import { afterEach, beforeEach, describe, expect, test } from "bun:test";
import * as fs from "node:fs/promises";
import * as os from "node:os";
import * as path from "node:path";
import { removeWithRetries } from "@oh-my-pi/pi-utils";
import { collectSubSessions } from "../src/export/html";

/**
 * Contract: a session at `<dir>/<name>.jsonl` embeds subagent transcripts from
 * `<dir>/<name>/<AgentId>.jsonl` (recursively) under slash-joined keys, with
 * parent links and last-entry leaf ids. Corrupt/empty/backup files are skipped.
 */

function sessionJsonl(id: string, entryIds: string[]): string {
	const lines = [
		JSON.stringify({ type: "session", version: 3, id, timestamp: "2026-06-12T00:00:00.000Z", cwd: "/tmp" }),
	];
	let parent: string | null = null;
	for (const entryId of entryIds) {
		lines.push(
			JSON.stringify({
				type: "model_change",
				id: entryId,
				parentId: parent,
				timestamp: "2026-06-12T00:00:01.000Z",
				model: "test/model",
			}),
		);
		parent = entryId;
	}
	return `${lines.join("\n")}\n`;
}

describe("collectSubSessions", () => {
	let root: string;
	let mainFile: string;

	beforeEach(async () => {
		root = await fs.mkdtemp(path.join(os.tmpdir(), "omp-subsessions-"));
		mainFile = path.join(root, "main.jsonl");
		await Bun.write(mainFile, sessionJsonl("main", ["m1"]));
	});

	afterEach(async () => {
		await removeWithRetries(root);
	});

	test("collects nested subagent sessions with parent links and leaf ids", async () => {
		await Bun.write(path.join(root, "main/Alpha.jsonl"), sessionJsonl("alpha", ["a1", "a2"]));
		await Bun.write(path.join(root, "main/Alpha/Child.jsonl"), sessionJsonl("child", ["c1"]));
		await Bun.write(path.join(root, "main/Beta.jsonl"), sessionJsonl("beta", ["b1"]));

		const subs = await collectSubSessions(mainFile);

		expect(Object.keys(subs).sort()).toEqual(["Alpha", "Alpha/Child", "Beta"]);
		expect(subs.Alpha).toMatchObject({ agentId: "Alpha", parent: null, leafId: "a2" });
		expect(subs.Alpha.entries.map(e => e.id)).toEqual(["a1", "a2"]);
		expect(subs.Alpha.header?.id).toBe("alpha");
		expect(subs["Alpha/Child"]).toMatchObject({ agentId: "Child", parent: "Alpha", leafId: "c1" });
		expect(subs.Beta).toMatchObject({ agentId: "Beta", parent: null, leafId: "b1" });
	});

	test("skips corrupt, empty, backup, and non-jsonl files", async () => {
		await Bun.write(path.join(root, "main/Good.jsonl"), sessionJsonl("good", ["g1"]));
		await Bun.write(path.join(root, "main/corrupt.jsonl"), "{not json\n");
		await Bun.write(path.join(root, "main/empty.jsonl"), "");
		await Bun.write(path.join(root, "main/Good.jsonl.123.bak"), sessionJsonl("bak", ["x1"]));
		await Bun.write(path.join(root, "main/notes.md"), "# notes\n");

		const subs = await collectSubSessions(mainFile);

		expect(Object.keys(subs)).toEqual(["Good"]);
	});

	test("returns empty record when no subagent dir exists", async () => {
		expect(await collectSubSessions(mainFile)).toEqual({});
		expect(await collectSubSessions(path.join(root, "not-a-session"))).toEqual({});
	});
});