export type ParsedChatAllowTarget =
  | { kind: "chat_id"; chatId: number }
  | { kind: "chat_guid"; chatGuid: string }
  | { kind: "chat_identifier"; chatIdentifier: string }
  | { kind: "handle"; handle: string };

export function isAllowedParsedChatSender<TParsed extends ParsedChatAllowTarget>(params: {
  allowFrom: Array<string | number>;
  sender: string;
  chatId?: number | null;
  chatGuid?: string | null;
  chatIdentifier?: string | null;
  emptyAllowFrom?: "deny" | "allow";
  normalizeSender: (sender: string) => string;
  parseAllowTarget: (entry: string) => TParsed;
}): boolean {
  const allowFrom = params.allowFrom.map((entry) => String(entry).trim());
  if (allowFrom.length === 0) {
    // Fail closed by default. Callers can opt into legacy "empty = allow all"
    // behavior explicitly when a surface intentionally treats an empty list as open.
    return params.emptyAllowFrom === "allow";
  }
  if (allowFrom.includes("*")) {
    return true;
  }

  const senderNormalized = params.normalizeSender(params.sender);
  const chatId = params.chatId ?? undefined;
  const chatGuid = params.chatGuid?.trim();
  const chatIdentifier = params.chatIdentifier?.trim();

  for (const entry of allowFrom) {
    if (!entry) continue;
    const parsed = params.parseAllowTarget(entry);
    if (parsed.kind === "chat_id" && chatId !== undefined) {
      if (parsed.chatId === chatId) return true;
    } else if (parsed.kind === "chat_guid" && chatGuid) {
      if (parsed.chatGuid === chatGuid) return true;
    } else if (parsed.kind === "chat_identifier" && chatIdentifier) {
      if (parsed.chatIdentifier === chatIdentifier) return true;
    } else if (parsed.kind === "handle" && senderNormalized) {
      if (parsed.handle === senderNormalized) return true;
    }
  }
  return false;
}
