#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <assert.h>
#include <fcntl.h>
#include <string.h>
#include <ctype.h>

#include <sys/types.h>
#include <sys/stat.h>

#include "common.h"

void 
Usage(char *program)
{
    fprintf(stderr, "Usage: %s <fifoFile> <dataFile>\n", program);
    exit(1);
}

void
CheckFiles(char *fifo, char *data)
{
    // make sure they are the right types of files
    if (IsFifo(fifo) == 0) {
	fprintf(stderr, "%s is not a FIFO!\n", fifo);
	exit(1);
    }

    if (IsRegular(data) == 0) {
	fprintf(stderr, "%s is not a regular file\n", fifo);
	exit(1);
    }
}

int
IsValid(char *str) {
    int len = strlen(str);

    if (len == 0)
	return 0;

    // check first digit special: minus sign or digit
    if ((str[0] != '-') && (isdigit(str[0]) == 0)) 
	return 0; 

    // check rest: just digits
    for (int i = 1; i < len; i++) {
	if (isdigit(str[i]) == 0) {
	    return 0; 
	}
    }
    return 1;
}

void
MsgSend(int pipe, msg_t *m) 
{
    // send on pipe
    if (write(pipe, m, sizeof(msg_t)) != sizeof(msg_t)) {
	perror("write");
	// not much to do about this other than continue
    }
}

int
main(int argc, char *argv[])
{
    // takes two arguments: fifofile and  datafile
    if (argc != 3) {
	Usage(argv[0]);
    }
    char *fifoFile = argv[1];
    char *dataFile = argv[2];

    // first, check that fifo is a FIFO, and data is a data file, then open both
    CheckFiles(fifoFile, dataFile);

    int pipe = open(fifoFile, O_WRONLY);
    if (pipe < 0) {
	perror("open");
	Usage(argv[0]);
    }

    FILE *fp = fopen(dataFile, "r");
    if (fp == NULL) {
	perror("fopen");
	Usage(argv[0]);
    }

    // 
    // main loop
    // 
    msg_t m;
    char line[MAX_LINE];
    while (fgets(line, MAX_LINE, fp) != NULL) {
	// printf("%s", line);

	// check for comments
	if (line[0] == '#') {
	    continue;
	}

	// parse line: use strtok() to split up line into little bits
	char *p = strtok(line, WHITESPACE); 
	while (p != NULL) {
	    // check if token is a valid integer
	    if (IsValid(p)) {
		// form message and send it
		m.type = DATA;
		m.data = atoi(p);
		MsgSend(pipe, &m);
	    } 

	    // get next token here
	    p = strtok(NULL, WHITESPACE);
	}
    }

    // all done, send the END message
    m.type = END; // doesn't matter what 'data' field is set to
    MsgSend(pipe, &m);

    // close up shop and be done with it
    close(pipe);
    fclose(fp);

    return 0;
}