#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 ARRLEN(a)   (sizeof (a) / sizeof *(a))
#define BUF_SIZE    256 * ARRLEN(WALLET)

// {"bitcoin":{"usd":69420.69}}
static int get_next_symbol(char *buf, float *price)
{
    static const char output[] = "\"%*[a-z]\":{\"" VS "\":%f}";
    char *tmp = strtok(buf, ",");

    if (!tmp) {
        return 1;
    }
    return !sscanf(tmp, output, price);
}

static size_t write_callback(char *response, size_t s, size_t n, void *buf)
{
    return snprintf(buf, MIN(s * n, BUF_SIZE), response);
}

static char *build_url(void)
{
    const char base[] = "https://api.coingecko.com/api/v3/simple/price?ids=%s&vs_currencies=" VS;
    size_t ids_size = 0;
    char *url;
    char ids[BUF_SIZE] = {0};

    for (size_t i = 0; WALLET[i].id; i++) {
        strcpy(ids + ids_size, WALLET[i].id);
        ids_size += strlen(WALLET[i].id);
        ids[ids_size++] = ',';
    }
    ids[ids_size - 1] = '\0';
    url = malloc(sizeof base + ids_size * (sizeof *url));
    if (!url) {
        return NULL;
    }
    sprintf(url, base, ids);
    return url;
}

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

    if (!url || !curl) {
        free(url);
        curl_easy_cleanup(curl);
        return 1;
    }
    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);
    curl_easy_cleanup(curl);
    free(url);
    return 0;
}

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

    if (err) {
        error(1, errno, "cannot init curl");
    }
    err = get_next_symbol(response + 1, &price);
    for (size_t i = 0; !err && WALLET[i].id; i++) {
        current = price * WALLET[i].value;
        printf(FMT " ", WALLET[i].fmt, current);
        sum += current;
        err = get_next_symbol(NULL, &price);
    }
    printf(FMT, "TOT", sum);
    return 0;
}