#define _XOPEN_SOURCE 700
#define _DEFAULT_SOURCE

#include <arpa/inet.h>
#include <assert.h>
#include <errno.h>
#include <fnmatch.h>
#include <getopt.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>

#include <zip.h>

#define MICO_HEADER "\211MiC\r\n\032\n"

static int lflag;
static int64_t fflag, tflag;

zip_t *zip;

struct bitreader {
	zip_file_t *input;

        uint64_t bitbuf;        // value of bits in write buffer
        int bitcount;   // number of bits in write buffer

	int eof;
};

static uint64_t
getbits1_msb(struct bitreader *input, int count)
{
        assert(count >= 1 && count <= 57);

        // Keep reading extra bytes until we have enough bits buffered
        // Big endian; our current bits are at the top of the word,
        // new bits get added at the bottom.
        while (input->bitcount < count) {
		unsigned char buf;
		int ret = zip_fread(input->input, &buf, sizeof buf);
		if (ret < 0) {
			printf("err: %s", zip_strerror(zip));
		}
		if (ret == 0) {
			input->eof = 1;
			return 0;
		}
                input->bitbuf |= (uint64_t)buf << (56 - input->bitcount);
                input->bitcount += 8;
        }

        // We now have enough bits present; the most significant
        // "count" bits in "bitbuf" are our result.
        uint64_t result = input->bitbuf >> (64 - count);

        // Now remove these bits from the buffer
        input->bitbuf <<= count;
        input->bitcount -= count;

        return result;
}

static int32_t
getsigned(struct bitreader *input, int count)
{
        uint64_t bits = getbits1_msb(input, count);
        uint64_t sign = 1 << (count - 1);

        if (bits & sign)
                return -(bits ^ sign) - 1;
        else
                return bits;
}

static int64_t
get1(struct bitreader *input)
{
        if (getbits1_msb(input, 1) == 0)
                return 0;
        if (getbits1_msb(input, 1) == 0)
                return getsigned(input, 7);
        if (getbits1_msb(input, 1) == 0)
                return getsigned(input, 9);
        if (getbits1_msb(input, 1) == 0)
                return getsigned(input, 12);

	int64_t v = getsigned(input, 32);
	v <<= 32;
	v |= getbits1_msb(input, 32);

	return v;
}

char *
mystrccpy(char *dst, char *src, int c)
{
	while ((*dst = *src)) {
		if (*dst == c) {
			*dst = 0;
			src++;
			return src;
		}
		dst++;
		src++;
	}

	return 0;
}

int64_t
parsetimestamp(char *t)
{
	int64_t ts;
	char *end;

	errno = 0;
	ts = strtoll(t, &end, 10);
	if (errno != 0 || *end) {
		fprintf(stderr, "can't parse unix milli timestamp: %s\n", t);
		exit(-1);
	}

	return ts;
}

void
parsetimerange(char *t)
{
	struct tm tm_from = { .tm_mday = 1 };
	struct tm tm_to;

	/* XXX switch to iso format, treat number as raw timestamp */

	switch(strlen(t)) {
	case 4:
		if (!strptime(t, "%Y", &tm_from))
			goto err;
		tm_to = tm_from;
		tm_to.tm_year++;
		break;
	case 7:
		if (!strptime(t, "%Y-%m", &tm_from))
			goto err;
		tm_to = tm_from;
		tm_to.tm_mon++;
		break;
	case 10:
		if (!strptime(t, "%Y-%m-%d", &tm_from))
			goto err;
		tm_to = tm_from;
		tm_to.tm_mday++;
		break;
	case 13:
		if (!strptime(t, "%Y-%m-%dT%H", &tm_from))
			goto err;
		tm_to = tm_from;
		tm_to.tm_hour++;
		break;
	case 16:
		if (!strptime(t, "%Y-%m-%dT%H:%M", &tm_from))
			goto err;
		tm_to = tm_from;
		tm_to.tm_min++;
		break;
	case 19:
		if (!strptime(t, "%Y-%m-%dT%H:%M:%S", &tm_from))
			goto err;
		tm_to = tm_from;
		tm_to.tm_sec++;
		break;
	default:
	err:
		fprintf(stderr, "can't recognize timestamp: %s\n", t);
		exit(-1);
	}

