#include <stdio.h>
#include <stdlib.h>
#include <error.h>
#include <sys/stat.h>
#include <inttypes.h>
#include <fcntl.h>
#include <errno.h>
#include <sys/mman.h>
#include <unistd.h>
#define S0(x) (x ? x : "")
struct entry {
	uint64_t time __attribute__((packed));
	uint64_t value __attribute__((packed));
} __attribute__((packed));
int najdi (struct entry * db, int first, int last, long long int čas) {
	if (first == last)
		return first;
	if (abs(first-last) == 1) {
		if (labs(čas/1000-first*1000) < labs(čas/1000-last*1000))
			return first;
		else
			return last;
	}
	if ((long long int) be64toh(db[(first+last)/2].time/1000) > čas*1000)
		return najdi(db, (first+last)/2, last, čas);
	else
		return najdi(db, first, (first+last)/2-1, čas);
}
int main (int argc, char ** argv) {
	int r = 0;
	if (argc < 1+2)
		error_at_line(1, 0, __FILE__, __LINE__, "uporaba: %s db informacije/preveri/rast/seštevek [natančnost=0] [začetek UNIXsek] [konec UNIXsek]\n\t"
"informacije: pove UNIXus prvega in UNIXus zadnjega zapisa\n\t"
"preveri: pove, če čas ni naraščajoč in kdaj se je števec resetiral\n\t"
"rast: TSV s podatki <UNIXms>:<Wh skupno> najgosteje na [natančnost=0] ms\n\t"
"seštevek: TSV s podatki <UNIXms>:<vatnih ur v [natančnost=10e3] ms>", S0(argv[0]));
	int fd = -1;
	struct entry * db = NULL;
	if ((fd = open(argv[1], O_RDONLY | O_CLOEXEC)) == -1)
		error_at_line(2, 0, __FILE__, __LINE__, "open");
	struct stat statbuf;
	if (fstat(fd, &statbuf) == -1) {
		error_at_line(0, errno, __FILE__, __LINE__, "fstat");
		r = 3;
		goto r;
	}
	unsigned entries = statbuf.st_size / sizeof(struct entry);
	if (!(db = mmap(NULL, statbuf.st_size, PROT_READ, MAP_SHARED, fd, 0))) {
		error_at_line(0, errno, __FILE__, __LINE__, "mmap");
		r = 4;
		goto r;
	}
	if (argv[2][0] == 'i') {
		printf("začetek\t%" PRIu64 " UNIXus\t%" PRIu64 " Wh\nkonec\t%" PRIu64 " UNIXus\t%" PRIu64 " Wh\nzapisov: %u\n", be64toh(db[0].time), be64toh(db[0].value), be64toh(db[entries-1].time), be64toh(db[entries-1].value), entries);
		goto r;
	}
	if (argv[2][0] == 'p') {
		uint64_t prev_time = 0;
		uint64_t prev_value = 0;
		for (unsigned i = 0; i < entries; i++) {
			if (be64toh(db[0].time) < prev_time)
				printf("čas se je zavrtel nazaj: i=%u a=%" PRIu64 " b=%" PRIu64 "\n", i, prev_time, be64toh(db[0].time));
			if (be64toh(db[0].value) < prev_value)
				printf("števec se je resetiral: i=%u a=%" PRIu64 " b=%" PRIu64 "\n", i, prev_value, be64toh(db[0].value));
			prev_time = be64toh(db[0].time);
			prev_value = be64toh(db[0].value);
		}
		goto r;
	}
	unsigned long long natančnost = 0;
	if (argv[2][0] == 's')
		natančnost = 10e3;
	if (argc >= 1+3)
		natančnost = atoi(argv[3]);
	unsigned začetek = 0;
	if (argc >= 1+4)
		začetek = najdi(db, 0, entries-1, atoi(argv[4]));
	unsigned konec = entries-1;
	if (argc >= 1+5)
		konec = najdi(db, 0, entries-1, atoi(argv[5]));
	if (argv[2][0] == 's') {
		uint64_t us = 0;
		uint64_t Wh = 0;
		unsigned long long prev_time = be64toh(db[začetek].time);
		unsigned long long prev_value = be64toh(db[začetek].value);
		for (unsigned i = začetek; i <= konec; i++) {
			if (us + (be64toh(db[i].time)-prev_time) >= natančnost*1000) {
				printf("%" PRIu64 "\t%" PRIu64 "\t%" PRIu64 "\t%" PRIu64 "\n", be64toh(db[i].time)-us, Wh, be64toh(db[i].time), us);
				us = 0;
				Wh = 0;
			}
			us += (be64toh(db[i].time)-prev_time);
			Wh += (be64toh(db[i].value)-prev_value);
			prev_time = be64toh(db[i].time);
			prev_value = be64toh(db[i].value);
		}
	} else {
		unsigned long long prev_print = 0;
		for (unsigned i = začetek; i <= konec; i++) {
			if (be64toh(db[i].time)-prev_print > natančnost*1000) {
				printf("%" PRIu64 "\t%" PRIu64 "\n", be64toh(db[i].time), be64toh(db[i].value));
				prev_print = be64toh(db[i].time);
			}
		}
	}
r:
	if (db != NULL)
		if (munmap(db, statbuf.st_size) == -1)
			error_at_line(98, errno, __FILE__, __LINE__, "munmap");
	if (fd == -1)
		if (close(fd) == -1)
			error_at_line(99, errno, __FILE__, __LINE__, "fclose");
	return r;
}