/*
 * Copyright 2018 Google Inc.
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */

#include "GrMtlPipelineState.h"

#include "GrContext.h"
#include "GrContextPriv.h"
#include "GrPipeline.h"
#include "GrRenderTarget.h"
#include "GrTexturePriv.h"
#include "GrMtlBuffer.h"
#include "GrMtlGpu.h"
#include "GrMtlSampler.h"
#include "GrMtlTexture.h"
#include "glsl/GrGLSLFragmentProcessor.h"
#include "glsl/GrGLSLGeometryProcessor.h"
#include "glsl/GrGLSLXferProcessor.h"

GrMtlPipelineState::SamplerBindings::SamplerBindings(const GrSamplerState& state,
                                                     GrTexture* texture,
                                                     GrShaderFlags flags,
                                                     GrMtlGpu* gpu)
        : fTexture(static_cast<GrMtlTexture*>(texture)->mtlTexture())
        , fVisibility(flags) {
    // TODO: use resource provider to get sampler.
    std::unique_ptr<GrMtlSampler> sampler(
            GrMtlSampler::Create(gpu, state, texture->texturePriv().maxMipMapLevel()));
    fSampler = sampler->mtlSamplerState();
}

GrMtlPipelineState::GrMtlPipelineState(
        GrMtlGpu* gpu,
        id<MTLRenderPipelineState> pipelineState,
        MTLPixelFormat pixelFormat,
        const GrGLSLBuiltinUniformHandles& builtinUniformHandles,
        const UniformInfoArray& uniforms,
        GrMtlBuffer* geometryUniformBuffer,
        GrMtlBuffer* fragmentUniformBuffer,
        uint32_t numSamplers,
        std::unique_ptr<GrGLSLPrimitiveProcessor> geometryProcessor,
        std::unique_ptr<GrGLSLXferProcessor> xferProcessor,
        std::unique_ptr<std::unique_ptr<GrGLSLFragmentProcessor>[]> fragmentProcessors,
        int fragmentProcessorCnt)
        : fGpu(gpu)
        , fPipelineState(pipelineState)
        , fPixelFormat(pixelFormat)
        , fBuiltinUniformHandles(builtinUniformHandles)
        , fGeometryUniformBuffer(geometryUniformBuffer)
        , fFragmentUniformBuffer(fragmentUniformBuffer)
        , fNumSamplers(numSamplers)
        , fGeometryProcessor(std::move(geometryProcessor))
        , fXferProcessor(std::move(xferProcessor))
        , fFragmentProcessors(std::move(fragmentProcessors))
        , fFragmentProcessorCnt(fragmentProcessorCnt)
        , fDataManager(uniforms, geometryUniformBuffer->sizeInBytes(),
                       fragmentUniformBuffer->sizeInBytes()) {
    (void) fPixelFormat; // Suppress unused-var warning.
}

void GrMtlPipelineState::setData(const GrPrimitiveProcessor& primProc,
                                 const GrPipeline& pipeline,
                                 const GrTextureProxy* const primProcTextures[]) {
    SkASSERT(primProcTextures || !primProc.numTextureSamplers());

    this->setRenderTargetState(pipeline.proxy());
    fGeometryProcessor->setData(fDataManager, primProc,
                                GrFragmentProcessor::CoordTransformIter(pipeline));
    fSamplerBindings.reset();
    for (int i = 0; i < primProc.numTextureSamplers(); ++i) {
        const auto& sampler = primProc.textureSampler(i);
        auto texture = static_cast<GrMtlTexture*>(primProcTextures[i]->peekTexture());
        fSamplerBindings.emplace_back(sampler.samplerState(), texture, sampler.visibility(), fGpu);
    }

    GrFragmentProcessor::Iter iter(pipeline);
    GrGLSLFragmentProcessor::Iter glslIter(fFragmentProcessors.get(), fFragmentProcessorCnt);
    const GrFragmentProcessor* fp = iter.next();
    GrGLSLFragmentProcessor* glslFP = glslIter.next();
    while (fp && glslFP) {
       glslFP->setData(fDataManager, *fp);
        for (int i = 0; i < fp->numTextureSamplers(); ++i) {
            const auto& sampler = fp->textureSampler(i);
            fSamplerBindings.emplace_back(sampler.samplerState(), sampler.peekTexture(),
                                          kFragment_GrShaderFlag, fGpu);
        }
        fp = iter.next();
        glslFP = glslIter.next();
    }
    SkASSERT(!fp && !glslFP);

    {
        SkIPoint offset;
        GrTexture* dstTexture = pipeline.peekDstTexture(&offset);

        fXferProcessor->setData(fDataManager, pipeline.getXferProcessor(), dstTexture, offset);
    }

    if (GrTextureProxy* dstTextureProxy = pipeline.dstTextureProxy()) {
        fSamplerBindings.emplace_back(GrSamplerState::ClampNearest(),
                                      dstTextureProxy->peekTexture(),
                                      kFragment_GrShaderFlag,
                                      fGpu);
    }

