#include "playback.h"

#include "project/clip.h"
#include "project/sequence.h"
#include "io/media.h"
#include "playback/audio.h"
#include "playback/cacher.h"
#include "panels/panels.h"
#include "panels/timeline.h"
#include "panels/viewer.h"
#include "project/effect.h"
#include "panels/effectcontrols.h"
#include "debug.h"

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

#include <QtMath>
#include <QObject>
#include <QOpenGLTexture>
#include <QOpenGLPixelTransferOptions>
#include <QOpenGLFramebufferObject>

#ifdef QT_DEBUG
//#define GCF_DEBUG
#endif

bool texture_failed = false;
bool rendering = false;

void open_clip(Clip* clip, bool multithreaded) {
	switch (clip->media_type) {
	case MEDIA_TYPE_FOOTAGE:
	case MEDIA_TYPE_TONE:
		clip->multithreaded = multithreaded;
		if (multithreaded) {
			if (clip->open_lock.tryLock()) {
				// maybe keep cacher instance in memory while clip exists for performance?
				clip->cacher = new Cacher(clip);
				QObject::connect(clip->cacher, SIGNAL(finished()), clip->cacher, SLOT(deleteLater()));
				clip->cacher->start((clip->track < 0) ? QThread::NormalPriority : QThread::TimeCriticalPriority);
			}
		} else {
			clip->finished_opening = false;
			clip->open = true;

			open_clip_worker(clip);
		}
		break;
	case MEDIA_TYPE_SEQUENCE:
	case MEDIA_TYPE_SOLID:
		clip->open = true;
		break;
	}
}

void close_clip(Clip* clip) {
	// destroy opengl texture in main thread
	if (clip->texture != NULL) {
		clip->texture->destroy();
		delete clip->texture;
		clip->texture = NULL;
	}

	for (int i=0;i<clip->effects.size();i++) {
		clip->effects.at(i)->close();
	}

	if (clip->fbo != NULL) {
		delete clip->fbo[0];
		delete clip->fbo[1];
		delete [] clip->fbo;
		clip->fbo = NULL;
	}

	switch (clip->media_type) {
	case MEDIA_TYPE_FOOTAGE:
	case MEDIA_TYPE_TONE:
		if (clip->multithreaded) {
			clip->cacher->caching = false;
			clip->can_cache.wakeAll();
		} else {
			close_clip_worker(clip);
		}
		break;
	case MEDIA_TYPE_SEQUENCE:
		closeActiveClips(static_cast<Sequence*>(clip->media), false);
	case MEDIA_TYPE_SOLID:
		clip->open = false;
		break;
	}
}

void cache_clip(Clip* clip, long playhead, bool reset, bool scrubbing, QVector<Clip*>& nests) {
	if (clip->media_type == MEDIA_TYPE_FOOTAGE || clip->media_type == MEDIA_TYPE_TONE) {
		if (clip->multithreaded) {
			clip->cacher->playhead = playhead;
			clip->cacher->reset = reset;
			clip->cacher->nests = nests;
            clip->cacher->scrubbing = scrubbing;

			clip->can_cache.wakeAll();
		} else {
			cache_clip_worker(clip, playhead, reset, scrubbing, nests);
		}
	}
}

void get_clip_frame(Clip* c, long playhead) {
	if (c->finished_opening) {
		MediaStream* ms = static_cast<Media*>(c->media)->get_stream_from_file_index(c->track < 0, c->media_stream);

		int64_t target_pts = playhead_to_timestamp(c, playhead);
        int64_t second_pts = qRound64(av_q2d(av_inv_q(c->stream->time_base)));
		if (ms->video_interlacing != VIDEO_PROGRESSIVE) {
			target_pts *= 2;
			second_pts *= 2;
		}
		AVFrame* target_frame = NULL;

		bool reset = false;
		bool cache = true;

