113 lines
4.4 KiB
TypeScript
113 lines
4.4 KiB
TypeScript
import {GuildEmoji} from "discord.js";
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import {client} from "../../../index";
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// Levenshtein distance coefficients for all transformation types.
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// TODO: Investigate what values result in the most optimal matching strategy.
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const directMatchWeight = 0.0;
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const uppercaseWeight = 0.2;
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const lowercaseWeight = 0.5;
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const substitutionWeight = 1.0;
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const deletionWeight = 1.5;
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const insertionWeight = 1.5;
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// Maximum Levenshtein distance for an emote to be considered a suitable match candidate.
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const maxAcceptedDistance = 3.0;
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// Algorithm taken from https://en.wikipedia.org/wiki/Levenshtein_distance#Iterative_with_two_matrix_rows
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// Modified for separate handling of uppercasing and lowercasing transformations.
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function levenshtein(s: string, t: string): number {
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const m = s.length;
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const n = t.length;
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let v0 = new Array(n + 1);
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let v1 = new Array(n + 1);
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let i, j;
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for (i = 0; i <= n; i++) v0[i] = i;
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for (i = 0; i < m; i++) {
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v1[0] = i + 1;
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for (j = 0; j < n; j++) {
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let r;
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if (s[i] === t[j]) r = directMatchWeight;
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else if (s[i] === t[j].toUpperCase()) r = uppercaseWeight;
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else if (s[i] === t[j].toLowerCase()) r = lowercaseWeight;
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else r = substitutionWeight;
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v1[j + 1] = Math.min(v0[j + 1] + deletionWeight, v1[j] + insertionWeight, v0[j] + r);
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}
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const tmp = v1;
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(v1 = v0), (v0 = tmp);
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}
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return v0[n];
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}
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function searchSimilarEmotes(query: string): GuildEmoji[] {
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const emoteCandidates: {emote: GuildEmoji; dist: number}[] = [];
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for (const emote of client.emojis.cache.values()) {
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const dist = levenshtein(emote.name, query);
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if (dist <= maxAcceptedDistance) {
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emoteCandidates.push({emote, dist});
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}
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}
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emoteCandidates.sort((b, a) => b.dist - a.dist);
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return emoteCandidates.map((em) => em.emote);
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}
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const unicodeEmojiRegex = /^(?:[\u2700-\u27bf]|(?:\ud83c[\udde6-\uddff]){2}|[\ud800-\udbff][\udc00-\udfff]|[\u0023-\u0039]\ufe0f?\u20e3|\u3299|\u3297|\u303d|\u3030|\u24c2|\ud83c[\udd70-\udd71]|\ud83c[\udd7e-\udd7f]|\ud83c\udd8e|\ud83c[\udd91-\udd9a]|\ud83c[\udde6-\uddff]|\ud83c[\ude01-\ude02]|\ud83c\ude1a|\ud83c\ude2f|\ud83c[\ude32-\ude3a]|\ud83c[\ude50-\ude51]|\u203c|\u2049|[\u25aa-\u25ab]|\u25b6|\u25c0|[\u25fb-\u25fe]|\u00a9|\u00ae|\u2122|\u2139|\ud83c\udc04|[\u2600-\u26FF]|\u2b05|\u2b06|\u2b07|\u2b1b|\u2b1c|\u2b50|\u2b55|\u231a|\u231b|\u2328|\u23cf|[\u23e9-\u23f3]|[\u23f8-\u23fa]|\ud83c\udccf|\u2934|\u2935|[\u2190-\u21ff])[\ufe00-\ufe0f]?$/;
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const discordEmoteMentionRegex = /^<a?:\w+:\d+>$/;
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const emoteNameWithSelectorRegex = /^(.+)~(\d+)$/;
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export function searchNearestEmote(query: string, additionalEmotes?: GuildEmoji[]): string {
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// Selector number used for disambiguating multiple emotes with same name.
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let selector = 0;
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// If the query has emoteName~123 format, extract the actual name and the selector number.
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const queryWithSelector = query.match(emoteNameWithSelectorRegex);
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if (queryWithSelector) {
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query = queryWithSelector[1];
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selector = +queryWithSelector[2];
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}
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// Try to match an emote name directly if the selector is for the closest match.
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if (selector == 0) {
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const directMatchEmote = client.emojis.cache.find((em) => em.name === query);
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if (directMatchEmote) return directMatchEmote.toString();
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}
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// Find all similar emote candidates within certian threshold and select Nth top one according to the selector.
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const similarEmotes = searchSimilarEmotes(query);
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if (similarEmotes.length > 0) {
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selector = Math.min(selector, similarEmotes.length - 1);
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return similarEmotes[selector].toString();
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}
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// Return some "missing/invalid emote" indicator.
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return "❓";
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}
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export function processEmoteQuery(query: string[], isFormatted: boolean): string[] {
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return query.map((emote) => {
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emote = emote.trim();
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// If the query directly matches a Unicode emoji or a Discord custom emote mention, pass it as-is.
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if (discordEmoteMentionRegex.test(emote) || unicodeEmojiRegex.test(emote)) return emote;
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// If formatted mode is enabled, parse whitespace and newline elements.
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if (isFormatted) {
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if (emote == "-") return " ";
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if (emote == "+") return "\n";
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if (emote == "_") return "\u200b";
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}
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return searchNearestEmote(emote);
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});
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}
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