/* -*- Mode: C++; tab-width: 4; c-basic-offset: 4; indent-tabs-mode: nil -*- */
/*
 * Copyright 2022-Present Couchbase, Inc.
 *
 * 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
 *
 *     http://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.
 */

#pragma once

#include <couchbase/build_config.hxx>

#include "core/impl/bootstrap_error.hxx"
#include "core/io/http_streaming_response.hxx"
#include "service_type.hxx"
#include "utils/movable_function.hxx"

#include <chrono>
#include <cinttypes>
#include <cstddef>
#include <map>
#include <memory>
#include <optional>
#include <string>
#include <system_error>
#include <vector>

namespace asio
{
class io_context;
} // namespace asio

namespace couchbase
{
class retry_strategy;
namespace tracing
{
class request_span;
} // namespace tracing
} // namespace couchbase

namespace couchbase::core
{
class http_request
{
public:
  service_type service{};
  std::string method{};
  std::string endpoint{};
  std::string path{};
  std::string body{};
  std::map<std::string, std::string> headers{};
  std::string content_type{};
  std::string client_context_id{};
  bool is_idempotent{};
  bool is_read_only{};
  std::string unique_id{};
  std::shared_ptr<couchbase::retry_strategy> retry_strategy{};
  std::chrono::milliseconds timeout{};
  std::shared_ptr<couchbase::tracing::request_span> parent_span{};

  struct {
    std::string user{};
    std::string undesired_endpoint{};
  } internal{};
};

namespace io
{
class http_streaming_response;
struct http_response;
} // namespace io

class http_response_impl;

class http_response_body
{
public:
  explicit http_response_body(std::shared_ptr<http_response_impl> impl);

  // cached_chunk_size > 0 makes the in-memory body deliver at most that many bytes per next()
  // call (a test seam simulating a socket that dribbles the response out, so back-pressure can be
  // exercised); 0 delivers the whole body in one chunk.
  static auto create_in_memory(asio::io_context& io,
                               std::string data,
                               std::size_t cached_chunk_size = 0) -> http_response_body;

  // Test-only fault-injection seam extending create_in_memory. The body first hands out `data` (in
  // cached_chunk_size-byte slices, 0 = all at once), then once that is drained:
  //   * if `stall` is true, the next pull never completes until cancel() is called, at which point
  //     it delivers request_canceled — this is how the row_streamer idle timer (and its
  //     read-only-aware timeout classification) is exercised deterministically; otherwise
  //   * the next pull's terminal carries `terminal_ec` (a simulated mid-stream transport error).
  static auto create_in_memory_faulty(asio::io_context& io,
                                      std::string data,
                                      std::size_t cached_chunk_size,
                                      std::error_code terminal_ec,
                                      bool stall) -> http_response_body;

  // See io::http_streaming_response_body::next: the bool is `has_more` (false marks end-of-stream).
  // An empty data string with has_more==true is a valid mid-stream chunk, not the terminal.
  void next(utils::movable_function<void(std::string, bool, std::error_code)> callback);
  void cancel();

private:
  std::shared_ptr<http_response_impl> impl_;
};

class http_response
{
public:
  http_response() = default;
  explicit http_response(io::http_streaming_response resp);

  [[nodiscard]] auto endpoint() const -> std::string;
  // Where this response was dispatched. Empty for the in-memory/fault test bodies, which have no
  // session behind them.
  [[nodiscard]] auto dispatch_info() const -> io::http_dispatch_info;
  [[nodiscard]] auto status_code() const -> std::uint32_t;
  [[nodiscard]] auto content_length() const -> std::size_t;

  [[nodiscard]] auto body() const -> http_response_body;
  void close();

private:
  std::shared_ptr<http_response_impl> impl_;
};

#ifdef COUCHBASE_CXX_CLIENT_COLUMNAR
using free_form_http_request_callback =
  utils::movable_function<void(http_response response, couchbase::core::error_union err)>;
#else
using free_form_http_request_callback =
  utils::movable_function<void(http_response response, std::error_code ec)>;
#endif

class buffered_http_response_impl;

class buffered_http_response
{
public:
  buffered_http_response() = default;
  explicit buffered_http_response(io::http_response resp);

  [[nodiscard]] auto endpoint() const -> std::string;
  [[nodiscard]] auto status_code() const -> std::uint32_t;
  [[nodiscard]] auto content_length() const -> std::size_t;

  [[nodiscard]] auto body() -> std::string;

private:
  std::shared_ptr<buffered_http_response_impl> impl_;
};

using buffered_free_form_http_request_callback =
  utils::movable_function<void(buffered_http_response response, std::error_code ec)>;
} // namespace couchbase::core
