//========================================================================
// 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 <limits.h>
#include <stdlib.h>
#include <string.h>


//------------------------------------------------------------------------
// Display resolution
//------------------------------------------------------------------------

typedef struct
{
    int width;
    int height;
} _GLFWvidsize;


//========================================================================
// List available resolutions
//========================================================================

static _GLFWvidsize* getResolutions(_GLFWmonitor* monitor, int* found)
{
    _GLFWvidsize* result = NULL;

    *found = 0;

    // Build array of available resolutions

    if (_glfwLibrary.X11.RandR.available)
    {
#if defined(_GLFW_HAS_XRANDR)
        XRRScreenResources* sr;
        int i, j, count = monitor->X11.output->nmode;

        sr = XRRGetScreenResources(_glfwLibrary.X11.display,
                                   _glfwLibrary.X11.root);

        result = (_GLFWvidsize*) malloc(sizeof(_GLFWvidsize) * count);

        for (i = 0;  i < count;  i++)
        {
            _GLFWvidsize size;

            for (j = 0;  j < sr->nmode;  j++)
            {
                if (sr->modes[j].id == monitor->X11.output->modes[i])
                    break;
            }

            if (j == sr->nmode)
                continue;

            size.width  = sr->modes[j].width;
            size.height = sr->modes[j].height;

            for (j = 0;  j < *found;  j++)
            {
                if (result[j].width == size.width &&
                    result[j].height == size.height)
                {
                    break;
                }
            }

            if (j < *found)
            {
                // This is a duplicate, so skip it
                continue;
            }

            result[*found] = size;
            (*found)++;
        }

        XRRFreeScreenResources(sr);
#endif /*_GLFW_HAS_XRANDR*/
    }

    if (result == NULL)
    {
        *found = 1;
        result = (_GLFWvidsize*) malloc(sizeof(_GLFWvidsize));

        result[0].width = DisplayWidth(_glfwLibrary.X11.display,
                                       _glfwLibrary.X11.screen);
        result[0].height = DisplayHeight(_glfwLibrary.X11.display,
                                         _glfwLibrary.X11.screen);
    }

    return result;
}


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

//========================================================================
// Finds the video mode closest in size to the specified desired size
//========================================================================

int _glfwGetClosestVideoMode(int* width, int* height, int* rate)
{
    int i, match, bestmatch;

    if (_glfwLibrary.X11.RandR.available)
    {
#if defined(_GLFW_HAS_XRANDR)
        int sizecount, bestsize;
        int ratecount, bestrate;
        short* ratelist;
        XRRScreenConfiguration* sc;
        XRRScreenSize* sizelist;

        sc = XRRGetScreenInfo(_glfwLibrary.X11.display, _glfwLibrary.X11.root);

        sizelist = XRRConfigSizes(sc, &sizecount);

        // Find the best matching mode
        bestsize  = -1;
        bestmatch = INT_MAX;
        for (i = 0;  i < sizecount;  i++)
        {
            match = (*width - sizelist[i].width) *
                    (*width - sizelist[i].width) +
                    (*height - sizelist[i].height) *
                    (*height - sizelist[i].height);
            if (match < bestmatch)
            {
                bestmatch = match;
                bestsize  = i;
            }
        }

        if (bestsize != -1)
        {
            // Report width & height of best matching mode
            *width = sizelist[bestsize].width;
            *height = sizelist[bestsize].height;

            if (*rate > 0)
            {
                ratelist = XRRConfigRates(sc, bestsize, &ratecount);

                bestrate = -1;
                bestmatch = INT_MAX;
                for (i = 0;  i < ratecount;  i++)
                {
                    match = abs(ratelist[i] - *rate);
                    if (match < bestmatch)
                    {
                        bestmatch = match;
                        bestrate = ratelist[i];
                    }
                }

                if (bestrate != -1)
                    *rate = bestrate;
            }
        }

        XRRFreeScreenConfigInfo(sc);

        if (bestsize != -1)
            return bestsize;
#endif /*_GLFW_HAS_XRANDR*/
    }

    // Default: Simply use the screen resolution
    *width = DisplayWidth(_glfwLibrary.X11.display, _glfwLibrary.X11.screen);
    *height = DisplayHeight(_glfwLibrary.X11.display, _glfwLibrary.X11.screen);

    return 0;
}


//========================================================================
// Change the current video mode
//========================================================================

void _glfwSetVideoModeMODE(int mode, int rate)
{
    if (_glfwLibrary.X11.RandR.available)
    {
#if defined(_GLFW_HAS_XRANDR)
        XRRScreenConfiguration* sc;
        Window root;

        root = _glfwLibrary.X11.root;
        sc   = XRRGetScreenInfo(_glfwLibrary.X11.display, root);

