#include "mlir/Dialect/Tensor/IR/Tensor.h"
#include "mlir/Dialect/Tosa/IR/TosaOps.h"
#include "mlir/IR/BuiltinTypes.h"
#include "mlir/IR/Location.h"
#include "mlir/Support/LogicalResult.h"
#include "mlir/Transforms/DialectConversion.h"

#include "llvm/ADT/SmallVector.h"

#include <cassert>

#include "src/Accelerators/PIM/Common/PimCommon.hpp"
#include "src/Accelerators/PIM/Conversion/ONNXToSpatial/Common.hpp"
#include "src/Accelerators/PIM/Dialect/Spatial/SpatialOps.hpp"
#include "src/Dialect/ONNX/ONNXOps.hpp"

using namespace mlir;

namespace onnx_mlir {
namespace {

static FailureOr<Value>
materializeScaledConstantTensor(Value value, float factor, ConversionPatternRewriter& rewriter, Location loc) {
  if (factor == 1.0f)
    return value;

  auto constantOp = value.getDefiningOp<arith::ConstantOp>();
  if (!constantOp)
    return failure();

  auto denseAttr = dyn_cast<DenseFPElementsAttr>(constantOp.getValue());
  if (!denseAttr)
    return failure();

  SmallVector<APFloat> scaledValues;
  scaledValues.reserve(denseAttr.getNumElements());
  APFloat scale(factor);
  bool hadFailure = false;
  for (const APFloat& originalValue : denseAttr.getValues<APFloat>()) {
    APFloat scaledValue(originalValue);
    if (scaledValue.multiply(scale, APFloat::rmNearestTiesToEven))
      hadFailure = true;
    scaledValues.push_back(std::move(scaledValue));
  }
  if (hadFailure)
    return failure();

  auto scaledAttr = DenseFPElementsAttr::get(cast<RankedTensorType>(denseAttr.getType()), scaledValues);
  return arith::ConstantOp::create(rewriter, loc, denseAttr.getType(), scaledAttr).getResult();
}

struct GemmToManyGemv : OpConversionPattern<ONNXGemmOp> {
  using OpConversionPattern::OpConversionPattern;

  LogicalResult matchAndRewrite(ONNXGemmOp gemmOp,
                                ONNXGemmOpAdaptor gemmOpAdaptor,
                                ConversionPatternRewriter& rewriter) const override;
};

struct GemvToSpatialCompute : OpConversionPattern<ONNXGemmOp> {
  using OpConversionPattern::OpConversionPattern;

  LogicalResult matchAndRewrite(ONNXGemmOp gemmOp,
                                ONNXGemmOpAdaptor gemmOpAdaptor,
                                ConversionPatternRewriter& rewriter) const override;
};

} // namespace

LogicalResult GemmToManyGemv::matchAndRewrite(ONNXGemmOp gemmOp,
                                              ONNXGemmOpAdaptor gemmOpAdaptor,
                                              ConversionPatternRewriter& rewriter) const {
  Location loc = gemmOp.getLoc();
  Value a = gemmOpAdaptor.getA();
  Value b = gemmOpAdaptor.getB();
  Value c = gemmOpAdaptor.getC();

  assert("A should have been transposed already" && !gemmOpAdaptor.getTransA());

  bool hasC = !isa<ONNXNoneOp>(c.getDefiningOp());

  auto aType = cast<RankedTensorType>(a.getType());
  auto outType = cast<RankedTensorType>(gemmOp.getY().getType());
  assert("Only support static shapes" && aType.hasStaticShape() && outType.hasStaticShape());

  const int64_t numOutRows = aType.getDimSize(0);

  // Only decompose when there are multiple rows to split
  if (numOutRows <= 1)
    return failure();

  auto scaledB = materializeScaledConstantTensor(b, gemmOpAdaptor.getAlpha().convertToFloat(), rewriter, loc);
  if (failed(scaledB))
    return failure();
  b = *scaledB;

