// Copyright 2017 Google LLC
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#ifndef GOOGLE_CLOUD_CPP_GOOGLE_CLOUD_BIGTABLE_MUTATIONS_H
#define GOOGLE_CLOUD_CPP_GOOGLE_CLOUD_BIGTABLE_MUTATIONS_H

#include "google/cloud/bigtable/cell.h"
#include "google/cloud/bigtable/row_key.h"
#include "google/cloud/bigtable/version.h"
#include "google/cloud/grpc_error_delegate.h"
#include "google/cloud/internal/big_endian.h"
#include "google/cloud/status.h"
#include "google/cloud/status_or.h"
#include "absl/meta/type_traits.h"
#include "google/bigtable/v2/bigtable.pb.h"
#include "google/bigtable/v2/data.pb.h"
#include <google/protobuf/util/message_differencer.h>
#include <grpcpp/grpcpp.h>
#include <chrono>
#include <string>
#include <type_traits>
#include <vector>

namespace google {
namespace cloud {
namespace bigtable {
GOOGLE_CLOUD_CPP_INLINE_NAMESPACE_BEGIN
/**
 * Represent a single change to a specific row in a Table.
 *
 * Mutations come in different forms, they can set a specific cell,
 * delete a specific cell or delete multiple cells in a row.
 */
struct Mutation {
  google::bigtable::v2::Mutation op;
};

/**
 * A magic value where the server sets the timestamp.
 *
 * Notice that using this value in a SetCell() mutation makes it non-idempotent,
 * and by default the client will not retry such mutations.
 */
constexpr std::int64_t ServerSetTimestamp() { return -1; }

/// Create a mutation to set a cell value.
template <typename ColumnType, typename ValueType>
Mutation SetCell(std::string family, ColumnType&& column,
                 std::chrono::milliseconds timestamp, ValueType&& value) {
  Mutation m;
  auto& set_cell = *m.op.mutable_set_cell();
  set_cell.set_family_name(std::move(family));
  set_cell.set_column_qualifier(std::forward<ColumnType>(column));
  set_cell.set_timestamp_micros(
      std::chrono::duration_cast<std::chrono::microseconds>(timestamp).count());
  set_cell.set_value(std::forward<ValueType>(value));
  return m;
}

/// Create a mutation to store a 64-bit big endian integer value.
template <typename ColumnType>
Mutation SetCell(std::string family, ColumnType&& column,
                 std::chrono::milliseconds timestamp, std::int64_t value) {
  Mutation m;
  auto& set_cell = *m.op.mutable_set_cell();
  set_cell.set_family_name(std::move(family));
  set_cell.set_column_qualifier(std::forward<ColumnType>(column));
  set_cell.set_timestamp_micros(
      std::chrono::duration_cast<std::chrono::microseconds>(timestamp).count());
  set_cell.set_value(google::cloud::internal::EncodeBigEndian(value));
  return m;
}

/**
 * Create a mutation to set a cell value where the server sets the time.
 *
 * These mutations are not idempotent and not retried by default.
 */
template <typename ColumnType, typename ValueType>
Mutation SetCell(std::string family, ColumnType&& column, ValueType&& value) {
  Mutation m;
  auto& set_cell = *m.op.mutable_set_cell();
  set_cell.set_family_name(std::move(family));
  set_cell.set_column_qualifier(std::forward<ColumnType>(column));
  set_cell.set_timestamp_micros(ServerSetTimestamp());
  set_cell.set_value(std::forward<ValueType>(value));
  return m;
}

/**
 * Create a mutation to store a 64-bit big endian integer value.
 *
 * @note This mutation is not idempotent, the default policies do not retry
 *   transient failures for this mutation.
 */
template <typename ColumnType>
Mutation SetCell(std::string family, ColumnType&& column, std::int64_t value) {
  Mutation m;
  auto& set_cell = *m.op.mutable_set_cell();
  set_cell.set_family_name(std::move(family));
  set_cell.set_column_qualifier(std::forward<ColumnType>(column));
  set_cell.set_timestamp_micros(ServerSetTimestamp());
  set_cell.set_value(google::cloud::internal::EncodeBigEndian(value));
  return m;
}

/**
 * Create a mutation to set a cell value based on a `bigtable::Cell`.
 *
 * These mutations are not idempotent and not retried by default.
 */
Mutation SetCell(Cell cell);