        // Remember old size and flag that we have changed the mode
        if (!_glfwLibrary.X11.FS.modeChanged)
        {
            _glfwLibrary.X11.FS.oldSizeID = XRRConfigCurrentConfiguration(sc, &_glfwLibrary.X11.FS.oldRotation);
            _glfwLibrary.X11.FS.oldWidth  = DisplayWidth(_glfwLibrary.X11.display,
                                                         _glfwLibrary.X11.screen);
            _glfwLibrary.X11.FS.oldHeight = DisplayHeight(_glfwLibrary.X11.display,
                                                          _glfwLibrary.X11.screen);

            _glfwLibrary.X11.FS.modeChanged = GL_TRUE;
        }

        if (rate > 0)
        {
            // Set desired configuration
            XRRSetScreenConfigAndRate(_glfwLibrary.X11.display,
                                      sc,
                                      root,
                                      mode,
                                      RR_Rotate_0,
                                      (short) rate,
                                      CurrentTime);
        }
        else
        {
            // Set desired configuration
            XRRSetScreenConfig(_glfwLibrary.X11.display,
                               sc,
                               root,
                               mode,
                               RR_Rotate_0,
                               CurrentTime);
        }

        XRRFreeScreenConfigInfo(sc);
#endif /*_GLFW_HAS_XRANDR*/
    }
}


//========================================================================
// Change the current video mode
//========================================================================

void _glfwSetVideoMode(int* width, int* height, int* rate)
{
    int bestmode;

    // Find a best match mode
    bestmode = _glfwGetClosestVideoMode(width, height, rate);

    // Change mode
    _glfwSetVideoModeMODE(bestmode, *rate);
}


//========================================================================
// Restore the previously saved (original) video mode
//========================================================================

void _glfwRestoreVideoMode(void)
{
    if (_glfwLibrary.X11.FS.modeChanged)
    {
        if (_glfwLibrary.X11.RandR.available)
        {
#if defined(_GLFW_HAS_XRANDR)
            XRRScreenConfiguration* sc;

            if (_glfwLibrary.X11.RandR.available)
            {
                sc = XRRGetScreenInfo(_glfwLibrary.X11.display,
                                      _glfwLibrary.X11.root);

                XRRSetScreenConfig(_glfwLibrary.X11.display,
                                   sc,
                                   _glfwLibrary.X11.root,
                                   _glfwLibrary.X11.FS.oldSizeID,
                                   _glfwLibrary.X11.FS.oldRotation,
                                   CurrentTime);

                XRRFreeScreenConfigInfo(sc);
            }
#endif /*_GLFW_HAS_XRANDR*/
        }

        _glfwLibrary.X11.FS.modeChanged = GL_FALSE;
    }
}


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


//========================================================================
// Return a list of available monitors
//========================================================================

_GLFWmonitor** _glfwPlatformGetMonitors(int* count)
{
    int found = 0;
    _GLFWmonitor** monitors = NULL;

    if (_glfwLibrary.X11.RandR.available)
    {
#if defined (_GLFW_HAS_XRANDR)
        int i;
        XRRScreenResources* sr;

        sr = XRRGetScreenResources(_glfwLibrary.X11.display,
                                   _glfwLibrary.X11.root);

        monitors = (_GLFWmonitor**) calloc(sr->noutput, sizeof(_GLFWmonitor*));
        if (!monitors)
        {
            XRRFreeScreenResources(sr);

            _glfwSetError(GLFW_OUT_OF_MEMORY, NULL);
            return NULL;
        }

        for (i = 0;  i < sr->noutput;  i++)
        {
            XRROutputInfo* oi;
            XRRCrtcInfo* ci;
            int physicalWidth, physicalHeight;

            oi = XRRGetOutputInfo(_glfwLibrary.X11.display, sr, sr->outputs[i]);
            if (oi->connection != RR_Connected)
            {
                XRRFreeOutputInfo(oi);
                continue;
            }

            if (oi->mm_width && oi->mm_height)
            {
                physicalWidth = oi->mm_width;
                physicalHeight = oi->mm_height;
            }
            else
            {
                physicalWidth = DisplayWidthMM(_glfwLibrary.X11.display,
                                               _glfwLibrary.X11.screen);
                physicalHeight = DisplayHeightMM(_glfwLibrary.X11.display,
                                                 _glfwLibrary.X11.screen);
            }

            ci = XRRGetCrtcInfo(_glfwLibrary.X11.display, sr, oi->crtc);

            monitors[found] = _glfwCreateMonitor(oi->name,
                                                 i == 0,
                                                 physicalWidth, physicalHeight,
                                                 ci->x, ci->y);

            XRRFreeCrtcInfo(ci);

            if (!monitors[found])
            {
                // TODO: wat
                return NULL;
            }

