// The outbound DM path for the bus notifier (packages/cli, lead decision 70).
// It uses the connector's bot token and REST client but not its gateway
// process: one binding, one recipient (`dmRecipient`, which must be a listed
// user), one DM channel opened on first use and kept in memory.
//
// The caller sees outcomes only: `{messageId}` on a confirmed send, or a
// RestOutcome (refused | unknown) it journals and retries. The recipient id,
// the channel id and the token never leave this module: not in a return
// value, an error message or a log line.

import { DiscordError } from "./errors.mjs";
import { bindingPath, loadBinding, readToken } from "./binding.mjs";
import { createRest, API_BASE, RestOutcome } from "./rest.mjs";

export function openDirect({ dataRoot, name, fetch = globalThis.fetch, base = API_BASE, sleep, log = () => {} }) {
  const binding = loadBinding(bindingPath(dataRoot, name));
  if (binding.dmRecipient === null) throw new DiscordError(`binding ${name}: no dmRecipient; the notifier has nobody to DM`, 2);
  const rest = createRest({ token: readToken(binding), fetch, base, sleep, log });
  const recipient = binding.dmRecipient;
  let channel = null;
  return Object.freeze({
    binding: binding.name,
    // Resolves {messageId}. Throws RestOutcome (refused | unknown). The
    // nonce makes Discord return the earlier message when an unknown send
    // is retried within its dedupe window.
    async send({ content, nonce }) {
      if (channel === null) {
        try {
          channel = await rest.createDm(recipient);
        } catch (err) {
          if (err instanceof RestOutcome) throw new RestOutcome(err.kind, `dm channel: ${err.kind}`, { status: err.details.status });
          throw err;
        }
      }
      try {
        const { messageId } = await rest.createMessage(channel, { content, nonce });
        return { messageId };
      } catch (err) {
        if (!(err instanceof RestOutcome)) throw err;
        // A refusal can mean the channel went away; open it again next time.
        if (err.kind === "refused") channel = null;
        throw new RestOutcome(err.kind, `dm: ${err.kind}`, { status: err.details.status });
      }
    },
  });
}