///@{
/**
 * @name Create mutations to delete a range of cells from a column.
 *
 * The following functions create a mutation that deletes all the
 * cells in the given column family and, column within the given
 * timestamp in the range.
 *
 * The function accepts any instantiation of `std::chrono::duration<>` for the
 * @p timestamp_begin and @p timestamp_end parameters.  For example:
 *
 * @code
 * using namespace std::chrono_literals; // C++14
 * bigtable::DeleteFromColumn("fam", "col", 0us, 10us)
 * @endcode
 *
 * The ending timestamp is exclusive, while the beginning timestamp is
 * inclusive.  That is, the interval is [@p timestamp_begin, @p timestamp_end).
 * The value 0 is special and treated as "unbounded" for both the begin and
 * end endpoints of the time range.  The Cloud Bigtable server rejects
 * invalid and empty ranges, i.e., any range where the endpoint is smaller or
 * equal than to the initial endpoint unless either endpoint is 0.
 *
 * @tparam Rep1 a placeholder to match the Rep tparam for @p timestamp_begin
 * type. The semantics of this template parameter are documented in
 * std::chrono::duration<>` (in brief, the underlying arithmetic type
 * used to store the number of ticks), for our purposes it is simply a
 * formal parameter.
 *
 * @tparam Rep2 similar formal parameter for the type of @p timestamp_end.
 *
 * @tparam Period1 a placeholder to match the Period tparam for
 * @p timestamp_begin type. The semantics of this template parameter are
 * documented in `std::chrono::duration<>` (in brief, the length of the tick
 * in seconds,vexpressed as a `std::ratio<>`), for our purposes it is simply
 * a formal parameter.
 *
 * @tparam Period2 similar formal parameter for the type of @p timestamp_end.
 *
 * @tparam ColumnType the type of the column qualifier. It should satisfy
 *   std::is_constructible<ColumnQualifierType, ColumnType>.
 */
template <typename Rep1, typename Period1, typename Rep2, typename Period2,
          typename ColumnType>
Mutation DeleteFromColumn(std::string family, ColumnType&& column,
                          std::chrono::duration<Rep1, Period1> timestamp_begin,
                          std::chrono::duration<Rep2, Period2> timestamp_end) {
  Mutation m;
  auto& d = *m.op.mutable_delete_from_column();
  d.set_family_name(std::move(family));
  d.set_column_qualifier(std::forward<ColumnType>(column));
  d.mutable_time_range()->set_start_timestamp_micros(
      std::chrono::duration_cast<std::chrono::microseconds>(timestamp_begin)
          .count());
  d.mutable_time_range()->set_end_timestamp_micros(
      std::chrono::duration_cast<std::chrono::microseconds>(timestamp_end)
          .count());
  return m;
}

///@{
/**
 * @name The following functions create a mutation that deletes all the
 * cells in the given column family and column, starting from and
 * including, @a timestamp_begin.
 *
 * The function accepts any instantiation of `std::chrono::duration<>` for the
 * @p timestamp_begin For example:
 *
 * @code
 * using namespace std::chrono_literals; // C++14
 * bigtable::DeleteFromColumn("fam", "col", 10us)
 * @endcode
 *
 * @tparam Rep1 a placeholder to match the Rep tparam for @p timestamp_begin
 * type. The semantics of this template parameter are documented in
 * `std::chrono::duration<>` (in brief, the underlying arithmetic type
 * used to store the number of ticks), for our purposes it is simply a
 * formal parameter.
 *
 * @tparam Period1 a placeholder to match the Period tparam for @p
 * timestamp_begin type. The semantics of this template parameter
 * are documented in `std::chrono::duration<>` (in brief, the length
 * of the tick in seconds, expressed as a `std::ratio<>`), for our
 * purposes it is simply a formal parameter.
 *
 * @tparam ColumnType the type of the column qualifier. It should satisfy
 *   std::is_constructible<ColumnQualifierType, ColumnType>.
 */
template <typename Rep1, typename Period1, typename ColumnType>
Mutation DeleteFromColumnStartingFrom(
    std::string family, ColumnType&& column,
    std::chrono::duration<Rep1, Period1> timestamp_begin) {
  Mutation m;
  auto& d = *m.op.mutable_delete_from_column();
  d.set_family_name(std::move(family));
  d.set_column_qualifier(std::forward<ColumnType>(column));
  d.mutable_time_range()->set_start_timestamp_micros(
      std::chrono::duration_cast<std::chrono::microseconds>(timestamp_begin)
          .count());
  return m;
}

