/**
 * @file Tests server/lib/db-retention.js and its Settings routes — a new
 * database is INCREMENTAL auto_vacuum, retention is off by default and purges
 * nothing then, when on it removes only finished sessions older than the
 * cutoff (with their events, agents and token rows) in bounded batches, the
 * free-page reclaim shrinks the freelist, GET/PUT /api/settings/retention
 * validate and persist the setting, and POST /api/settings/compact needs
 * confirm and runs a VACUUM in a worker. The database and settings file are
 * temp paths.
 * @author Nguyễn Ngọc Trí Vĩ <vinnt@smartgift.vn>
 */

const os = require("node:os");
const fs = require("node:fs");
const path = require("node:path");
const { describe, it, before, after } = require("node:test");
const assert = require("node:assert/strict");

const ROOT = fs.mkdtempSync(path.join(os.tmpdir(), "agenthub-db-retention-"));
process.env.DASHBOARD_DB_PATH = path.join(ROOT, "dashboard.db");
process.env.AGENTHUB_SETTINGS_FILE = path.join(ROOT, "settings.env");
process.env.DASHBOARD_LIVENESS_PROBE = "0";
delete process.env.AGENTHUB_RETENTION_DAYS;

const { createApp, startServer } = require("../index");
const { db } = require("../db");
const retention = require("../lib/db-retention");

let server;
let BASE;
before(async () => {
  server = await startServer(createApp(), 0);
  BASE = `http://127.0.0.1:${server.address().port}`;
});
after(() => {
  server?.close();
  delete process.env.AGENTHUB_RETENTION_DAYS;
  fs.rmSync(ROOT, { recursive: true, force: true });
});

async function call(method, urlPath, body) {
  const res = await fetch(BASE + urlPath, {
    method,
    headers: body ? { "content-type": "application/json" } : {},
    body: body ? JSON.stringify(body) : undefined,
  });
  return { status: res.status, body: await res.json() };
}

const daysAgo = (n) => new Date(Date.now() - n * 86400 * 1000).toISOString();

function seed(id, status, startedAt, events = 3) {
  db.prepare(
    "INSERT INTO sessions (id, name, status, cwd, started_at, updated_at) VALUES (?, ?, ?, '/tmp', ?, ?)"
  ).run(id, id, status, startedAt, startedAt);
  const ins = db.prepare(
    "INSERT INTO events (session_id, event_type, summary, data, created_at) VALUES (?, 'PostToolUse', 's', ?, ?)"
  );
  for (let i = 0; i < events; i++)
    ins.run(id, JSON.stringify({ pad: "x".repeat(2000) }), startedAt);
}
const exists = (id) => !!db.prepare("SELECT 1 FROM sessions WHERE id = ?").get(id);
const eventCount = (id) =>
  db.prepare("SELECT COUNT(*) AS n FROM events WHERE session_id = ?").get(id).n;

describe("auto_vacuum", () => {
  it("a new database is INCREMENTAL", () => {
    assert.equal(db.pragma("auto_vacuum", { simple: true }), 2);
    assert.equal(retention.spaceInfo(db).auto_vacuum, "incremental");
  });
});

describe("retentionConfig", () => {
  it("is off by default and for anything out of range", () => {
    assert.equal(retention.retentionConfig({}).days, 0);
    for (const v of ["", "0", "-3", "1.5", "abc", "99999"]) {
      assert.equal(retention.retentionConfig({ AGENTHUB_RETENTION_DAYS: v }).days, 0, v);
    }
    assert.equal(retention.retentionConfig({ AGENTHUB_RETENTION_DAYS: "30" }).days, 30);
  });
});

describe("scheduled maintenance", () => {
  it("purges nothing while retention is off", async () => {
    seed("ret-off-old", "completed", daysAgo(400));
    const out = await retention.runScheduledMaintenance({ db });
    assert.equal(out.retention, undefined);
    assert.ok(exists("ret-off-old"));
    db.prepare("DELETE FROM sessions WHERE id = 'ret-off-old'").run();
  });

