/*
 * Copyright (c) 2008 Apple Inc.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
 * THE ABOVE LISTED COPYRIGHT HOLDER(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 * DEALINGS IN THE SOFTWARE.
 */

#include <stdio.h>
#include <stdlib.h>
#include <assert.h>
#include <OpenGL/OpenGL.h>
#include <OpenGL/gl.h>
#include <OpenGL/glu.h>
#include <OpenGL/glext.h>
#include <ApplicationServices/ApplicationServices.h>

#include "capabilities.h"

static void handleBufferModes(struct glCapabilitiesConfig *c, GLint bufferModes) {
    if(bufferModes & kCGLStereoscopicBit) {
	c->stereo = true;
    }

    if(bufferModes & kCGLDoubleBufferBit) {
	c->buffers = 2;
    } else {
	c->buffers = 1;
    }
}

static void handleStencilModes(struct glCapabilitiesConfig *c, GLint smodes) {
    int offset = 0;
    
    if(kCGL0Bit & smodes)
	c->stencil_bit_depths[offset++] = 0;

    if(kCGL1Bit & smodes)
	c->stencil_bit_depths[offset++] = 1;

    if(kCGL2Bit & smodes)
	c->stencil_bit_depths[offset++] = 2;
    
    if(kCGL3Bit & smodes)
	c->stencil_bit_depths[offset++] = 3;

    if(kCGL4Bit & smodes)
	c->stencil_bit_depths[offset++] = 4;

    if(kCGL5Bit & smodes)
	c->stencil_bit_depths[offset++] = 5;
    
    if(kCGL6Bit & smodes)
	c->stencil_bit_depths[offset++] = 6;

    if(kCGL8Bit & smodes)
	c->stencil_bit_depths[offset++] = 8;

    if(kCGL10Bit & smodes)
	c->stencil_bit_depths[offset++] = 10;

    if(kCGL12Bit & smodes)
	c->stencil_bit_depths[offset++] = 12;

    if(kCGL16Bit & smodes)
	c->stencil_bit_depths[offset++] = 16;

    if(kCGL24Bit & smodes)
	c->stencil_bit_depths[offset++] = 24;

    if(kCGL32Bit & smodes)
	c->stencil_bit_depths[offset++] = 32;
    
    if(kCGL48Bit & smodes)
	c->stencil_bit_depths[offset++] = 48;
    
    if(kCGL64Bit & smodes)
	c->stencil_bit_depths[offset++] = 64;
    
    if(kCGL96Bit & smodes)
	c->stencil_bit_depths[offset++] = 96;
    
    if(kCGL128Bit & smodes)
	c->stencil_bit_depths[offset++] = 128;

    assert(offset < GLCAPS_STENCIL_BIT_DEPTH_BUFFERS);

    c->total_stencil_bit_depths = offset;
}

static int handleColorAndAccumulation(struct glColorBufCapabilities *c, 
				       GLint cmodes, int forAccum) {
    int offset = 0;
        
    /*1*/
    if(kCGLRGB444Bit & cmodes) {
	c[offset].r = 4;
	c[offset].g = 4; 
	c[offset].b = 4;
	++offset;
    }
    
    /*2*/
    if(kCGLARGB4444Bit & cmodes) {
	c[offset].a = 4;
	c[offset].r = 4;
	c[offset].g = 4;
	c[offset].b = 4;
	c[offset].is_argb = true;
	++offset;
    }
    
    /*3*/
    if(kCGLRGB444A8Bit & cmodes) {
	c[offset].r = 4;
	c[offset].g = 4;
	c[offset].b = 4;
	c[offset].a = 8;
	++offset;
    }

    /*4*/
    if(kCGLRGB555Bit & cmodes) {
	c[offset].r = 5;
	c[offset].g = 5;
	c[offset].b = 5;
	++offset;
    }

    /*5*/
    if(kCGLARGB1555Bit & cmodes) {
	c[offset].a = 1;
	c[offset].r = 5;
	c[offset].g = 5;
	c[offset].b = 5;
	c[offset].is_argb = true;
	++offset;
    }

    /*6*/
    if(kCGLRGB555A8Bit & cmodes) {
	c[offset].r = 5;
	c[offset].g = 5; 
	c[offset].b = 5;
	c[offset].a = 8;
	++offset;
    }

    /*7*/
    if(kCGLRGB565Bit & cmodes) {
	c[offset].r = 5;
	c[offset].g = 6;
	c[offset].b = 5;
	++offset;
    }

    /*8*/
    if(kCGLRGB565A8Bit & cmodes) {
	c[offset].r = 5;
	c[offset].g = 6;
	c[offset].b = 5;
	c[offset].a = 8;
	++offset;
    }

    /*9*/
    if(kCGLRGB888Bit & cmodes) {
	c[offset].r = 8;
	c[offset].g = 8;
	c[offset].b = 8;
	++offset;
    }

