#define _ALL_SOURCE
#include "atomic.h"
#include "libc.h"
#include "locale_impl.h"
#include <locale.h>
#include <stdlib.h>
#include <string.h>
#include <threads.h>

static char buf[LC_ALL * (LOCALE_NAME_MAX + 1)];

static char* setlocale_one_unlocked(int cat, const char* name) {
    const struct __locale_map* lm;

    if (name)
        libc.global_locale.cat[cat] = lm = __get_locale(cat, name);
    else
        lm = libc.global_locale.cat[cat];

    return (char*)(lm ? lm->name : "C");
}

char* __strchrnul(const char*, int);

char* setlocale(int cat, const char* name) {
    static mtx_t lock = MTX_INIT;

    if ((unsigned)cat > LC_ALL)
        return 0;

    mtx_lock(&lock);

    /* For LC_ALL, setlocale is required to return a string which
     * encodes the current setting for all categories. The format of
     * this string is unspecified, and only the following code, which
     * performs both the serialization and deserialization, depends
     * on the format, so it can easily be changed if needed. */
    if (cat == LC_ALL) {
        int i;
        if (name) {
            char part[LOCALE_NAME_MAX + 1] = "C.UTF-8";
            const char* p = name;
            for (i = 0; i < LC_ALL; i++) {
                const char* z = __strchrnul(p, ';');
                if (z - p <= LOCALE_NAME_MAX) {
                    memcpy(part, p, z - p);
                    part[z - p] = 0;
                    if (*z)
                        p = z + 1;
                }
                setlocale_one_unlocked(i, part);
            }
        }
        char* s = buf;
        for (i = 0; i < LC_ALL; i++) {
            const struct __locale_map* lm = libc.global_locale.cat[i];
            const char* part = lm ? lm->name : "C";
            size_t l = strlen(part);
            memcpy(s, part, l);
            s[l] = ';';
            s += l + 1;
        }
        *--s = 0;
        mtx_unlock(&lock);
        return buf;
    }

    char* ret = setlocale_one_unlocked(cat, name);

    mtx_unlock(&lock);

    return ret;
}