// A stand-in harness turn for the thread launch tests (row 121, #1615). It
// keeps a history in $MOSAIC_SESSION_DIR, which for a thread run is the
// thread's store, and a transcript per turn under $HOME/.claude/projects.
// It answers with the message body and what both held before this turn, so
// a test reads from the reply what a later run of the same thread kept.

import { appendFileSync, existsSync, readdirSync, readFileSync, writeFileSync } from "node:fs";
import { join } from "node:path";

const request = process.env.MOSAIC_REQUEST ?? "";
const body = request.match(/^Message [^\n]*:\n\n([\s\S]*)$/m)?.[1] ?? "";
const historyFile = join(process.env.MOSAIC_SESSION_DIR, "history");
const before = existsSync(historyFile) ? readFileSync(historyFile, "utf8").split("\n").filter(Boolean) : [];
const projects = join(process.env.HOME, ".claude", "projects");
const transcripts = existsSync(projects) ? readdirSync(projects).sort() : null;
// A turn longer than the test's idle time.
if (body === "slow") Atomics.wait(new Int32Array(new SharedArrayBuffer(4)), 0, 0, 3000);
appendFileSync(historyFile, `${body}\n`);
if (transcripts) writeFileSync(join(projects, `turn-${before.length + 1}.jsonl`), `${JSON.stringify(body)}\n`);
process.stdout.write(`THREAD ${JSON.stringify({ body, before, transcripts })}\n`);
writeFileSync(process.env.MOSAIC_TURN_MARKER, "done\n");