    /*10*/
    if(kCGLARGB8888Bit & cmodes) {
	c[offset].a = 8;
	c[offset].r = 8;
	c[offset].g = 8;
	c[offset].b = 8;
	c[offset].is_argb = true;
	++offset;
    }

    /*11*/
    if(kCGLRGB888A8Bit & cmodes) {
	c[offset].r = 8;
	c[offset].g = 8;
	c[offset].b = 8;
	c[offset].a = 8;
	++offset;
    }

    if(forAccum) {
//#if 0
    /* FIXME
     * Disable this path, because some part of libGL, X, or Xplugin 
     * doesn't work with sizes greater than 8.
     * When this is enabled and visuals are chosen using depths
     * such as 16, the result is that the windows don't redraw
     * and are often white, until a resize.
     */

    /*12*/
    if(kCGLRGB101010Bit & cmodes) {
	c[offset].r = 10;
	c[offset].g = 10;
	c[offset].b = 10;
	++offset;
    }

    /*13*/
    if(kCGLARGB2101010Bit & cmodes) {
	c[offset].a = 2;
	c[offset].r = 10;
	c[offset].g = 10;
	c[offset].b = 10;
	c[offset].is_argb = true;
	++offset;
    }

    /*14*/
    if(kCGLRGB101010_A8Bit & cmodes) {
	c[offset].r = 10;
	c[offset].g = 10;
	c[offset].b = 10;
	c[offset].a = 8;
	++offset;
    }

    /*15*/
    if(kCGLRGB121212Bit & cmodes) {
	c[offset].r = 12;
	c[offset].g = 12;
	c[offset].b = 12;
	++offset;	
    }

    /*16*/
    if(kCGLARGB12121212Bit & cmodes) {
	c[offset].a = 12;
	c[offset].r = 12;
	c[offset].g = 12;
	c[offset].b = 12;
	c[offset].is_argb = true;
	++offset;
    }

    /*17*/
    if(kCGLRGB161616Bit & cmodes) {
	c[offset].r = 16;
	c[offset].g = 16;
	c[offset].b = 16;
	++offset;
    }

    /*18*/
    if(kCGLRGBA16161616Bit & cmodes) {
	c[offset].r = 16;
	c[offset].g = 16;
	c[offset].b = 16;
	c[offset].a = 16;
	++offset;
    }
    }
//#endif

    /* FIXME should we handle the floating point color modes, and if so, how? */
      
    return offset;
}


static void handleColorModes(struct glCapabilitiesConfig *c, GLint cmodes) {
    c->total_color_buffers = handleColorAndAccumulation(c->color_buffers,
							cmodes, 0);
    
    assert(c->total_color_buffers < GLCAPS_COLOR_BUFFERS);
}

static void handleAccumulationModes(struct glCapabilitiesConfig *c, GLint cmodes) {
    c->total_accum_buffers = handleColorAndAccumulation(c->accum_buffers,
							cmodes, 1);
    assert(c->total_accum_buffers < GLCAPS_COLOR_BUFFERS);
}

static void handleDepthModes(struct glCapabilitiesConfig *c, GLint dmodes) {
    int offset = 0;
#define DEPTH(flag,value) do { \
	if(dmodes & flag) { \
	    c->depth_buffers[offset++] = value; \
	} \
    } while(0)

    /*1*/
    DEPTH(kCGL0Bit, 0);
    /*2*/
    DEPTH(kCGL1Bit, 1);
    /*3*/
    DEPTH(kCGL2Bit, 2);
    /*4*/
    DEPTH(kCGL3Bit, 3);
    /*5*/
    DEPTH(kCGL4Bit, 4);
    /*6*/
    DEPTH(kCGL5Bit, 5);
    /*7*/
    DEPTH(kCGL6Bit, 6);
    /*8*/
    DEPTH(kCGL8Bit, 8);
    /*9*/
    DEPTH(kCGL10Bit, 10);
    /*10*/
    DEPTH(kCGL12Bit, 12);
    /*11*/
    DEPTH(kCGL16Bit, 16);
    /*12*/
    DEPTH(kCGL24Bit, 24);
    /*13*/
    DEPTH(kCGL32Bit, 32);
    /*14*/
    DEPTH(kCGL48Bit, 48);
    /*15*/
    DEPTH(kCGL64Bit, 64);
    /*16*/
    DEPTH(kCGL96Bit, 96);
    /*17*/
    DEPTH(kCGL128Bit, 128);

#undef DEPTH

    c->total_depth_buffer_depths = offset;
    assert(c->total_depth_buffer_depths < GLCAPS_DEPTH_BUFFERS);
}

/* Return non-zero if an error occured. */
static CGLError handleRendererDescriptions(CGLRendererInfoObj info, GLint r, 
					   struct glCapabilitiesConfig *c) {
    CGLError err;
    GLint accelerated = 0, flags = 0, aux = 0, samplebufs = 0, samples = 0;

    err = CGLDescribeRenderer (info, r, kCGLRPAccelerated, &accelerated);

    if(err)
	return err;
    
    c->accelerated = accelerated;

