#include <curl/curl.h>
#include <errno.h>
#include <error.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/param.h>
#include "config.h"

#define BUF_SIZE 1024

// [{"symbol":"BTCUSDT","price":"69420.69420"}]
static int get_next_symbol(char* buf, float* price)
{
    static const char output[] = "\"symbol\":\"%*[^\"]\",\"price\":\"%f\"";
    char* tmp = strtok(buf, "{");

    if (!tmp) {
        return 1;
    }
    tmp = strtok(0, "}");
    if (!tmp) {
        return 1;
    }
    return !sscanf(tmp, output, price);
}

static size_t write_callback(char *response, size_t s, size_t n, void *buf)
{
    size_t size = s * n;

    return snprintf(buf, MIN(size, BUF_SIZE), response);
}

static char* build_url(void)
{
    static const char base[] =
        "https://api.binance.com/api/v3/ticker/price?symbols=[";
    size_t s = sizeof base;
    char* url;

    for (size_t i = 0; WALLET[i].to; i++) {
        s += strlen(WALLET[i].from) + strlen(WALLET[i].to) + 3; // ["SYMBOL",]
    }
    url = malloc(s);
    if (!url) {
        return 0;
    }
    strcpy(url, base);
    for (size_t i = 0; WALLET[i].to; i++) {
        strcat(strcat(strcat(strcat(
            url,
            "\""),
            WALLET[i].from),
            WALLET[i].to),
            "\","
        );
    }
    url[strlen(url) - 1] = ']';
    return url;
}

static CURL* init_curl(char* response)
{
    char* url = build_url();
    CURL* curl = curl_easy_init();


    if (!url || !curl) {
        free(url);
        curl_easy_cleanup(curl);
        return 0;
    }
    curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, write_callback);
    curl_easy_setopt(curl, CURLOPT_WRITEDATA, response);
    curl_easy_setopt(curl, CURLOPT_URL, url);
    curl_easy_perform(curl);
    free(url);
    return curl;
}

int main(void)
{
    char response[BUF_SIZE];
    CURL* curl = init_curl(response);
    int err;
    float price, current;
    float sum = 0;

    if (!curl) {
        error(1, errno, "cannot init curl");
    }
    err = get_next_symbol(response, &price);
    for (size_t i = 0; !err && WALLET[i].to; i++) {
        current = price * WALLET[i].value;
        printf("%s=%.2f" CUR " ", WALLET[i].from, current);
        sum += current;
        err = get_next_symbol(0, &price);
    }
    printf("TOT=%.2f" CUR "\n", sum);
    curl_easy_cleanup(curl);
    return 0;
}