// Copyright (c) 2006-2007, Rodrigo Braz Monteiro
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
//
//   * Redistributions of source code must retain the above copyright notice,
//     this list of conditions and the following disclaimer.
//   * Redistributions in binary form must reproduce the above copyright notice,
//     this list of conditions and the following disclaimer in the documentation
//     and/or other materials provided with the distribution.
//   * Neither the name of the Aegisub Group nor the names of its contributors
//     may be used to endorse or promote products derived from this software
//     without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
// ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
// LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
// CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
// SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
// CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
// ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
// POSSIBILITY OF SUCH DAMAGE.
//
// -----------------------------------------------------------------------------
//
// AEGISUB
//
// Website: http://aegisub.cellosoft.com
// Contact: mailto:zeratul@cellosoft.com
//


///////////
// Headers

#ifdef WITH_FFMPEG

#ifdef WIN32
#define EMULATE_INTTYPES
#define __STDC_CONSTANT_MACROS 1
#include <stdint.h>
#endif /* WIN32 */

#include <wx/wxprec.h>
#include <wx/image.h>
#include <algorithm>
#include <vector>
#include "video_provider_lavc.h"
#include "mkv_wrap.h"
#include "lavc_file.h"
#include "utils.h"
#include "vfr.h"
#include "ass_file.h"
#include "lavc_keyframes.h"
#include "video_context.h"
#include "options.h"


///////////////
// Constructor
LAVCVideoProvider::LAVCVideoProvider(Aegisub::String filename,double fps) {
	// Init variables
	codecContext = NULL;
	lavcfile = NULL;
	codec = NULL;
	stream = NULL;
	frame = NULL;
	frameRGB = NULL;
	bufferRGB = NULL;
	sws_context = NULL;
	buffer1 = NULL;
	buffer2 = NULL;
	buffer1Size = 0;
	buffer2Size = 0;
	vidStream = -1;
	validFrame = false;
	framesData.clear();

	// Load
	LoadVideo(filename,fps);
}


//////////////
// Destructor
LAVCVideoProvider::~LAVCVideoProvider() {
	Close();
}


//////////////
// Load video
void LAVCVideoProvider::LoadVideo(Aegisub::String filename, double fps) {
	// Close first
	Close();

	lavcfile = LAVCFile::Create(filename);
	// Load
	try {
		int result = 0;

		// Find video stream
		vidStream = -1;
		codecContext = NULL;
		for (int i=0; i < (int)lavcfile->fctx->nb_streams; i++) {
			codecContext = lavcfile->fctx->streams[i]->codec;
			if (codecContext->codec_type == CODEC_TYPE_VIDEO) {
				stream = lavcfile->fctx->streams[i];
				vidStream = i;
				break;
			}
		}
		if (vidStream == -1) throw _T("ffmpeg video provider: Could not find a video stream");

		// Find codec
		codec = avcodec_find_decoder(codecContext->codec_id);
		if (!codec) throw _T("ffmpeg video provider: Could not find suitable video decoder");

		// Enable truncation
		//if (codec->capabilities & CODEC_CAP_TRUNCATED) codecContext->flags |= CODEC_FLAG_TRUNCATED;

		// Open codec
		result = avcodec_open(codecContext,codec);
		if (result < 0) throw _T("ffmpeg video provider: Failed to open video decoder");

		// Parse file for keyframes and other useful stuff
		LAVCKeyFrames LAVCFrameData(filename);
		KeyFramesList = LAVCFrameData.GetKeyFrames();
		keyFramesLoaded = true;
		// set length etc.
		length = LAVCFrameData.GetNumFrames();
		framesData = LAVCFrameData.GetFrameData();

		// Allocate frame
		frame = avcodec_alloc_frame();

		// Set frame
		frameNumber = -1;
		lastFrameNumber = -1;

		allowUnsafeSeeking = Options.AsBool(_T("FFmpeg allow unsafe seeking"));
	}

	// Catch errors
	catch (...) {
		Close();
		throw;
	}
}


///////////////
// Close video
void LAVCVideoProvider::Close() {
	// Clean buffers
	if (buffer1) delete buffer1;
	if (buffer2) delete buffer2;
	buffer1 = NULL;
	buffer2 = NULL;
	buffer1Size = 0;
	buffer2Size = 0;

	// Clean frame
	if (frame) av_free((void*)frame);
	frame = NULL;
	
	// Free SWS context and other stuff from RGB conversion
	if (sws_context)
		sws_freeContext(sws_context);
	sws_context = NULL;
	if(frameRGB)
		av_free(frameRGB);
	frameRGB = NULL;
	if(bufferRGB)
		delete(bufferRGB);
	bufferRGB = NULL;
	
	// Close codec context
	if (codec && codecContext) avcodec_close(codecContext);
	codecContext = NULL;
	codec = NULL;

	// Close format context
	if (lavcfile)
		lavcfile->Release();
	lavcfile = NULL;
}


//////////////////
// Get next frame
bool LAVCVideoProvider::GetNextFrame(int64_t *startDTS) {
	AVPacket packet;
	*startDTS = -1; // magic
	
	// Read packet
	while (av_read_frame(lavcfile->fctx, &packet)>=0) {
		// Check if packet is part of video stream
		if(packet.stream_index == vidStream) {
			// Decode frame
			int frameFinished;
			if (*startDTS < 0)
				*startDTS = packet.dts;

			avcodec_decode_video(codecContext, frame, &frameFinished, packet.data, packet.size);

