#include "json.h"

#include <math.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "util.h"

static void put(Json *j, const char *s, size_t n)
{
    if (j->len + n + 1 > j->cap) {
        size_t c = j->cap ? j->cap : 4096;
        while (c < j->len + n + 1)
            c *= 2;
        j->buf = xrealloc(j->buf, c, 1);
        j->cap = c;
    }
    memcpy(j->buf + j->len, s, n);
    j->len += n;
    j->buf[j->len] = 0;
}

static void puts_(Json *j, const char *s) { put(j, s, strlen(s)); }

/* virgule avant un élément si ce n'est pas le premier du conteneur courant */
static void sep(Json *j)
{
    if (j->depth > 0 && j->need_comma[j->depth])
        put(j, ",", 1);
    if (j->depth > 0)
        j->need_comma[j->depth] = 1;
}

void js_init(Json *j) { memset(j, 0, sizeof *j); }
void js_free(Json *j) { free(j->buf); memset(j, 0, sizeof *j); }

static void open_(Json *j, const char *c)
{
    sep(j);
    puts_(j, c);
    if (j->depth >= 63)
        die("JSON trop profond");
    j->depth++;
    j->need_comma[j->depth] = 0;
}

void js_obj(Json *j) { open_(j, "{"); }
void js_arr(Json *j) { open_(j, "["); }
void js_end_obj(Json *j) { j->depth--; puts_(j, "}"); }
void js_end_arr(Json *j) { j->depth--; puts_(j, "]"); }

static void quoted(Json *j, const char *s)
{
    put(j, "\"", 1);
    for (const unsigned char *p = (const unsigned char *)s; *p; p++) {
        char e[8];
        if (*p == '"' || *p == '\\') {
            e[0] = '\\';
            e[1] = (char)*p;
            put(j, e, 2);
        } else if (*p < 0x20) {
            snprintf(e, sizeof e, "\\u%04x", *p);
            puts_(j, e);
        } else {
            put(j, (const char *)p, 1);
        }
    }
    put(j, "\"", 1);
}

void js_key(Json *j, const char *k)
{
    sep(j);
    quoted(j, k);
    put(j, ":", 1);
    j->need_comma[j->depth] = 0;   /* la valeur qui suit ne prend pas de virgule */
}

void js_str(Json *j, const char *s) { sep(j); quoted(j, s); }

void js_num(Json *j, double v, int decimals)
{
    sep(j);
    if (!isfinite(v)) {
        puts_(j, "null");
        return;
    }
    char b[64];
    snprintf(b, sizeof b, "%.*f", decimals, v);
    /* pas de zéros inutiles : 12.50 → 12.5, 3.0 → 3 */
    if (decimals > 0) {
        char *e = b + strlen(b) - 1;
        while (*e == '0')
            *e-- = 0;
        if (*e == '.')
            *e = 0;
    }
    if (strcmp(b, "-0") == 0)
        strcpy(b, "0");
    puts_(j, b);
}

void js_int(Json *j, long long v)
{
    sep(j);
    char b[32];
    snprintf(b, sizeof b, "%lld", v);
    puts_(j, b);
}

void js_null(Json *j) { sep(j); puts_(j, "null"); }

void js_save(Json *j, const char *path) { write_file_atomic(path, j->buf ? j->buf : "", j->len); }