import * as iter from './iterator.js';
import { User } from './state/remote/users.svelte.js';

const RUN_COALESCE_MAX_INTERVAL = 10 /* min */ * 60 /* sec */ * 1000; /* ms */

export function runs(messages, self) {
  const bareRuns = iter.chunkBy(messages, runKey, continueRun);
  return iter.map(bareRuns, (run) => summarizeRun(self, run));
}

function summarizeRun(self, { key, chunk }) {
  const [sender, at] = key;
  return {
    sender: sender.name,
    ownMessage: sender.id === self.id,
    messages: chunk
  };
}

function runKey(message) {
  return [message.sender, message.at];
}

function continueRun([lastSender, lastAt], [newSender, newAt]) {
  return User.equal(lastSender, newSender) && newAt - lastAt < RUN_COALESCE_MAX_INTERVAL;
}