///@{
/**
 * @name The following functions create a mutation that deletes all the
 * cells in the given column family and column, Delete up to @a timestamp_end,
 * but excluding, @a timestamp_end.
 *
 * The function accepts any instantiation of `std::chrono::duration<>` for the
 * @p timestamp_end For example:
 *
 * @code
 * using namespace std::chrono_literals; // C++14
 * bigtable::DeleteFromColumn("fam", "col", 10us)
 * @endcode
 *
 * @tparam Rep2 a placeholder to match the Rep tparam for @p timestamp_end type.
 * The semantics of this template parameter are documented in
 * `std::chrono::duration<>` (in brief, the underlying arithmetic type
 * used to store the number of ticks), for our purposes it is simply a
 * formal parameter.
 *
 * @tparam Period2 a placeholder to match the Period tparam for @p timestamp_end
 * type. The semantics of this template parameter are documented in
 * `std::chrono::duration<>` (in brief, the length of the tick in seconds,
 * expressed as a `std::ratio<>`), for our purposes it is simply a formal
 * parameter.
 *
 * @tparam ColumnType the type of the column qualifier. It should satisfy
 *   std::is_constructible<ColumnQualifierType, ColumnType>.
 */
template <typename Rep2, typename Period2, typename ColumnType>
Mutation DeleteFromColumnEndingAt(
    std::string family, ColumnType&& column,
    std::chrono::duration<Rep2, Period2> timestamp_end) {
  Mutation m;
  auto& d = *m.op.mutable_delete_from_column();
  d.set_family_name(std::move(family));
  d.set_column_qualifier(std::forward<ColumnType>(column));
  d.mutable_time_range()->set_end_timestamp_micros(
      std::chrono::duration_cast<std::chrono::microseconds>(timestamp_end)
          .count());
  return m;
}

/// Delete all the values for the column.
template <typename ColumnType>
Mutation DeleteFromColumn(std::string family, ColumnType&& column) {
  Mutation m;
  auto& d = *m.op.mutable_delete_from_column();
  d.set_family_name(std::move(family));
  d.set_column_qualifier(std::forward<ColumnType>(column));
  return m;
}
///@}

/// Create a mutation to delete all the cells in a column family.
Mutation DeleteFromFamily(std::string family);

/// Create a mutation to delete all the cells in a row.
Mutation DeleteFromRow();

/**
 * Represent a single row mutation.
 *
 * Bigtable can perform multiple changes to a single row atomically.
 * This class represents 0 or more changes to apply to a single row.
 * The changes may include setting cells (which implicitly insert the
 * values), deleting values, etc.
 */
class SingleRowMutation {
 public:
  /// Create an empty mutation.
  template <typename RowKey,
            /// @cond implementation_details
            std::enable_if_t<std::is_constructible<RowKeyType, RowKey>::value,
                             int> = 0
            /// @endcond
            >
  // NOLINTNEXTLINE(bugprone-forwarding-reference-overload)
  explicit SingleRowMutation(RowKey&& row_key) {
    request_.set_row_key(RowKeyType(std::forward<RowKey>(row_key)));
  }

  /// Create a row mutation from a initializer list.
  template <typename RowKey>
  SingleRowMutation(RowKey&& row_key, std::initializer_list<Mutation> list) {
    request_.set_row_key(std::forward<RowKey>(row_key));
    for (auto&& i : list) {
      *request_.add_mutations() = i.op;
    }
  }

  /// Create a single-row multiple-cell mutation from a variadic list.
  template <typename RowKey, typename... M,
            /// @cond implementation_details
            std::enable_if_t<std::is_constructible<RowKeyType, RowKey>::value,
                             int> = 0
            /// @endcond
            >
  explicit SingleRowMutation(RowKey&& row_key, M&&... m) {
    static_assert(
        absl::conjunction<std::is_convertible<M, Mutation>...>::value,
        "The arguments passed to SingleRowMutation(std::string, ...) must be "
        "convertible to Mutation");
    request_.set_row_key(std::forward<RowKey>(row_key));
    emplace_many(std::forward<M>(m)...);
  }

