/*
  Copyright (c) 2019 Sogou, 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.

  Author: Xie Han (xiehan@sogou-inc.com)
*/

#ifndef _HTTPMESSAGE_H_
#define _HTTPMESSAGE_H_

#include <string.h>
#include <utility>
#include <string>
#include "list.h"
#include "ProtocolMessage.h"
#include "http_parser.h"

/**
 * @file   HttpMessage.h
 * @brief  Http Protocol Interface
 */

namespace protocol
{

struct HttpMessageHeader
{
	const void *name;
	size_t name_len;
	const void *value;
	size_t value_len;
};

class HttpMessage : public ProtocolMessage
{
public:
	const char *get_http_version() const
	{
		return http_parser_get_version(this->parser);
	}

	bool set_http_version(const char *version)
	{
		return http_parser_set_version(version, this->parser) == 0;
	}

	/* is_chunked(), is_keep_alive() only reflect the parsed result.
	 * set_header(), add_header() do not effect on it. */
	bool is_chunked() const
	{
		return http_parser_chunked(this->parser);
	}

	bool is_keep_alive() const
	{
		return http_parser_keep_alive(this->parser);
	}

	bool add_header(const struct HttpMessageHeader *header)
	{
		return http_parser_add_header(header->name, header->name_len,
									  header->value, header->value_len,
									  this->parser) == 0;
	}

	bool add_header_pair(const char *name, const char *value)
	{
		return http_parser_add_header(name, strlen(name),
									  value, strlen(value),
									  this->parser) == 0;
	}

	bool set_header(const struct HttpMessageHeader *header)
	{
		return http_parser_set_header(header->name, header->name_len,
									  header->value, header->value_len,
									  this->parser) == 0;
	}

	bool set_header_pair(const char *name, const char *value)
	{
		return http_parser_set_header(name, strlen(name),
									  value, strlen(value),
									  this->parser) == 0;
	}

	bool get_parsed_body(const void **body, size_t *size) const
	{
		return http_parser_get_body(body, size, this->parser) == 0;
	}

	/* Call when the message is incomplete, but you want the parsed body.
	 * If get_parse_body() still returns false after calling this function,
	 * even header is incomplete. In a success state task, messages are
	 * always complete. */
	void end_parsing()
	{
		http_parser_close_message(this->parser);
	}

	/* Output body is for sending. Want to transfer a message received, maybe:
	 * msg->get_parsed_body(&body, &size);
	 * msg->append_output_body_nocopy(body, size); */
	bool append_output_body(const void *buf, size_t size);
	bool append_output_body_nocopy(const void *buf, size_t size);
	void clear_output_body();
	size_t get_output_body_size() const
	{
		return this->output_body_size;
	}

	/* std::string interface */
public:
	bool get_http_version(std::string& version) const
	{
		const char *str = this->get_http_version();

		if (str)
		{
			version.assign(str);
			return true;
		}

		return false;
	}

	bool set_http_version(const std::string& version)
	{
		return this->set_http_version(version.c_str());
	}

	bool add_header_pair(const std::string& name, const std::string& value)
	{
		return http_parser_add_header(name.c_str(), name.size(),
									  value.c_str(), value.size(),
									  this->parser) == 0;
	}

	bool set_header_pair(const std::string& name, const std::string& value)
	{
		return http_parser_set_header(name.c_str(), name.size(),
									  value.c_str(), value.size(),
									  this->parser) == 0;
	}

	bool append_output_body(const std::string& buf)
	{
		return this->append_output_body(buf.c_str(), buf.size());
	}

protected:
	http_parser_t *parser;
	size_t cur_size;

public:
	/* for header visitors. */
	const http_parser_t *get_parser() const
	{
		return this->parser;
	}

protected:
	virtual int encode(struct iovec vectors[], int max);
	virtual int append(const void *buf, size_t *size);

private:
	struct list_head *combine_from(struct list_head *pos, size_t size);

private:
	struct list_head output_body;
	size_t output_body_size;

public:
	HttpMessage(bool is_resp) : parser(new http_parser_t)
	{
		http_parser_init(is_resp, this->parser);
		INIT_LIST_HEAD(&this->output_body);
		this->output_body_size = 0;
		this->cur_size = 0;
	}

	virtual ~HttpMessage()
	{
		this->clear_output_body();
		if (this->parser)
		{
			http_parser_deinit(this->parser);
			delete this->parser;
		}
	}

	/* for std::move() */
public:
	HttpMessage(HttpMessage&& msg);
	HttpMessage& operator = (HttpMessage&& msg);
};

class HttpRequest : public HttpMessage
{
public:
	const char *get_method() const
	{
		return http_parser_get_method(this->parser);
	}

	const char *get_request_uri() const
	{
		return http_parser_get_uri(this->parser);
	}

	bool set_method(const char *method)
	{
		return http_parser_set_method(method, this->parser) == 0;
	}

	bool set_request_uri(const char *uri)
	{
		return http_parser_set_uri(uri, this->parser) == 0;
	}

	/* std::string interface */
public:
	bool get_method(std::string& method) const
	{
		const char *str = this->get_method();

		if (str)
		{
			method.assign(str);
			return true;
		}

		return false;
	}

	bool get_request_uri(std::string& uri) const
	{
		const char *str = this->get_request_uri();

		if (str)
		{
			uri.assign(str);
			return true;
		}

		return false;
	}

	bool set_method(const std::string& method)
	{
		return this->set_method(method.c_str());
	}

	bool set_request_uri(const std::string& uri)
	{
		return this->set_request_uri(uri.c_str());
	}

protected:
	virtual int append(const void *buf, size_t *size);

private:
	int handle_expect_continue();

public:
	HttpRequest() : HttpMessage(false) { }

	/* for std::move() */
public:
	HttpRequest(HttpRequest&& req) = default;
	HttpRequest& operator = (HttpRequest&& req) = default;
};

class HttpResponse : public HttpMessage
{
public:
	const char *get_status_code() const
	{
		return http_parser_get_code(this->parser);
	}

	const char *get_reason_phrase() const
	{
		return http_parser_get_phrase(this->parser);
	}

	bool set_status_code(const char *code)
	{
		return http_parser_set_code(code, this->parser) == 0;
	}

	bool set_reason_phrase(const char *phrase)
	{
		return http_parser_set_phrase(phrase, this->parser) == 0;
	}

	/* Tell the parser, it is a HEAD response. */
	void parse_zero_body()
	{
		this->parser->transfer_length = 0;
	}

	/* std::string interface */
public:
	bool get_status_code(std::string& code) const
	{
		const char *str = this->get_status_code();

		if (str)
		{
			code.assign(str);
			return true;
		}

		return false;
	}

	bool get_reason_phrase(std::string& phrase) const
	{
		const char *str = this->get_reason_phrase();

		if (str)
		{
			phrase.assign(str);
			return true;
		}

		return false;
	}

	bool set_status_code(const std::string& code)
	{
		return this->set_status_code(code.c_str());
	}

	bool set_reason_phrase(const std::string& phrase)
	{
		return this->set_reason_phrase(phrase.c_str());
	}

protected:
	virtual int append(const void *buf, size_t *size);

public:
	HttpResponse() : HttpMessage(true) { }

	/* for std::move() */
public:
	HttpResponse(HttpResponse&& resp) = default;
	HttpResponse& operator = (HttpResponse&& resp) = default;
};

}

#endif