/*
Copyright 2016 Aviral Dasgupta
Copyright 2017 Vector Creations Ltd
Copyright 2017, 2018 New Vector Ltd
Copyright 2019 The Matrix.org Foundation C.I.C.
Copyright 2022 Ryan Browne <code@commonlawfeature.com>

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 { uniq, sortBy } from "lodash";
import EMOTICON_REGEX from "emojibase-regex/emoticon";
import { Room } from "matrix-js-sdk/src/models/room";

import { _t } from "../languageHandler";
import AutocompleteProvider from "./AutocompleteProvider";
import QueryMatcher from "./QueryMatcher";
import { PillCompletion } from "./Components";
import { ICompletion, ISelectionRange } from "./Autocompleter";
import SettingsStore from "../settings/SettingsStore";
import { EMOJI, IEmoji, getEmojiFromUnicode } from "../emoji";
import { TimelineRenderingType } from "../contexts/RoomContext";
import * as recent from "../emojipicker/recent";

const LIMIT = 20;

// Match for ascii-style ";-)" emoticons or ":wink:" shortcodes provided by emojibase
// anchored to only match from the start of parts otherwise it'll show emoji suggestions whilst typing matrix IDs
const EMOJI_REGEX = new RegExp("(" + EMOTICON_REGEX.source + "|(?:^|\\s):[+-\\w]*:?)$", "g");

interface ISortedEmoji {
    emoji: IEmoji;
    _orderBy: number;
}

const SORTED_EMOJI: ISortedEmoji[] = EMOJI.sort((a, b) => {
    if (a.group === b.group) {
        return a.order - b.order;
    }
    return a.group - b.group;
}).map((emoji, index) => ({
    emoji,
    // Include the index so that we can preserve the original order
    _orderBy: index,
}));

function score(query: string, space: string): number {
    const index = space.indexOf(query);
    if (index === -1) {
        return Infinity;
    } else {
        return index;
    }
}

function colonsTrimmed(str: string): string {
    // Trim off leading and potentially trailing `:` to correctly match the emoji data as they exist in emojibase.
    // Notes: The regex is pinned to the start and end of the string so that we can use the lazy-capturing `*?` matcher.
    // It needs to be lazy so that the trailing `:` is not captured in the replacement group, if it exists.
    return str.replace(/^:(.*?):?$/, "$1");
}

export default class EmojiProvider extends AutocompleteProvider {
    public matcher: QueryMatcher<ISortedEmoji>;
    public nameMatcher: QueryMatcher<ISortedEmoji>;
    private readonly recentlyUsed: IEmoji[];

    public constructor(room: Room, renderingType?: TimelineRenderingType) {
        super({ commandRegex: EMOJI_REGEX, renderingType });
        this.matcher = new QueryMatcher<ISortedEmoji>(SORTED_EMOJI, {
            keys: [],
            funcs: [(o) => o.emoji.shortcodes.map((s) => `:${s}:`)],
            // For matching against ascii equivalents
            shouldMatchWordsOnly: false,
        });
        this.nameMatcher = new QueryMatcher(SORTED_EMOJI, {
            keys: ["emoji.label"],
            // For removing punctuation
            shouldMatchWordsOnly: true,
        });

        this.recentlyUsed = Array.from(new Set(recent.get().map(getEmojiFromUnicode).filter(Boolean)));
    }

    public async getCompletions(
        query: string,
        selection: ISelectionRange,
        force?: boolean,
        limit = -1,
    ): Promise<ICompletion[]> {
        if (!SettingsStore.getValue("MessageComposerInput.suggestEmoji")) {
            return []; // don't give any suggestions if the user doesn't want them
        }

        let completions: ISortedEmoji[] = [];
        const { command, range } = this.getCurrentCommand(query, selection);

        if (command && command[0].length > 2) {
            const matchedString = command[0];
            completions = this.matcher.match(matchedString, limit);

            // Do second match with shouldMatchWordsOnly in order to match against 'name'
            completions = completions.concat(this.nameMatcher.match(matchedString));

            let sorters = [];
            // make sure that emoticons come first
            sorters.push((c) => score(matchedString, c.emoji.emoticon || ""));

            // then sort by score (Infinity if matchedString not in shortcode)
            sorters.push((c) => score(matchedString, c.emoji.shortcodes[0]));
            // then sort by max score of all shortcodes, trim off the `:`
            const trimmedMatch = colonsTrimmed(matchedString);
            sorters.push((c) => Math.min(...c.emoji.shortcodes.map((s) => score(trimmedMatch, s))));
            // If the matchedString is not empty, sort by length of shortcode. Example:
            //  matchedString = ":bookmark"
            //  completions = [":bookmark:", ":bookmark_tabs:", ...]
            if (matchedString.length > 1) {
                sorters.push((c) => c.emoji.shortcodes[0].length);
            }
            // Finally, sort by original ordering
            sorters.push((c) => c._orderBy);
            completions = sortBy<ISortedEmoji>(uniq(completions), sorters);

            completions = completions.slice(0, LIMIT);

            // Do a second sort to place emoji matching with frequently used one on top
            sorters = [];
            this.recentlyUsed.forEach((emoji) => {
                sorters.push((c) => score(emoji.shortcodes[0], c.emoji.shortcodes[0]));
            });
            completions = sortBy<ISortedEmoji>(uniq(completions), sorters);

            return completions.map((c) => ({
                completion: c.emoji.unicode,
                component: (
                    <PillCompletion title={`:${c.emoji.shortcodes[0]}:`} aria-label={c.emoji.unicode}>
                        <span>{c.emoji.unicode}</span>
                    </PillCompletion>
                ),
                range,
            }));
        }
        return [];
    }

    public getName(): string {
        return "😃 " + _t("Emoji");
    }

    public renderCompletions(completions: React.ReactNode[]): React.ReactNode {
        return (
            <div
                className="mx_Autocomplete_Completion_container_pill"
                role="presentation"
                aria-label={_t("Emoji Autocomplete")}
            >
                {completions}
            </div>
        );
    }
}