rootslab/syllabus

/*
 * Σ Syllabus, a collection of helpers mix-ins to encode Redis
 * commands and to decode Redis replies builded upon Sermone.
 *
 * Copyright(c) 2013-present Guglielmo Ferri <44gatti@gmail.com>
 * MIT Licensed
 */

exports.Syllabus = function ( develop ) {
    var Bolgia = require( 'bolgia' )
        , Hoar = require( 'hoar' )
        , lte = Hoar.lte
        , doString = Bolgia.doString
        , update = Bolgia.update
        , count = Bolgia.count
        , ooo = Bolgia.circles
        , okeys = Object.keys
        // load Redis commands and infos mix-ins
        , syllabus = update( {}, require( './commands/' ) )
        , types = syllabus.types
        , infos = develop ? update( {}, require( './infos/' ) ) : {}
        , lua = update( {}, require( './lua/' ) )
        , formatters = update( {}, require( './formatters/' ) )
        // Redis URL
        , url_redis_cmd = 'http://redis.io/commands'
        // build commands info objects, scanning mix-ins
        , info = function ( cname ) {
            var carr = cname ? cname.toLowerCase().split( ' ' ) : [ 'NONE' ]
                , c = 0
                , o = syllabus.commands
                , x = infos
                , cmd = carr[ 0 ]
                , result = {
                    req : cname
                    , name : undefined
                    , args : -1
                    , type : undefined
                    , cmd : undefined
                    , sub : []
                }
                , t = null
                , l = null
                ;
            for ( t in types) {
                if ( ~ types[ t ].indexOf( cmd ) ) {
                    // set command category type
                    result.type = t;
                    for ( ; c < carr.length; cmd = carr[ ++c ] ) {
                        o = o[ cmd ];
                        if ( ! o ) break;
                        if ( x ) x = x[ cmd ];
                    }
                    switch ( doString( o ) ) {
                        case ooo.obj:
                            /*
                             * o is an object not a function, scan
                             * to get direct children sub-commands.
                             */
                            for ( c in o ) result.sub.push( c.toUpperCase() );
                        break;
                        default:
                            // fn, get the number of arguments
                            result.args = o ? o.length : -1;
                            // build redis.io url
                            l = carr[ 1 ] ? ( carr[ 0 ] + '-' + carr[ 1 ] ) : carr[ 0 ];
                            result.url = url_redis_cmd + '/' + l.toLowerCase();
                            update( result, x );
                        break;
                    }
                    result.name = carr.join( '.' );
                    result.cmd = cname.toUpperCase();
                    break;
                }
            }

            return result;
        }
        /*
         * Recursively scan and add/remove info method 
         * property to all commands, also composite ones
         * like OBJECT REFCOUNT..
         */
        , stick = function ( enable, type, prefix ) {
            var p = prefix || ''
                , en = ( doString( enable ) === ooo.und ) ? true : enable
                , o = null
                , obj = type || syllabus.commands
                , el = null
                , fname = null
                // count parent and child commands
                , cnt = 0
                ;
            for ( o in obj ) {
                el = obj[ o ];
                fname = p ? ( p + ' ' + o ) : String( o );
                switch ( doString( el ) ) {
                    case ooo.fun:
                        if ( ! en ) {
                            delete( el.info );
                            ++cnt;
                            continue;
                        }
                        el.info = info.bind( this, fname );
                        ++cnt;
                    break;
                    case ooo.obj:
                        cnt += stick( en, el, fname );
                    break;
                }
            }
            return cnt;
        }
        , size = function () {
            var types = syllabus.types
                // count non-obj properties ( leafs )
                , c = count( syllabus.commands, true )
                , t = null
                , result = { commands : c, types : {} }
                ;
            for ( t in types ) result.types[ t ] = count( types[ t ] );
            return result;
        }
        // prune command from types
        , tprune = function ( cmd ) {
            var types = syllabus.types
                , type = null
                , t = null
                , k = null
                ;
            for ( t in types) {
                type = types[ t ];
                if ( ~ ( k = type.indexOf( cmd ) ) ) {
                    type.splice( k, 1 );
                    break;
                }
            }
        }
        // prune commands for development mode if necessary
        , prune = function ( oinf, osyl ) {
             var version = null
                , commands =  doString( osyl ) === ooo.obj ? osyl : syllabus.commands
                , sinfo = doString( oinf ) === ooo.obj ? oinf : infos
                , cmd = null
                , c = null
                , trash = function ( name ) {
                    delete commands[ name ];
                    delete sinfo[ name ];
                    // prune command from types
                    tprune( name );
                }
                , helpers = { info : info, stick : stick, size : size, semver : '*' }
                ;
            if ( ( doString( develop ) === ooo.str ) && ( develop !== '*' ) ) {
                helpers.semver = develop;
                // prune commands, check versions
                for ( cmd in sinfo ) {
                    c = sinfo[ cmd ];
                    version = c.since;
                    if ( ! version ) {
                        // nested commands, like OBJECT, PUBSUB, ..
                        prune( c, commands[ cmd ] );
                        /* 
                         * A parent command is empty, all
                         * children was removed, delete it.
                         */
                        if ( ! okeys( c ).length ) trash( cmd );
                    }
                    if ( ! lte( version, develop ) ) trash( cmd );
                }
            }
            return update( syllabus, helpers );
        }
        ;
    // lua scripts and cache
    syllabus.lua = lua;
    // syllabus formatters
    syllabus.formatters = formatters;
    /*
     * check if development mode is on,
     * otherwise return default syllabus.
     */
    return develop ? prune() : syllabus;
};