#include <linux/dvb/frontend.h>
#include <linux/dvb/dmx.h>
#include <linux/dvb/audio.h>
#include <linux/dvb/version.h>
#include <sys/ioctl.h>
#include <fcntl.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>

#define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]))

struct channel {
	int id;
	const char *name;
	unsigned int frequency;
	unsigned int ts_id;
};

static struct channel isdbt_channels[] = {
	{ 13, "13ch",   473142857 },
	{ 14, "14ch",   479142857 },
	{ 15, "15ch",   485142857 },
	{ 16, "16ch",   491142857 },
	{ 17, "17ch",   497142857 },
	{ 18, "18ch",   503142857 },
	{ 19, "19ch",   509142857 },
	{ 20, "20ch",   509142857 },
	{ 21, "21ch",   515142857 },
	{ 22, "22ch",   521142857 },
	{ 23, "23ch",   527142857 },
	{ 24, "24ch",   533142857 },
	{ 25, "25ch",   539142857 },
	{ 26, "26ch",   545142857 },
	{ 27, "27ch",   551142857 },
	{ 28, "28ch",   557142857 },
	{ 29, "29ch",   563142857 },
	{ 30, "30ch",   569142857 },
	{ 31, "31ch",   575142857 },
	{ 32, "32ch",   581142857 },
	{ 33, "33ch",   587142857 },
	{ 34, "34ch",   593142857 },
	{ 35, "35ch",   599142857 },
	{ 36, "36ch",   605142857 },
	{ 37, "37ch",   611142857 },
	{ 38, "38ch",   617142857 },
	{ 39, "39ch",   623142857 },
	{ 40, "40ch",   629142857 },
	{ 41, "41ch",   635142857 },
	{ 42, "42ch",   641142857 },
	{ 43, "43ch",   647142857 },
	{ 44, "44ch",   653142857 },
	{ 45, "45ch",   659142857 },
	{ 46, "46ch",   665142857 },
	{ 47, "47ch",   671142857 },
	{ 48, "48ch",   677142857 },
	{ 49, "49ch",   683142857 },
	{ 50, "50ch",   689142857 },
	{ 51, "51ch",   695142857 },
	{ 52, "52ch",   701142857 },
	{ 53, "53ch",   707142857 },
	{ 54, "54ch",   713142857 },
	{ 55, "55ch",   719142857 },
	{ 56, "56ch",   725142857 },
	{ 57, "57ch",   731142857 },
	{ 58, "58ch",   737142857 },
	{ 59, "59ch",   743142857 },
	{ 60, "60ch",   749142857 },
	{ 61, "61ch",   755142857 },
	{ 62, "62ch",   761142857 },
};

static struct channel isdbs_channels[] = {
	{ 101, "NHK BS-1",          1318000, 0x40f1 },
	{ 102, "NHK BS-2",          1318000, 0x40f1 },
	{ 103, "NHK BS-Hi",         1318000, 0x40f2 },
	{ 141, "BS日テレ",          1279640, 0x40d0 },
	{ 151, "BS朝日",            1049480, 0x4010 },
	{ 161, "BS-i",              1049480, 0x4011 },
	{ 171, "BSジャパン",        1087840, 0x4031 },
	{ 181, "BSフジ",            1279640, 0x40d1 },
	{ 191, "WOWOW",             1087840, 0x4030 },
	{ 200, "STAR CHANNEL HV",   1202920, 0x4091 },
	{ 211, "BS11",              1202920, 0x4090 },
	{ 222, "TwellV",            1202920, 0x4092 },
};

static struct channel *
lookup_channel(int id, struct channel *channels, int nr)
{
	int i;
	struct channel *channel;
	for (i = 0; i < nr; i++) {
		channel = &channels[i];
		if (channel->id == id)
			return channel;
	}
	return NULL;
}

static int search(int adapter_nr, int channel_id)
{
	char file[256];
	int fd;
	struct dvb_frontend_info info;
	struct channel *channel;
	struct dtv_property prop[3];
	struct dtv_properties props;
	int i;
	fe_status_t status;

	sprintf(file, "/dev/dvb/adapter%d/frontend0", adapter_nr);
	if ((fd = open(file, O_RDWR)) < 0) {
		perror("open");
		return -1;
	}

	if (ioctl(fd, FE_GET_INFO, &info) < 0) {
		perror("ioctl FE_GET_INFO");
		goto out;
	}

	if (info.type == FE_QPSK) {
		channel = lookup_channel(channel_id, isdbs_channels,
					 ARRAY_SIZE(isdbs_channels));
	} else if (info.type == FE_OFDM) {
		channel = lookup_channel(channel_id, isdbt_channels,
					 ARRAY_SIZE(isdbt_channels));
	} else {
		fprintf(stderr, "Unknown type of adapter\n");
		goto out;
	}
	if (channel == NULL) {
		fprintf(stderr, "Unknown id of channel\n");
		goto out;
	}

	prop[0].cmd = DTV_FREQUENCY;
	prop[0].u.data = channel->frequency;
	prop[1].cmd = DTV_ISDBS_TS_ID_LEGACY;
	prop[1].u.data = channel->ts_id;
	prop[2].cmd = DTV_TUNE;

	props.props = prop;
	props.num = 3;

	if ((ioctl(fd, FE_SET_PROPERTY, &props)) < 0) {
		perror("ioctl FE_SET_PROPERTY");
		goto out;
	}

	for (i = 0; i < 4; i++) {
		if (ioctl(fd, FE_READ_STATUS, &status) < 0) {
			perror("ioctl FE_READ_STATUS");
			goto out;
		}
		if (status & FE_HAS_LOCK) {
			fprintf(stderr, "Successfully tuned to %s .\n",
				channel->name);
			return 0;
		}
		sleep(1);
	}

	fprintf(stderr, "Failed to tune to %s (status %02x).\n",
		channel->name, status);

out:
	close(fd);
	return -1;
}

static int track(int adapter_nr)
{
	char file[256];
	int fd;
	struct dmx_pes_filter_params filter;

	filter.pid = 0x2000;
	filter.input = DMX_IN_FRONTEND;
	filter.output = DMX_OUT_TS_TAP;
	filter.pes_type =  DMX_PES_VIDEO;
	filter.flags = DMX_IMMEDIATE_START;

	sprintf(file, "/dev/dvb/adapter%d/demux0", adapter_nr);
	if ((fd = open(file, O_RDWR)) < 0) {
		perror("open");
		return -1;
	}


	if (ioctl(fd, DMX_SET_PES_FILTER, &filter) < 0) {
		perror("ioctl DMX_SET_PES_FILTER");
		close(fd);
		return -1;
	}

	while (1)
		sleep(3);

	/* never returns */
}

int main(int argc, char *argv[]) {
	int adapter_nr;
	int channel_id;
	int fd;
	int ret;

	if (argc <= 2) {
		fprintf(stderr, "Usage: %s adapter_nr channel_id\n", argv[0]);
		return 1;
	}

	adapter_nr = strtol(argv[1], NULL, 0);
	channel_id = strtol(argv[2], NULL, 10);

	fd = search(adapter_nr, channel_id);
	if (fd < 0)
		return 1;

	ret = track(adapter_nr);
	close(fd);

	return ret < 0;
}