const j = (obj: unknown): string => `${JSON.stringify(obj)}\n`;

type ReplayRecord = {

type?: string;

id?: string;

message?: {

role?: string;

content?: string;

};

};

async function readJsonlRecords(filePath: string): Promise<ReplayRecord[]> {

const records: ReplayRecord[] = [];

const raw = await fs.readFile(filePath, "utf8");

for (const line of raw.split(/\r?\n/)) {

if (line.trim().length === 0) {

continue;

}

records.push(JSON.parse(line) as ReplayRecord);

}

return records;

}

describe("replayRecentUserAssistantMessages", () => {

let root = "";

beforeEach(async () => {

await fs.writeFile(source, lines.join(""), "utf8");

expect(await call(source, target)).toBe(DEFAULT_REPLAY_MAX_MESSAGES);

const records = (await fs.readFile(target, "utf8"))

.split(/\r?\n/)

.filter((line) => line.trim().length > 0)

.map((line) => JSON.parse(line));

const records = await readJsonlRecords(target);

expect(records[0]).toMatchObject({ type: "session", id: "new-session" });

expect(records).toHaveLength(1 + DEFAULT_REPLAY_MAX_MESSAGES);

for (const r of records.slice(1)) {

expect(["user", "assistant"]).toContain(r.message.role);

expect(["user", "assistant"]).toContain(r.message?.role);

}

expect(await call(path.join(root, "missing.jsonl"), path.join(root, "out.jsonl"))).toBe(0);

await fs.writeFile(source, lines.join(""), "utf8");

expect(await call(source, target)).toBe(DEFAULT_REPLAY_MAX_MESSAGES - 1);

const records = (await fs.readFile(target, "utf8"))

.split(/\r?\n/)

.filter((line) => line.trim().length > 0)

.map((line) => JSON.parse(line));

const records = await readJsonlRecords(target);

expect(records.reduce((count, r) => count + (r.type === "session" ? 1 : 0), 0)).toBe(1);

expect(records[0]).toMatchObject({ id: "existing" });

expect(records[1].message.role).toBe("user");

expect(records[1].message?.role).toBe("user");

});

it("coalesces same-role runs so replayed records strictly alternate", async () => {

);

expect(await call(source, target)).toBe(4);

const records = (await fs.readFile(target, "utf8"))

.split(/\r?\n/)

.filter((line) => line.trim().length > 0)

.map((line) => JSON.parse(line));

expect(records.slice(1).map((r) => r.message.role)).toEqual([

const records = await readJsonlRecords(target);

expect(records.slice(1).map((r) => r.message?.role)).toEqual([

"user",

"assistant",

"user",

"assistant",

]);

expect(records.slice(1).map((r) => r.message.content)).toEqual([

expect(records.slice(1).map((r) => r.message?.content)).toEqual([

"latest user",

"latest assistant",

"follow-up",