#include "mlir/Dialect/Arith/IR/Arith.h"
#include "mlir/Dialect/Tensor/IR/Tensor.h"

#include "llvm/ADT/SmallVector.h"

#include "ShapeTilingUtils.hpp"
#include "src/Accelerators/PIM/Common/IR/ConstantUtils.hpp"
#include "src/Accelerators/PIM/Compiler/PimCompilerOptions.hpp"
#include "src/Accelerators/PIM/Conversion/ONNXToSpatial/Common/Common.hpp"

using namespace mlir;

namespace onnx_mlir {

SmallVector<Value> sliceTensor(
  const Value& tensorToSlice, size_t axis, int64_t sliceSize, PatternRewriter& rewriter, Location loc) {
  ArrayRef<long> shape = getTensorShape(tensorToSlice);
  assert("Invalid axis" && axis < shape.size());

  SmallVector<OpFoldResult> strides(shape.size(), rewriter.getIndexAttr(1));
  SmallVector<OpFoldResult> offsets = getZeroOffsets(rewriter, shape.size());
  SmallVector<OpFoldResult> sizes = getStaticSizes(rewriter, shape);
  sizes[axis] = rewriter.getIndexAttr(sliceSize);

  long length = shape[axis];
  auto [numSlices, lastSliceSize] = ceilIntegerDivideWithRemainder(length, sliceSize);
  SmallVector<Value> slices;
  slices.reserve(numSlices);

  for (int64_t i = 0; i < numSlices; i++) {
    offsets[axis] = rewriter.getIndexAttr(i * sliceSize);
    int64_t currentSliceSize = sliceSize;
    if (i == numSlices - 1 && lastSliceSize != 0) {
      currentSliceSize = lastSliceSize;
      sizes[axis] = rewriter.getIndexAttr(lastSliceSize);
    }

    SmallVector<int64_t> sliceShape(shape.begin(), shape.end());
    sliceShape[axis] = currentSliceSize;
    auto sliceType =
      RankedTensorType::get(sliceShape, cast<RankedTensorType>(tensorToSlice.getType()).getElementType());

    Value slice;
    if (isCompileTimeComputable(tensorToSlice)) {
      slice = tensor::ExtractSliceOp::create(rewriter, loc, tensorToSlice, offsets, sizes, strides);
    }
    else {
      auto sliceCompute =
        createSpatCompute<1>(rewriter, loc, TypeRange {sliceType}, {}, ValueRange {tensorToSlice}, [&](Value input) {
          Value computedSlice = tensor::ExtractSliceOp::create(rewriter, loc, input, offsets, sizes, strides);
          spatial::SpatYieldOp::create(rewriter, loc, computedSlice);
        });
      slice = sliceCompute.getResult(0);
    }
    slices.push_back(slice);
  }

  return slices;
}

SmallVector<Value>
sliceVector(const Value& vectorToSlice, int64_t sliceSize, PatternRewriter& rewriter, Location loc) {
  ArrayRef<long> shape = getTensorShape(vectorToSlice);
  assert("Not a vector" && isVectorShape(shape));
  size_t axis = shape[0] != 1 ? 0 : 1;
  return sliceTensor(vectorToSlice, axis, sliceSize, rewriter, loc);
}

DenseMap<CoreId, SmallVector<Value>>
sliceVectorPerCrossbarPerCore(const Value& vectorToSlice, PatternRewriter& rewriter, Location loc) {
  SmallVector<Value> slices = sliceVector(vectorToSlice, crossbarSize, rewriter, loc);
  DenseMap<CoreId, SmallVector<Value>> slicesPerCore;
  for (size_t sliceId = 0; sliceId < slices.size(); sliceId++) {
    size_t coreId = sliceId / crossbarCountInCore;
    slicesPerCore[coreId].push_back(slices[sliceId]);
  }
  return slicesPerCore;
}

Value extractAxisSlice(
  PatternRewriter& rewriter, Location loc, Value source, int64_t axis, int64_t offset, int64_t size) {
  auto sourceType = cast<RankedTensorType>(source.getType());
  SmallVector<int64_t> resultShape(sourceType.getShape());
  resultShape[axis] = size;
  auto resultType = RankedTensorType::get(resultShape, sourceType.getElementType(), sourceType.getEncoding());

  SmallVector<OpFoldResult> offsets = getZeroOffsets(rewriter, sourceType.getRank());
  SmallVector<OpFoldResult> sizes = getStaticSizes(rewriter, sourceType.getShape());
  offsets[axis] = rewriter.getIndexAttr(offset);
  sizes[axis] = rewriter.getIndexAttr(size);
  return tensor::ExtractSliceOp::create(
           rewriter, loc, resultType, source, offsets, sizes, getUnitStrides(rewriter, sourceType.getRank()))
    .getResult();
}

Value extractStaticSliceOrIdentity(RewriterBase& rewriter,
                                   Location loc,
                                   Value source,
                                   RankedTensorType resultType,
                                   ArrayRef<OpFoldResult> offsets,
                                   ArrayRef<OpFoldResult> sizes,
                                   ArrayRef<OpFoldResult> strides) {
  auto sourceType = cast<RankedTensorType>(source.getType());
  size_t rank = static_cast<size_t>(sourceType.getRank());

  bool isIdentitySlice =
    sourceType == resultType && sourceType.hasStaticShape() && offsets.size() == rank && sizes.size() == rank
    && strides.size() == rank;
  if (isIdentitySlice) {
    ArrayRef<int64_t> sourceShape = sourceType.getShape();
    for (auto [dim, offset, size, stride] : llvm::zip_equal(sourceShape, offsets, sizes, strides)) {
      std::optional<int64_t> staticOffset = mlir::getConstantIntValue(offset);
      std::optional<int64_t> staticSize = mlir::getConstantIntValue(size);
      std::optional<int64_t> staticStride = mlir::getConstantIntValue(stride);
      if (!staticOffset || !staticSize || !staticStride || *staticOffset != 0 || *staticSize != dim || *staticStride != 1) {
        isIdentitySlice = false;
        break;
      }
    }
  }

  if (isIdentitySlice)
    return source;

  return tensor::ExtractSliceOp::create(rewriter, loc, resultType, source, offsets, sizes, strides).getResult();
}

Value insertStaticSlice(
  PatternRewriter& rewriter, Location loc, Value source, Value dest, ArrayRef<OpFoldResult> offsets) {
  auto sourceType = cast<RankedTensorType>(source.getType());
  return tensor::InsertSliceOp::create(rewriter,
                                       loc,
                                       source,
                                       dest,
                                       offsets,
                                       getStaticSizes(rewriter, sourceType.getShape()),
                                       getUnitStrides(rewriter, sourceType.getRank()))
    .getResult();
}

} // namespace onnx_mlir