// SPDX-FileCopyrightText: Copyright 2024 shadPS4 Emulator Project
// SPDX-License-Identifier: GPL-2.0-or-later

#include <boost/container/static_vector.hpp>
#include "shader_recompiler/backend/spirv/emit_spirv_instructions.h"
#include "shader_recompiler/backend/spirv/spirv_emit_context.h"

namespace Shader::Backend::SPIRV {

struct ImageOperands {
    void Add(spv::ImageOperandsMask new_mask, Id value) {
        mask = static_cast<spv::ImageOperandsMask>(static_cast<u32>(mask) |
                                                   static_cast<u32>(new_mask));
        operands.push_back(value);
    }

    spv::ImageOperandsMask mask{};
    boost::container::static_vector<Id, 4> operands;
};

Id EmitImageSampleImplicitLod(EmitContext& ctx, IR::Inst* inst, u32 handle, Id coords, Id bias_lc,
                              Id offset) {
    const auto& texture = ctx.images[handle & 0xFFFF];
    const Id image = ctx.OpLoad(texture.image_type, texture.id);
    const Id sampler = ctx.OpLoad(ctx.sampler_type, ctx.samplers[handle >> 16]);
    const Id sampled_image = ctx.OpSampledImage(texture.sampled_type, image, sampler);
    ImageOperands operands;
    if (Sirit::ValidId(offset)) {
        operands.Add(spv::ImageOperandsMask::ConstOffset, offset);
    }
    return ctx.OpImageSampleImplicitLod(ctx.F32[4], sampled_image, coords, operands.mask,
                                        operands.operands);
}

Id EmitImageSampleExplicitLod(EmitContext& ctx, IR::Inst* inst, u32 handle, Id coords, Id bias_lc,
                              Id offset) {
    const auto& texture = ctx.images[handle & 0xFFFF];
    const Id image = ctx.OpLoad(texture.image_type, texture.id);
    const Id sampler = ctx.OpLoad(ctx.sampler_type, ctx.samplers[handle >> 16]);
    const Id sampled_image = ctx.OpSampledImage(texture.sampled_type, image, sampler);
    return ctx.OpImageSampleExplicitLod(ctx.F32[4], sampled_image, coords,
                                        spv::ImageOperandsMask::Lod, ctx.ConstF32(0.f));
}

Id EmitImageSampleDrefImplicitLod(EmitContext& ctx, IR::Inst* inst, u32 handle, Id coords, Id dref,
                                  Id bias_lc, const IR::Value& offset) {
    const auto& texture = ctx.images[handle & 0xFFFF];
    const Id image = ctx.OpLoad(texture.image_type, texture.id);
    const Id sampler = ctx.OpLoad(ctx.sampler_type, ctx.samplers[handle >> 16]);
    const Id sampled_image = ctx.OpSampledImage(texture.sampled_type, image, sampler);
    return ctx.OpImageSampleDrefImplicitLod(ctx.F32[1], sampled_image, coords, dref);
}

Id EmitImageSampleDrefExplicitLod(EmitContext& ctx, IR::Inst* inst, u32 handle, Id coords, Id dref,
                                  Id bias_lc, Id offset) {
    const auto& texture = ctx.images[handle & 0xFFFF];
    const Id image = ctx.OpLoad(texture.image_type, texture.id);
    const Id sampler = ctx.OpLoad(ctx.sampler_type, ctx.samplers[handle >> 16]);
    const Id sampled_image = ctx.OpSampledImage(texture.sampled_type, image, sampler);
    return ctx.OpImageSampleDrefExplicitLod(ctx.F32[1], sampled_image, coords, dref,
                                            spv::ImageOperandsMask::Lod, ctx.ConstF32(0.f));
}

Id EmitImageGather(EmitContext& ctx, IR::Inst* inst, const IR::Value& index, Id coords,
                   const IR::Value& offset, const IR::Value& offset2) {
    UNREACHABLE_MSG("SPIR-V Instruction");
}

