'use strict';

var clone = require('clone');
var objectAssign = require('object-assign');
var Transform = require('readable-stream/transform');
var common = require('./common');
var Parser = require('./parser');

module.exports = function (options, userConfig) {
    var tasksPromise = common.parseTasks(options);

    var config = {
        keepUnassigned: false,
        keepBlockTags: false,
        resolvePaths: false
    };

    if (typeof userConfig === 'boolean') {
        config.keepUnassigned = userConfig;
    } else if (typeof userConfig === 'object') {
        objectAssign(config, userConfig);
    }

    return new Transform({
        objectMode: true,
        transform: function (file, enc, callback) {
            tasksPromise
                .then(function (tasks) {

                    var parser = new Parser(clone(tasks), config, file);

                    if (file.isBuffer()) {
                        parser.write(file.contents);
                        parser.end();

                        var contents = new Buffer(0);
                        parser.on('data', function (data) {
                            contents = Buffer.concat([contents, data]);
                        });
                        parser.once('end', function () {
                            file.contents = contents;
                            callback(null, file);
                        });
                        return;
                    }

                    if (file.isStream()) {
                        file.contents = file.contents.pipe(parser);
                    }

                    callback(null, file);
                })
            .catch(callback);
        }
    });
};