learncrypto/source/app.d

import std.getopt;
import std.string : format;
import std.stdio: stderr, writeln;

import cipher : Cipher;
import actions;

int main(string[] args)
{
    bool[string] actions = [ "genKey"  : false,
                             "encrypt" : false,
                             "decrypt" : false ];

    Cipher cipher = Cipher.chacha20;
    string keyFileName = "symkey.asc";
    bool armor;

    GetoptResult result;
    try
    {
        result = getopt(
            args,
            std.getopt.config.bundling,
            "gen-key|g", "Generate a new 256 bit key.", &actions["genKey"],
            "encrypt|e", "Encrypt a message.", &actions["encrypt"],
            "decrypt|d", "Decrypt a message.", &actions["decrypt"],
            "cipher|c", "The cipher to use (default: %s).".format(cipher), &cipher,
            "key|k", "The file which contains the key (default: %s).".format(keyFileName), &keyFileName,
            "armor|a", "use ascii-armored I/O.", &armor);
    }
    catch(Exception e)
    {
        stderr.writeln(e.msg);
        return 1;
    }

    size_t numberOfActions;
    foreach(value; actions.values)
        numberOfActions += value;

    if(numberOfActions == 1)
    {
        try
        {
            if(actions["genKey"])
            {
                generateKey(armor);
            }
            else if(actions["encrypt"])
            {
                encrypt(keyFileName, cipher, armor);
            }
            else if(actions["decrypt"])
            {
                decrypt(keyFileName, cipher, armor);
            }
        }
        catch(Exception e)
        {
            stderr.writeln(e.msg);
            return 1;
        }
    }
    else
    {
        result.helpWanted = true;
    }

    if(result.helpWanted)
        printHelp(result.options);

    return 0;
}

void printHelp(Option[] options)
{
    defaultGetoptPrinter("Usage: ./learncrypt [options]\n\nCommon options:",
        options[$-1..$]);
    defaultGetoptPrinter("\nGlobal options:",
        options[$-2..$-1]);
    defaultGetoptPrinter("\nActions:",
        options[0..3]);
    defaultGetoptPrinter("\nAction options:",
        options[3..5]);
}