//========================================================================
// GLFW 3.3 Win32 - www.glfw.org
//------------------------------------------------------------------------
// Copyright (c) 2002-2006 Marcus Geelnard
// Copyright (c) 2006-2016 Camilla Löwy <elmindreda@glfw.org>
//
// This software is provided 'as-is', without any express or implied
// warranty. In no event will the authors be held liable for any damages
// arising from the use of this software.
//
// Permission is granted to anyone to use this software for any purpose,
// including commercial applications, and to alter it and redistribute it
// freely, subject to the following restrictions:
//
// 1. The origin of this software must not be misrepresented; you must not
//    claim that you wrote the original software. If you use this software
//    in a product, an acknowledgment in the product documentation would
//    be appreciated but is not required.
//
// 2. Altered source versions must be plainly marked as such, and must not
//    be misrepresented as being the original software.
//
// 3. This notice may not be removed or altered from any source
//    distribution.
//
//========================================================================

#include "internal.h"

#include <stdlib.h>
#include <string.h>
#include <limits.h>
#include <malloc.h>


// Create monitor from an adapter and (optionally) a display
//
static _GLFWmonitor* createMonitor(DISPLAY_DEVICEW* adapter,
                                   DISPLAY_DEVICEW* display)
{
    _GLFWmonitor* monitor;
    char* name;
    HDC dc;

    if (display)
        name = _glfwCreateUTF8FromWideStringWin32(display->DeviceString);
    else
        name = _glfwCreateUTF8FromWideStringWin32(adapter->DeviceString);
    if (!name)
        return NULL;

    dc = CreateDCW(L"DISPLAY", adapter->DeviceName, NULL, NULL);

    monitor = _glfwAllocMonitor(name,
                                GetDeviceCaps(dc, HORZSIZE),
                                GetDeviceCaps(dc, VERTSIZE));

    DeleteDC(dc);
    free(name);

    if (adapter->StateFlags & DISPLAY_DEVICE_MODESPRUNED)
        monitor->win32.modesPruned = GLFW_TRUE;

    wcscpy(monitor->win32.adapterName, adapter->DeviceName);
    WideCharToMultiByte(CP_UTF8, 0,
                        adapter->DeviceName, -1,
                        monitor->win32.publicAdapterName,
                        sizeof(monitor->win32.publicAdapterName),
                        NULL, NULL);

    if (display)
    {
        wcscpy(monitor->win32.displayName, display->DeviceName);
        WideCharToMultiByte(CP_UTF8, 0,
                            display->DeviceName, -1,
                            monitor->win32.publicDisplayName,
                            sizeof(monitor->win32.publicDisplayName),
                            NULL, NULL);
    }

    return monitor;
}


//////////////////////////////////////////////////////////////////////////
//////                       GLFW internal API                      //////
//////////////////////////////////////////////////////////////////////////

// Poll for changes in the set of connected monitors
//
void _glfwPollMonitorsWin32(void)
{
    int i, disconnectedCount;
    _GLFWmonitor** disconnected;
    DWORD adapterIndex, displayIndex;
    DISPLAY_DEVICEW adapter, display;
    GLFWbool hasDisplays = GLFW_FALSE;

    disconnectedCount = _glfw.monitorCount;
    disconnected = calloc(_glfw.monitorCount, sizeof(_GLFWmonitor*));
    memcpy(disconnected,
           _glfw.monitors,
           _glfw.monitorCount * sizeof(_GLFWmonitor*));

    // HACK: Check if any active adapters have connected displays
    //       If not, this is a headless system or a VMware guest

    for (adapterIndex = 0;  ;  adapterIndex++)
    {
        ZeroMemory(&adapter, sizeof(DISPLAY_DEVICEW));
        adapter.cb = sizeof(DISPLAY_DEVICEW);

        if (!EnumDisplayDevicesW(NULL, adapterIndex, &adapter, 0))
            break;

        if (!(adapter.StateFlags & DISPLAY_DEVICE_ACTIVE))
            continue;

        ZeroMemory(&display, sizeof(DISPLAY_DEVICEW));
        display.cb = sizeof(DISPLAY_DEVICEW);

        if (EnumDisplayDevicesW(adapter.DeviceName, 0, &display, 0))
        {
            hasDisplays = GLFW_TRUE;
            break;
        }
    }

    for (adapterIndex = 0;  ;  adapterIndex++)
    {
        int type = _GLFW_INSERT_LAST;

