module ircd.message;

import std.string;
import std.functional;
import std.array;
import std.algorithm;
import std.conv;

struct Message
{
    string prefix;
    string command;
    string[] parameters;
    bool prefixedParameter;

    //NOTE: The RFCs don't state what this is exactly, but common implementations use the byte count of the message parameters
    ulong bytes;

    static Message fromString(string line)
    {
        string prefix = null;
        if (line.startsWith(':'))
        {
            line = line[1 .. $];
            prefix = line[0 .. line.indexOf(' ')];
            line = line[prefix.length + 1 .. $];
        }

        //stop early when no space character can be found (message without parameters)
        if (!line.canFind(' '))
        {
            return Message(prefix, line, [], false);
        }

        auto command = line[0 .. line.indexOf(' ')];
        line = line[command.length + 1 .. $];
        auto bytes = line.length;
        string[] params = [];
        bool prefixedParam;
        while (true)
        {
            if (line.startsWith(':'))
            {
                params ~= line[1 .. $];
                prefixedParam = true;
                break;
            }
            else if (line.canFind(' '))
            {
                auto param = line[0 .. line.indexOf(' ')];
                line = line[param.length + 1 .. $];
                params ~= param;
            }
            else
            {
                params ~= line;
                break;
            }
        }

        return Message(prefix, command, params, prefixedParam, bytes);
    }

    string toString()
    {
        auto message = "";
        if (prefix != null)
        {
            message = ":" ~ prefix ~ " ";
        }

        if (parameters.length == 0)
        {
            return message ~ command;
        }

        message ~= command ~ " ";
        if (parameters.length > 1)
        {
            message ~= parameters[0 .. $ - 1].join(' ') ~ " ";
        }

        if (parameters[$ - 1].canFind(' ') || prefixedParameter)
        {
            message ~= ":";
        }
        message ~= parameters[$ - 1];

        return message;
    }
}