/*
 *  runfile - rf
 *
 *  a no-dependancy, minimal
 *  POSIX C99 Make/justfile
 *  alternative to run commands.
 *
 *             czjstmax
 *   <jstmaxlol at
 *      disroot dot org>
 *
 *  check MAINTAINERS file
 */

#define _POSIX_C_SOURCE 200809L

#define RUNFILE_VER_MAJ 1     /* anything that changes how rfile are written in the slightest */
#define RUNFILE_VER_MIN 1     /* anything that varies the UX of the program (i.e. CLI flags)  */ 
#define RUNFILE_VER_FIX 20    /* optimizations, slight logic tweaks, anything that is not     */
                              /* noticeable by the user but impacts the dev experience enough */
#include <stdio.h>            /* to be important                                              */
#include <ctype.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <stdbool.h>
#include <wordexp.h>
#include <sys/wait.h>

void usage();

int main(int argc, char **argv)
{
    char *section = NULL;
    bool in_section = false;
    bool should_run = false;

    // check cli arguments
    // if (argc < 2) {
    //     printf("<rf> not enough arguments.\n");
    //     usage();
    //     return 1;
    // }
    if (argc >= 2) {
        for (int i = 1; i < argc; i++) {
            if (strcmp(argv[i], "-h") == 0 || strcmp(argv[i], "--help") == 0) {
                usage();
                return 0;
            }
        }
    }

    FILE *f = fopen("rfile", "r");

    if (!f) {
        fprintf(stderr, "no rfile found.\n");
        return 1;
    }

    wordexp_t p;
    char *line = NULL;
    size_t len = 0;

    while (getline(&line, &len, f) != -1) {
        line[strcspn(line, "\n")] = '\0';
        char *cmd = line;

        while (isspace(*cmd))
            cmd++;

        if (*cmd == '\0')
            continue;
        else if (cmd[0] == '#')
            continue;
        else if (strncmp(cmd, "@:", 2) == 0) {
            for (size_t i = 0; i < strlen(cmd); i++)
                printf("-");

            printf("\n%s\n", cmd);

            for (size_t i = 0; i < strlen(cmd); i++)
                printf("-");

            printf("\n\n");
            continue;
        }
        else if (strcmp(cmd, "}") == 0 || strcmp(line, "}") == 0) {
            in_section = false;

            free(section);
            section = NULL;

            continue;
        }

        char *brace = strchr(cmd, '{');
        if (brace) {
            *brace = '\0';

            size_t l = strlen(cmd);

            while (l > 0 && (cmd[l-1] == ' ' || cmd[l-1] == '\t')) {
                cmd[l-1] = '\0';
                l--;
            }

            free(section);
            section = strdup(cmd);
            in_section = true;

            continue;
        }
        
        should_run = false;

        if (argc == 1) {
            should_run = !in_section;
        }
        else {
            should_run = in_section &&
                         section &&
                         strcmp(argv[1], section) == 0;
        }

        if (!should_run)
            continue;

        printf("$ %s\n", cmd);

        if (wordexp(cmd, &p, 0) != 0) {
            fprintf(stderr, "wordexp failed\n");
            continue;
        }

        pid_t pid = fork();
        if (pid == 0) {
            execvp(p.we_wordv[0], p.we_wordv);

            perror("failed to run command");

            fclose(f);
            _exit(1);
        }

        waitpid(pid, NULL, 0);
        wordfree(&p);
    }

    free(line);
    fclose(f);
    return 0;
}

void usage()
{
    printf(
        "runfile usage - version %d.%d.%d\n"
        "syn: rf [section]\n"
        , RUNFILE_VER_MAJ, RUNFILE_VER_MIN, RUNFILE_VER_FIX
    );
}