#include "RSS.hpp"
#include <iomanip>
#include <iostream>
#include <ctime>
#include <memory>
#include <stdexcept>
#include <curl/curl.h>

RSS::RSS(std::string url) {
    URL = url;
    channelInfo = ChannelInfo(url);
    parse(request());
}

size_t WriteCallback(void* contents, size_t size, size_t nmemb, std::string* userp) {
    size_t totalSize = size * nmemb;
    userp->append((char*)contents, totalSize);
    return totalSize;
}

std::string RSS::request() {
    std::unique_ptr<CURL, decltype(&curl_easy_cleanup)> curl (
            curl_easy_init(), &curl_easy_cleanup);

    if (!curl) {
        throw std::runtime_error("Failed to initialize CURL");
    }

    std::string data;

    curl_easy_setopt(curl.get(), CURLOPT_URL, URL.c_str());
    curl_easy_setopt(curl.get(), CURLOPT_WRITEFUNCTION, WriteCallback);
    curl_easy_setopt(curl.get(), CURLOPT_WRITEDATA, &data);
    curl_easy_setopt(curl.get(), CURLOPT_FOLLOWLOCATION, 1L);

    auto res = curl_easy_perform(curl.get());
    if (res != CURLE_OK) {
        throw std::runtime_error(std::string("CURL request failed: ") + curl_easy_strerror(res));
    }

    curl_easy_cleanup(curl.get());
    return data;
}

void RSS::parse(std::string contents) {
    // std::cout << "starting tokenization..." << std::endl;
    try {
        auto leaf = XML_leaf(contents).GetChild("channel");
        if (leaf.Raw == "<>") 
            throw new std::runtime_error("The feed does not contain <channel> element");

        this->channelInfo.Title = leaf.GetChild("title").Value;

        auto items = leaf.GetChildren("item");
        for (auto item : items)
            Entries.push_back(RSS_Entry(item));
    } catch (const char *err) {
        std::cout << "Failed to parse feed '" << URL << "' :" << err << std::endl;
        return;
    }
}

RSS_Entry::RSS_Entry(XML_leaf node) {
    Title = node.GetChild("title").GetValue();
    URL = node.GetChild("link").GetValue();
    Contents = node.GetChild("description").GetValue();

    // auto pubDateField = node.GetChild("pubDate");
    // if (pubDateField.Value.length() == 0) return;
    // std::cout << "pub date" << pubDateField.Value << std::endl;
    // strptime(pubDateField.Value.c_str(), "%Y-%m-%dT%H:%M:%SZ", &pubDate);
}

void RSS_Entry::print() {
    std::cout 
        << "==============================\n"
        << Title << '\n'
        // << std::put_time(&pubDate, "%Y-%m-%d %H:%M:%S") << '\n'
        << Contents << '\n'
        << URL<< '\n';
}