path: root/src/SimpleHandlers.cpp

#include "SimpleHandlers.hpp"

#include "Response.hpp"

#include <array>
#include <cctype>
#include <memory>
#include <string>
#include <iomanip>
#include <sstream>
#include <iostream>
#include <stdexcept>

using namespace Response;

Handler::json Handler::klingerHandler(std::string const &arguments, std::string const &session, void *payload) {
    (void) payload;
    return simple_response("Bonjour!");
}

Handler::json Handler::wikiHandler(std::string const &arguments, std::string const &session, void *payload) {
    (void) payload;

    std::vector<json> linkAnnotations;
    linkAnnotations.emplace_back(create_annotation(Reply::AnnotationType::link, "Wikipedia"));
    linkAnnotations.emplace_back(create_annotation(Reply::AnnotationType::underline));

    std::vector<json> reply_vec;
    reply_vec.emplace_back(create_text("Visit "));
    reply_vec.emplace_back(create_text("https://eo.wikipedia.org/", std::move(linkAnnotations)));
    reply_vec.emplace_back(create_text(" today!"));

    return create_response(std::move(reply_vec), session, true);
}

Handler::json Handler::helpHandler(std::string const &arguments, std::string const &session, void *payload) {
    auto commands = (std::vector<CommandHandler> *) payload;

    std::vector<json> reply_vec;
    reply_vec.emplace_back(create_text(
            "Reading from the gospel according to saint N,\n"
            "And you shall feast upon the fruits and vegetables as I do in the offering for they will make you strong.\n"
            "\n"
            "Dear my fellow users, these are my official commands, which are offered to my believers.\n"
            "\n"));

    for (auto const &itor : *commands) {
        std::vector<json> commandAnnotations;

        commandAnnotations.emplace_back(
                create_annotation(Reply::AnnotationType::command, std::move(itor.get_description())));

        reply_vec.emplace_back(create_text("- "));
        reply_vec.emplace_back(create_text(itor.command, std::move(commandAnnotations)));
    }

    reply_vec.emplace_back(create_text(
            "\n"
            "Thanks for using me. Takk skal du ha.\n"
            "Bussy\n"
            "N"));

    return create_response(std::move(reply_vec), session, true);
}

Handler::json Handler::stopHandler(std::string const &arguments, std::string const &session, void *payload) {
    auto app = (crow::SimpleApp *) payload;

    auto args = tokenizeArguments(arguments);

    if (args.empty()) {
        return simple_response("Needs PIN!", session, true);
    }

    int admin_pin;
    std::ifstream infile("/root/.n_admin_pin");

    if (!(infile >> admin_pin) || admin_pin != std::stoi(args.at(0))) {
        return simple_response("No PIN registered on server, admin commands unavailable", session, true);
    }

    app->stop();

    std::vector<json> annotations;
    annotations.emplace_back(create_annotation(Reply::AnnotationType::bold));

    std::vector<json> reply_vec;
    reply_vec.emplace_back(create_text("stopped", std::move(annotations)));

    return create_response(std::move(reply_vec), session, true);
}

json Handler::sayHandler(const std::string &arguments, const std::string &session, void *payload) {
    (void) payload;
    return simple_response(arguments, session, true);
}

std::string url_encode(std::string const &value) {
    std::ostringstream escaped;
    escaped.fill('0');
    escaped << std::hex;

    for (char c : value) {
        // Keep alphanumeric and other accepted characters intact
        if (isalnum(c) || c == '-' || c == '_' || c == '.' || c == '~') {
            escaped << c;
            continue;
        }

        // Any other characters are percent-encoded
        escaped << std::uppercase;
        escaped << '%' << std::setw(2) << int((unsigned char) c);
        escaped << std::nouppercase;
    }

    return escaped.str();
}

std::string exec(const char* cmd) {
    std::array<char, 128> buffer{};
    std::string result;
    std::unique_ptr<FILE, decltype(&pclose)> pipe(popen(cmd, "r"), pclose);
    if (!pipe) {
        throw std::runtime_error("popen() failed!");
    }
    while (fgets(buffer.data(), buffer.size(), pipe.get()) != nullptr) {
        result += buffer.data();
    }
    return result;
}

