#include <iostream>
#include <thread>
#include <filesystem>
#include <opencv2/opencv.hpp>
#define SDL_MAIN_HANDLED
#include <SDL2/SDL.h>

#include "util.h"
#include "mediaDecoder.h"
#include "shaderService.h"
#include "shader.h"
#include "audioDecoder.h"
using std::cout;

constexpr int SCREEN_WIDTH = 640;
constexpr int SCREEN_HEIGHT = 480;

struct OpenglVideoParam
{
	SDL_GLContext glContext;
	unsigned int VAO, VBO, EBO;
	unsigned int texs[3];
};

int InitAudio(SDL_Window* window, SDL_Renderer* renderer, const char* targetFilePath, MediaParam& param)
{
	InitDecoder(targetFilePath, param);
	window = SDL_CreateWindow("mp", SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED, SCREEN_WIDTH, SCREEN_HEIGHT, SDL_WINDOW_SHOWN);
	renderer= SDL_CreateRenderer(window, -1, SDL_RENDERER_ACCELERATED | SDL_RENDERER_PRESENTVSYNC);
	std::jthread(RequestAudioPacket, std::ref(param)).detach();
	SDL_AudioSpec des;
	des.freq = param.audioParam.codecCtx->sample_rate;
	des.channels = param.audioParam.codecCtx->ch_layout.nb_channels;
	des.format = AUDIO_S16SYS;
	des.samples = 1024;
	des.silence = 0;
	std::tuple<SDL_Window*, SDL_Renderer*, AudioParam*>* callbackParam = new std::tuple{window, renderer, &(param.audioParam)};
	des.userdata = callbackParam;
	des.callback = audioCallback;
	if (SDL_OpenAudio(&des, nullptr) < 0)
	{
		cout << SDL_GetError() << "\n";
		return -1;
	}
	SDL_PauseAudio(0);
	return 0;
}

int InitVideo(SDL_Window*& window, const char* targetFilepath, MediaParam& param, OpenglVideoParam& openglVideoParam, ShaderService*& shaderService)
{
	InitDecoder(targetFilepath, param);
	//FIX: when app exited, the fmtCtx was freed, so need notify decode thread to stop decode and exit.
	std::jthread(RequestVideoPacket, std::ref(param)).detach();
	std::jthread(RequestVideoFrame, std::ref(param)).detach();
	const int client_width = param.videoParam.width / 2;
	const int client_height = param.videoParam.height / 2;
	window = SDL_CreateWindow(
		"MP",
		SDL_WINDOWPOS_UNDEFINED,
		SDL_WINDOWPOS_UNDEFINED,
		client_width,
		client_height,
		SDL_WINDOW_SHOWN | SDL_WINDOW_OPENGL);
	if (!window)
	{
		cout << SDL_GetError() << "\n";
		return -1;
	}
	SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, 3);
	SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 3);
	SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK, SDL_GL_CONTEXT_PROFILE_CORE);

	openglVideoParam.glContext = SDL_GL_CreateContext(window);
	if (!openglVideoParam.glContext)
	{
		cout << SDL_GetError() << "\n";
		return -1;
	}

	if (!gladLoadGLLoader((GLADloadproc)SDL_GL_GetProcAddress))
	{
		auto error = glad_glGetError();
		return static_cast<int>(error);
	}

	float vertices[] = {
		1.f, 1.f, 0.0, 1.0, 0.0,
		1.f, -1.f, 0.0, 1.0, 1.0,
		-1.f, -1.f, 0.0, 0.0, 1.0,
		-1.f, 1.f, 0.0, 0.0, 0.0 };
	unsigned int indices[]{
		0,
		1,
		3,
		1,
		2,
		3,
	};

	glGenVertexArrays(1, &openglVideoParam.VAO);
	glGenBuffers(1, &openglVideoParam.VBO);
	glGenBuffers(1, &openglVideoParam.EBO);
	glBindVertexArray(openglVideoParam.VAO);
	glBindBuffer(GL_ARRAY_BUFFER, openglVideoParam.VBO);
	glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
	glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, openglVideoParam.EBO);
	glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(indices), indices, GL_STATIC_DRAW);
	glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 5 * sizeof(float), 0);
	glEnableVertexAttribArray(0);
	glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 5 * sizeof(float), reinterpret_cast<void*>(3 * sizeof(float)));
	glEnableVertexAttribArray(1);
	glGenTextures(3, openglVideoParam.texs);
	for (const unsigned int tex : openglVideoParam.texs)
	{
		glBindTexture(GL_TEXTURE_2D, tex);
		glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
		glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
		glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
		glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
	}

	shaderService = new ShaderService{ vSource.data(), fSource.data() };
	shaderService->Use();
	shaderService->SetUniform<int>("textureY", 0);
	shaderService->SetUniform<int>("textureU", 1);
	shaderService->SetUniform<int>("textureV", 2);
	return 0;
}

void RenderPicture(SDL_Window* window, SDL_Renderer* renderer, SDL_Texture* texture)
{
	SDL_SetRenderTarget(renderer, texture);
	SDL_SetRenderTarget(renderer, nullptr);
	SDL_RenderCopy(renderer, texture, nullptr, nullptr);
	SDL_RenderPresent(renderer);
}