Id EmitImageGatherDref(EmitContext& ctx, IR::Inst* inst, u32 handle, Id coords,
                       const IR::Value& offset, const IR::Value& offset2, Id dref) {
    const auto& texture = ctx.images[handle & 0xFFFF];
    const Id image = ctx.OpLoad(texture.image_type, texture.id);
    const Id sampler = ctx.OpLoad(ctx.sampler_type, ctx.samplers[handle >> 16]);
    const Id sampled_image = ctx.OpSampledImage(texture.sampled_type, image, sampler);
    return ctx.OpImageDrefGather(ctx.F32[4], sampled_image, coords, dref);
}

Id EmitImageFetch(EmitContext& ctx, IR::Inst* inst, u32 handle, Id coords, Id offset, Id lod,
                  Id ms) {
    const auto& texture = ctx.images[handle & 0xFFFF];
    const Id image = ctx.OpLoad(texture.image_type, texture.id);
    if (Sirit::ValidId(lod)) {
        return ctx.OpImageFetch(ctx.F32[4], image, coords, spv::ImageOperandsMask::Lod, lod);
    } else {
        return ctx.OpImageFetch(ctx.F32[4], image, coords);
    }
}

Id EmitImageQueryDimensions(EmitContext& ctx, IR::Inst* inst, u32 handle, Id lod, bool skip_mips) {
    const auto& texture = ctx.images[handle & 0xFFFF];
    const Id image = ctx.OpLoad(texture.image_type, texture.id);
    const auto type = ctx.info.images[handle & 0xFFFF].type;
    const Id zero = ctx.u32_zero_value;
    const auto mips{[&] { return skip_mips ? zero : ctx.OpImageQueryLevels(ctx.U32[1], image); }};
    const bool uses_lod{type != AmdGpu::ImageType::Color2DMsaa &&
                        type != AmdGpu::ImageType::Buffer};
    const auto query{[&](Id type) {
        return uses_lod ? ctx.OpImageQuerySizeLod(type, image, lod)
                        : ctx.OpImageQuerySize(type, image);
    }};
    switch (type) {
    case AmdGpu::ImageType::Color1D:
        return ctx.OpCompositeConstruct(ctx.U32[4], query(ctx.U32[1]), zero, zero, mips());
    case AmdGpu::ImageType::Color1DArray:
    case AmdGpu::ImageType::Color2D:
    case AmdGpu::ImageType::Cube:
        return ctx.OpCompositeConstruct(ctx.U32[4], query(ctx.U32[2]), zero, mips());
    case AmdGpu::ImageType::Color2DArray:
    case AmdGpu::ImageType::Color3D:
        return ctx.OpCompositeConstruct(ctx.U32[4], query(ctx.U32[3]), mips());
    default:
        UNREACHABLE_MSG("SPIR-V Instruction");
    }
}

Id EmitImageQueryLod(EmitContext& ctx, IR::Inst* inst, u32 handle, Id coords) {
    const auto& texture = ctx.images[handle & 0xFFFF];
    const Id image = ctx.OpLoad(texture.image_type, texture.id);
    const Id sampler = ctx.OpLoad(ctx.sampler_type, ctx.samplers[handle >> 16]);
    const Id sampled_image = ctx.OpSampledImage(texture.sampled_type, image, sampler);
    const Id zero{ctx.f32_zero_value};
    return ctx.OpImageQueryLod(ctx.F32[2], sampled_image, coords);
}

Id EmitImageGradient(EmitContext& ctx, IR::Inst* inst, const IR::Value& index, Id coords,
                     Id derivatives, const IR::Value& offset, Id lod_clamp) {
    UNREACHABLE_MSG("SPIR-V Instruction");
}

Id EmitImageRead(EmitContext& ctx, IR::Inst* inst, const IR::Value& index, Id coords) {
    UNREACHABLE_MSG("SPIR-V Instruction");
}

void EmitImageWrite(EmitContext& ctx, IR::Inst* inst, u32 handle, Id coords, Id color) {
    const auto& texture = ctx.images[handle & 0xFFFF];
    const Id image = ctx.OpLoad(texture.image_type, texture.id);
    ctx.OpImageWrite(image, ctx.OpBitcast(ctx.S32[2], coords), color);
}

} // namespace Shader::Backend::SPIRV
