//    OpenVPN -- An application to securely tunnel IP networks
//               over a single port, with support for SSL/TLS-based
//               session authentication and key exchange,
//               packet encryption, packet authentication, and
//               packet compression.
//
//    Copyright (C) 2012-2020 OpenVPN Inc.
//
//    This program is free software: you can redistribute it and/or modify
//    it under the terms of the GNU Affero General Public License Version 3
//    as published by the Free Software Foundation.
//
//    This program is distributed in the hope that it will be useful,
//    but WITHOUT ANY WARRANTY; without even the implied warranty of
//    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
//    GNU Affero General Public License for more details.
//
//    You should have received a copy of the GNU Affero General Public License
//    along with this program in the COPYING file.
//    If not, see <http://www.gnu.org/licenses/>.

#ifndef OPENVPN_HTTP_URLPARM_H
#define OPENVPN_HTTP_URLPARM_H

#include <string>
#include <sstream>
#include <vector>

#include <openvpn/common/number.hpp>
#include <openvpn/http/urlencode.hpp>
#include <openvpn/http/webexcept.hpp>
#include <openvpn/common/string.hpp>

namespace openvpn {
  namespace URL {
    OPENVPN_EXCEPTION(url_parameter_error);

    struct Parm
    {
      Parm() {}

      Parm(const std::string& name_arg, const std::string& value_arg)
	: name(name_arg), value(value_arg)
      {
      }

      std::string to_string() const
      {
	std::ostringstream out;
	out << name << '=' << value;
	return out.str();
      }

      std::string name;
      std::string value;
    };

    class ParmList : public std::vector<Parm>
    {
    public:
      ParmList(const std::string& uri)
      {
	try {
	  const std::vector<std::string> req_parms = string::split(uri, '?', 1);
	  request_ = req_parms[0];
	  if (req_parms.size() == 2)
	    {
	      const std::vector<std::string> kv_list = string::split(req_parms[1], '&');
	      for (auto &kvstr : kv_list)
		{
		  const std::vector<std::string> kv = string::split(kvstr, '=', 1);
		  Parm p;
		  p.name = decode(kv[0]);
		  if (kv.size() == 2)
		    p.value = decode(kv[1]);
		  push_back(std::move(p));
		}
	    }
	}
	catch (const std::exception& e)
	  {
	    throw HTTP::WebException(HTTP::Status::BadRequest, e.what());
	  }
      }

      const Parm* get(const std::string& key) const
      {
	for (auto &p : *this)
	  {
	    if (key == p.name)
	      return &p;
	  }
	return nullptr;
      }

      std::string get_value(const std::string& key) const
      {
	const Parm* p = get(key);
	if (p)
	  return p->value;
	else
	  return "";
      }

      const std::string& get_value_required(const std::string& key) const
      {
	const Parm* p = get(key);
	if (p)
	  return p->value;
	else
	  throw url_parameter_error(key + " : not found");
      }

      template <typename T>
      T get_num(const std::string& name, const std::string& short_name, const T default_value) const
      {
	const Parm* p = get(name);
	if (!p && !short_name.empty())
	  p = get(short_name);
	if (p)
	  return parse_number_throw<T>(p->value, name);
	else
	  return default_value;
      }

      template <typename T>
      T get_num_required(const std::string& name, const std::string& short_name) const
      {
	const Parm* p = get(name);
	if (!p && !short_name.empty())
	  p = get(short_name);
	if (!p)
	  throw url_parameter_error(name + " : not found");
	return parse_number_throw<T>(p->value, name);
      }

      bool get_bool(const std::string& name, const std::string& short_name, const bool default_value) const
      {
	const Parm* p = get(name);
	if (!p && !short_name.empty())
	  p = get(short_name);
	if (p)
	  {
	    if (p->value == "0")
	      return false;
	    else if (p->value == "1")
	      return true;
	    else
	      throw url_parameter_error(name + ": parameter must be 0 or 1");
	  }
	else
	  return default_value;
      }

      std::string get_string(const std::string& name, const std::string& short_name) const
      {
	const Parm* p = get(name);
	if (!p && !short_name.empty())
	  p = get(short_name);
	if (p)
	  return p->value;
	else
	  return "";
      }

      std::string get_string_required(const std::string& name, const std::string& short_name) const
      {
	const Parm* p = get(name);
	if (!p && !short_name.empty())
	  p = get(short_name);
	if (!p)
	  throw url_parameter_error(name + " : not found");
	return p->value;
      }

      std::string to_string() const
      {
	std::ostringstream out;
	for (size_t i = 0; i < size(); ++i)
	  out << '[' << i << "] " << (*this)[i].to_string() << std::endl;
	return out.str();
      }

      std::string request(const bool remove_leading_slash) const
      {
	std::string ret = request_;
	if (remove_leading_slash)
	  {
	    if (ret.length() > 0 && ret[0] == '/')
	      ret = ret.substr(1);
	    else
	      throw HTTP::WebException(HTTP::Status::BadRequest, "URI missing leading slash");
	  }
	if (ret.empty())
	  throw HTTP::WebException(HTTP::Status::BadRequest, "URI resource is empty");
	return ret;
      }

      const std::string& request() const
      {
	return request_;
      }

    private:
      std::string request_;
    };

  }
}

#endif