	fflag = timegm(&tm_from) * 1000;
	tflag = (timegm(&tm_to) * 1000) - 1;
}

#define ntohll(x) ((1==ntohl(1)) ? (x) : ((uint64_t)ntohl((x) & 0xFFFFFFFF) << 32) | ntohl((x) >> 32))

int
main(int argc, char *argv[])
{
	int c;
	while ((c = getopt(argc, argv, "f:lt:r:")) != -1) {
		switch (c) {
		case 'l': lflag = 1; break;
		case 'f': fflag = parsetimestamp(optarg); break;
		case 't': tflag = parsetimestamp(optarg); break;
		case 'r': parsetimerange(optarg); break;
		case '?':
		usage:
			fprintf(stderr, "usage: %s [-l] [-f TIME] [-t TIME] input.zip [filter...]\n", argv[0]);
			exit(-1);
		}
	}

	if (argc - optind < 1)
		goto usage;

	setenv("TZ", "", 1);
	tzset();

	zip = zip_open(argv[optind], ZIP_RDONLY, 0);

	int entries = zip_get_num_entries(zip, 0);

	for (int i = 0; i < entries; i += 2) {
		struct bitreader ts = { 0 };
		struct bitreader vs = { 0 };

		/* XXX verify assumptions on zip file order */
		ts.input = zip_fopen_index(zip, i, 0);
		vs.input = zip_fopen_index(zip, i+1, 0);

		char *name = strdup(zip_get_name(zip, i, ZIP_FL_ENC_RAW));
		char *s = strchr(name, '/');
		*s = '{';
		s = strrchr(name, '/');
		*s++ = '}';
		*s = 0;

		int keep = 1;
		for (int j = optind + 1; j < argc; j++) {
			if (strchr(argv[j], '=')) { // filter on label
				char label[255];
				char *s = strchr(name, '{');
				if (!s) {
					keep = 0;
					break;
				}
				s++;

				int any = 0;
				do {
					s = mystrccpy(label, s, ',');
					if (fnmatch(argv[j], label, 0) == 0) {
						any = 1;
						break;
					}
				} while(s);
				if (!any)
					keep = 0;
			} else { // filter on name
				char series[255];
				mystrccpy(series, name, '{');

				if (fnmatch(argv[j], series, 0) == FNM_NOMATCH) {
					keep = 0;
					break;
				}
			}
		}

		if (!keep)
			continue;

		if (lflag) {
			printf("%s\n", name);
			continue;
		}

		char header[8];
		uint64_t len, lenv;
		int ret = zip_fread(ts.input, &header, sizeof header);
		if (ret < 0) {
			printf("err: %s", zip_strerror(zip));
		}

		if (memcmp(header, MICO_HEADER, 8) != 0) {
			printf("wrong header\n");
			continue;
		}

		ret = zip_fread(ts.input, &len, sizeof len);
		if (ret < 0) {
			printf("err: %s", zip_strerror(zip));
		}

		len = ntohll(len);

		ret = zip_fread(vs.input, &header, sizeof header);
		if (ret < 0) {
			printf("err: %s", zip_strerror(zip));
		}

		if (memcmp(header, MICO_HEADER, 8) != 0) {
			printf("wrong header\n");
			continue;
		}

		ret = zip_fread(vs.input, &lenv, sizeof lenv);
		if (ret < 0) {
			printf("err: %s", zip_strerror(zip));
		}

		lenv = ntohll(lenv);

		if (len != lenv) {
			fprintf(stderr, "time and value length don't agree: %ld != %ld\n", len, lenv);
			exit(-1);
		}

		int64_t t = 0, td = 0;
		double v = 0.0;

		for (uint64_t j = 0; j < len; j++) {
			int64_t tdd = get1(&ts);
			int64_t vd = get1(&vs);

			td += tdd;
			t += td;
			v += vd;

			if (fflag && t < fflag)
				continue;
			if (tflag && t > tflag)
				break;

			printf("%s %f %ld\n", name, v/10000.0, t);
		}
	}
}