			// Success?
			if(frameFinished) {
				// Set time
				lastDecodeTime = packet.dts;

				// Free packet and return
				av_free_packet(&packet);
				return true;
			}
		}
		// free packet
		av_free_packet(&packet);
    }

	// No more packets
	return false;
}

/////////////
// Get frame
const AegiVideoFrame LAVCVideoProvider::GetFrame(int n,int formatType) {
	// Return stored frame
	// n = MID(0,n,GetFrameCount()-1);
	if (n == lastFrameNumber) {
		if (!validFrame) validFrame = true;
		return curFrame;
	}

	if (frameNumber < 0)
		frameNumber = 0;

	// Find closest keyframe to the frame we want
	int closestKeyFrame = FindClosestKeyframe(n);

	bool hasSeeked = false;

	// do we really need to seek?
	// 10 frames is used as a margin to prevent excessive seeking since the predicted best keyframe isn't always selected by avformat
	if (n < frameNumber || closestKeyFrame > frameNumber+10) {
		// turns out we did need it, just do it
		av_seek_frame(lavcfile->fctx, vidStream, framesData[closestKeyFrame].DTS, AVSEEK_FLAG_BACKWARD);
		avcodec_flush_buffers(codecContext);
		hasSeeked = true;
	}

	// regardless of whether we sekeed or not, decode frames until we have the one we want
	do {
		int64_t startTime;
		GetNextFrame(&startTime);

		if (hasSeeked) {
			hasSeeked = false;

			// is the seek destination known? does it belong to a frame?
			if (startTime < 0 || (frameNumber = FrameFromDTS(startTime)) < 0) {
				// guessing destination, may be unsafe
				if (allowUnsafeSeeking)
					frameNumber = ClosestFrameFromDTS(startTime);
				else
					throw _T("ffmpeg video provider: frame accurate seeking failed");
			}

		}

		frameNumber++;
	} while (frameNumber <= n);
	
	
	// Get aegisub frame
	AegiVideoFrame &final = curFrame;
	
	if (frame) {
		int w = codecContext->width;
		int h = codecContext->height;
		PixelFormat srcFormat = codecContext->pix_fmt;
		PixelFormat dstFormat = PIX_FMT_BGRA;

		// Allocate RGB32 buffer
		if(!sws_context) //first frame
		{
			frameRGB = avcodec_alloc_frame();
			unsigned int dstSize = avpicture_get_size(dstFormat,w,h);
			bufferRGB = new uint8_t[dstSize];
			
			sws_context = sws_getContext(w, h, srcFormat, w, h, dstFormat, SWS_PRINT_INFO | SWS_BICUBIC, NULL, NULL, NULL);
			// sws_getContext() always returns NULL if context creation failed
			if (sws_context == NULL)
				throw _T("ffmpeg video provider: failed to initialize SwScaler colorspace conversion");
		}
		avpicture_fill((AVPicture*) frameRGB, bufferRGB, dstFormat, w, h);
		
		// Set AegiVideoFrame
		final.w = codecContext->width;
		final.h = codecContext->height;
		final.flipped = false;
		final.invertChannels = true;
		final.format = FORMAT_RGB32;

		// Allocate
		for (int i=0;i<4;i++) final.pitch[i] = frameRGB->linesize[i];
		final.Allocate();
		
		// Convert to RGB32, and write directly to the output frame
		sws_scale(sws_context, frame->data, frame->linesize, 0, h, final.data, frameRGB->linesize);
		
	}
	else // No frame available
	{
		final = AegiVideoFrame(GetWidth(),GetHeight());
	}

	// Set current frame
	validFrame = true;
	lastFrameNumber = n;

	// Return
	return final;
}


////////////////
// Get position
int LAVCVideoProvider::GetPosition() {
	return frameNumber;
}


////////////////////////
// Get number of frames
int LAVCVideoProvider::GetFrameCount() {
	return length;
}


//////////////////
// Get frame rate
double LAVCVideoProvider::GetFPS() {
	return double(stream->r_frame_rate.num) / double(stream->r_frame_rate.den);
}


//////////////////////
// Get original width
int LAVCVideoProvider::GetWidth() {
	return codecContext->width;
}


///////////////////////
// Get original height
int LAVCVideoProvider::GetHeight() {
	return codecContext->height;
}

//////////////////////
// Find the keyframe we should seek to if we want to seek to a given frame N
int LAVCVideoProvider::FindClosestKeyframe(int frameN) {
	for (int i = frameN; i > 0; i--)
		if (framesData[i].isKeyFrame)
			return i;
	return 0;
}

//////////////////////
// Convert a DTS into a frame number
int LAVCVideoProvider::FrameFromDTS(int64_t ADTS) {
	for (int i = 0; i < (int)framesData.size(); i++)
		if (framesData[i].DTS == ADTS)
			return i;
	return -1;
}

//////////////////////
// Find closest frame to the given DTS
int LAVCVideoProvider::ClosestFrameFromDTS(int64_t ADTS) {
	int n = 0; 
	int64_t bestDiff = 0xFFFFFFFFFFFFFFLL; // big number
	for (int i = 0; i < (int)framesData.size(); i++) {
		int64_t currentDiff = FFABS(framesData[i].DTS - ADTS);
		if (currentDiff < bestDiff) {
			bestDiff = currentDiff;
			n = i;
		}
	}
	return n;
}

#endif // WITH_FFMPEG