#define _XOPEN_SOURCE 500
#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <unistd.h>

#include "video_decode.h"
#include "util.h"

static inline void
pswap(void **p1, void **p2)
{
	void *tmp;

	tmp = *p1;
	*p1 = *p2;
	*p2 = tmp;
}

/* print time in format: "hh:mm:ss.xxx" */
static void
print_time(int64_t msec) {

	int hh = msec / 1000 / 60 / 60;
	msec -= hh * 1000 * 60 * 60;
	int mm = msec / 1000 / 60;
	msec -= mm * 1000 * 60;
	int ss = msec / 1000;
	msec -= ss * 1000;

	printf("%02d:%02d:%02d.%03jd", hh, mm, ss, msec);
}

static void
start_new_szene(int64_t prev_szene_end, int64_t start)
{
	static int prev_dts_start = 0;

	print_time(prev_dts_start);
	printf(" ");
	print_time(prev_szene_end - prev_dts_start);
	prev_dts_start = start;
}

static double
frame_diff(struct video_frame *frame_a, struct video_frame *frame_b)
{
	double average = 0;
	uint8_t *row_a = frame_a->data, *col_a = NULL;
	uint8_t *row_b = frame_b->data, *col_b = NULL;

	for (int y = 0; y < frame_a->height; ++y) {
		col_a = row_a;
		col_b = row_b;
		for (int x = 0; x < frame_a->width; ++x) {
			average += abs(*col_a - *col_b);
			col_a++;
			col_b++;
		}
		row_a += frame_a->stride;
		row_b += frame_b->stride;
	}

	return average / (frame_a->width * frame_a->height);
}

static double
frame_average(struct video_frame *frame)
{
	double average = 0;
	uint8_t *row = frame->data;
	uint8_t *col = NULL;

	for (int y = 0; y < frame->height; ++y) {
		col = row;
		for (int x = 0; x < frame->width; ++x) {
			average += *col;
			col++;
		}
		row += frame->stride;
	}

	return average / (frame->width * frame->height);
}

static void
usage(void)
{
	fprintf(stderr, "advtime [-a] [-d] FILE\n");
	exit(EXIT_FAILURE);
}

int
main(int argc, char **argv)
{
	struct video_decode *vd;
	struct video_frame *frame_a = NULL, *frame_b = NULL;
	int ret, ch;
	int diff_flag = 0, average_flag = 0, frame_flag = 0, showcut_flag = 0;
	int64_t timestamp = 0;
	double diff = 0.0, old_diff = 0.0;
	char filename[BUFSIZ];

	while ((ch = getopt(argc, argv, "adfs")) != -1) {
		switch (ch) {
		case 'a':
			average_flag = 1;
			break;
		case 'd':
			diff_flag = 1;
			break;
		case 'f':
			diff_flag = 1;
			break;
		case 's':
			showcut_flag = 1;
			break;
		default:
			usage();
			/* NOTREACHED */
		}
	}
	argc -= optind;
	argv += optind;

	if (argc < 1)
		usage();

	if (argc == 2 && strtol(argv[1], NULL, 10) > 0)
		timestamp = strtol(argv[1], NULL, 10);

	ret = video_decode_init(&vd, argv[0], timestamp);
	if (ret < 0)
		return -ret;

	ret = video_decode_get_frame(vd, &frame_a);
	if (ret < 0)
		return -ret;
/*
	printf("fps: %d\n", vd->fmt_ctx->fps_probe_size);
	printf("streams: %d\n", vd->fmt_ctx->nb_streams);
	printf("filename: %s\n", vd->fmt_ctx->filename);
	printf("streams: %d\n", vd->fmt_ctx->streams[0]->duration);
	printf("duration: %d\n", vd->fmt_ctx->streams[1]->duration);
	printf("nb_frames: %d\n", vd->fmt_ctx->streams[0]->nb_frames);
	printf("avg frame rate: %f\n",
		av_q2d(vd->fmt_ctx->streams[0]->avg_frame_rate));
	printf("real frame rate: %f\n",
		av_q2d(vd->fmt_ctx->streams[0]->r_frame_rate));
	printf("first: %ji\n", vd->fmt_ctx->streams[0]->first_dts);
	printf("cur: %ji\n", vd->fmt_ctx->streams[0]->cur_dts);
	printf("reference: %ji\n", vd->fmt_ctx->streams[0]->reference_dts);
*/
	for (int i = 0; video_decode_get_frame(vd, &frame_b) > 0; ++i) {

		if (frame_flag)		/* print frame number */
			printf("%d\t", i);

		if (average_flag)		/* print frame average */
			printf("%f", frame_average(frame_a));

		if (average_flag && diff_flag)
			printf("\t");

		if (diff_flag) {
			diff = frame_diff(frame_a, frame_b);
//			printf("%f", diff);
//			printf("\t%f", (diff - old_diff));
			old_diff = diff;
		}

		if (diff > 40.0) {
			start_new_szene(frame_a->dts, frame_b->dts);

			if (!frame_flag && !average_flag) {
				printf("\n");
				fflush(stdout);
			}

			if (showcut_flag == 1) {
				snprintf(filename, BUFSIZ, "img/%04i.pgm", i);
				frame_mix(frame_a, frame_b);

				if (pgm_save(frame_a->data, frame_a->stride,
					     frame_a->width, frame_a->height,
					     filename) < 0)
					exit(EXIT_FAILURE);
			}
		}

		if (frame_flag || average_flag) {
			printf("\n");
			fflush(stdout);
		}

		pswap((void **)&frame_a, (void **)&frame_b);
	}

	if (diff_flag) {
		/* acutally we just finalize the last frame here */
		start_new_szene(frame_a->dts, 0);
		printf("\n");
	}

	video_decode_free_frame(&frame_a);
	video_decode_free_frame(&frame_b);
	video_decode_uninit(&vd);
	return EXIT_SUCCESS;
}