void InitImg(SDL_Window*& window, const char* filepath, SDL_Renderer*& renderer, SDL_Surface*& surface, SDL_Texture*& texture)
{
	const cv::Mat img = cv::imread(filepath);
	auto width = img.cols, height = img.rows;
	cv::Mat target;
	SDL_Rect rect;
	SDL_GetDisplayBounds(0, &rect);
	width = width > rect.w ? rect.w - 100 : width;
	height = height > rect.h ? rect.h - 100 : height;
	const cv::Size size{ width, height };
	cv::resize(img, target, size, 0, 0, cv::INTER_LINEAR_EXACT);
	window = SDL_CreateWindow("mp", SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED, width, height, SDL_WINDOW_SHOWN);
	surface = SDL_CreateRGBSurfaceWithFormat(0, width, height, 24, SDL_PIXELFORMAT_RGB24);
	memcpy(surface->pixels, target.data, static_cast<size_t>(width) * height * target.channels());
	renderer = SDL_CreateRenderer(window, -1, SDL_RENDERER_ACCELERATED | SDL_RENDERER_PRESENTVSYNC);
	texture = SDL_CreateTextureFromSurface(renderer, surface);
}

void OpenglRenderVideo(MediaParam& param, const OpenglVideoParam& openglVideoParam, ShaderService* shaderService)
{
	AVFrame* frame = av_frame_alloc();
	param.videoParam.frameQueue.pop(frame, true, param.videoParam.quit);
	// TODO: TIMER
	glBindTexture(GL_TEXTURE_2D, openglVideoParam.texs[0]);
	glPixelStoref(GL_UNPACK_ROW_LENGTH, static_cast<float>(frame->linesize[0]));
	glTexImage2D(GL_TEXTURE_2D, 0, GL_RED, frame->width, frame->height, 0, GL_RED, GL_UNSIGNED_BYTE, frame->data[0]);

	glActiveTexture(GL_TEXTURE1);
	glBindTexture(GL_TEXTURE_2D, openglVideoParam.texs[1]);
	glPixelStoref(GL_UNPACK_ROW_LENGTH, static_cast<float>(frame->linesize[1]));
	glTexImage2D(GL_TEXTURE_2D, 0, GL_RED, frame->width / 2, frame->height / 2, 0, GL_RED, GL_UNSIGNED_BYTE, frame->data[1]);

	glActiveTexture(GL_TEXTURE2);
	glBindTexture(GL_TEXTURE_2D, openglVideoParam.texs[2]);
	glPixelStoref(GL_UNPACK_ROW_LENGTH, static_cast<float>(frame->linesize[2]));
	glTexImage2D(GL_TEXTURE_2D, 0, GL_RED, frame->width / 2, frame->height / 2, 0, GL_RED, GL_UNSIGNED_BYTE, frame->data[2]);

	av_frame_free(&frame);
	glPixelStorei(GL_UNPACK_ROW_LENGTH, 0);

	shaderService->Use();
	glBindVertexArray(openglVideoParam.VAO);
	glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, nullptr);
}

int main(int argc, char** argv)
{
	// Check File
	const char* targetFilepath = argv[1];
	if (targetFilepath == nullptr || !exists(targetFilepath))
	{
		cout << "File Not Exist\n";
		return 0;
	}
	const FileType fileType = Util::GetFileType(targetFilepath);
	if (fileType == FileType::ERRORTYPE)
	{
		cout << "unsupported file type\n";
		return 0;
	}

	// INIT

	SDL_Window* window = nullptr;
	MediaParam mediaParam{};
	OpenglVideoParam openglVideoParam{};
	ShaderService* shaderService = nullptr;
	SDL_Surface* surface = nullptr;
	SDL_Renderer* renderer = nullptr;
	SDL_Texture* texture = nullptr;
	double framerate = .0f;
	if (SDL_Init(SDL_INIT_EVERYTHING) < 0)
	{
		cout << SDL_GetError() << "\n";
		return -1;
	}
	switch (fileType)
	{
	case FileType::VIDEO:
	{
		InitVideo(window, targetFilepath, mediaParam, openglVideoParam, shaderService);
		const auto stream_frame_rate = mediaParam.fmtCtx->streams[mediaParam.videoParam.videoStreamIndex]->avg_frame_rate;
		framerate = static_cast<double>(stream_frame_rate.den) / stream_frame_rate.num;
		break;
	}
	case FileType::IMG:
	{
		InitImg(window, targetFilepath, renderer, surface, texture);
		break;
	}
	case FileType::AUDIO:
	{
		InitAudio(window, renderer, targetFilepath, mediaParam);
		break;
	}
	case FileType::ERRORTYPE:
		return -1;
	}

	bool quit = false;
	auto current_time = std::chrono::system_clock::now();
	SDL_Event event;
	while (!quit)
	{
		while (SDL_PollEvent(&event))
		{
			switch (event.type)
			{
			case SDL_KEYDOWN:
				switch (event.key.keysym.scancode)
				{
				case SDL_SCANCODE_ESCAPE:
					quit = true;
					break;
				default:
					break;
				}
				break;
			case SDL_QUIT:
				quit = true;
				break;
			default:
				break;
			}
		}

		// Render
		switch (fileType)
		{
		case FileType::VIDEO:
			OpenglRenderVideo(mediaParam, openglVideoParam, shaderService);
			SDL_GL_SwapWindow(window);
			std::this_thread::sleep_until(current_time + std::chrono::milliseconds(30));
			current_time = std::chrono::system_clock::now();
			break;
		case FileType::IMG:
			RenderPicture(window, renderer, texture);
			break;
		case FileType::AUDIO:
			break;
		default:
			break;
		}
	}

	avcodec_close(mediaParam.videoParam.codecCtx);
	avformat_close_input(&(mediaParam.fmtCtx));
	SDL_GL_DeleteContext(openglVideoParam.glContext);
	SDL_DestroyWindow(window);
	SDL_Quit();
	return 0;
}