OpenFrontIO/src/server/Privilege.ts

import {
  DataSet,
  RegExpMatcher,
  collapseDuplicatesTransformer,
  englishDataset,
  pattern,
  resolveConfusablesTransformer,
  resolveLeetSpeakTransformer,
  skipNonAlphabeticTransformer,
  toAsciiLowerCaseTransformer,
} from "obscenity";
import { Cosmetics } from "../core/CosmeticSchemas";
import { decodePatternData } from "../core/PatternDecoder";
import {
  FlagSchema,
  PlayerColor,
  PlayerCosmeticRefs,
  PlayerCosmetics,
  PlayerPattern,
} from "../core/Schemas";
import { simpleHash } from "../core/Util";

export const shadowNames = [
  "UnhuggedToday",
  "DaddysLilChamp",
  "BunnyKisses67",
  "SnugglePuppy",
  "CuddleMonster67",
  "DaddysLilStar",
  "SnuggleMuffin",
  "PeesALittle",
  "PleaseFullSendMe",
  "NanasLilMan",
  "NoAlliances",
  "TryingTooHard67",
  "MommysLilStinker",
  "NeedHugs",
  "MommysLilPeanut",
  "IWillBetrayU",
  "DaddysLilTater",
  "PreciousBubbles",
  "67 Cringelord",
  "Peace And Love",
  "AlmostPottyTrained",
];

export function createMatcher(bannedWords: string[]): RegExpMatcher {
  const customDataset = new DataSet<{ originalWord: string }>().addAll(
    englishDataset,
  );

  for (const word of bannedWords) {
    try {
      customDataset.addPhrase((phrase) =>
        phrase.setMetadata({ originalWord: word }).addPattern(pattern`${word}`),
      );
    } catch (e) {
      console.error(`Invalid banned word pattern "${word}": ${e}`);
    }
  }

  return new RegExpMatcher({
    ...customDataset.build(),
    blacklistMatcherTransformers: [
      toAsciiLowerCaseTransformer(),
      resolveConfusablesTransformer(),
      resolveLeetSpeakTransformer(),
      collapseDuplicatesTransformer(),
      skipNonAlphabeticTransformer(),
    ],
  });
}

/**
 * Sanitizes and censors profane usernames and clan tags separately.
 * Profane username is overwritten, profane clan tag is removed.
 *
 * Removing bad clan tags won't hurt existing clans nor cause desyncs:
 * - full name including clan tag was overwritten in the past, if any part of name was bad
 * - only each separate local player name with a profane clan tag will remain, no clan team assignment
 *
 * Examples:
 * - username="GoodName", clanTag=null -> { username: "GoodName", clanTag: null }
 * - username="BadName", clanTag=null -> { username: "Censored", clanTag: null }
 * - username="GoodName", clanTag="CLaN" -> { username: "GoodName", clanTag: "CLAN" }
 * - username="GoodName", clanTag="BAD" -> { username: "GoodName", clanTag: null }
 * - username="BadName", clanTag="BAD" -> { username: "Censored", clanTag: null }
 */

function censorWithMatcher(
  username: string,
  clanTag: string | null,
  matcher: RegExpMatcher,
): { username: string; clanTag: string | null } {
  const usernameIsProfane = matcher.hasMatch(username);
  const censoredName = usernameIsProfane
    ? shadowNames[simpleHash(username) % shadowNames.length]
    : username;

  const clanTagIsProfane = clanTag ? matcher.hasMatch(clanTag) : false;
  const censoredClanTag =
    clanTag && !clanTagIsProfane ? clanTag.toUpperCase() : null;

  return { username: censoredName, clanTag: censoredClanTag };
}

type CosmeticResult =
  | { type: "allowed"; cosmetics: PlayerCosmetics }
  | { type: "forbidden"; reason: string };

export interface PrivilegeChecker {
  isAllowed(flares: string[], refs: PlayerCosmeticRefs): CosmeticResult;
  censor(
    username: string,
    clanTag: string | null,
  ): { username: string; clanTag: string | null };
}

export class PrivilegeCheckerImpl implements PrivilegeChecker {
  private matcher: RegExpMatcher;

  constructor(
    private cosmetics: Cosmetics,
    private b64urlDecode: (base64: string) => Uint8Array,
    bannedWords: string[],
  ) {
    this.matcher = createMatcher(bannedWords);
  }

  isAllowed(flares: string[], refs: PlayerCosmeticRefs): CosmeticResult {
    const cosmetics: PlayerCosmetics = {};
    if (refs.patternName) {
      try {
        cosmetics.pattern = this.isPatternAllowed(
          flares,
          refs.patternName,
          refs.patternColorPaletteName ?? null,
        );
      } catch (e) {
        return { type: "forbidden", reason: "invalid pattern: " + e.message };
      }
    }
    if (refs.color) {
      try {
        cosmetics.color = this.isColorAllowed(flares, refs.color);
      } catch (e) {
        return { type: "forbidden", reason: "invalid color: " + e.message };
      }
    }
    if (refs.flag) {
      const result = FlagSchema.safeParse(refs.flag);
      if (!result.success) {
        return {
          type: "forbidden",
          reason: "invalid flag: " + result.error.message,
        };
      }
      cosmetics.flag = result.data;
    }

    return { type: "allowed", cosmetics };
  }

  isPatternAllowed(
    flares: readonly string[],
    name: string,
    colorPaletteName: string | null,
  ): PlayerPattern {
    // Look for the pattern in the cosmetics.json config
    const found = this.cosmetics.patterns[name];
    if (!found) throw new Error(`Pattern ${name} not found`);

    try {
      decodePatternData(found.pattern, this.b64urlDecode);
    } catch (e) {
      throw new Error(`Invalid pattern ${name}`);
    }

    const colorPalette = this.cosmetics.colorPalettes?.[colorPaletteName ?? ""];

    if (flares.includes("pattern:*")) {
      return {
        name: found.name,
        patternData: found.pattern,
        colorPalette,
      } satisfies PlayerPattern;
    }

    const flareName =
      `pattern:${found.name}` +
      (colorPaletteName ? `:${colorPaletteName}` : "");

    if (flares.includes(flareName)) {
      // Player has a flare for this pattern
      return {
        name: found.name,
        patternData: found.pattern,
        colorPalette,
      } satisfies PlayerPattern;
    } else {
      throw new Error(`No flares for pattern ${name}`);
    }
  }

  isColorAllowed(flares: string[], color: string): PlayerColor {
    const allowedColors = flares
      .filter((flare) => flare.startsWith("color:"))
      .map((flare) => flare.split(":")[1]);
    if (!allowedColors.includes(color)) {
      throw new Error(`Color ${color} not allowed`);
    }
    return { color };
  }

  censor(
    username: string,
    clanTag: string | null,
  ): { username: string; clanTag: string | null } {
    return censorWithMatcher(username, clanTag, this.matcher);
  }
}

// Default matcher with no custom banned words (just englishDataset)
const defaultMatcher = createMatcher([]);

export class FailOpenPrivilegeChecker implements PrivilegeChecker {
  isAllowed(flares: string[], refs: PlayerCosmeticRefs): CosmeticResult {
    return { type: "allowed", cosmetics: {} };
  }

  censor(
    username: string,
    clanTag: string | null,
  ): { username: string; clanTag: string | null } {
    return censorWithMatcher(username, clanTag, defaultMatcher);
  }
}