  RankedTensorType cType = nullptr;
  bool cHasNumOutRows = false;
  if (hasC) {
    auto scaledC = materializeScaledConstantTensor(c, gemmOpAdaptor.getBeta().convertToFloat(), rewriter, loc);
    if (failed(scaledC))
      return failure();
    c = *scaledC;
    cType = cast<RankedTensorType>(c.getType());
    // Expand rank-1 bias [N] to rank-2 [1, N] for uniform handling
    if (cType.getRank() == 1) {
      auto expandedType = RankedTensorType::get({1, cType.getDimSize(0)}, cType.getElementType());
      c = tensor::ExpandShapeOp::create(rewriter,
                                        loc,
                                        expandedType,
                                        c,
                                        SmallVector<ReassociationIndices> {
                                          {0, 1}
      });
      cType = expandedType;
    }
    assert("Only support rank 2 tensor for C" && cType.getRank() == 2);
    cHasNumOutRows = cType.getDimSize(0) == numOutRows;
  }

  auto outRowType = RankedTensorType::get({1, outType.getDimSize(1)}, outType.getElementType());

  SmallVector<Value> gemvOps;
  gemvOps.reserve(numOutRows);
  for (int64_t rowIdx = 0; rowIdx < numOutRows; rowIdx++) {
    SmallVector<OpFoldResult> offsets = {rewriter.getIndexAttr(rowIdx), rewriter.getIndexAttr(0)};
    SmallVector<OpFoldResult> sizes = {rewriter.getIndexAttr(1), rewriter.getIndexAttr(aType.getDimSize(1))};
    SmallVector<OpFoldResult> strides = {rewriter.getIndexAttr(1), rewriter.getIndexAttr(1)};
    auto aSliceType = RankedTensorType::get({1, aType.getDimSize(1)}, aType.getElementType());
    auto aSlice = tensor::ExtractSliceOp::create(rewriter, loc, aSliceType, a, offsets, sizes, strides).getResult();

    Value cSlice = c;
    if (hasC) {
      if (cHasNumOutRows) {
        SmallVector<OpFoldResult> offsets = {rewriter.getIndexAttr(rowIdx), rewriter.getIndexAttr(0)};
        SmallVector<OpFoldResult> sizes = {rewriter.getIndexAttr(1), rewriter.getIndexAttr(cType.getDimSize(1))};
        SmallVector<OpFoldResult> strides = {rewriter.getIndexAttr(1), rewriter.getIndexAttr(1)};
        auto cSliceType = RankedTensorType::get({1, cType.getDimSize(1)}, cType.getElementType());
        cSlice = tensor::ExtractSliceOp::create(rewriter, loc, cSliceType, c, offsets, sizes, strides).getResult();
      }
      else
        assert("C should be a vector" && isVectorShape(getTensorShape(c)));
    }

    auto gemvOp = ONNXGemmOp::create(rewriter,
                                     loc,
                                     outRowType,
                                     aSlice,
                                     b,
                                     cSlice,
                                     rewriter.getF32FloatAttr(1.0f),
                                     rewriter.getF32FloatAttr(1.0f),
                                     gemmOp.getTransAAttr(),
                                     gemmOp.getTransBAttr());
    gemvOps.push_back(gemvOp.getY());
  }

  auto concatComputeOp = createSpatCompute(rewriter, loc, gemmOp.getType(), {}, gemvOps, [&](ValueRange gemvOpsArgs) {
    auto concatOp = tensor::ConcatOp::create(rewriter, loc, /*axis=*/0, gemvOpsArgs);
    spatial::SpatYieldOp::create(rewriter, loc, concatOp.getResult());
  });

  rewriter.replaceOp(gemmOp, concatComputeOp);
  return success();
}

LogicalResult GemvToSpatialCompute::matchAndRewrite(ONNXGemmOp gemmOp,
                                                    ONNXGemmOpAdaptor gemmOpAdaptor,
                                                    ConversionPatternRewriter& rewriter) const {
  Location gemmLoc = gemmOp.getLoc();
  Value a = gemmOpAdaptor.getA();
  Value b = gemmOpAdaptor.getB();
  Value c = gemmOpAdaptor.getC();
  Value out = gemmOp.getY();

