#include <curl/curl.h>
#include <nlohmann/json.hpp>

#include <algorithm>
#include <iomanip>
#include <iostream>
#include <string>
#include <utility>
#include <vector>

// libcurl hands the body over in pieces: append each one to a string
static size_t append(char* data, size_t size, size_t n, void* body) {
    static_cast<std::string*>(body)->append(data, size * n);
    return size * n;
}

int main() {
    // Read both funds' files; each has the date of its own issuer's file
    std::vector<std::pair<std::string, nlohmann::json>> funds;
    for (std::string ticker : {"voo", "qqq"}) {
        std::string url = "https://tickerinside.com/api/v1/fund/" + ticker
                          + ".json";
        std::string body;
        CURL* curl = curl_easy_init();
        curl_easy_setopt(curl, CURLOPT_URL, url.c_str());
        curl_easy_setopt(curl, CURLOPT_USERAGENT,
                         "MyProject/1.0 (+https://example.com)");
        curl_easy_setopt(curl, CURLOPT_FAILONERROR, 1L);
        curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, append);
        curl_easy_setopt(curl, CURLOPT_WRITEDATA, &body);
        CURLcode rc = curl_easy_perform(curl);
        curl_easy_cleanup(curl);
        if (rc != CURLE_OK) {
            std::cerr << curl_easy_strerror(rc) << "\n";
            return 1;
        }
        auto fund = nlohmann::json::parse(body);
        std::cout << fund["ticker"].get<std::string>() << " holdings_as_of "
                  << fund["holdings_as_of"].get<std::string>() << "\n";
        funds.emplace_back(ticker, fund);
    }

    // Overlap by weight, as the site computes it: for every ticker both
    // funds hold, add the smaller of its two weights
    auto& a = funds[0].second["holdings"];
    auto& b = funds[1].second["holdings"];
    double overlap = 0;
    int shared = 0;
    for (auto& [t, w] : a.items()) {
        if (b.contains(t)) {
            overlap += std::min(w.get<double>(), b[t].get<double>());
            ++shared;
        }
    }
    std::cout << "overlap by weight " << std::fixed << std::setprecision(1)
              << overlap << "%, " << shared << " companies in both\n";

    // The lines to print under the figure, one per fund file
    for (auto& [ticker, fund] : funds) {
        std::cout << fund["cite_as"].get<std::string>() << "\n";
    }
}