#include "previewgenerator.h"

#include "media.h"
#include "panels/viewer.h"
#include "panels/project.h"
#include "io/config.h"
#include "io/path.h"
#include "debug.h"

#include <QPainter>
#include <QPixmap>
#include <QtMath>
#include <QTreeWidgetItem>
#include <QSemaphore>
#include <QCryptographicHash>
#include <QFile>
#include <QDir>
#include <QDateTime>

#define WAVEFORM_RESOLUTION 64

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

QSemaphore sem(5); // only 5 preview generators can run at one time

PreviewGenerator::PreviewGenerator(QTreeWidgetItem* i, Media* m, bool r) :
	QThread(0),
	fmt_ctx(NULL),
	item(i),
	media(m),
	retrieve_duration(false),
	contains_still_image(false),
	replace(r),
	cancelled(false)
{
    data_path = get_data_path() + "/previews";
	QDir data_dir(data_path);
	if (!data_dir.exists()) {
		data_dir.mkpath(".");
	}

	connect(this, SIGNAL(finished()), this, SLOT(deleteLater()));
}

void PreviewGenerator::parse_media() {
    // detect video/audio streams in file
    for (int i=0;i<(int)fmt_ctx->nb_streams;i++) {
        // Find the decoder for the video stream
        if (avcodec_find_decoder(fmt_ctx->streams[i]->codecpar->codec_id) == NULL) {
			dout << "[ERROR] Unsupported codec in stream" << i << "of file" << media->name;
        } else {
            MediaStream* ms = media->get_stream_from_file_index(fmt_ctx->streams[i]->codecpar->codec_type == AVMEDIA_TYPE_VIDEO, i);
            bool append = false;
            if (ms == NULL) {
                ms = new MediaStream();
                ms->preview_done = false;
                ms->file_index = i;
                append = true;
            }
			if (fmt_ctx->streams[i]->codecpar->codec_type == AVMEDIA_TYPE_VIDEO
					&& fmt_ctx->streams[i]->codecpar->width > 0
					&& fmt_ctx->streams[i]->codecpar->height > 0) {

                /*dout << "avg_frame_rate was:" << fmt_ctx->streams[i]->avg_frame_rate.num << "/" << fmt_ctx->streams[i]->avg_frame_rate.den;
				dout << "r_frame_rate was:" << fmt_ctx->streams[i]->r_frame_rate.num << "/" << fmt_ctx->streams[i]->r_frame_rate.den;
				dout << "codec_frame_rate was:" << fmt_ctx->streams[i]->codec->framerate.num << "/" << fmt_ctx->streams[i]->codec->framerate.den;
				dout << "nb_frames was:" << fmt_ctx->streams[i]->nb_frames;
                dout << "duration was:" << fmt_ctx->streams[i]->duration << "OR fmt_ctx's duration is:" << fmt_ctx->duration;*/

                // heuristic to determine if video is a still image
				if (fmt_ctx->streams[i]->avg_frame_rate.den == 0
                        && fmt_ctx->streams[i]->codecpar->codec_id != AV_CODEC_ID_DNXHD) { // silly hack but this is the only scenario i've seen this
					ms->infinite_length = true;
					contains_still_image = true;
					ms->video_frame_rate = 0;
				} else {
					ms->infinite_length = false;
					if (fmt_ctx->streams[i]->r_frame_rate.den == 0) {
						ms->video_frame_rate = av_q2d(fmt_ctx->streams[i]->avg_frame_rate);
					} else {
						ms->video_frame_rate = av_q2d(fmt_ctx->streams[i]->r_frame_rate);
					}
				}
				ms->video_width = fmt_ctx->streams[i]->codecpar->width;
				ms->video_height = fmt_ctx->streams[i]->codecpar->height;

				// default value, we get the true value later in generate_waveform()
				ms->video_auto_interlacing = VIDEO_PROGRESSIVE;
				ms->video_interlacing = VIDEO_PROGRESSIVE;

				if (append) media->video_tracks.append(ms);
            } else if (fmt_ctx->streams[i]->codecpar->codec_type == AVMEDIA_TYPE_AUDIO) {
                ms->audio_channels = fmt_ctx->streams[i]->codecpar->channels;
                ms->audio_layout = fmt_ctx->streams[i]->codecpar->channel_layout;
                ms->audio_frequency = fmt_ctx->streams[i]->codecpar->sample_rate;
                if (append) media->audio_tracks.append(ms);
			} else if (append) {
				delete ms;
			}
        }
    }
	media->length = fmt_ctx->duration;

	if (fmt_ctx->duration == INT64_MIN) {
		retrieve_duration = true;
	} else {
		finalize_media();
	}
}