  float alpha = gemmOpAdaptor.getAlpha().convertToFloat();
  float beta = gemmOpAdaptor.getBeta().convertToFloat();
  bool transA = gemmOpAdaptor.getTransA();
  bool transB = gemmOpAdaptor.getTransB();

  auto aType = cast<RankedTensorType>(a.getType());
  auto bType = cast<RankedTensorType>(b.getType());
  auto outType = cast<RankedTensorType>(out.getType());

  RankedTensorType cType = nullptr;
  bool hasC = !isa<ONNXNoneOp>(c.getDefiningOp());
  if (hasC) {
    cType = cast<RankedTensorType>(c.getType());
    // Expand rank-1 bias [N] to rank-2 [1, N] for uniform handling
    if (cType.getRank() == 1) {
      auto expandedType = RankedTensorType::get({1, cType.getDimSize(0)}, cType.getElementType());
      c = tensor::ExpandShapeOp::create(rewriter,
                                        gemmLoc,
                                        expandedType,
                                        c,
                                        SmallVector<ReassociationIndices> {
                                          {0, 1}
      });
      cType = expandedType;
    }
    assert("Only support rank 2 tensor for C" && cType.getRank() == 2);
  }

  assert("Only support static shapes" && aType.hasStaticShape() && bType.hasStaticShape()
         && (!hasC || cType.hasStaticShape()) && outType.hasStaticShape());

  if (!isVectorShape(aType.getShape()) || (hasC && !isVectorShape(cType.getShape())))
    // Not a gemv
    return failure();

  if (transA) {
    auto aShape = aType.getShape();
    auto transposedType = aType.cloneWith(ArrayRef({aShape[1], aShape[0]}), aType.getElementType());
    a = ONNXTransposeOp::create(rewriter, gemmLoc, transposedType, a, rewriter.getI64ArrayAttr({1, 0}));
  }
  if (transB) {
    auto bShape = bType.getShape();
    auto transposedType = bType.cloneWith(ArrayRef({bShape[1], bShape[0]}), bType.getElementType());
    b = ONNXTransposeOp::create(rewriter, gemmLoc, transposedType, b, rewriter.getI64ArrayAttr({1, 0}));
    bType = cast<RankedTensorType>(b.getType());
  }

  if (alpha != 1.0f) {
    auto scaledB = materializeScaledConstantTensor(b, alpha, rewriter, gemmLoc);
    if (failed(scaledB))
      return failure();
    b = *scaledB;
    bType = cast<RankedTensorType>(b.getType());
    alpha = 1.0f;
  }
  if (hasC && beta != 1.0f) {
    auto scaledC = materializeScaledConstantTensor(c, beta, rewriter, gemmLoc);
    if (failed(scaledC))
      return failure();
    c = *scaledC;
    cType = cast<RankedTensorType>(c.getType());
    beta = 1.0f;
  }

  auto [aNumHSlices, aLastHSliceSize] = ceilIntegerDivideWithRemainder(aType.getDimSize(1), crossbarSize.getValue());
  auto [bNumHSlices, bLastHSliceSize] = ceilIntegerDivideWithRemainder(bType.getDimSize(1), crossbarSize.getValue());
  auto bNumVSlices = aNumHSlices;
  auto bLastVSliceSize = aLastHSliceSize;
  auto cNumHSlices = bNumHSlices;
  auto cLastHSliceSize = bLastHSliceSize;
  auto outNumHSlices = cNumHSlices;
  auto outLastHSliceSize = cLastHSliceSize;

  const size_t coresPerVSlice = ceilIntegerDivide(bNumVSlices, crossbarCountInCore.getValue());

  DenseMap<CoreId, SmallVector<Value>> aHSlices = sliceVectorPerCrossbarPerCore(a, rewriter, gemmLoc);