		c->queue_lock.lock();
		if (c->queue.size() > 0) {
			if (ms->infinite_length) {
				target_frame = c->queue.at(0);
#ifdef GCF_DEBUG
				dout << "GCF ==> USE PRECISE (INFINITE)";
#endif
			} else {
				// correct frame may be somewhere else in the queue
				int closest_frame = 0;

				for (int i=1;i<c->queue.size();i++) {
					//dout << "results for" << i << qAbs(c->queue.at(i)->pts - target_pts) << qAbs(c->queue.at(closest_frame)->pts - target_pts) << c->queue.at(i)->pts << target_pts;

					if (c->queue.at(i)->pts == target_pts) {
#ifdef GCF_DEBUG
						dout << "GCF ==> USE PRECISE";
#endif
						closest_frame = i;
						break;
					} else if (c->queue.at(i)->pts > c->queue.at(closest_frame)->pts && c->queue.at(i)->pts < target_pts) {
						closest_frame = i;
					}
				}

				// remove all frames earlier than this one from the queue
				target_frame = c->queue.at(closest_frame);
				int64_t next_pts = INT64_MAX;
				int64_t minimum_ts = target_frame->pts;
				/*if (c->reverse) {
					minimum_ts += quarter_pts;
				} else {
					minimum_ts -= quarter_pts;
				}*/
				//dout << "closest frame was" << closest_frame << "with" << target_frame->pts << "/" << target_pts;
				for (int i=0;i<c->queue.size();i++) {
					if (c->queue.at(i)->pts > target_frame->pts && c->queue.at(i)->pts < next_pts) {
						next_pts = c->queue.at(i)->pts;
					}
					if (c->queue.at(i) != target_frame && ((c->queue.at(i)->pts > minimum_ts) == c->reverse)) {
						//dout << "removed frame at" << i << "because its pts was" << c->queue.at(i)->pts << "compared to" << target_frame->pts;
						av_frame_free(&c->queue[i]); // may be a little heavy for the UI thread?
						c->queue.removeAt(i);
						i--;
					}
				}
				if (next_pts == INT64_MAX) next_pts = target_frame->pts + target_frame->pkt_duration;

				// we didn't get the exact timestamp
				if (target_frame->pts != target_pts) {
					if (target_pts > target_frame->pts && target_pts <= next_pts) {
#ifdef GCF_DEBUG
						dout << "GCF ==> USE IMPRECISE";
#endif
					} else {
						int64_t pts_diff = qAbs(target_pts - target_frame->pts);
						if (c->reached_end && target_pts > target_frame->pts) {
#ifdef GCF_DEBUG
							dout << "GCF ==> EOF TOLERANT";
#endif
							c->reached_end = false;
							cache = false;
						} else if (target_pts < target_frame->pts || pts_diff > second_pts) {

#ifdef GCF_DEBUG
							dout << "GCF ==> RESET" << target_pts << "(" << target_frame->pts << "-" << target_frame->pts+target_frame->pkt_duration << ")";
#endif
							target_frame = NULL;
							reset = true;
						} else {
#ifdef GCF_DEBUG
							dout << "GCF ==> WAIT - target pts:" << target_pts << "closest frame:" << target_frame->pts;
#endif
							if (c->queue.size() >= c->max_queue_size) c->queue_remove_earliest();
							c->ignore_reverse = true;
							target_frame = NULL;
						}
					}
				}
			}
		} else {
			reset = true;
		}

		if (target_frame == NULL || reset) {
			// reset cache
			texture_failed = true;
			dout << "[INFO] Frame queue couldn't keep up - either the user seeked or the system is overloaded (queue size:" << c->queue.size() << ")";
		}

		if (target_frame != NULL) {
			// add gate if this is the same frame
			glPixelStorei(GL_UNPACK_ROW_LENGTH, target_frame->linesize[0]/4);
			c->texture->setData(0, QOpenGLTexture::RGBA, QOpenGLTexture::UInt8, target_frame->data[0]);
			glPixelStorei(GL_UNPACK_ROW_LENGTH, 0);
		}

		c->queue_lock.unlock();

