/*
 * Copyright 2017 Google Inc.
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */

#include "GrMtlUtil.h"

#include "GrTypesPriv.h"

bool GrPixelConfigToMTLFormat(GrPixelConfig config, MTLPixelFormat* format) {
    MTLPixelFormat dontCare;
    if (!format) {
        format = &dontCare;
    }

    switch (config) {
        case kUnknown_GrPixelConfig:
            return false;
        case kRGBA_8888_GrPixelConfig:
            *format = MTLPixelFormatRGBA8Unorm;
            return true;
        case kBGRA_8888_GrPixelConfig:
            *format = MTLPixelFormatBGRA8Unorm;
            return true;
        case kSRGBA_8888_GrPixelConfig:
            *format = MTLPixelFormatRGBA8Unorm_sRGB;
            return true;
        case kSBGRA_8888_GrPixelConfig:
            *format = MTLPixelFormatBGRA8Unorm_sRGB;
            return true;
        case kRGBA_8888_sint_GrPixelConfig:
            *format = MTLPixelFormatRGBA8Sint;
            return true;
        case kRGB_565_GrPixelConfig:
#ifdef SK_BUILD_FOR_IOS
            *format = MTLPixelFormatR5G6B5Unorm;
            return true;
#else
            return false;
#endif
        case kRGBA_4444_GrPixelConfig:
#ifdef SK_BUILD_FOR_IOS
            *format = MTLPixelFormatABGR4Unorm;
            return true;
#else
            return false;
#endif
        case kAlpha_8_GrPixelConfig: // fall through
        case kAlpha_8_as_Red_GrPixelConfig:
            *format = MTLPixelFormatR8Unorm;
            return true;
        case kAlpha_8_as_Alpha_GrPixelConfig:
            return false;
        case kGray_8_GrPixelConfig: // fall through
        case kGray_8_as_Red_GrPixelConfig:
            *format = MTLPixelFormatR8Unorm;
            return true;
        case kGray_8_as_Lum_GrPixelConfig:
            return false;
        case kRGBA_float_GrPixelConfig:
            *format = MTLPixelFormatRGBA32Float;
            return true;
        case kRG_float_GrPixelConfig:
            *format = MTLPixelFormatRG32Float;
            return true;
        case kRGBA_half_GrPixelConfig:
            *format = MTLPixelFormatRGBA16Float;
            return true;
        case kAlpha_half_GrPixelConfig: // fall through
        case kAlpha_half_as_Red_GrPixelConfig:
            *format = MTLPixelFormatR16Float;
            return true;
    }
    SK_ABORT("Unexpected config");
    return false;
}

GrPixelConfig GrMTLFormatToPixelConfig(MTLPixelFormat format) {
    switch (format) {
        case MTLPixelFormatRGBA8Unorm:
            return kRGBA_8888_GrPixelConfig;
        case MTLPixelFormatBGRA8Unorm:
            return kBGRA_8888_GrPixelConfig;
        case MTLPixelFormatRGBA8Unorm_sRGB:
            return kSRGBA_8888_GrPixelConfig;
        case MTLPixelFormatBGRA8Unorm_sRGB:
            return kSBGRA_8888_GrPixelConfig;
        case MTLPixelFormatRGBA8Sint:
            return kRGBA_8888_sint_GrPixelConfig;
#ifdef SK_BUILD_FOR_IOS
        case MTLPixelFormatB5G6R5Unorm:
            return kRGB_565_GrPixelConfig;
        case MTLPixelFormatABGR4Unorm:
            return kRGBA_4444_GrPixelConfig;
#endif
        case MTLPixelFormatR8Unorm:
            // We currently set this to be Alpha_8 and have no way to go to Gray_8
            return kAlpha_8_GrPixelConfig;
        case MTLPixelFormatRGBA32Float:
            return kRGBA_float_GrPixelConfig;
        case MTLPixelFormatRG32Float:
            return kRG_float_GrPixelConfig;
        case MTLPixelFormatRGBA16Float:
            return kRGBA_half_GrPixelConfig;
        case MTLPixelFormatR16Float:
            return kAlpha_half_GrPixelConfig;
        default:
            return kUnknown_GrPixelConfig;
    }
}

bool GrMTLFormatIsSRGB(MTLPixelFormat format, MTLPixelFormat* linearFormat) {
    MTLPixelFormat linearFmt = format;
    switch (format) {
        case MTLPixelFormatRGBA8Unorm_sRGB:
            linearFmt = MTLPixelFormatRGBA8Unorm;
            break;
        case MTLPixelFormatBGRA8Unorm_sRGB:
            linearFmt = MTLPixelFormatBGRA8Unorm;
            break;
        default:
            break;
    }

    if (linearFormat) {
        *linearFormat = linearFmt;
    }
    return (linearFmt != format);
}