bool PreviewGenerator::retrieve_preview(const QString& hash) {
	// returns true if generate_waveform must be run, false if we got all previews from cached files

	if (retrieve_duration) {
		return true;
	}

	bool found = true;
	for (int i=0;i<media->video_tracks.size();i++) {
		MediaStream* ms = media->video_tracks.at(i);
		QString thumb_path = get_thumbnail_path(hash, ms);
		QFile f(thumb_path);
		if (f.exists()) {
			//dout << "loaded thumb" << ms->file_index << "from" << thumb_path;
			ms->video_preview.load(thumb_path);
			ms->preview_done = true;
		} else {
			found = false;
			break;
		}
	}
	for (int i=0;i<media->audio_tracks.size();i++) {
		MediaStream* ms = media->audio_tracks.at(i);
		QString waveform_path = get_waveform_path(hash, ms);
		QFile f(waveform_path);
		if (f.exists()) {
			//dout << "loaded wave" << ms->file_index << "from" << waveform_path;
			f.open(QFile::ReadOnly);
			QByteArray data = f.readAll();
			ms->audio_preview.resize(data.size());
			for (int j=0;j<data.size();j++) {
				// faster way?
				ms->audio_preview[j] = data.at(j);
			}
			ms->preview_done = true;
			f.close();
		} else {
			found = false;
			break;
		}
	}
	if (!found) {
		for (int i=0;i<media->video_tracks.size();i++) {
			MediaStream* ms = media->video_tracks.at(i);
			ms->preview_done = false;
		}
		for (int i=0;i<media->audio_tracks.size();i++) {
			MediaStream* ms = media->audio_tracks.at(i);
			ms->audio_preview.clear();
			ms->preview_done = false;
		}
	}
	return !found;
}

void PreviewGenerator::finalize_media() {
    media->ready_lock.unlock();
	media->ready = true;


    if (media->video_tracks.size() == 0) {
        emit set_icon(ICON_TYPE_AUDIO, replace);
    } else if (contains_still_image) {
        emit set_icon(ICON_TYPE_IMAGE, replace);
    } else {
        emit set_icon(ICON_TYPE_VIDEO, replace);
    }

    if (!contains_still_image || media->audio_tracks.size() > 0) {
        double frame_rate = 30;
        if (!contains_still_image && media->video_tracks.size() > 0) frame_rate = media->video_tracks.at(0)->video_frame_rate;
        item->setText(1, frame_to_timecode(media->get_length_in_frames(frame_rate), config.timecode_view, frame_rate));
      
        if (media->video_tracks.size() > 0) {
            item->setText(2, QString::number(frame_rate) + " FPS");
        } else {
            item->setText(2, QString::number(media->audio_tracks.at(0)->audio_frequency) + " Hz");
        }
    }
	}
}

void PreviewGenerator::generate_waveform() {
    SwsContext* sws_ctx;
    SwrContext* swr_ctx;
    AVFrame* temp_frame = av_frame_alloc();
    AVCodecContext** codec_ctx = new AVCodecContext* [fmt_ctx->nb_streams];
	int64_t* media_lengths = new int64_t[fmt_ctx->nb_streams]{0};
    for (unsigned int i=0;i<fmt_ctx->nb_streams;i++) {
        codec_ctx[i] = NULL;
        if (fmt_ctx->streams[i]->codecpar->codec_type == AVMEDIA_TYPE_VIDEO || fmt_ctx->streams[i]->codecpar->codec_type == AVMEDIA_TYPE_AUDIO) {
            AVCodec* codec = avcodec_find_decoder(fmt_ctx->streams[i]->codecpar->codec_id);
			if (codec != NULL) {
				codec_ctx[i] = avcodec_alloc_context3(codec);
				avcodec_parameters_to_context(codec_ctx[i], fmt_ctx->streams[i]->codecpar);
				avcodec_open2(codec_ctx[i], codec, NULL);
				if (fmt_ctx->streams[i]->codecpar->codec_type == AVMEDIA_TYPE_AUDIO && codec_ctx[i]->channel_layout == 0) {
					codec_ctx[i]->channel_layout = av_get_default_channel_layout(fmt_ctx->streams[i]->codecpar->channels);
				}
			}
        }
	}

	AVPacket* packet = av_packet_alloc();
    bool done = true;

    bool end_of_file = false;