  /// Create a row mutation from gRPC proto
  explicit SingleRowMutation(
      ::google::bigtable::v2::MutateRowsRequest::Entry entry) {
    using std::swap;
    swap(*request_.mutable_row_key(), *entry.mutable_row_key());
    swap(*request_.mutable_mutations(), *entry.mutable_mutations());
  }

  /// Create a row mutation from gRPC proto
  explicit SingleRowMutation(::google::bigtable::v2::MutateRowRequest request)
      : request_(std::move(request)) {}

  // Add a mutation at the end.
  SingleRowMutation& emplace_back(Mutation mut) {
    *request_.add_mutations() = std::move(mut.op);
    return *this;
  }

  // Get the row key.
  RowKeyType const& row_key() const { return request_.row_key(); }

  friend class Table;

  SingleRowMutation(SingleRowMutation&&) = default;
  SingleRowMutation& operator=(SingleRowMutation&&) = default;
  SingleRowMutation(SingleRowMutation const&) = default;
  SingleRowMutation& operator=(SingleRowMutation const&) = default;

  friend bool operator==(SingleRowMutation const& a,
                         SingleRowMutation const& b) noexcept {
    return google::protobuf::util::MessageDifferencer::Equivalent(a.request_,
                                                                  b.request_);
  }
  friend bool operator!=(SingleRowMutation const& a,
                         SingleRowMutation const& b) noexcept {
    return !(a == b);
  }

  /// Move the contents into a bigtable::v2::MutateRowsRequest::Entry.
  void MoveTo(google::bigtable::v2::MutateRowsRequest::Entry* entry) {
    entry->set_row_key(std::move(*request_.mutable_row_key()));
    *entry->mutable_mutations() = std::move(*request_.mutable_mutations());
  }

  /// Transfer the contents to @p request.
  void MoveTo(google::bigtable::v2::MutateRowRequest& request) {
    request.set_row_key(std::move(*request_.mutable_row_key()));
    *request.mutable_mutations() = std::move(*request_.mutable_mutations());
  }

  /// Remove the contents of the mutation.
  void Clear() { request_.Clear(); }

 private:
  /// Add multiple mutations to single row
  template <typename... M>
  void emplace_many(Mutation first, M&&... tail) {
    emplace_back(std::move(first));
    emplace_many(std::forward<M>(tail)...);
  }

  void emplace_many(Mutation m) { emplace_back(std::move(m)); }

  ::google::bigtable::v2::MutateRowRequest request_;
};

/**
 * A SingleRowMutation that failed.
 *
 * A multi-row mutation returns the list of operations that failed,
 * this class encapsulates both the failure and the original
 * mutation.  The application can then choose to resend the mutation,
 * or log it, or save it for processing via some other means.
 */
class FailedMutation {
 public:
  FailedMutation(google::cloud::Status status, int index)
      : status_(std::move(status)), original_index_(index) {}

  FailedMutation(google::rpc::Status const& status, int index)
      : status_(MakeStatusFromRpcError(status)), original_index_(index) {}

  FailedMutation(FailedMutation&&) = default;
  FailedMutation& operator=(FailedMutation&&) = default;
  FailedMutation(FailedMutation const&) = default;
  FailedMutation& operator=(FailedMutation const&) = default;

  friend bool operator==(FailedMutation const& a,
                         FailedMutation const& b) noexcept {
    return a.status_ == b.status_ && a.original_index_ == b.original_index_;
  }
  friend bool operator!=(FailedMutation const& a,
                         FailedMutation const& b) noexcept {
    return !(a == b);
  }

  ///@{
  /// @name accessors
  google::cloud::Status const& status() const { return status_; }
  int original_index() const { return original_index_; }
  ///@}

  friend class BulkMutation;

 private:
  google::cloud::Status status_;
  int original_index_;
};

/**
 * Report unrecoverable errors in a partially completed mutation.
 */
class PermanentMutationFailure : public std::runtime_error {
 public:
  PermanentMutationFailure(char const* msg,
                           std::vector<FailedMutation> failures)
      : std::runtime_error(msg), failures_(std::move(failures)) {}

  PermanentMutationFailure(char const* msg, grpc::Status status,
                           std::vector<FailedMutation> failures)
      : std::runtime_error(msg),
        failures_(std::move(failures)),
        status_(std::move(status)) {}

