"use strict";

import * as _ from "underscore";
import tasks from "./tasks";

// TaskProcessor does not look like EventEmitter, so no need to extend EventEmitter and use `emit' here.
const createTaskProcessor = (task, outerProcessor: TaskProcessor, callback) => {
    const result: TaskProcessor = {};
    const createTaskWorker = () => tasks[task.type](task.params || {}, result);
    const errors: string[] = [];
    const process = () => createTaskWorker().process();
    const getOuterPrefix = (prefix) => {
        if (task.name && prefix) {
            return `${task.name}/${prefix}`;
        }

        return String(task.name || "") + String(prefix || "");
    };
    const onError = (message, prefix) => {
        errors.push(message);
        outerProcessor.onError(message, getOuterPrefix(prefix));
    };
    const onWarn = (message, prefix) => outerProcessor.onWarn(message, getOuterPrefix(prefix));
    const onInfo = (message, prefix) => outerProcessor.onInfo(message, getOuterPrefix(prefix));
    const processTask = (innerTask, innerCallback) => {
        const innerProcessor = createTaskProcessor(innerTask, result, innerCallback);

        innerProcessor.process();
    };
    const done = () => callback(errors.join("\r\n"));

    result.process = process;
    result.onError = onError;
    result.onWarn = onWarn;
    result.onInfo = onInfo;
    result.processTask = processTask;
    result.done = done;
    result.context = outerProcessor.context;

    return result;
};

const pushMessage = (list, message, parts, index) => {
    if (!index) {
        list.$allMessages = list.$allMessages || [];
        list.$allMessages.push({
            message,
            prefix: parts.join("/"),
        });
    }

    list.$messages = list.$messages || [];
    if (index === parts.length) {
        return list.$messages.push(message);
    }

    return pushMessage(list, message, parts, index + 1);
};

const addFlag = (flags) => (flagName) => {
    flags[flagName] = true;
};

const containsFlag = (flags) => (flagName) => flags[flagName];

export const processTask = (task, context, callback) => {
    const errors = {};
    const warns = {};
    const infos = {};
    const messages = {};
    const messageProcessor = (list) => (message, prefix) => {
        const parts = prefix.split("/");

        pushMessage(list, message, parts, 0);
        pushMessage(messages, message, parts, 0);
    };
    const flags = {};
    const processor = createTaskProcessor(task, {
        context: _.extend(context, {
            addFlag: addFlag(flags),
            containsFlag: containsFlag(flags),
        }),
        onError: messageProcessor(errors),
        onInfo: messageProcessor(infos),
        onWarn: messageProcessor(warns),
    }, (err) => callback(err, {
        errors,
        infos,
        messages,
        warns,
    }));

    processor.process();
};