  DenseMap<HSliceId, DenseMap<CoreId, SmallVector<Value>>> bTiles =
    tileMatrix(b, crossbarSize, crossbarSize, rewriter, gemmLoc);

  SmallVector<Value> cHSlices;
  if (hasC && cType.getDimSize(0) == 1 && cType.getDimSize(1) == 1)
    c = broadcastToVector(c, bType.getDimSize(1), rewriter, gemmLoc);
  if (hasC)
    cHSlices = sliceVector(c, crossbarSize, rewriter, gemmLoc);

  RankedTensorType outHSliceType =
    RankedTensorType::get({1, static_cast<long>(crossbarSize)}, outType.getElementType());
  RankedTensorType outLastHSliceType =
    RankedTensorType::get({1, static_cast<long>(bLastHSliceSize)}, outType.getElementType());

  SmallVector<Value> outHSlices;
  outHSlices.reserve(outNumHSlices);
  for (size_t outSliceId = 0; outSliceId < outNumHSlices; outSliceId++) {
    RankedTensorType currOutHSliceType = outHSliceType;
    if (outSliceId == outNumHSlices - 1 && outLastHSliceSize != 0)
      currOutHSliceType = outLastHSliceType;

    SmallVector<Value> partialResults;
    partialResults.reserve(coresPerVSlice);
    for (size_t coreId = 0; coreId < coresPerVSlice; coreId++) {
      SmallVector<Value> weights;
      weights.reserve(aHSlices[coreId].size());

      for (size_t aSliceId = 0; aSliceId < aHSlices[coreId].size(); aSliceId++)
        weights.push_back(bTiles[outSliceId][coreId][aSliceId]);

      auto computeOp = createSpatCompute(
        rewriter, gemmLoc, currOutHSliceType, weights, aHSlices[coreId], [&](ValueRange aHSlicesArgs) {
          SmallVector<Value> vmmOutputs;
          vmmOutputs.reserve(aHSlicesArgs.size());
          for (auto [aHSliceId, computeArg] : llvm::enumerate(aHSlicesArgs))
            vmmOutputs.push_back(
              spatial::SpatWeightedVMMOp::create(rewriter, gemmLoc, currOutHSliceType, aHSliceId, computeArg));
          assert(!vmmOutputs.empty() && "vmmOutputs must be non-empty");

          Value partialVmmSum = sumTensors(vmmOutputs, rewriter);
          spatial::SpatYieldOp::create(rewriter, gemmLoc, partialVmmSum);
        });

      partialResults.push_back(computeOp.getResult(0));
    }

    if (hasC) {
      Value cHSlice = cHSlices[outSliceId];
      partialResults.push_back(cHSlice);
    }

    auto reduceComputeOp =
      createSpatCompute(rewriter, gemmLoc, currOutHSliceType, {}, partialResults, [&](ValueRange blockArgs) {
        SmallVector<Value> values(blockArgs.begin(), blockArgs.end());
        Value outHSlice = sumTensors(values, rewriter);
        spatial::SpatYieldOp::create(rewriter, gemmLoc, outHSlice);
      });

    outHSlices.push_back(reduceComputeOp.getResult(0));
  }

  auto concatComputeOp =
    createSpatCompute(rewriter, gemmLoc, gemmOp.getType(), {}, outHSlices, [&](ValueRange blockArgs) {
      auto concatOp = tensor::ConcatOp::create(rewriter, gemmLoc, /*axis=*/1, blockArgs);
      spatial::SpatYieldOp::create(rewriter, gemmLoc, concatOp.getResult());
    });

  rewriter.replaceOp(gemmOp, concatComputeOp);
  return success();
}

void populateGemmPatterns(RewritePatternSet& patterns, MLIRContext* ctx) {
  patterns.insert<GemmToManyGemv>(ctx);
  patterns.insert<GemvToSpatialCompute>(ctx);
}

} // namespace onnx_mlir