import { randomUUID } from 'node:crypto';
import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest';
import { newFixture, type Fixture } from '../helpers/fixture.js';

vi.mock('../../src/lib/server/integrations/komodo.js', () => ({ komodoInspectHealthy: vi.fn() }));
vi.mock('../../src/lib/server/integrations/rcon.js', () => ({ rconStatusResult: vi.fn() }));

const server = 'managed';
const now = Date.parse('2026-10-05T16:00:00Z');
const healthy = { ok: true as const, state: 'running' };
const playing = { ok: true as const, endpoint: { host: 'localhost', port: 28960 }, rawReply: 'status',
    status: { players: 2, map: 'zombie_theater', gametype: 'zom', roster: [] } };
let fixture: Fixture;

beforeEach(async () => {
    vi.resetModules(); vi.clearAllMocks();
    fixture = await newFixture([]);
    vi.useFakeTimers({ toFake: ['Date'] }); vi.setSystemTime(now);
});
afterEach(async () => { vi.useRealTimers(); await fixture.cleanup(); vi.restoreAllMocks(); });

async function setup() {
    const { db } = await import('../../src/lib/server/db/index.js');
    const database = db();
    database.prepare('INSERT INTO servers(name,komodo_name,created_at,game_port) VALUES(?,?,?,28960)')
        .run(server, server, new Date(now).toISOString());
    const { komodoInspectHealthy } = await import('../../src/lib/server/integrations/komodo.js');
    const { rconStatusResult } = await import('../../src/lib/server/integrations/rcon.js');
    const inspect = vi.mocked(komodoInspectHealthy).mockResolvedValue(healthy);
    const rcon = vi.mocked(rconStatusResult).mockResolvedValue(playing);
    return { database, inspect, rcon, ...await import('../../src/lib/server/fleet/health-observations.js') };
}

async function native(api: Awaited<ReturnType<typeof setup>>) {
    const hosts = await import('../../src/lib/server/hosts/index.js');
    const host = hosts.createHost({ name: 'Monitoring host' });
    hosts.enrollHost(hosts.createEnrollment(host.id).token, { protocolVersion: 1 });
    const instanceId = randomUUID();
    api.database.prepare(`INSERT INTO native_instances(id,server,host_id,library_id,image,port,created_at)
        VALUES(?,?,?,'library','image',28960,?)`).run(instanceId, server, host.id, new Date(now).toISOString());
    return { host, instanceId, hosts };
}

function deferred<T>() {
    let resolve!: (value: T) => void;
    const promise = new Promise<T>(done => { resolve = done; });
    return { promise, resolve };
}

describe('shared monitoring observations', () => {
    it.each(['inspect', 'rcon'] as const)('reuses %s results until 30 seconds after request start without refreshing their timestamp', async kind => {
        const api = await setup();
        const call = kind === 'inspect' ? api.inspectForMonitoring : api.rconForMonitoring;
        const request = kind === 'inspect' ? api.inspect : api.rcon;
        const first = await call(server);
        expect(first.observedAt).toBe(new Date(now).toISOString());
        vi.setSystemTime(now + 29_999);
        expect(await call(server)).toEqual(first);
        expect(request).toHaveBeenCalledTimes(1);
        vi.setSystemTime(now + 30_000);
        expect((await call(server)).observedAt).toBe(new Date(now + 30_000).toISOString());
        expect(request).toHaveBeenCalledTimes(2);
    });

    it('shares overlapping monitoring requests, but keeps inspection and RCON separate', async () => {
        const api = await setup();
        const pending = deferred<typeof healthy>();
        api.inspect.mockReturnValueOnce(pending.promise);
        const observations = [api.inspectForMonitoring(server), api.inspectForMonitoring(server)];
        await api.rconForMonitoring(server);
        expect(api.inspect).toHaveBeenCalledTimes(1);
        expect(api.rcon).toHaveBeenCalledTimes(1);
        vi.setSystemTime(now + 5000);
        pending.resolve(healthy);
        expect(await Promise.all(observations)).toEqual(Array(2).fill({ result: healthy, observedAt: new Date(now + 5000).toISOString() }));
    });

    it('timestamps a slow result on completion without making it reusable after its request expires', async () => {
        const api = await setup();
        const pending = deferred<typeof healthy>();
        api.inspect.mockReturnValueOnce(pending.promise);
        const observation = api.inspectForMonitoring(server);
        await Promise.resolve();
        vi.setSystemTime(now + 31_000);
        pending.resolve(healthy);
        expect(await observation).toEqual({ result: healthy, observedAt: new Date(now + 31_000).toISOString() });
        await api.inspectForMonitoring(server);
        expect(api.inspect).toHaveBeenCalledTimes(2);
    });

