DROPDOWN, defaultText);
}

HWND
ALF_AddSelectionOnlyComboBox(HWND win, WORD id, UINT x, UINT y)
{
    return ALF_InternalAddComboBox(win, id, x, y, CBS_DROPDOWNLIST, NULL);
}

int /* index */
ALF_ComboBoxAddString(HWND combo, const TCHAR *text)
{
    return (int)SendMessage(combo, CB_ADDSTRING, 0, (LPARAM)text);
}

TCHAR *
ALF_ComboBoxCurrentText(HWND combo)
{
    return ALF_Text(combo);
}

void
ALF_ComboBoxSetText(HWND combo, const TCHAR *text)
{
    return ALF_SetText(combo, text);
}

int
ALF_ComboBoxCurrentIndex(HWND combo)
{
    return (int)SendMessage(combo, CB_GETCURSEL, 0, 0);
}

void
ALF_ComboBoxSetCurrentIndex(HWND combo, int index)
{
    SendMessage(combo, CB_SETCURSEL, (WPARAM)index, 0);
}

TCHAR * // free with HeapFree
ALF_ComboBoxStringForIndex(HWND combo, int index)
{
    int len = (int)SendMessage(combo, CB_GETLBTEXTLEN, (WPARAM)index, 0);
    if (len > 0) {
        TCHAR* buf = (TCHAR*)HeapAlloc(GetProcessHeap(), HEAP_ZERO_MEMORY|HEAP_GENERATE_EXCEPTIONS, (len + 1)*sizeof(WCHAR));
        if (SendMessage(combo, CB_GETLBTEXT, (WPARAM)index, (LPARAM)buf)) {
            return buf;
        } else {
            HeapFree(GetProcessHeap(), 0, buf);
        }
    }

    return NULL;
}

void
ALF_ComboBoxInsertString(HWND combo, int index, const TCHAR *text)
{
    SendMessage(combo, CB_INSERTSTRING, (WPARAM)index, (LPARAM)text);
}

void
ALF_ComboBoxRemoveString(HWND combo, int index)
{
    SendMessage(combo, CB_DELETESTRING, (WPARAM)index, 0);
}