/************************************************************************
 *Usage
 *To start : ./reminder -k start -t "Text to remind" -c "repeat time"
 *To stop  : ./remnder -k stop
 */

#include <unistd.h>
#include <stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <stdlib.h>
#include <sysexits.h>
#include <string.h>


void usage(char * const *arg) {
    printf ("Usage : %s [OPTIONS]\n",arg[0]);
    printf ("        -k start/stop\n");
    printf ("        -t <Reminder text>\n");
    printf ("        -c <countdown(30-300)>\n");
    printf ("        -h Help on usage. ");
    printf ("\n");
    exit(EX_USAGE);
}

void start_routine(char *myname, char *rem, int countdown) {
    FILE *fd = NULL;
    char *script;
    strcpy(script,"./reminder.sh");
    char *content = malloc(1000 * sizeof(char));

    if ( !(fd = fopen(script,"w+")) ) {
        printf("Unable to open/create %s\n",script);
        printf("Error code is %d\n",fd);
        exit(EX_CANTCREAT);
    }
    if (chmod(script,S_IXUSR|S_IRUSR|S_IWUSR|S_IXGRP)) {
        printf("Unable to give execute permission to %s\n",script);
        remove(script);
        exit(EX_CANTCREAT);
    }

    sprintf(content,"#/bin/bash\n");
    sprintf(content,"%sprintf \'\\033[2J\\033[H\'\n",content);
    sprintf(content,"%sprintf '\\033[1m\\033[12;3f%s\\033[0m\\n\\n'\n",content,rem);
    sprintf(content,"%ssleep 5\n",content);
    sprintf(content,"%sexit 0\n",content);

    fwrite(content,sizeof(char),strlen(content),fd);

    fclose(fd);
    free(content);

    while (1) {
        system("xterm -e ./reminder.sh &");
        sleep(countdown);
    }
}

void stop_routine() {
    return;

}

int main(int argc,char * const *argv) {

    char * myname = argv[0];
    int opt;

    int kflag = 0;
    int tflag = 0;
    int cflag = 0;
    char *state;
    char *text;
    int countdown;
    int start = 0;
    int stop = 0;
    pid_t parent_pid,child_pid,pid;
    int status;
    parent_pid=getpid();

    while ((opt = getopt(argc, argv,"hk:t:c:")) != -1 ) {
        switch (opt) {
        case 'k' :
            kflag = 1;
            //DEBUG
            //printf("optarg : %s\n",optarg);
            state = optarg;
            break;
        case 't' :
            tflag = 1;
            text = optarg;
            break;
        case 'c' :
            cflag = 1;
            countdown = atoi(optarg);
            break;
        case 'h' :
            usage (argv);
            break;
            /*    case '?' :
            printf("%s: invalid option.\n",argv[0]);
            usage(argv);
            break;
             */
        }
    }
    //DEBUG
    //printf("%s\n",state);
    if (!kflag) {
        printf ("%s: missing -k option.\n",myname);
        usage(argv);
    } else if (strcmp(state,"start") && strcmp(state,"stop")) {
        printf ("%s: illegel use -k option.\n",myname);
        usage(argv);
    }
    if (!tflag) {
        strcpy(text,"Are you forgetting something?");
    }
    if (!cflag) {
        countdown = 60;
    } else if (countdown < 30 || countdown >300) {
        countdown = 60;
    }


    //Check if the program was invoked to start or stop the applicatio.
    if ( ! strcmp(state,"start")) // if (state == "start")
        start = 1;
    else
        stop = 1;

    printf ("\033[2J\033[H");

    if ( start ) {

        /* The reminder text and the countdown is printed in
         * the main window.
         * This will be done by a child process.
         * We will fork() off now and let the child do the rest of the
         * starting up. So to stop the program we will just kill of the child.
         */
        printf("Starting %s with the below inputs\n",myname);
        printf ("\nReminder text : %s\n",text);
        printf ("Repeat time : %d\n\n",countdown);
        printf ("Run %s with -k stop to stop\n",myname);

        if (( child_pid = fork() ) == -1) {
            perror("fork error");
            exit(EX_UNAVAILABLE);
        }
    } else {
        printf("Stopping %s\n",myname);
        stop_routine();
        exit(EX_OK);
    }

    if (! child_pid) {        //Child process
        start_routine(myname,text,countdown);
    } else {                //Parent process

        if ((pid = wait(&status)) == -1) {
            perror("Wait error\n");
            exit(EX_UNAVAILABLE);
        }
        if (WEXITSTATUS(status)) {
            printf("Reminder has finished exectution.\n");
            return 0;
        } else if (WIFSIGNALED(status)) {
            if ( WTERMSIG(status) == 6 ) {
                printf("Reminder stopped normally using -k stop option\n");
                return 0;
            } else {
                printf("Reminder terminated abnormally by signale: %d\n",
                        WTERMSIG(status));
                exit(EX_UNAVAILABLE);
            }
        }


    }

    return 0;
}