/*  PCSX2 - PS2 Emulator for PCs
 *  Copyright (C) 2002-2023 PCSX2 Dev Team
 *
 *  PCSX2 is free software: you can redistribute it and/or modify it under the terms
 *  of the GNU Lesser General Public License as published by the Free Software Found-
 *  ation, either version 3 of the License, or (at your option) any later version.
 *
 *  PCSX2 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 General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License along with PCSX2.
 *  If not, see <http://www.gnu.org/licenses/>.
 */

#pragma once

#include "common/Pcsx2Defs.h"

#include <atomic>
#include <functional>
#include <memory>
#include <mutex>
#include <string>
#include <string_view>
#include <variant>
#include <vector>

class ProgressCallback;

class HTTPDownloader
{
public:
	enum : s32
	{
		HTTP_STATUS_CANCELLED = -3,
		HTTP_STATUS_TIMEOUT = -2,
		HTTP_STATUS_ERROR = -1,
		HTTP_STATUS_OK = 200
	};

	struct Request
	{
		using Data = std::vector<u8>;
		using Callback = std::function<void(s32 status_code, const std::string& content_type, Data data)>;

		enum class Type
		{
			Get,
			Post,
		};

		enum class State
		{
			Pending,
			Cancelled,
			Started,
			Receiving,
			Complete,
		};

		HTTPDownloader* parent;
		Callback callback;
		ProgressCallback* progress;
		std::string url;
		std::string post_data;
		std::string content_type;
		Data data;
		u64 start_time;
		s32 status_code = 0;
		u32 content_length = 0;
		u32 last_progress_update = 0;
		Type type = Type::Get;
		std::atomic<State> state{State::Pending};
	};

	HTTPDownloader();
	virtual ~HTTPDownloader();

	static std::unique_ptr<HTTPDownloader> Create(std::string user_agent = DEFAULT_USER_AGENT);
	static std::string URLEncode(const std::string_view& str);
	static std::string URLDecode(const std::string_view& str);
	static std::string GetExtensionForContentType(const std::string& content_type);

	void SetTimeout(float timeout);
	void SetMaxActiveRequests(u32 max_active_requests);

	void CreateRequest(std::string url, Request::Callback callback, ProgressCallback* progress = nullptr);
	void CreatePostRequest(std::string url, std::string post_data, Request::Callback callback, ProgressCallback* progress = nullptr);
	void PollRequests();
	void WaitForAllRequests();
	bool HasAnyRequests();

	static const char DEFAULT_USER_AGENT[];

protected:
	virtual Request* InternalCreateRequest() = 0;
	virtual void InternalPollRequests() = 0;

	virtual bool StartRequest(Request* request) = 0;
	virtual void CloseRequest(Request* request) = 0;

	void LockedAddRequest(Request* request);
	u32 LockedGetActiveRequestCount();
	void LockedPollRequests(std::unique_lock<std::mutex>& lock);

	float m_timeout;
	u32 m_max_active_requests;

	std::mutex m_pending_http_request_lock;
	std::vector<Request*> m_pending_http_requests;
};