#include "chatmessage.hpp"

#include "ircexception.hpp"

#include <QException>

std::unordered_map<QString, QString> ChatMessage::parseTags(QString tagStr)
{
    enum
    {
        FindingKey,
        FindingValue,
        ValueEscaped,
    } state;
    QString s = tagStr;
    if (s.startsWith('@'))
        s = s.mid(1);
    std::unordered_map<QString, QString> tags;
    QString key = "";
    QString value = "";
    state = FindingKey;
    for(const auto c : std::as_const(s))
    {
        switch (state)
        {
        case FindingKey:
            if (c == '=')
                state = FindingValue;
            else if (c == ';')
            {
                state = FindingKey;
                tags[key] = "";
                key = "";
            }
            else if (c == ' ')
            {
                tags[key] = "";
                goto EndParse;
            }
            else
                key += c;
            break;
        case FindingValue:
            if (c == '\\')
            {
                state = ValueEscaped;
            }
            else if (c == ';')
            {
                tags[key] = value;
                key = value = "";
                state = FindingKey;
            }
            else if (c == ' ')
            {
                tags[key] = value;
                goto EndParse;
            }
            else if (c == '\r' || c == '\n' || c == '\0')
                throw IrcParseException("Invalid character in tag string", s);
            else
            {
                value += c;
            }
            break;
        case ValueEscaped:
            if (c == ':')
            {
                value += ';';
                state = FindingValue;
            }
            else if (c == 's')
            {
                value += ' ';
                state = FindingValue;
            }
            else if (c == '\\')
            {
                value += '\\';
                state = FindingValue;
            }
            else if (c == 'r')
            {
                value += '\r';
                state = FindingValue;
            }
            else if (c == 'n')
            {
                value += '\n';
                state = FindingValue;
            }
            else if (c == ';')
            {
                tags[key] = value;
                key = value = "";
                state = FindingKey;
            }
            //spaces should already be stripped, but handle this as end of tags just in case
            else if (c == ' ')
            {
                tags[key] = value;
                key = value = "";
                goto EndParse;
            }
            else if (c == '\r' || c == '\n' || c == '\0')
                throw IrcParseException("Invalid character in tag string", s);
            else
            {
                value += c;
                state = FindingValue;
            }
            break;
        default:
            throw new QException();
        }
    }
    //this is reached after processing the last character without hitting a space
    tags[key] = value;
EndParse:
    return tags;
}

ChatMessage* ChatMessage::Parse(QString message)
{
    QString rawMessage = message;
    std::unordered_map<QString, QString> tags;
    QString sender = "";
    QList<QString> parameters;
    QString prefix = "";

    QString s = message;
    if (s.startsWith('@'))
    {
        s = s.mid(1);
        //first ' ' acts as the delimeter
        auto split = s.split(' ');
        auto tagString = split.takeFirst();
        s = split.join(' ');
        tags = parseTags(tagString);
    }
    //message has source
    if (s.startsWith(':'))
    {
        s = s.mid(1);
        auto split = s.split(' ');
        prefix = split.takeFirst();
        s = split.join(' ');
        while (s[0] == ' ')
            s = s.mid(1);
    }
    auto spl_command = s.split(' ');
    IrcMessageType type = IrcMessageType::parse(spl_command.takeFirst());
    //message has parameters
    if (!spl_command.isEmpty())
    {
        s = spl_command.join(' ');
        //message has single parameter marked as the final parameter
        //this needs to be handled specially because the leading ' '
        //is stripped
        if (s.startsWith(':'))
        {
            parameters.append(s.mid(1));
        }
        else
        {
            auto spl_final = s.split(" :");
            auto spl_initial = spl_final.takeFirst().split(' ', Qt::SkipEmptyParts);
            for (auto& part : spl_initial)
            {
                part = part.trimmed();
            }
            parameters.append(spl_initial);
            if (!spl_final.isEmpty())
                parameters.append(spl_final.join(" :"));
        }
    }
    return new ChatMessage(rawMessage, tags, sender, parameters, prefix, type);
}



ChatMessage::ChatMessage(QString rawMessage, std::unordered_map<QString, QString> tags,
                         QString sender, QList<QString> parameters, QString prefix,
                         IrcMessageType type)
    : _rawMessage(rawMessage), _tags(tags), _sender(sender), _parameters(parameters),
    _prefix(prefix), _type(type)
{

}

QString ChatMessage::rawMessage() const
{
    return _rawMessage;
}

const std::unordered_map<QString, QString>* ChatMessage::tags() const
{
    return &_tags;
}

QString ChatMessage::sender() const
{
    return _sender;
}

const QList<QString>* ChatMessage::parameters() const
{
    return &_parameters;
}

QString ChatMessage::prefix() const
{
    return _prefix;
}

IrcMessageType ChatMessage::type() const
{
    return _type;
}



PrivmsgView::PrivmsgView(const ChatMessage* msg)
    : parent(msg)
{
    if (parent->type() != Expected)
        throw IrcIncorrectTypeException(Expected, parent->type());
}

QString PrivmsgView::message() const
{
    return parent->parameters()->last();
}

QString PrivmsgView::user() const
{
    static constexpr const char* KEY = "display-name";
    if (parent->tags()->contains(KEY))
        return parent->tags()->at(KEY);
    throw IrcTagNotFoundException(KEY);
}

PingView::PingView(const ChatMessage* msg)
    : parent(msg)
{
    if (parent->type() != Expected)
        throw IrcIncorrectTypeException(Expected, parent->type());
}

QString PingView::toPong() const
{
    return parent->rawMessage().replace("PING", "PONG");
}