//========================================================================
// GLFW - An OpenGL library
// Platform:    X11 (Unix)
// API version: 3.0
// WWW:         http://www.glfw.org/
//------------------------------------------------------------------------
// Copyright (c) 2002-2006 Marcus Geelnard
// Copyright (c) 2006-2010 Camilla Berglund <elmindreda@elmindreda.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>

// The MinGW package for Debian lacks this
#ifndef EDS_ROTATEDMODE
#define EDS_ROTATEDMODE 0x00000004
#endif


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

_GLFWmonitor** _glfwCreateMonitor(_GLFWmonitor** current,
                                  DISPLAY_DEVICE* adapter,
                                  DISPLAY_DEVICE* monitor,
                                  DEVMODE* setting)
{
    HDC dc = NULL;

    *current = _glfwMalloc(sizeof(_GLFWmonitor));
    memset(*current, 0, sizeof(_GLFWmonitor));

    dc = CreateDC("DISPLAY", monitor->DeviceString, NULL, NULL);

    (*current)->physicalWidth  = GetDeviceCaps(dc, HORZSIZE);
    (*current)->physicalHeight = GetDeviceCaps(dc, VERTSIZE);

    DeleteDC(dc);

    (*current)->name = _glfwMalloc(strlen(monitor->DeviceName) + 1);
    memcpy((*current)->name, monitor->DeviceName, strlen(monitor->DeviceName) + 1);
    (*current)->name[strlen(monitor->DeviceName)] = '\0';

    (*current)->screenX = setting->dmPosition.x;
    (*current)->screenY = setting->dmPosition.y;

    memcpy((*current)->Win32.name, adapter->DeviceName, 32);
    return &((*current)->next);
}

_GLFWmonitor* _glfwDestroyMonitor(_GLFWmonitor* monitor)
{
    _GLFWmonitor* result;

    result = monitor->next;

    _glfwFree(monitor->name);
    _glfwFree(monitor);

    return result;
}

// todo: This is ugly. The platform should only allocate a list of the current devices.
// The platform independent code should be in charge of the handling for the initial
// setup, refreshing and freeing the list.
void _glfwInitMonitors(void)
{
    _GLFWmonitor** curMonitor;

    DISPLAY_DEVICE adapter;
    DWORD adapterNum;

    DISPLAY_DEVICE monitor;

    DEVMODE setting;
    DWORD settingNum;

    curMonitor = &_glfwLibrary.monitorListHead;

    adapter.cb = sizeof(DISPLAY_DEVICE);
    adapterNum = 0;

    monitor.cb = sizeof(DISPLAY_DEVICE);
    setting.dmSize = sizeof(DEVMODE);
    settingNum = 0;

    while (EnumDisplayDevices(NULL, adapterNum++, &adapter, 0))
    {
        if (adapter.StateFlags & DISPLAY_DEVICE_MIRRORING_DRIVER || !(adapter.StateFlags & DISPLAY_DEVICE_ACTIVE))
            continue;

        EnumDisplaySettingsEx(adapter.DeviceName,
                              ENUM_CURRENT_SETTINGS,
                              &setting,
                              EDS_ROTATEDMODE);

        EnumDisplayDevices(adapter.DeviceName, 0, &monitor, 0);

        curMonitor = _glfwCreateMonitor(curMonitor, &adapter, &monitor, &setting);
    }
}

void _glfwRefreshMonitors(void)
{
    DISPLAY_DEVICE adapter;
    DWORD adapterNum = 0;

    DISPLAY_DEVICE monitor;

    DEVMODE setting;

    _GLFWmonitor* newMonitorList = NULL;
    _GLFWmonitor** curMonitor = &newMonitorList;

    _GLFWmonitor* curNewMonitor;
    _GLFWmonitor* curOldMonitor;

    while (EnumDisplayDevices(NULL, adapterNum++, &adapter, 0))
    {
        if (adapter.StateFlags & DISPLAY_DEVICE_MIRRORING_DRIVER || !(adapter.StateFlags & DISPLAY_DEVICE_ACTIVE))
            continue;

        EnumDisplaySettingsEx(adapter.DeviceName, ENUM_CURRENT_SETTINGS, &setting, EDS_ROTATEDMODE);

        EnumDisplayDevices(adapter.DeviceName, 0, &monitor, 0);

        curMonitor = _glfwCreateMonitor(curMonitor, &adapter, &monitor, &setting);
    }

    curNewMonitor = newMonitorList;
    curOldMonitor = _glfwLibrary.monitorListHead;

    while (_glfwLibrary.monitorCallback && (curNewMonitor || curOldMonitor))
    {
        _GLFWmonitor* lookAheadOldMonitor;
        _GLFWmonitor* lookAheadNewMonitor;

        if (curOldMonitor && curNewMonitor && !strcmp(curOldMonitor->name, curOldMonitor->name))
        {
            curNewMonitor = curNewMonitor->next;
            curOldMonitor = curOldMonitor->next;
            continue;
        }

        if (curNewMonitor && !curOldMonitor)
        {
            _glfwLibrary.monitorCallback(curNewMonitor, GLFW_MONITOR_CONNECTED);
            curNewMonitor = curNewMonitor->next;
            continue;
        }

        if (!curNewMonitor && curOldMonitor)
        {
            _glfwLibrary.monitorCallback(curOldMonitor, GLFW_MONITOR_DISCONNECTED);
            curOldMonitor = curOldMonitor->next;
            continue;
        }

        lookAheadOldMonitor = curOldMonitor->next;
        lookAheadNewMonitor = curNewMonitor->next;

        while (lookAheadOldMonitor && !strcmp(curNewMonitor->name, lookAheadOldMonitor->name))
            lookAheadOldMonitor = lookAheadOldMonitor->next;

        while (lookAheadNewMonitor && !strcmp(curOldMonitor->name, lookAheadNewMonitor->name))
            lookAheadNewMonitor = lookAheadNewMonitor->next;

        if (!lookAheadOldMonitor)
        {
            // nothing found in the old monitor list, that matches the current new monitor.
            _glfwLibrary.monitorCallback(curNewMonitor, GLFW_MONITOR_CONNECTED);
            curNewMonitor = curNewMonitor->next;
        }
        else
        {
            while (strcmp(curOldMonitor->name, lookAheadOldMonitor->name))
            {
                _glfwLibrary.monitorCallback(curOldMonitor, GLFW_MONITOR_DISCONNECTED);
                curOldMonitor = curOldMonitor->next;
            }
        }

        if (!lookAheadNewMonitor)
        {
            // nothing found in the new monitor list, that matches the current old monitor.
            _glfwLibrary.monitorCallback(curOldMonitor, GLFW_MONITOR_DISCONNECTED);
            curOldMonitor = curOldMonitor->next;
        }
        else
        {
            while (strcmp(curNewMonitor->name, lookAheadNewMonitor->name))
            {
                _glfwLibrary.monitorCallback(curNewMonitor, GLFW_MONITOR_CONNECTED);
                curNewMonitor = curNewMonitor->next;
            }
        }
    }

    _glfwTerminateMonitors();
    _glfwLibrary.monitorListHead = newMonitorList;
}