#include "av.hpp"

extern "C" {
#include <libavutil/frame.h>
#include <libavformat/avformat.h>
#include <libavcodec/avcodec.h>
#include <libswscale/swscale.h>
}

#include <string>
#include <cassert>

namespace av {

	format_context format_open_input(const std::string& filename, AVInputFormat* format, AVDictionary** options){
		AVFormatContext * ctx = nullptr;
		avformat_open_input(&ctx, filename.c_str(), format, options);
		if(!ctx) throw error("Unable to open input " + filename);
		// This might be optional, but AFAIK people always do this after opening input
		avformat_find_stream_info(ctx, options);
		return {ctx, [](auto x){ avformat_close_input(&x); }};
	}

	format_context format_alloc_context(){
		auto ptr = avformat_alloc_context();
		if(!ptr) throw error("Could not allocate AVFormatContext");
		return {avformat_alloc_context(), &avformat_free_context};
	}


	open_codec codec_open(AVCodecContext* ctx, AVCodec* codec, AVDictionary** options){
		if(!ctx) throw error("Invalid codec context");
		if(!codec) throw error("Invalid codec");
		if(avcodec_open2(ctx, codec, options) < 0) throw error("Could not open codec");
		return {ctx, [](auto x){ avcodec_close(x); }};
	}


	packet read_frame(format_context& ctx, packet_buffer& p){
		if(!av_read_frame(ctx.get(), &p)){
			return {nullptr, &av_free_packet};
		} else {
			return {&p, &av_free_packet};
		}
	}


	frame frame_alloc() {
		auto ptr = av_frame_alloc();
		if(!ptr) throw error("Could not allocate AVFrame");
		return {ptr, [](auto x){ av_frame_free(&x); }};
	}

	frame frame_clone(const frame& f){
		auto ptr = av_frame_clone(f.get());
		if(!ptr) throw error("Could not clone AVFrame");
		return {ptr, [](auto x){ av_frame_free(&x); }};
	}

	AVPixelFormat get_format(const frame& f){
		return static_cast<AVPixelFormat>(f->format);
	}

}