static std::string const base64_chars =
        "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
        "abcdefghijklmnopqrstuvwxyz"
        "0123456789+/";

std::string base64_encode(unsigned char const *input, unsigned int const len) {
    std::string ret;
    size_t i = 0;
    unsigned char bytes[3];
    unsigned char sextets[4];

    while (i <= (len - 3)) {
        bytes[0] = *(input++);
        bytes[1] = *(input++);
        bytes[2] = *(input++);

        sextets[0] = (bytes[0] & 0xfc) >> 2;    // Cuts last two bits off of first byte
        sextets[1] = ((bytes[0] & 0x03) << 4) + ((bytes[1] & 0xf0)
                >> 4);   // Takes last two bits from first byte and adds it to first 4 bits of 2nd byte
        sextets[2] = ((bytes[1] & 0x0f) << 2) + ((bytes[2] & 0xc0)
                >> 6);   // Takes last 4 bits of 2nd byte and adds it to first 2 bits of third byte
        sextets[3] = bytes[2] & 0x3f;   // takes last 6 bits of third byte

        for (unsigned char sextet : sextets) {
            ret += base64_chars[sextet];
        }

        i += 3; // increases to go to third byte
    }

    if (i != len) {
        size_t k = 0;
        size_t j = len - i; // Find index of last byte
        while (k < j) {     // Sets first bytes
            bytes[k] = *(input++);
            ++k;
        }

        while (j < 3) {     // Set last bytes to 0x00
            bytes[j] = '\0';
            ++j;
        }

        sextets[0] = (bytes[0] & 0xfc) >> 2;    // Cuts last two bits off of first byte
        sextets[1] = ((bytes[0] & 0x03) << 4) + ((bytes[1] & 0xf0)
                >> 4);   // Takes last two bits from first byte and adds it to first 4 bits of 2nd byte
        sextets[2] = ((bytes[1] & 0x0f) << 2) + ((bytes[2] & 0xc0)
                >> 6);   // Takes last 4 bits of 2nd byte and adds it to first 2 bits of third byte
        // No last one is needed, because if there were 4, then (i == len) == true

        for (j = 0; j < (len - i) + 1; ++j) {   // Gets sextets that include data
            ret += base64_chars[sextets[j]];    // Appends them to string
        }

        while ((j++) < 4)   // Appends remaining ='s
            ret += '=';

    }

    return ret;
}

std::string base64_encode_file(std::string const &path) {
    std::vector<char> temp;

    std::ifstream infile;
    infile.open(path, std::ios::binary);     // Open file in binary mode
    if (infile.is_open()) {
        while (!infile.eof()) {
            char c = (char) infile.get();
            temp.push_back(c);
        }
        infile.close();
    } else {
        std::cerr << path << " Error: " << strerror(errno) << std::endl;
        return "File could not be opened";
    }
    std::string ret(temp.begin(), temp.end() - 1);
    ret = base64_encode((unsigned const char *) ret.c_str(), ret.size());

    return ret;
}

json Handler::latexRenderHandler(std::string const &arguments, std::string const &session, void *payload) {
    (void) payload;

    std::string file = exec("mktemp");

    std::cout << ("file " + file) << exec(("file " + file).c_str()) << std::endl;

    std::string result = exec(("curl -s 'https://latex.codecogs.com/png.latex?" + url_encode(arguments) + "' "
            "-H 'User-Agent: Mozilla/5.0 (Windows NT 10.0; rv:78.0) Gecko/20100101 Firefox/78.0' "
            "-H 'Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8' "
            "-H 'Accept-Language: en-US,en;q=0.5' --compressed -H 'DNT: 1' -H 'Connection: keep-alive' "
            "-H 'Upgrade-Insecure-Requests: 1' --output " + file).c_str());

    std::cout << ("file " + file) << exec(("file " + file).c_str()) << std::endl;

    if (!result.empty())
        return simple_response("Error: " + result + "\n"
                                    "Please report to an admin", session, false);

    std::vector<json> reply_vec;
    std::vector<json> annotations;

    annotations.emplace_back(
            create_annotation(Reply::AnnotationType::attachment, "latex.png;png;" + base64_encode_file(file)));

    reply_vec.emplace_back(create_text("", std::move(annotations)));

    return create_response(std::move(reply_vec), session, true);
}