  /**
   * The details of each mutation failure.
   *
   * Because BulkApply() and Apply() take ownership of the data in the mutations
   * the failures are returned with their full contents, in case the application
   * wants to take further action with them.  Any successful mutations are
   * discarded.
   *
   * Any mutations that fail with an unknown state are included with a
   * `grpc::StatusCode::OK`.
   */
  std::vector<FailedMutation> const& failures() const { return failures_; }

  /**
   * The `grpc::Status` of the request.
   *
   * Notice that it can return `grpc::Status::OK` when there are partial
   * failures in a `BulkApply()` operation.
   */
  grpc::Status const& status() const { return status_; }

 private:
  std::vector<FailedMutation> failures_;
  grpc::Status status_;
};

/**
 * Represent a set of mutations across multiple rows.
 *
 * Cloud Bigtable can batch multiple mutations in a single request.
 * The mutations are not atomic, but it is more efficient to send them
 * in a batch than to make multiple smaller requests.
 */
class BulkMutation {
 public:
  /// Create an empty set of mutations.
  BulkMutation() = default;

  /// Create a multi-row mutation from a range of SingleRowMutations.
  template <typename Iterator>
  BulkMutation(Iterator begin, Iterator end) {
    static_assert(
        std::is_convertible<decltype(*begin), SingleRowMutation>::value,
        "The iterator value type must be convertible to SingleRowMutation");
    for (auto i = begin; i != end; ++i) {
      push_back(*i);
    }
  }

  /// Create a multi-row mutation from a initializer list.
  BulkMutation(std::initializer_list<SingleRowMutation> list)
      : BulkMutation(list.begin(), list.end()) {}

  /// Create a multi-row mutation from a SingleRowMutation
  explicit BulkMutation(SingleRowMutation mutation) : BulkMutation() {
    emplace_back(std::move(mutation));
  }

  /// Create a multi-row mutation from two SingleRowMutation
  BulkMutation(SingleRowMutation m1, SingleRowMutation m2) : BulkMutation() {
    emplace_back(std::move(m1));
    emplace_back(std::move(m2));
  }

  /// Create a multi-row mutation from a variadic list.
  template <typename... M,
            /// @cond implementation_details
            std::enable_if_t<absl::conjunction<std::is_convertible<
                                 M, SingleRowMutation>...>::value,
                             int> = 0
            /// @endcond
            >
  // NOLINTNEXTLINE(google-explicit-constructor)
  BulkMutation(M&&... m) : BulkMutation() {
    emplace_many(std::forward<M>(m)...);
  }

  // Add a mutation to the batch.
  BulkMutation& emplace_back(SingleRowMutation mut) {
    mut.MoveTo(request_.add_entries());
    return *this;
  }

  // Add a failed mutation to the batch.
  BulkMutation& emplace_back(FailedMutation fm) {
    fm.status_ = google::cloud::Status();
    return *this;
  }

  // Add a mutation to the batch.
  BulkMutation& push_back(SingleRowMutation mut) {
    mut.MoveTo(request_.add_entries());
    return *this;
  }

  /// Move the contents into a bigtable::v2::MutateRowsRequest
  void MoveTo(google::bigtable::v2::MutateRowsRequest* request) {
    request_.Swap(request);
    request_ = {};
  }

  /// Return true if there are no mutations in this set.
  bool empty() const { return request_.entries().empty(); }

  /// Return the number of mutations in this set.
  std::size_t size() const { return request_.entries().size(); }

  /// Return the estimated size in bytes of all the mutations in this set.
  std::size_t estimated_size_in_bytes() const {
    return request_.ByteSizeLong();
  }

 private:
  template <typename... M>
  void emplace_many(SingleRowMutation first, M&&... tail) {
    emplace_back(std::move(first));
    emplace_many(std::forward<M>(tail)...);
  }

  void emplace_many(SingleRowMutation m) { emplace_back(std::move(m)); }

  google::bigtable::v2::MutateRowsRequest request_;
};

GOOGLE_CLOUD_CPP_INLINE_NAMESPACE_END
}  // namespace bigtable
}  // namespace cloud
}  // namespace google

#endif  // GOOGLE_CLOUD_CPP_GOOGLE_CLOUD_BIGTABLE_MUTATIONS_H
