#include <protocol/protocol.hpp>
#include <mail.hpp>

#include <functional>
#include <string>
#include <vector>
#include <map>
#include <unordered_map>
#include <iostream>
#include <cstdio>

const bool debug = false;

using namespace std;

mail::session_map_t sessions;

void on_ready(protocol::protocol_t& protocol, protocol::message_t message) {
    protocol.send({"register", "filter", "smtp-in", "data"});
    protocol.send({"register", "filter", "smtp-in", "data-line"});
    protocol.send({"register", "filter", "smtp-in", "commit"});
    protocol.send({"register", "ready"});
    cerr << "Ready to accept messages from SMTPD" << endl;
}

void on_data(protocol::protocol_t& protocol, protocol::message_t message) {
    cerr << "Accepting new message from SMTPD" << endl;
    auto session_key = protocol::session_key_from(message);
    auto session_token = protocol::session_token_from(message);
    sessions.emplace(session_key, mail::session_t{});
    protocol.proceed(session_key, session_token);
}

void on_data_line(protocol::protocol_t& protocol, protocol::message_t message) {
    debug && cerr << "Received data line from SMTPD" << endl;

    auto tokens = protocol::token::decompose(message.input);
    auto session_key = protocol::session_key_from(tokens);
    auto session_token = protocol::session_token_from(tokens);
    try {
        auto& session = sessions.at(session_key);
        auto& data_line = tokens.at(7);

        if(!session.has_header) {
            if(data_line == "") {
                session.has_header = true;
                return;
            }

            if(data_line.substr(0, 6) == "X-Spam" ||
               data_line.substr(0, 10) == "X-Bogosity") {
                cerr << "Found and stripped incoming spam filter header:" << endl;
                cerr << data_line << endl;
                return;
            }

            if(data_line.substr(0, 5) == "From:" ||
               data_line.substr(0, 8) == "Subject:") {
                cerr << data_line << endl;
            }

            session.message.header.push_back(data_line);
            return;
        }

        if(data_line == ".") {
            FILE* f = popen("bogofilter -vu 1>&2", "w");
            for(string& line : session.message.header) {
                fprintf(f, "%s\n", line.c_str());
            }
            fwrite("\n", 1, 1, f);
            for(string& line : session.message.body) {
                fprintf(f, "%s\n", line.c_str());
            }
            int status = pclose(f);
            session.status = WEXITSTATUS(status);

            if(session.status == 0) {
                session.message.header.push_back("X-Spam: Yes");
            }

            protocol.submit_message(session_key, session_token, session.message.header, session.message.body);

            return;
        }

        if(data_line == "..") {
            session.message.body.push_back(".");
            return;
        }

        session.message.body.push_back(data_line);
    } catch(out_of_range& e) {
        cerr << "Unknown session key from SMTPD" << endl;
        protocol.fail(session_key, session_token);
    }
}

void on_commit(protocol::protocol_t& protocol, protocol::message_t message) {
    debug && cerr << "Commit request from SMTPD" << endl;
    auto session_key = protocol::session_key_from(message);
    auto session_token = protocol::session_token_from(message);
    try {
        auto& session = sessions.at(session_key);
        protocol.proceed(session_key, session_token);
    } catch(out_of_range& e) {
        cerr << "Unknown session key from SMTPD" << endl;
        protocol.fail(session_key, session_token);
    }

    sessions.erase(session_key);
}

int main(int argc, char** argv) {
    protocol::ios_protocol_t protocol(cin, cout);
    protocol::handler_map_t handlers;

    handlers.emplace("config|ready", on_ready);
    handlers.emplace("filter|*|*|smtp-in|data", on_data);
    handlers.emplace("filter|*|*|smtp-in|data-line", on_data_line);
    handlers.emplace("filter|*|*|smtp-in|commit", on_commit);

    if(debug) {
        cerr << "Handler patterns:" << endl;
        for(auto&& [first, second] : handlers) {
            cerr << "\t" << first << endl;
        }
    }

    cerr << "Bogofilter-SMTPD started" << endl;

    protocol.set_handlers(handlers);
    protocol.run();

    return 0;
}