	// get the ball rolling
	do {
		av_read_frame(fmt_ctx, packet);
	} while (codec_ctx[packet->stream_index] == NULL);
	avcodec_send_packet(codec_ctx[packet->stream_index], packet);

	while (!end_of_file) {
		while (codec_ctx[packet->stream_index] == NULL || avcodec_receive_frame(codec_ctx[packet->stream_index], temp_frame) == AVERROR(EAGAIN)) {
			av_packet_unref(packet);
			int read_ret = av_read_frame(fmt_ctx, packet);
            if (read_ret < 0) {
                end_of_file = true;
				if (read_ret != AVERROR_EOF) dout << "[ERROR] Failed to read packet for preview generation" << read_ret;
                break;
            }
			if (codec_ctx[packet->stream_index] != NULL) {
				int send_ret = avcodec_send_packet(codec_ctx[packet->stream_index], packet);
                if (send_ret < 0 && send_ret != AVERROR(EAGAIN)) {
					dout << "[ERROR] Failed to send packet for preview generation - aborting" << send_ret;
                    end_of_file = true;
                    break;
                }
            }
		}
        if (!end_of_file) {
			MediaStream* s = media->get_stream_from_file_index(fmt_ctx->streams[packet->stream_index]->codecpar->codec_type == AVMEDIA_TYPE_VIDEO, packet->stream_index);
			if (s != NULL) {
				if (fmt_ctx->streams[packet->stream_index]->codecpar->codec_type == AVMEDIA_TYPE_VIDEO) {
					if (!s->preview_done) {
						int dstH = 120;
						int dstW = dstH * ((float)temp_frame->width/(float)temp_frame->height);
						uint8_t* data = new uint8_t[dstW*dstH*3];

						sws_ctx = sws_getContext(
								temp_frame->width,
								temp_frame->height,
								static_cast<AVPixelFormat>(temp_frame->format),
								dstW,
								dstH,
								static_cast<AVPixelFormat>(AV_PIX_FMT_RGB24),
								SWS_FAST_BILINEAR,
								NULL,
								NULL,
								NULL
							);

						int linesize[AV_NUM_DATA_POINTERS];
						linesize[0] = dstW*3;
						sws_scale(sws_ctx, temp_frame->data, temp_frame->linesize, 0, temp_frame->height, &data, linesize);

						s->video_preview = QImage(data, dstW, dstH, linesize[0], QImage::Format_RGB888);

						// is video interlaced?
						s->video_auto_interlacing = (temp_frame->interlaced_frame) ? ((temp_frame->top_field_first) ? VIDEO_TOP_FIELD_FIRST : VIDEO_BOTTOM_FIELD_FIRST) : VIDEO_PROGRESSIVE;
						s->video_interlacing = s->video_auto_interlacing;

						s->preview_done = true;

						sws_freeContext(sws_ctx);

						if (!retrieve_duration) {
							avcodec_close(codec_ctx[packet->stream_index]);
							codec_ctx[packet->stream_index] = NULL;
						}
					}
					media_lengths[packet->stream_index]++;
				} else if (fmt_ctx->streams[packet->stream_index]->codecpar->codec_type == AVMEDIA_TYPE_AUDIO) {
					int interval = qFloor((temp_frame->sample_rate/WAVEFORM_RESOLUTION)/4)*4;

					AVFrame* swr_frame = av_frame_alloc();
					swr_frame->channel_layout = temp_frame->channel_layout;
					swr_frame->sample_rate = temp_frame->sample_rate;
					swr_frame->format = AV_SAMPLE_FMT_S16P;

					swr_ctx = swr_alloc_set_opts(
								NULL,
								temp_frame->channel_layout,
								static_cast<AVSampleFormat>(swr_frame->format),
								temp_frame->sample_rate,
								temp_frame->channel_layout,
								static_cast<AVSampleFormat>(temp_frame->format),
								temp_frame->sample_rate,
								0,
								NULL
							);

					swr_init(swr_ctx);

					swr_convert_frame(swr_ctx, swr_frame, temp_frame);

					// TODO implement a way to terminate this if the user suddenly closes the project while the waveform is being generated
					int sample_size = av_get_bytes_per_sample(static_cast<AVSampleFormat>(swr_frame->format));
					int nb_bytes = swr_frame->nb_samples * sample_size;
					int byte_interval = interval * sample_size;
					for (int i=0;i<nb_bytes;i+=byte_interval) {
						for (int j=0;j<swr_frame->channels;j++) {
							qint16 min = 0;
							qint16 max = 0;
							for (int k=0;k<byte_interval;k+=sample_size) {
								if (i+k < nb_bytes) {
									qint16 sample = ((swr_frame->data[j][i+k+1] << 8) | swr_frame->data[j][i+k]);
									if (sample > max) {
										max = sample;
									} else if (sample < min) {
										min = sample;
									}
								} else {
									break;
								}
							}
							s->audio_preview.append(min >> 8);
							s->audio_preview.append(max >> 8);
							if (cancelled) break;
						}
					}

