#include "rendering.h"
#include <jsmn.h>
#include <file_parsing.h>
#include <utils.h>

int not_null(const entry_struct *entry, const jsmntok_t *t){
    return strncmp("null", entry->json + t->start, min(4, t->end - t->start)) != 0;
}

inline void append_token(VALUE string, const entry_struct *entry, const jsmntok_t *t){
    rb_str_cat(string, entry->json + t->start, t->end - t->start); //TODO: add token sanity checks
}

void append_entry(VALUE string, const entry_struct *entry){
    jsmn_parser parser;
    jsmn_init(&parser);

    jsmntok_t t[128]; //TODO: document how many labels we can process
    int r = jsmn_parse(&parser, entry->json, entry->json_size, t, sizeof(t)/sizeof(t[0]));

    if (r < 3) {
        return; //TODO: better handle this case
    }

    //TODO: check (r - 4) % 2 == 0
    int label_cnt = (r-5)/2;

    append_token(string, entry, &t[2]);
    if (label_cnt > 0){
        rb_str_cat(string, "{", 1);

        for(int i = 0; i < label_cnt; i++){
            int key = 4 + i;
            int val = 5 + label_cnt + i;
            //TODO: add type checks
            append_token(string, entry, &t[key]);
            rb_str_cat(string, "=", 1);

            rb_str_cat(string, "\"", 1);
            if (not_null(entry, &t[val])){
                append_token(string, entry, &t[val]);
            }
            rb_str_cat(string, "\"", 1);

            if (i < label_cnt - 1){
                rb_str_cat(string, ",", 1);
            }
        }

        if (is_pid_significant(entry)){
            rb_str_cat(string, ",pid=\"", 6);
            rb_str_append(string, entry->pid);
            rb_str_cat(string, "\"", 1);
        }

        rb_str_cat(string, "}", 1);
    }

    char value[255];

    //TODO: fix value representation %g doesn't math what Go expects
    int written = snprintf(value, sizeof(value), " %g\n", entry->value);
    rb_str_cat(string, value, written);
}

void append_entry_head(VALUE string, const entry_struct *entry){
    static const char help_beg[] = "# HELP ";
    static const char help_fin[] = " Multiprocess metric\n";

    rb_str_cat(string, help_beg, sizeof(help_beg) - 1);
    rb_str_cat(string, entry->name, entry->name_len);
    rb_str_cat(string, help_fin, sizeof(help_fin) - 1);

    static const char type_beg[] = "# TYPE ";

    rb_str_cat(string, type_beg, sizeof(type_beg) - 1);
    rb_str_cat(string, entry->name, entry->name_len);
    rb_str_cat(string, " ", 1);
    rb_str_cat2(string, rb_id2name(entry->type));
    rb_str_cat(string, "\n", 1);
}

VALUE entries_to_string(entry_struct **sorted_entries, size_t entries_count){
    VALUE rv = rb_str_new("", 0);

    entry_struct *previous = NULL;

    for(size_t i = 0; i < entries_count; i ++){
        entry_struct *entry = sorted_entries[i];
        if (!previous || previous->name_len != entry->name_len || strncmp(entry->name, previous->name, entry->name_len) != 0) {
            previous = entry;
            append_entry_head(rv, entry);
        }

        append_entry(rv, entry);
    }

    return rv;
}