            // This is retained until the monitor object is destroyed
            monitors[found]->X11.output = oi;
            found++;
        }
#endif /*_GLFW_HAS_XRANDR*/
    }

    *count = found;
    return monitors;
}


//========================================================================
// Destroy a monitor struct
//========================================================================

void _glfwPlatformDestroyMonitor(_GLFWmonitor* monitor)
{
    if (_glfwLibrary.X11.RandR.available)
    {
#if defined (_GLFW_HAS_XRANDR)
        XRRFreeOutputInfo(monitor->X11.output);
#endif /*_GLFW_HAS_XRANDR*/
    }
}


//========================================================================
// List available video modes
//========================================================================

GLFWvidmode* _glfwPlatformGetVideoModes(_GLFWmonitor* monitor, int* found)
{
    XVisualInfo* visuals;
    XVisualInfo dummy;
    int i, j, visualCount, sizeCount, rgbCount;
    int* rgbs;
    _GLFWvidsize* sizes;
    GLFWvidmode* result;

    visuals = XGetVisualInfo(_glfwLibrary.X11.display, 0, &dummy, &visualCount);
    if (visuals == NULL)
    {
        _glfwSetError(GLFW_PLATFORM_ERROR,
                      "X11: Failed to retrieve the available visuals");
        return 0;
    }

    // Build array of available RGB channel depths

    rgbs = (int*) malloc(sizeof(int) * visualCount);
    rgbCount = 0;

    for (i = 0;  i < visualCount;  i++)
    {
        int gl, rgba, rgb, r, g, b;

        glXGetConfig(_glfwLibrary.X11.display, &visuals[i], GLX_USE_GL, &gl);
        glXGetConfig(_glfwLibrary.X11.display, &visuals[i], GLX_RGBA, &rgba);

        if (!gl || !rgba)
        {
            // The visual lacks OpenGL or true color, so skip it
            continue;
        }

        // Convert to RGB channel depths and encode
        _glfwSplitBPP(visuals[i].depth, &r, &g, &b);
        rgb = (r << 16) | (g << 8) | b;

        for (j = 0;  j < rgbCount;  j++)
        {
            if (rgbs[j] == rgb)
                break;
        }

        if (j < rgbCount)
        {
            // This channel depth is a duplicate, so skip it
            continue;
        }

        rgbs[rgbCount] = rgb;
        rgbCount++;
    }

    XFree(visuals);

    // Build all permutations of channel depths and resolutions

    sizes = getResolutions(monitor, &sizeCount);

    result = (GLFWvidmode*) malloc(sizeof(GLFWvidmode) * rgbCount * sizeCount);
    *found = 0;

    for (i = 0;  i < rgbCount;  i++)
    {
        for (j = 0;  j < sizeCount;  j++)
        {
            result[*found].width     = sizes[j].width;
            result[*found].height    = sizes[j].height;
            result[*found].redBits   = (rgbs[i] >> 16) & 255;
            result[*found].greenBits = (rgbs[i] >> 8) & 255;
            result[*found].blueBits  = rgbs[i] & 255;

            (*found)++;
        }
    }

    free(sizes);
    free(rgbs);

    return result;
}


//========================================================================
// Get the current video mode for the specified monitor
//========================================================================

void _glfwPlatformGetVideoMode(_GLFWmonitor* monitor, GLFWvidmode* mode)
{
    if (_glfwLibrary.X11.RandR.available)
    {
#if defined (_GLFW_HAS_XRANDR)
        XRRScreenResources* sr;
        XRRCrtcInfo* ci;

        sr = XRRGetScreenResources(_glfwLibrary.X11.display,
                                   _glfwLibrary.X11.root);
        if (!sr)
        {
            _glfwSetError(GLFW_PLATFORM_ERROR,
                          "X11: Failed to retrieve RandR screen resources");
            return;
        }

        ci = XRRGetCrtcInfo(_glfwLibrary.X11.display,
                            sr, monitor->X11.output->crtc);
        if (!ci)
        {
            XRRFreeScreenResources(sr);

            _glfwSetError(GLFW_PLATFORM_ERROR,
                          "X11: Failed to retrieve RandR crtc info");
            return;
        }

        mode->width = ci->width;
        mode->height = ci->height;

        XRRFreeCrtcInfo(ci);
        XRRFreeScreenResources(sr);
#endif /*_GLFW_HAS_XRANDR*/
    }
    else
    {
        mode->width = DisplayWidth(_glfwLibrary.X11.display,
                                _glfwLibrary.X11.screen);
        mode->height = DisplayHeight(_glfwLibrary.X11.display,
                                    _glfwLibrary.X11.screen);
    }

    _glfwSplitBPP(DefaultDepth(_glfwLibrary.X11.display,
                               _glfwLibrary.X11.screen),
                  &mode->redBits, &mode->greenBits, &mode->blueBits);
}