        ZeroMemory(&adapter, sizeof(DISPLAY_DEVICEW));
        adapter.cb = sizeof(DISPLAY_DEVICEW);

        if (!EnumDisplayDevicesW(NULL, adapterIndex, &adapter, 0))
            break;

        if (!(adapter.StateFlags & DISPLAY_DEVICE_ACTIVE))
            continue;

        if (adapter.StateFlags & DISPLAY_DEVICE_PRIMARY_DEVICE)
            type = _GLFW_INSERT_FIRST;

        if (hasDisplays)
        {
            for (displayIndex = 0;  ;  displayIndex++)
            {
                ZeroMemory(&display, sizeof(DISPLAY_DEVICEW));
                display.cb = sizeof(DISPLAY_DEVICEW);

                if (!EnumDisplayDevicesW(adapter.DeviceName, displayIndex, &display, 0))
                    break;

                for (i = 0;  i < disconnectedCount;  i++)
                {
                    if (disconnected[i] &&
                        wcscmp(disconnected[i]->win32.displayName,
                               display.DeviceName) == 0)
                    {
                        disconnected[i] = NULL;
                        break;
                    }
                }

                if (i < disconnectedCount)
                    continue;

                _glfwInputMonitor(createMonitor(&adapter, &display),
                                  GLFW_CONNECTED, type);

                type = _GLFW_INSERT_LAST;
            }
        }
        else
        {
            for (i = 0;  i < disconnectedCount;  i++)
            {
                if (disconnected[i] &&
                    wcscmp(disconnected[i]->win32.adapterName,
                           adapter.DeviceName) == 0)
                {
                    disconnected[i] = NULL;
                    break;
                }
            }

            if (i < disconnectedCount)
                continue;

            _glfwInputMonitor(createMonitor(&adapter, NULL),
                              GLFW_CONNECTED, type);
        }
    }

    for (i = 0;  i < disconnectedCount;  i++)
    {
        if (disconnected[i])
            _glfwInputMonitor(disconnected[i], GLFW_DISCONNECTED, 0);
    }

    free(disconnected);
}

// Change the current video mode
//
GLFWbool _glfwSetVideoModeWin32(_GLFWmonitor* monitor, const GLFWvidmode* desired)
{
    GLFWvidmode current;
    const GLFWvidmode* best;
    DEVMODEW dm;
    LONG result;

    best = _glfwChooseVideoMode(monitor, desired);
    _glfwPlatformGetVideoMode(monitor, &current);
    if (_glfwCompareVideoModes(&current, best) == 0)
        return GLFW_TRUE;

    ZeroMemory(&dm, sizeof(dm));
    dm.dmSize = sizeof(DEVMODEW);
    dm.dmFields           = DM_PELSWIDTH | DM_PELSHEIGHT | DM_BITSPERPEL |
                            DM_DISPLAYFREQUENCY;
    dm.dmPelsWidth        = best->width;
    dm.dmPelsHeight       = best->height;
    dm.dmBitsPerPel       = best->redBits + best->greenBits + best->blueBits;
    dm.dmDisplayFrequency = best->refreshRate;

    if (dm.dmBitsPerPel < 15 || dm.dmBitsPerPel >= 24)
        dm.dmBitsPerPel = 32;

    result = ChangeDisplaySettingsExW(monitor->win32.adapterName,
                                      &dm,
                                      NULL,
                                      CDS_FULLSCREEN,
                                      NULL);
    if (result != DISP_CHANGE_SUCCESSFUL)
    {
        const char* description = "Unknown error";

        if (result == DISP_CHANGE_BADDUALVIEW)
            description = "The system uses DualView";
        else if (result == DISP_CHANGE_BADFLAGS)
            description = "Invalid flags";
        else if (result == DISP_CHANGE_BADMODE)
            description = "Graphics mode not supported";
        else if (result == DISP_CHANGE_BADPARAM)
            description = "Invalid parameter";
        else if (result == DISP_CHANGE_FAILED)
            description = "Graphics mode failed";
        else if (result == DISP_CHANGE_NOTUPDATED)
            description = "Failed to write to registry";
        else if (result == DISP_CHANGE_RESTART)
            description = "Computer restart required";

        _glfwInputError(GLFW_PLATFORM_ERROR,
                        "Win32: Failed to set video mode: %s",
                        description);

        return GLFW_FALSE;
    }

    monitor->win32.modeChanged = GLFW_TRUE;
    return GLFW_TRUE;
}

// Restore the previously saved (original) video mode
//
void _glfwRestoreVideoModeWin32(_GLFWmonitor* monitor)
{
    if (monitor->win32.modeChanged)
    {
        ChangeDisplaySettingsExW(monitor->win32.adapterName,
                                 NULL, NULL, CDS_FULLSCREEN, NULL);
        monitor->win32.modeChanged = GLFW_FALSE;
    }
}


//////////////////////////////////////////////////////////////////////////
//////                       GLFW platform API                      //////
//////////////////////////////////////////////////////////////////////////

void _glfwPlatformGetMonitorPos(_GLFWmonitor* monitor, int* xpos, int* ypos)
{
    DEVMODEW settings;
    ZeroMemory(&settings, sizeof(DEVMODEW));
    settings.dmSize = sizeof(DEVMODEW);

    EnumDisplaySettingsExW(monitor->win32.adapterName,
                           ENUM_CURRENT_SETTINGS,
                           &settings,
                           EDS_ROTATEDMODE);

    if (xpos)
        *xpos = settings.dmPosition.x;
    if (ypos)
        *ypos = settings.dmPosition.y;
}