    SkASSERT(fNumSamplers == fSamplerBindings.count());
    if (fGeometryUniformBuffer || fFragmentUniformBuffer) {
        fDataManager.uploadUniformBuffers(fGpu, fGeometryUniformBuffer.get(),
                                          fFragmentUniformBuffer.get());
    }
}

void GrMtlPipelineState::bind(id<MTLRenderCommandEncoder> renderCmdEncoder) {
    if (fGeometryUniformBuffer) {
        [renderCmdEncoder setVertexBuffer: fGeometryUniformBuffer->mtlBuffer()
                                   offset: 0
                                  atIndex: GrMtlUniformHandler::kGeometryBinding];
    }
    if (fFragmentUniformBuffer) {
        [renderCmdEncoder setFragmentBuffer: fFragmentUniformBuffer->mtlBuffer()
                                     offset: 0
                                    atIndex: GrMtlUniformHandler::kFragBinding];
    }
    SkASSERT(fNumSamplers == fSamplerBindings.count());
    for (int index = 0; index < fNumSamplers; ++index) {
        if (fSamplerBindings[index].fVisibility & kVertex_GrShaderFlag) {
            [renderCmdEncoder setVertexTexture: fSamplerBindings[index].fTexture
                                       atIndex: index];
            [renderCmdEncoder setVertexSamplerState: fSamplerBindings[index].fSampler
                                            atIndex: index];
        }
        if (fSamplerBindings[index].fVisibility & kFragment_GrShaderFlag) {
            [renderCmdEncoder setFragmentTexture: fSamplerBindings[index].fTexture
                                         atIndex: index];
            [renderCmdEncoder setFragmentSamplerState: fSamplerBindings[index].fSampler
                                              atIndex: index];
        }
    }
}

void GrMtlPipelineState::setRenderTargetState(const GrRenderTargetProxy* proxy) {
    GrRenderTarget* rt = proxy->peekRenderTarget();

    // Load the RT height uniform if it is needed to y-flip gl_FragCoord.
    if (fBuiltinUniformHandles.fRTHeightUni.isValid() &&
        fRenderTargetState.fRenderTargetSize.fHeight != rt->height()) {
        fDataManager.set1f(fBuiltinUniformHandles.fRTHeightUni, SkIntToScalar(rt->height()));
    }

    // set RT adjustment
    SkISize size;
    size.set(rt->width(), rt->height());
    SkASSERT(fBuiltinUniformHandles.fRTAdjustmentUni.isValid());
    if (fRenderTargetState.fRenderTargetOrigin != proxy->origin() ||
        fRenderTargetState.fRenderTargetSize != size) {
        fRenderTargetState.fRenderTargetSize = size;
        fRenderTargetState.fRenderTargetOrigin = proxy->origin();

        float rtAdjustmentVec[4];
        fRenderTargetState.getRTAdjustmentVec(rtAdjustmentVec);
        fDataManager.set4fv(fBuiltinUniformHandles.fRTAdjustmentUni, 1, rtAdjustmentVec);
    }
}

static bool blend_coeff_refs_constant(GrBlendCoeff coeff) {
    switch (coeff) {
        case kConstC_GrBlendCoeff:
        case kIConstC_GrBlendCoeff:
        case kConstA_GrBlendCoeff:
        case kIConstA_GrBlendCoeff:
            return true;
        default:
            return false;
    }
}

void GrMtlPipelineState::setBlendConstants(id<MTLRenderCommandEncoder> renderCmdEncoder,
                                           GrPixelConfig config,
                                           const GrXferProcessor& xferProcessor) {
    if (!renderCmdEncoder) {
        return;
    }

    GrXferProcessor::BlendInfo blendInfo;
    xferProcessor.getBlendInfo(&blendInfo);
    GrBlendCoeff srcCoeff = blendInfo.fSrcBlend;
    GrBlendCoeff dstCoeff = blendInfo.fDstBlend;
    if (blend_coeff_refs_constant(srcCoeff) || blend_coeff_refs_constant(dstCoeff)) {
        float floatColors[4];
        // Swizzle the blend to match what the shader will output.
        const GrSwizzle& swizzle = fGpu->caps()->shaderCaps()->configOutputSwizzle(config);
        GrColor blendConst = swizzle.applyTo(blendInfo.fBlendConstant);
        GrColorToRGBAFloat(blendConst, floatColors);

        [renderCmdEncoder setBlendColorRed: floatColors[0]
                                     green: floatColors[1]
                                      blue: floatColors[2]
                                     alpha: floatColors[3]];
    }
}