#include <wait.h>
#include <stdio.h>
#include <zconf.h>
#include <cstdlib>
#include <cstring>
#include <cerrno>


#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wmissing-noreturn"

int builtin_command(char **argv);

int parse_line(char *, char **argv);

void eval(char *cmd_line);

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

    char cmd_line[8888];

    while (1) {
        printf(">");
        fgets(cmd_line, 8888, stdin);
        cmd_line[(strlen(cmd_line))] = '\0';

        printf(" len:%d", strlen(cmd_line));
        eval(cmd_line);

    }

}

int builtin_command(char **argv) {
    if (strcmp(argv[0], "quit") == 0)
        exit(0);
    if (strcmp(argv[0], "&") == 0)
        return 1;
    return 0;
}

void eval(char *cmd_line) {
    printf("eval \n");
    char *cmd_buf = cmd_line;
    char *argv[1000];

    printf("%d", strlen(cmd_buf));;
    int bg = parse_line(cmd_buf, argv);


    if (argv[0] == NULL) {
        return;
    }


    pid_t pid;
    if (builtin_command(argv) == 0) {
        if ((pid = fork()) == 0) {
            if (execve(argv[0], argv, environ) < 0) {
                printf("%s :Command not found .\n", argv[0]);
                exit(0);
            }

        }
        printf("bg=%d\n",bg);
        if (!bg) {
            int status;
            if (waitpid(pid, &status, 0) < 0) {
                fprintf(stderr, "%s", strerror(errno));
                exit(0);
            }
        } else
            printf("%d %s", pid, cmd_line);

    }

    return;


}


int parse_line(char *cmd_buf, char **argv) {

    char *delim;
    int argc=0;
    int bg;

    cmd_buf[strlen(cmd_buf) - 1] = ' ';

    while (*cmd_buf && (*cmd_buf == ' '))
        cmd_buf++;

    while ((delim = strchr(cmd_buf, ' '))) {
        argv[argc++] = cmd_buf;
        *delim = '\0';
        cmd_buf = delim + 1;
        while (*cmd_buf && (*cmd_buf == ' '))
            cmd_buf++;
    }


    argv[argc] = NULL;


    if (argc == 0)
        return 1;




    if ((bg = (*argv[argc - 1] == '&')) != 0) {
        argv[--argc] = NULL;

    }
    return bg;
}