#include "command.h"
#include "lslib.h"

#include <dirent.h>
#include <grp.h>
#include <stdlib.h>
#include <sys/stat.h>
#include <unistd.h>
#include <string.h>
#include <sys/types.h>
#include <pwd.h>

static struct {
    bool recurse;
    bool list_changed;
    bool verbose;
    bool quiet;
    uid_t uid;
    gid_t gid;
} flags;

static void help (void) {
    printf("Usage: chown [-Rcvf]... USER[:[GRP]] FILE...\n\n");
    printf("Change the owner and/or group of FILEs to USER and/or GRP\n\n");
    printf("\t-R\tRecurse\n");
	printf("\t-c\tList changed files\n");
	printf("\t-v\tVerbose\n");
	printf("\t-f\tHide errors\n");
}

static int short_arg(char c, char* next) {
    UNUSED(next);
    switch (c) {
        case 'R':
            flags.recurse = true;
            break;
        case 'c':
            flags.list_changed = true;
            break;
        case 'v':
            flags.verbose = true;
            break;
        case 'f':
            flags.quiet = true;
            break;
        default:
            return ARG_INVALID;
    }
    return ARG_UNUSED;
}

static void chown_file(char* path) {
    int save;
    struct stat s;
    DIR* d;
    struct dirent* file;

    save = push_path_buffer(path);
    
    if (chown(get_path_buffer(), flags.uid, flags.gid) < 0) {
        if (!flags.quiet) {
            error_s("cannot chown '%s'", get_path_buffer());
        }
        pop_path_buffer(save);
        return;
    } else if (flags.list_changed) {
        printf("chown: changed '%s' to %u:%u\n", get_path_buffer(), flags.uid, flags.gid);
    }

    if (!flags.recurse) {
        pop_path_buffer(save);
        return;
    }

    if (lstat(get_path_buffer(), &s) < 0) {
        if (!flags.quiet) {
            error_s("cannot stat '%s'", get_path_buffer());
        }
        pop_path_buffer(save);
        return;
    }

    if (!S_ISDIR(s.st_mode)) {
        pop_path_buffer(save);
        return;
    }

    d = opendir(get_path_buffer());
    if (d == NULL) {
        if (!flags.quiet) {
            error_s("cannot open dir '%s'", get_path_buffer());
        }
        pop_path_buffer(save);
        return;
    }

    while ((file = readdir(d)) != NULL) {
        if (is_dot_dir(file->d_name)) continue;
        chown_file(file->d_name);
    }
    
    closedir(d);
    pop_path_buffer(save);
}

static void parse_ownership(char* str) {
    char* user = str;
    char* group = NULL;
    char* end = NULL;
    unsigned long i;
    struct passwd* p = NULL;
    struct group* g = NULL; 

    for (i = 0; i < strlen(str); i++) {
        if (str[i] == ':') {
            str[i] = '\0';
            group = &str[i] + 1;
            break;
        }
    }

    flags.uid = strtol(user, &end, 10);
    if (end != user) goto group;

    if ((p = getpwnam(user)) == NULL) {
        error("invalid user '%s'", user);
    } else {
        flags.uid = p->pw_uid;
    }

group:

    if (group == NULL) {
        if (p == NULL) {
            flags.gid = flags.uid;
        } else {
            flags.gid = p->pw_gid;
        }
        return;
    }

    flags.gid = strtol(group, &end, 10);
    if (end != group) return;

    if ((g = getgrnam(group)) == NULL) {
        error("invalid group '%s'", group);
    } else {
        flags.gid = g->gr_gid;
    }
}

COMMAND(chown_cmd) {

    int start, i;
    
    flags.recurse = false;
    flags.list_changed = false;
    flags.verbose = false;
    flags.quiet = false;

    start = parse_args(argc, argv, help, short_arg, NULL);

    if (argc - start < 1) {
        if (!flags.quiet) {
            error("no onwership passed");
        } else {
            return EXIT_FAILURE;
        }
    }

    parse_ownership(argv[start]);

    if (argc - start < 1) {
        if (!flags.quiet) {
            error("no files passed");
        } else {
            return EXIT_FAILURE;
        }
    }

    for (i = start + 1; i < argc; i++) {
        chown_file(argv[i]);
    }

    return EXIT_SUCCESS;
}