GLFWvidmode* _glfwPlatformGetVideoModes(_GLFWmonitor* monitor, int* count)
{
    int modeIndex = 0, size = 0;
    GLFWvidmode* result = NULL;

    *count = 0;

    for (;;)
    {
        int i;
        GLFWvidmode mode;
        DEVMODEW dm;

        ZeroMemory(&dm, sizeof(DEVMODEW));
        dm.dmSize = sizeof(DEVMODEW);

        if (!EnumDisplaySettingsW(monitor->win32.adapterName, modeIndex, &dm))
            break;

        modeIndex++;

        // Skip modes with less than 15 BPP
        if (dm.dmBitsPerPel < 15)
            continue;

        mode.width  = dm.dmPelsWidth;
        mode.height = dm.dmPelsHeight;
        mode.refreshRate = dm.dmDisplayFrequency;
        _glfwSplitBPP(dm.dmBitsPerPel,
                      &mode.redBits,
                      &mode.greenBits,
                      &mode.blueBits);

        for (i = 0;  i < *count;  i++)
        {
            if (_glfwCompareVideoModes(result + i, &mode) == 0)
                break;
        }

        // Skip duplicate modes
        if (i < *count)
            continue;

        if (monitor->win32.modesPruned)
        {
            // Skip modes not supported by the connected displays
            if (ChangeDisplaySettingsExW(monitor->win32.adapterName,
                                         &dm,
                                         NULL,
                                         CDS_TEST,
                                         NULL) != DISP_CHANGE_SUCCESSFUL)
            {
                continue;
            }
        }

        if (*count == size)
        {
            size += 128;
            result = (GLFWvidmode*) realloc(result, size * sizeof(GLFWvidmode));
        }

        (*count)++;
        result[*count - 1] = mode;
    }

    if (!*count)
    {
        // HACK: Report the current mode if no valid modes were found
        result = calloc(1, sizeof(GLFWvidmode));
        _glfwPlatformGetVideoMode(monitor, result);
        *count = 1;
    }

    return result;
}

void _glfwPlatformGetVideoMode(_GLFWmonitor* monitor, GLFWvidmode* mode)
{
    DEVMODEW dm;

    ZeroMemory(&dm, sizeof(DEVMODEW));
    dm.dmSize = sizeof(DEVMODEW);

    EnumDisplaySettingsW(monitor->win32.adapterName, ENUM_CURRENT_SETTINGS, &dm);

    mode->width  = dm.dmPelsWidth;
    mode->height = dm.dmPelsHeight;
    mode->refreshRate = dm.dmDisplayFrequency;
    _glfwSplitBPP(dm.dmBitsPerPel,
                  &mode->redBits,
                  &mode->greenBits,
                  &mode->blueBits);
}

void _glfwPlatformGetGammaRamp(_GLFWmonitor* monitor, GLFWgammaramp* ramp)
{
    HDC dc;
    WORD values[768];

    dc = CreateDCW(L"DISPLAY", monitor->win32.adapterName, NULL, NULL);
    GetDeviceGammaRamp(dc, values);
    DeleteDC(dc);

    _glfwAllocGammaArrays(ramp, 256);

    memcpy(ramp->red,   values +   0, 256 * sizeof(unsigned short));
    memcpy(ramp->green, values + 256, 256 * sizeof(unsigned short));
    memcpy(ramp->blue,  values + 512, 256 * sizeof(unsigned short));
}

void _glfwPlatformSetGammaRamp(_GLFWmonitor* monitor, const GLFWgammaramp* ramp)
{
    HDC dc;
    WORD values[768];

    if (ramp->size != 256)
    {
        _glfwInputError(GLFW_PLATFORM_ERROR,
                        "Win32: Gamma ramp size must be 256");
        return;
    }

    memcpy(values +   0, ramp->red,   256 * sizeof(unsigned short));
    memcpy(values + 256, ramp->green, 256 * sizeof(unsigned short));
    memcpy(values + 512, ramp->blue,  256 * sizeof(unsigned short));

    dc = CreateDCW(L"DISPLAY", monitor->win32.adapterName, NULL, NULL);
    SetDeviceGammaRamp(dc, values);
    DeleteDC(dc);
}


//////////////////////////////////////////////////////////////////////////
//////                        GLFW native API                       //////
//////////////////////////////////////////////////////////////////////////

GLFWAPI const char* glfwGetWin32Adapter(GLFWmonitor* handle)
{
    _GLFWmonitor* monitor = (_GLFWmonitor*) handle;
    _GLFW_REQUIRE_INIT_OR_RETURN(NULL);
    return monitor->win32.publicAdapterName;
}

GLFWAPI const char* glfwGetWin32Monitor(GLFWmonitor* handle)
{
    _GLFWmonitor* monitor = (_GLFWmonitor*) handle;
    _GLFW_REQUIRE_INIT_OR_RETURN(NULL);
    return monitor->win32.publicDisplayName;
}