		// get more frames
        QVector<Clip*> empty;
        if (cache) cache_clip(c, playhead, reset, false, empty);
	}
}

long playhead_to_clip_frame(Clip* c, long playhead) {
	return (qMax(0L, playhead - c->timeline_in) + c->clip_in);
}

double playhead_to_clip_seconds(Clip* c, long playhead) {
	// returns time in seconds
	long clip_frame = playhead_to_clip_frame(c, playhead);
	if (c->reverse) clip_frame = c->getMaximumLength() - clip_frame - 1;
	return ((double) clip_frame/c->sequence->frame_rate)*c->speed;
}

int64_t seconds_to_timestamp(Clip* c, double seconds) {
	return qRound64(seconds * av_q2d(av_inv_q(c->stream->time_base))) + qMax((int64_t) 0, c->stream->start_time);
}

int64_t playhead_to_timestamp(Clip* c, long playhead) {
	return seconds_to_timestamp(c, playhead_to_clip_seconds(c, playhead));
}

int retrieve_next_frame(Clip* c, AVFrame* f) {
	int result = 0;
    int receive_ret;

	// do we need to retrieve a new packet for a new frame?
	av_frame_unref(f);
    while ((receive_ret = avcodec_receive_frame(c->codecCtx, f)) == AVERROR(EAGAIN)) {
		int read_ret = 0;
		do {
			if (c->pkt_written) {
				av_packet_unref(c->pkt);
				c->pkt_written = false;
			}
			read_ret = av_read_frame(c->formatCtx, c->pkt);
			if (read_ret >= 0) {
				c->pkt_written = true;
			}
        } while (read_ret >= 0 && c->pkt->stream_index != c->media_stream);

		if (read_ret >= 0) {
			int send_ret = avcodec_send_packet(c->codecCtx, c->pkt);
			if (send_ret < 0) {
				dout << "[ERROR] Failed to send packet to decoder." << send_ret;
                return send_ret;
			}
        } else {
			if (read_ret == AVERROR_EOF) {
				int send_ret = avcodec_send_packet(c->codecCtx, NULL);
				if (send_ret < 0) {
					dout << "[ERROR] Failed to send packet to decoder." << send_ret;
					return send_ret;
				}
			} else {
				dout << "[ERROR] Could not read frame." << read_ret;
				return read_ret; // skips trying to find a frame at all
			}
		}
	}
	if (receive_ret < 0) {
		if (receive_ret != AVERROR_EOF) dout << "[ERROR] Failed to receive packet from decoder." << receive_ret;
		result = receive_ret;
	}

	return result;
}

bool is_clip_active(Clip* c, long playhead) {
    return c->enabled
			&& c->timeline_in < playhead + ceil(c->sequence->frame_rate*2)
            && c->timeline_out > playhead
			&& playhead - c->timeline_in + c->clip_in < c->getMaximumLength();
}

void set_sequence(Sequence* s) {
	closeActiveClips(sequence, true);
	panel_effect_controls->clear_effects(true);
    sequence = s;
	panel_sequence_viewer->set_main_sequence();
    panel_timeline->update_sequence();
    panel_timeline->setFocus();
}

void closeActiveClips(Sequence *s, bool wait) {
	if (s != NULL) {
        for (int i=0;i<s->clips.size();i++) {
            Clip* c = s->clips.at(i);
			if (c != NULL) {
				if (c->media_type == MEDIA_TYPE_SEQUENCE) {
					closeActiveClips(static_cast<Sequence*>(c->media), wait);
					close_clip(c);
				} else if (c->media_type == MEDIA_TYPE_FOOTAGE && c->open) {
					close_clip(c);
					if (c->multithreaded && wait) c->cacher->wait();
				}
			}
		}
	}
}