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import { parseShareAddress } from "../../core-validators/addresses.ts";import { Crypto } from "../../crypto/crypto.ts";import { Peer } from "../../peer/peer.ts";import {  extractTemplateVariablesFromPath,  globToQueryAndRegex,  parseTemplate,} from "../../query/query-helpers.ts";import { Replica } from "../../replica/replica.ts";import { ShareAddress } from "../../util/doc-types.ts";import { notErr } from "../../util/errors.ts";import { IServerExtension } from "./extension.ts";
interface ExtensionServerSettingsOpts {  /** The address of the share to read settings from. */  settingsShare: ShareAddress;  /** The method used to create the replica for the settings share. */  onCreateReplica: (    settingsShareAddress: string,  ) => Replica;}
const HOSTED_SHARE_TEMPLATE =  `/server-settings/1.*/shares/{shareHash}/{hostType}`;
/** A server extension which reads settings from a specified share, e.g. which shares to host on the server. Settings are modified by other peers syncing with this server. */export class ExtensionServerSettings implements IServerExtension {  private configReplica: Replica;  private onCreateReplica: (    configurationShareAddress: string,  ) => Replica;
  constructor(opts: ExtensionServerSettingsOpts) {    this.configReplica = opts.onCreateReplica(opts.settingsShare);    this.onCreateReplica = opts.onCreateReplica;  }
  register(peer: Peer): Promise<void> {    peer.addReplica(this.configReplica);
    const onCreateReplica = this.onCreateReplica;
    const { glob } = parseTemplate(HOSTED_SHARE_TEMPLATE);    const { query, regex } = globToQueryAndRegex(glob);
    const configShareAddress = this.configReplica.share;
    this.configReplica.getQueryStream(query, "everything").pipeTo(      new WritableStream({        async write(event) {          if (event.kind === "existing" || event.kind === "success") {            if (              regex != null &&              new RegExp(regex).test(event.doc.path)            ) {              const pathVariables = extractTemplateVariablesFromPath(                HOSTED_SHARE_TEMPLATE,                event.doc.path,              );
              if (!pathVariables) {                return;              }
              const shareHash = pathVariables["shareHash"];
              const configHash = await Crypto.sha256base32(                configShareAddress,              );
              if (shareHash === configHash) {                return;              }
              if (                event.doc.text.length > 0 &&                notErr(parseShareAddress(event.doc.text)) &&                !peer.hasShare(event.doc.text)              ) {                // Add                const replica = onCreateReplica(event.doc.text);
                peer.addReplica(replica);
                console.log("Server settings:", `now hosting ${replica.share}`);              } else if (event.doc.text.length === 0) {                let replicaToClose;
                for (const replica of peer.replicas()) {                  const rShareHash = await Crypto.sha256base32(                    replica.share,                  );
                  if (rShareHash === shareHash) {                    replicaToClose = replica;                  }                }
                if (replicaToClose) {                  await replicaToClose.close(true);                  peer.removeReplica(replicaToClose);                  console.log(                    "Server settings:",                    `stopped hosting ${replicaToClose.share}`,                  );                }              }            }          }
          if (event.kind === "expire") {            if (              regex != null &&              new RegExp(regex).test(event.doc.path)            ) {              // Remove              const pathVariables = extractTemplateVariablesFromPath(                HOSTED_SHARE_TEMPLATE,                event.doc.path,              );
              if (!pathVariables) {                return;              }
              const shareAddress = pathVariables["shareAddress"];
              const replicaToClose = peer.getReplica(shareAddress);
              if (replicaToClose) {                await replicaToClose.close(true);                peer.removeReplica(replicaToClose);                console.log(                  "Server settings:",                  `stopped hosting ${replicaToClose.share}`,                );              }            }          }        },      }),    );
    return Promise.resolve();  }
  handler(_req: Request): Promise<Response | null> {    return Promise.resolve(null);  }}