					swr_free(&swr_ctx);
					av_frame_unref(swr_frame);
					av_frame_free(&swr_frame);

					if (cancelled) {
						end_of_file = true;
						break;
					}
				}
			}

			// check if we've got all our previews
			if (retrieve_duration) {
				done = false;
			} else if (media->audio_tracks.size() == 0) {
				done = true;
				for (int i=0;i<media->video_tracks.size();i++) {
					if (!media->video_tracks.at(i)->preview_done) {
						done = false;
						break;
					}
				}
				if (done) {
					end_of_file = true;
					break;
				}
			}
			av_packet_unref(packet);
        }
    }
    for (int i=0;i<media->audio_tracks.size();i++) {
        media->audio_tracks.at(i)->preview_done = true;
    }
    av_frame_free(&temp_frame);
	av_packet_free(&packet);
    for (unsigned int i=0;i<fmt_ctx->nb_streams;i++) {
        if (codec_ctx[i] != NULL) {
            avcodec_close(codec_ctx[i]);
        }
	}
	if (retrieve_duration) {
		media->length = 0;
		int maximum_stream = 0;
		for (unsigned int i=0;i<fmt_ctx->nb_streams;i++) {
			if (media_lengths[i] > media_lengths[maximum_stream]) {
				maximum_stream = i;
			}
		}
		media->length = (double) media_lengths[maximum_stream] / av_q2d(fmt_ctx->streams[maximum_stream]->avg_frame_rate) * AV_TIME_BASE; // TODO redo with PTS
		finalize_media();
	}
	delete [] media_lengths;
	delete [] codec_ctx;
}

QString PreviewGenerator::get_thumbnail_path(const QString& hash, MediaStream* ms) {
	return data_path + "/" + hash + "t" + QString::number(ms->file_index);
}

QString PreviewGenerator::get_waveform_path(const QString& hash, MediaStream* ms) {
	return data_path + "/" + hash + "w" + QString::number(ms->file_index);
}

void PreviewGenerator::run() {	
    Q_ASSERT(media != NULL);
	Q_ASSERT(item != NULL);

    QByteArray ba = media->url.toLatin1();
    char* filename = new char[ba.size()+1];
	strcpy(filename, ba.data());

	QString errorStr;
    bool error = false;
    int errCode = avformat_open_input(&fmt_ctx, filename, NULL, NULL);
    if(errCode != 0) {
        char err[1024];
        av_strerror(errCode, err, 1024);
		errorStr = "Could not open file - " + QString(err);
        error = true;
    } else {
        errCode = avformat_find_stream_info(fmt_ctx, NULL);
        if (errCode < 0) {
            char err[1024];
            av_strerror(errCode, err, 1024);
			errorStr = "Could not find stream information - " + QString(err);
            error = true;
        } else {
            av_dump_format(fmt_ctx, 0, filename, 0);
			parse_media();
			sem.acquire();

			// see if we already have data for this
			QFileInfo file_info(media->url);
			QString cache_file = media->url + QString::number(file_info.lastModified().toMSecsSinceEpoch());
			QString hash = QCryptographicHash::hash(cache_file.toLatin1(), QCryptographicHash::Md5).toHex();

			if (retrieve_preview(hash)) {
				generate_waveform();

				// save preview to file
				for (int i=0;i<media->video_tracks.size();i++) {
					MediaStream* ms = media->video_tracks.at(i);
					if (ms->video_preview.save(get_thumbnail_path(hash, ms), "PNG")) {
						//dout << "saved" << ms->file_index << "thumb to" << get_thumbnail_path(hash, ms);
					}
				}
				for (int i=0;i<media->audio_tracks.size();i++) {
					MediaStream* ms = media->audio_tracks.at(i);
					QFile f(get_waveform_path(hash, ms));
					f.open(QFile::WriteOnly);
					f.write(ms->audio_preview.constData(), ms->audio_preview.size());
					f.close();
					//dout << "saved" << ms->file_index << "waveform to" << get_waveform_path(hash, ms);
				}
			}

			sem.release();
        }
        avformat_close_input(&fmt_ctx);
	}

	if (error) {
		update_footage_tooltip(item, media, errorStr);
		emit set_icon(ICON_TYPE_ERROR, replace);
		media->ready_lock.unlock();
	} else {
		update_footage_tooltip(item, media);
    }

    delete [] filename;
	media->preview_gen = NULL;
}

void PreviewGenerator::cancel() {
	cancelled = true;
}