#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#define maxtofrom 10
/* ocountflag means that it will only count
 how many entries there are then quit */

long from=0, to=0, end=0;
int inflag=0, outflag=0, ocountflag=0, delflag=0, commaflag=0;
char tester[100000]; /* if you have a line longer than this then you have a problem. */
char *filename;

void prepcomms(char *where)
{
	int fromcount=0, tocount=0;
	char cfrom[maxtofrom+8];
	char cto[maxtofrom+8];
	for (int j=0; where[j] && j<=(maxtofrom*2+8); j++) {
		if (where[j]==',') { commaflag=1; continue; }
		switch (where[j]) {
			case 'i': inflag = 1;
		        	  break;
			case 'p': outflag = 1; 
			          break;
			case 'd': delflag = 1;; 
			          break;
			case 'c': ocountflag = 1;
			          break;
		}
		if (!commaflag) cfrom[fromcount++] = where[j];
		else cto[tocount++] = where[j];
	}
	if (commaflag) {
		from = atol(cfrom);
		to = atol(cto);
	} else {
		to = (from=atol(cfrom));
	}
	if (!from && commaflag && to) {
		fputs("clip: must have a number before comma\n", stderr);
		free(filename);
		exit(1);
	}
	if (from > to) {
		fputs("clip: first number must be less than second\n", stderr);
		free(filename);
		exit(1);
	}
}

void cookargs(int c, char *v[])
{
	if (c>1) {
		for (int i=1; v[i]; i++) {
			if (v[i][0]=='-' && v[i][1] && v[i][1]=='f' && v[i+1]) {
				filename = v[i+1];
				i++; /* makes cursor skip file name */
			}
			else prepcomms(v[i]);
		}
		if (!inflag && !outflag && !delflag && !ocountflag) {
			fputs("usage: clip [-f filename] [justcount|in|out #,#|delete #,#]\n", stderr);
			free(filename);
			exit(1);
		}
	} else {
		fputs("usage: clip [-f filename] [count|in|print #,#|delete #,#]\n", stderr);
		free(filename);
		exit(1);
	}
}

int main(int argc, char *argv[])
{
	filename = malloc(3000);
	sprintf(filename, "%s/%s", getenv("HOME"), ".clipboard");
	char delim[31] = "------------------------------\n";
	FILE *filep;
	long counter = 0;
	cookargs(argc, argv); /* can change file name based on what comes after "-f" */

	if ((filep=fopen(filename, "a+"))==NULL) {
		fprintf(stderr, "clip: cannot open %s", filename);
		free(filename);
		exit(1);
	}
	if (inflag) {
		char inbuf[1000000];
		fread(inbuf, sizeof(inbuf), 1, stdin);
		fprintf(filep, "%s%s", delim, inbuf);
		fclose(filep);
		free(filename);
		exit(1);
	}

	while (fgets(tester, sizeof(tester), filep))
		if (memcmp(tester, delim, sizeof(delim))==0)
			end++;

	rewind(filep);
	if (ocountflag) {
		printf("%ld\n", end);
		goto ending; /* stops program after outputting count */
	}

	if (end==0) {
		fputs("nothing to act on\n", stderr);
		fclose(filep);
		free(filename);
		exit(1);
	}
	if (to>end) {
		fputs("clip: end point too big\n", stderr);
		fclose(filep);
		free(filename);
		exit(1);
	}
	if (!from && !to && commaflag) { from=1; to=end; }
	if (!from && !to && !commaflag) { from = end; to = end; }
	if (delflag) {
		FILE *tdelfilep;
		int delimflag=0;
		if ((tdelfilep=fopen(".clipboard~~~", "w+"))==NULL) {
			fputs("clip: cannot create temporary file\n", stderr);
			fclose(filep);
			free(filename);
			exit(1);
		}
		while (counter <= end && fgets(tester, sizeof(tester), filep)) {
			if (memcmp(tester, delim, sizeof(delim))==0) {
				counter++;
				delimflag=1;
				continue;
			}
			if (counter < from || counter > to) {
				fprintf(tdelfilep, "%s%s", delimflag?delim:"", tester);
				delimflag=0;
			}
		}
		rename(".clipboard~~~", filename);
		goto ending;
	}

	if (outflag) {
		while (counter <= end  && fgets(tester, sizeof(tester), filep)) {
			if (memcmp(tester, delim, sizeof(delim))==0) {
				counter++;
				continue;
			}
			if (counter >= from && counter <= to) {
				fputs(tester, stdout);
			}
		}
	}
ending:
	free(filename);
 	fclose(filep);
	return 0;
}