  it("purges only finished sessions older than the cutoff, with their rows", async () => {
    seed("ret-old-done", "completed", daysAgo(100));
    seed("ret-old-err", "error", daysAgo(100));
    seed("ret-old-active", "active", daysAgo(100));
    seed("ret-new-done", "completed", daysAgo(5));
    db.prepare(
      "INSERT INTO token_usage (session_id, model, input_tokens) VALUES ('ret-old-done', 'm', 1)"
    ).run();
    process.env.AGENTHUB_RETENTION_DAYS = "30";
    try {
      const out = await retention.runScheduledMaintenance({ db });
      assert.equal(out.retention.purged_sessions, 2);
      assert.equal(out.retention.purged_events, 6);
    } finally {
      delete process.env.AGENTHUB_RETENTION_DAYS;
    }
    assert.ok(!exists("ret-old-done"));
    assert.ok(!exists("ret-old-err"));
    assert.equal(eventCount("ret-old-done"), 0);
    assert.equal(
      db.prepare("SELECT COUNT(*) AS n FROM token_usage WHERE session_id = 'ret-old-done'").get().n,
      0
    );
    assert.ok(exists("ret-old-active"), "an active session is never purged");
    assert.ok(exists("ret-new-done"), "a recent session is kept");
    assert.equal(eventCount("ret-new-done"), 3);
  });

  it("works in bounded batches and stops at the per-run cap", async () => {
    for (let i = 0; i < 7; i++) seed(`ret-batch-${i}`, "abandoned", daysAgo(50), 1);
    const first = await retention.applyRetention({ db, days: 10, batch: 2, maxSessions: 5 });
    assert.equal(first.purged_sessions, 5);
    const second = await retention.applyRetention({ db, days: 10, batch: 2, maxSessions: 5 });
    assert.equal(second.purged_sessions, 2);
    const third = await retention.applyRetention({ db, days: 10 });
    assert.equal(third.purged_sessions, 0);
  });

  it("returns free pages to the OS", async () => {
    for (let i = 0; i < 40; i++) seed(`ret-big-${i}`, "completed", daysAgo(60), 20);
    await retention.applyRetention({ db, days: 30 });
    const before = db.pragma("freelist_count", { simple: true });
    assert.ok(before > 50, `expected free pages, got ${before}`);
    const out = await retention.reclaimFreePages({ db, minPages: 10, slice: 16 });
    assert.ok(out.reclaimed_pages > 0);
    assert.ok(db.pragma("freelist_count", { simple: true }) < before);
  });
});

describe("routes", () => {
  it("GET reports retention off by default", async () => {
    const r = await call("GET", "/api/settings/retention");
    assert.equal(r.status, 200);
    assert.equal(r.body.days, 0);
    assert.equal(r.body.compacting, false);
    assert.equal(r.body.space.auto_vacuum, "incremental");
  });

  it("PUT validates and persists, 0 turns it off", async () => {
    for (const bad of [-1, 1.5, "7", 99999, null]) {
      const r = await call("PUT", "/api/settings/retention", { days: bad });
      assert.equal(r.status, 400, String(bad));
    }
    let r = await call("PUT", "/api/settings/retention", { days: 90 });
    assert.equal(r.status, 200);
    assert.equal(r.body.days, 90);
    assert.match(fs.readFileSync(process.env.AGENTHUB_SETTINGS_FILE, "utf8"), /RETENTION_DAYS=90/);
    r = await call("PUT", "/api/settings/retention", { days: 0 });
    assert.equal(r.body.days, 0);
  });

  it("POST /compact needs confirm and then vacuums", async () => {
    let r = await call("POST", "/api/settings/compact", {});
    assert.equal(r.status, 400);
    r = await call("POST", "/api/settings/compact", { confirm: true });
    assert.equal(r.status, 202);
    for (let i = 0; i < 200 && retention.isCompacting(); i++) {
      await new Promise((res) => setTimeout(res, 50));
    }
    const last = retention.lastCompactResult();
    assert.equal(last?.ok, true, last?.error);
    assert.equal(db.pragma("auto_vacuum", { simple: true }), 2);
  });
});