/*
Copyright 2016 Aviral Dasgupta
Copyright 2017 Vector Creations Ltd

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.
*/

import React from 'react';
import { _t } from '../languageHandler';
import AutocompleteProvider from './AutocompleteProvider';
import Fuse from 'fuse.js';
import {TextualCompletion} from './Components';

// Warning: Since the description string will be translated in _t(result.description), all these strings below must be in i18n/strings/en_EN.json file
const COMMANDS = [
    {
        command: '/me',
        args: '<message>',
        description: 'Displays action',
    },
    {
        command: '/ban',
        args: '<user-id> [reason]',
        description: 'Bans user with given id',
    },
    {
        command: '/deop',
        args: '<user-id>',
        description: 'Deops user with given id',
    },
    {
        command: '/invite',
        args: '<user-id>',
        description: 'Invites user with given id to current room',
    },
    {
        command: '/join',
        args: '<room-alias>',
        description: 'Joins room with given alias',
    },
    {
        command: '/kick',
        args: '<user-id> [reason]',
        description: 'Kicks user with given id',
    },
    {
        command: '/nick',
        args: '<display-name>',
        description: 'Changes your display nickname',
    },
    {
        command: '/ddg',
        args: '<query>',
        description: 'Searches DuckDuckGo for results',
    },
];

const COMMAND_RE = /(^\/\w*)/g;

let instance = null;

export default class CommandProvider extends AutocompleteProvider {
    constructor() {
        super(COMMAND_RE);
        this.fuse = new Fuse(COMMANDS, {
           keys: ['command', 'args', 'description'],
        });
    }

    async getCompletions(query: string, selection: {start: number, end: number}) {
        let completions = [];
        const {command, range} = this.getCurrentCommand(query, selection);
        if (command) {
            completions = this.fuse.search(command[0]).map((result) => {
                return {
                    completion: result.command + ' ',
                    component: (<TextualCompletion
                        title={result.command}
                        subtitle={result.args}
                        description={ _t(result.description) }
                        />),
                    range,
                };
            });
        }
        return completions;
    }

    getName() {
        return '*️⃣ ' + _t('Commands');
    }

    static getInstance(): CommandProvider {
        if (instance === null) instance = new CommandProvider();

        return instance;
    }

    renderCompletions(completions: [React.Component]): ?React.Component {
        return <div className="mx_Autocomplete_Completion_container_block">
            {completions}
        </div>;
    }
}