/*
 * Copyright 2011 eBay Software Foundation
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
'use strict';

function getConsole() {
    if (typeof console === 'undefined') {
        // probably IE and Developer Tools are not open
        return null;
    }

    if (!console.log.apply || !console.log.call) {
        // not a real log (for old IE versions)
        return null;
    }

    return console;
}

var _console = getConsole();
var _noop = _console ? null : function() {};

function getStackTrace(error) {
    var stacktraces = require('raptor-stacktraces');
    return (stacktraces && stacktraces.trace) ? stacktraces.trace(error) : (error || '');
}

function ConsoleAppender() {
}


ConsoleAppender.prototype = {
    /**
     * Log statements for all levels pass through this method.
     */
    log: _console ? function(logEvent) {
        var logLevel = logEvent.logLevel;

        var logFn = _console[logLevel.methodName] || _console.log;
        if (!logFn) {
            return;
        }

        try {
            var args = logEvent.args.slice(0);
            var len = args.length;
            var error;

            for (var i=0; i<len-1; i++) {
                var arg = args[i];
                if (arg instanceof Error) {
                    args[i] = getStackTrace(arg);
                }
            }
            
            var lastArg = args[len-1];

            if (lastArg instanceof Error) {
                error = lastArg;
                args[len-1] = '';
            }

            var logArgs = [logLevel.name + ' ' + logEvent.getLoggerName() + ':'].concat(args);

            // log the message at the level specified
            logFn.apply(_console, logArgs);

            if (error) {
                logFn.call(_console, error.stack || error.toString());

                var cause = error._cause;
                while (cause) {
                    logFn.call(_console, 'Caused by:');
                    logFn.call(_console, cause.stack || cause.toString());
                    cause = cause._cause;
                }
            }

            if (logLevel.level === 0) {
                if (_console.trace) {
                    _console.trace();
                } else {
                    var stackTrace = getStackTrace();
                    if (stackTrace && _console.log) {
                        _console.log(stackTrace);
                    }
                }
            }

        } catch (e) {
            logFn = _console.error || logFn;
            logFn.call(_console, e);
        }
    } : _noop,

    /**
     * Log the contents of the given object at the DEBUG level.
     */
    dump: _console ? function(obj, desc) {
        if (console.debug) {
            console.log((desc ? 'DUMP ' + desc : 'DUMP') + ':');
            console.debug(obj);
        }
    } : _noop
};

module.exports = ConsoleAppender;