    /* Buffering modes: single/double, stereo */
    err = CGLDescribeRenderer(info, r, kCGLRPBufferModes, &flags);

    if(err)
	return err;
    
    handleBufferModes(c, flags);
    
    /* AUX buffers */
    err = CGLDescribeRenderer(info, r, kCGLRPMaxAuxBuffers, &aux);

    if(err)
	return err;
    
    c->aux_buffers = aux;

    
    /* Depth buffer size */
    err = CGLDescribeRenderer(info, r, kCGLRPDepthModes, &flags);
    
    if(err)
	return err;

    handleDepthModes(c, flags);


    /* Multisample buffers */
    err = CGLDescribeRenderer(info, r, kCGLRPMaxSampleBuffers, &samplebufs);

    if(err)
	return err;

    c->multisample_buffers = samplebufs;
    

    /* Multisample samples per multisample buffer */
    err = CGLDescribeRenderer(info, r, kCGLRPMaxSamples, &samples);

    if(err)
	return err;

    c->multisample_samples = samples;


    /* Stencil bit depths */
    err = CGLDescribeRenderer(info, r, kCGLRPStencilModes, &flags);

    if(err)
	return err;

    handleStencilModes(c, flags);   


    /* Color modes (RGB/RGBA depths supported */
    err = CGLDescribeRenderer(info, r, kCGLRPColorModes, &flags);

    if(err)
	return err;
    
    handleColorModes(c, flags);

    err = CGLDescribeRenderer(info, r, kCGLRPAccumModes, &flags);

    if(err)
	return err;

    handleAccumulationModes(c, flags);
    
    return kCGLNoError;
}

static void initCapabilities(struct glCapabilities *cap) {
    cap->configurations = NULL;
    cap->total_configurations = 0;
}

static void initConfig(struct glCapabilitiesConfig *c) {
    int i;

    c->accelerated = false;
    c->stereo = false;
    c->aux_buffers = 0;
    c->buffers = 0;

    c->total_depth_buffer_depths = 0;

    for(i = 0; i < GLCAPS_DEPTH_BUFFERS; ++i) {
	c->depth_buffers[i] = GLCAPS_INVALID_DEPTH_VALUE;
    }

    c->multisample_buffers = 0;
    c->multisample_samples = 0;

    c->total_stencil_bit_depths = 0;

    for(i = 0; i < GLCAPS_STENCIL_BIT_DEPTH_BUFFERS; ++i) {
	c->stencil_bit_depths[i] = GLCAPS_INVALID_STENCIL_DEPTH;
    }
   
    c->total_color_buffers = 0;

    for(i = 0; i < GLCAPS_COLOR_BUFFERS; ++i) {
	c->color_buffers[i].r =	c->color_buffers[i].g =
	    c->color_buffers[i].b = c->color_buffers[i].a = 
	    GLCAPS_COLOR_BUF_INVALID_VALUE;
	c->color_buffers[i].is_argb = false;
     }

    c->total_accum_buffers = 0;

    for(i = 0; i < GLCAPS_COLOR_BUFFERS; ++i) {
	c->accum_buffers[i].r = c->accum_buffers[i].g =
	    c->accum_buffers[i].b = c->accum_buffers[i].a =
	    GLCAPS_COLOR_BUF_INVALID_VALUE;
	c->accum_buffers[i].is_argb = false;
    }

    c->next = NULL;
}

void freeGlCapabilities(struct glCapabilities *cap) {
    struct glCapabilitiesConfig *conf, *next;
    
    conf = cap->configurations;

    while(conf) {
	next = conf->next;
	free(conf);
	conf = next;
    }

    cap->configurations = NULL;    
}

/*Return true if an error occured. */
bool getGlCapabilities(struct glCapabilities *cap) {
	CGLRendererInfoObj info;
    CGLError err;
	GLint numRenderers = 0, r;

    initCapabilities(cap);

	err = CGLQueryRendererInfo((GLuint)-1, &info, &numRenderers);
    if(err) {
	    fprintf(stderr, "CGLQueryRendererInfo error: %s\n", CGLErrorString(err));
        return err;
	}

	for(r = 0; r < numRenderers; r++) {
	    struct glCapabilitiesConfig tmpconf, *conf;

	    initConfig(&tmpconf);

	    err = handleRendererDescriptions(info, r, &tmpconf);
	    if(err) {
            fprintf(stderr, "handleRendererDescriptions returned error: %s\n", CGLErrorString(err));
            fprintf(stderr, "trying to continue...\n");
            continue;
	    }

	    conf = malloc(sizeof(*conf));
	    if(NULL == conf) {
            perror("malloc");
            abort();
	    }

	    /* Copy the struct. */
	    *conf = tmpconf;

	    /* Now link the configuration into the list. */
	    conf->next = cap->configurations;
	    cap->configurations = conf;
	}

    CGLDestroyRendererInfo(info);

    /* No error occured.  We are done. */
    return kCGLNoError;
}