/**
	This file is a part of rexy's matrix client
	Copyright (C) 2019 rexy712

	This program is free software: you can redistribute it and/or modify
	it under the terms of the GNU Affero General Public License as published by
	the Free Software Foundation, either version 3 of the License, or
	(at your option) any later version.

	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.  If not, see <http://www.gnu.org/licenses/>.
*/

#	include "libav/frame.hpp"
#	include "libav/codec/context.hpp"
#	include "libav/fmt/context.hpp"
#	include "libav/packet.hpp"

extern "C"{
#  include <libswscale/swscale.h> //sws_scale
#  include <libavutil/imgutils.h> //av_image_alloc
}

#include <cstdlib> //size_t

namespace matrix::internal{
	struct libav_initializer{
		libav_initializer(void){
			REGISTER_LIBAV();
		}
	};
	static int initlibav(void){
		static libav_initializer init;
		return 0;
	}

	static libavcodec::context _get_libav_jpg_context(AVRational src, size_t w, size_t h){
		AVCodec* jpg_codec = avcodec_find_encoder(AV_CODEC_ID_MJPEG);
		libavcodec::context jctx(jpg_codec);
		jctx->pix_fmt = AV_PIX_FMT_YUVJ420P;
		jctx->width = w;
		jctx->height = h;
		jctx->codec_id = AV_CODEC_ID_MJPEG;
		jctx->codec_type = AVMEDIA_TYPE_VIDEO;
		if(src.num == 0 || src.den == 0)
			jctx->time_base = AVRational{1, 30};
		else
			jctx->time_base = src;
		jctx.open();
		return jctx;
	}

	[[maybe_unused]]
	static void _change_color_range(SwsContext* sws_ctx){
		int dummy[4];
		int src_range, dest_range;
		int br, con, sat;
		sws_getColorspaceDetails(sws_ctx, (int**)&dummy, &src_range, (int**)&dummy, &dest_range, &br, &con, &sat);
		const int* coefs = sws_getCoefficients(SWS_CS_DEFAULT);
		src_range = 2;
		sws_setColorspaceDetails(sws_ctx, coefs, src_range, coefs, dest_range, br, con, sat);
	}
	static void _calc_video_thumbnail_dims(size_t target, size_t src_w, size_t src_h, size_t* w, size_t* h){
		size_t target_width = src_w;
		size_t target_height = src_h;
		if(target_width > target_height){
			if(target_width > target){
				target_height = target_height * ((float)target / target_width);
				target_width = target;
			}
		}else{
			if(target_height > target){
				target_width = target_width * ((float)target / target_height);
				target_height = target;
			}
		}
		*w = target_width;
		*h = target_height;
	}
	static libav::packet _create_video_thumbnail(libavfmt::input_context& src, libavcodec::context& src_ctx, int index, size_t targw, size_t targh){
		libavcodec::context jpg_context = _get_libav_jpg_context(src_ctx->time_base, targw, targh);
		libav::frame src_frame(src_ctx->width, src_ctx->height, src_ctx->pix_fmt);
		libav::frame jpg_frame(src_ctx->width, src_ctx->height, jpg_context->pix_fmt);

		libav::packet packet;

		SwsContext* sws_ctx = sws_getContext(src_ctx->width, src_ctx->height, src_ctx->pix_fmt,
		                                     targw, targh, AV_PIX_FMT_YUV420P,
		                                     SWS_BILINEAR, NULL, NULL, NULL);
		//_change_color_range(sws_ctx);

		av_image_alloc(jpg_frame->data, jpg_frame->linesize, targw, targh, jpg_context->pix_fmt, 32);
		jpg_frame.set_freep();
		while(av_read_frame(src, packet) >= 0){
			if(packet->stream_index == index){
				avcodec_send_packet(src_ctx, packet);
				if(avcodec_receive_frame(src_ctx, src_frame) >= 0)
					break;
			}
			av_packet_unref(packet);
		}
		sws_scale(sws_ctx, src_frame->data, src_frame->linesize, 0, src_ctx->height, jpg_frame->data, jpg_frame->linesize);

		sws_freeContext(sws_ctx);

		if(avcodec_send_frame(jpg_context, jpg_frame) < 0){
			return libav::packet(nullptr);
		}
		if(avcodec_receive_packet(jpg_context, packet) < 0){
			return libav::packet(nullptr);
		}
		return packet;
	}
	static raii::string get_libav_mimetype(const libav::fmt::input_context& ctx){
		const char* first = strstr(ctx->iformat->name, ",");
		if(first)
			return raii::string("video/" + raii::static_string(ctx->iformat->name, first - ctx->iformat->name));
		return raii::string("video/" + raii::static_string(ctx->iformat->name));
	}
}

#endif