#include "fesa/math/matrix.h"

#include <limits>
#include <stdexcept>
#include <utility>

#include "math/dense_blas_internal.h"

namespace fesa {
namespace {

/// @brief Rejects shape overflow before logical dimensions diverge from
/// storage.
std::size_t CheckedStorageSize(const std::size_t rows,
                               const std::size_t columns) {
  if (columns != 0 &&
      rows > (std::numeric_limits<std::size_t>::max)() / columns) {
    throw std::length_error{
        "Dense matrix dimensions exceed the storage size range."};
  }
  return rows * columns;
}

}  // namespace

Matrix::Matrix(const std::size_t rows, const std::size_t columns,
               const double value)
    : rows_(rows),
      columns_(columns),
      values_(CheckedStorageSize(rows, columns), value) {}

Matrix::Matrix(const Matrix& other)
    : rows_(other.rows_),
      columns_(other.columns_),
      values_(other.values_.size()) {
  dense_blas_internal::CopyValues(other.values_.data(), other.values_.size(),
                                  values_.data());
}

Matrix::Matrix(Matrix&& other) noexcept
    : rows_(other.rows_),
      columns_(other.columns_),
      values_(std::move(other.values_)) {
  other.rows_ = 0;
  other.columns_ = 0;
  other.values_.clear();
}

Matrix& Matrix::operator=(const Matrix& other) {
  if (this != &other) {
    std::vector<double> copied(other.values_.size());
    dense_blas_internal::CopyValues(other.values_.data(), other.values_.size(),
                                    copied.data());
    rows_ = other.rows_;
    columns_ = other.columns_;
    values_.swap(copied);
  }
  return *this;
}

Matrix& Matrix::operator=(Matrix&& other) noexcept {
  if (this != &other) {
    rows_ = other.rows_;
    columns_ = other.columns_;
    values_ = std::move(other.values_);
    other.rows_ = 0;
    other.columns_ = 0;
    other.values_.clear();
  }
  return *this;
}

std::size_t Matrix::Rows() const noexcept { return rows_; }

std::size_t Matrix::Columns() const noexcept { return columns_; }

double* Matrix::Data() noexcept { return values_.data(); }

const double* Matrix::Data() const noexcept { return values_.data(); }

double Matrix::Norm() const {
  return dense_blas_internal::NormValues(Data(), values_.size());
}

void Matrix::Scale(const double alpha) {
  dense_blas_internal::ScaleValues(alpha, Data(), values_.size());
}

double& Matrix::operator()(const std::size_t row, const std::size_t column) {
  if (row >= rows_ || column >= columns_) {
    throw std::out_of_range{"Matrix index is outside its dimensions."};
  }
  return values_[row * columns_ + column];
}

const double& Matrix::operator()(const std::size_t row,
                                 const std::size_t column) const {
  if (row >= rows_ || column >= columns_) {
    throw std::out_of_range{"Matrix index is outside its dimensions."};
  }
  return values_[row * columns_ + column];
}

Vector Matrix::Multiply(const Vector& rhs) const {
  return dense_blas_internal::Multiply(*this, rhs);
}

Matrix Matrix::Multiply(const Matrix& rhs) const {
  return dense_blas_internal::Multiply(*this, rhs);
}

}  // namespace fesa