    it('reuses the saved completion timestamp while expiring from the earlier request start', async () => {
        const api = await setup();
        const pending = deferred<typeof healthy>();
        api.inspect.mockReturnValueOnce(pending.promise);
        const observation = api.inspectForMonitoring(server);
        await Promise.resolve();
        vi.setSystemTime(now + 20_000);
        pending.resolve(healthy);
        const completed = await observation;
        api.database.prepare('UPDATE servers SET container_checked_at=? WHERE name=?').run(completed.observedAt, server);
        vi.setSystemTime(now + 25_000);
        expect(await api.inspectForMonitoring(server)).toEqual(completed);
        expect(api.inspect).toHaveBeenCalledTimes(1);
        vi.setSystemTime(now + 30_000);
        await api.inspectForMonitoring(server);
        expect(api.inspect).toHaveBeenCalledTimes(2);
    });

    it('does not reuse observations from a future clock', async () => {
        const api = await setup();
        await api.inspectForMonitoring(server);
        vi.setSystemTime(now - 1);
        await api.inspectForMonitoring(server);
        expect(api.inspect).toHaveBeenCalledTimes(2);
    });

    it('does not cache failed results or rejected requests', async () => {
        const api = await setup();
        api.inspect.mockResolvedValueOnce({ ok: false, state: 'stopped', reason: 'Stopped' });
        expect((await api.inspectForMonitoring(server)).result.ok).toBe(false);
        await api.inspectForMonitoring(server);
        expect(api.inspect).toHaveBeenCalledTimes(2);
        api.rcon.mockRejectedValueOnce(new Error('Unavailable'));
        await expect(api.rconForMonitoring(server)).rejects.toThrow('Unavailable');
        await api.rconForMonitoring(server);
        expect(api.rcon).toHaveBeenCalledTimes(2);
    });

    it('forced checks bypass completed results and evict old success when the forced result fails', async () => {
        const api = await setup();
        await api.inspectForMonitoring(server);
        api.inspect.mockResolvedValueOnce({ ok: false, state: 'stopped', reason: 'Stopped' });
        expect((await api.inspectForMonitoring(server, true)).result.ok).toBe(false);
        await api.inspectForMonitoring(server);
        expect(api.inspect).toHaveBeenCalledTimes(3);
    });

    it('forced checks bypass wrapper overlap and an older reply cannot replace the newer cache entry', async () => {
        const api = await setup();
        const old = deferred<typeof healthy>();
        api.inspect.mockReturnValueOnce(old.promise);
        const first = api.inspectForMonitoring(server);
        await Promise.resolve();
        vi.setSystemTime(now + 1000);
        const latest = await api.inspectForMonitoring(server, true);
        old.resolve(healthy); await first;
        expect(await api.inspectForMonitoring(server)).toEqual(latest);
        expect(api.inspect).toHaveBeenCalledTimes(2);
    });

    it.each(['registration', 'lifecycle', 'desired state', 'stop'] as const)('invalidates cached observations after a %s change', async change => {
        const api = await setup();
        await api.inspectForMonitoring(server);
        if (change === 'registration') api.database.prepare('UPDATE servers SET created_at=? WHERE name=?').run(new Date(now + 1).toISOString(), server);
        if (change === 'lifecycle') api.database.prepare('INSERT INTO restart_rollout(server,requested_at) VALUES(?,?)').run(server, new Date(now + 1).toISOString());
        if (change === 'desired state') api.database.prepare("UPDATE servers SET desired_state='stopped' WHERE name=?").run(server);
        if (change === 'stop') api.database.prepare(`INSERT INTO server_deployments(id,server,action,state,stage,started_at,submitted_at,triggered_by)
            VALUES('stop',?,'stop','awaiting-health','Stopping',?,?,'ui')`).run(server, new Date(now).toISOString(), new Date(now + 1).toISOString());
        await api.inspectForMonitoring(server);
        expect(api.inspect).toHaveBeenCalledTimes(2);
    });

    it('invalidates integration changes and accepts legacy port discovery by the successful RCON probe', async () => {
        const api = await setup();
        await api.inspectForMonitoring(server);
        api.database.prepare("UPDATE servers SET komodo_name='replacement' WHERE name=?").run(server);
        await api.inspectForMonitoring(server);
        expect(api.inspect).toHaveBeenCalledTimes(2);
        api.database.prepare('UPDATE servers SET game_port=NULL WHERE name=?').run(server);
        api.rcon.mockImplementationOnce(async () => {
            api.database.prepare('UPDATE servers SET game_port=28960 WHERE name=?').run(server);
            return playing;
        });
        expect((await api.rconForMonitoring(server)).result).toEqual(playing);
        await api.rconForMonitoring(server);
        expect(api.rcon).toHaveBeenCalledTimes(1);
        api.database.prepare('UPDATE servers SET game_port=28961 WHERE name=?').run(server);
        await api.rconForMonitoring(server);
        expect(api.rcon).toHaveBeenCalledTimes(2);
    });

    it.each(['inspect', 'rcon'] as const)('does not reuse %s after a newer manual observation', async kind => {
        const api = await setup();
        const call = kind === 'inspect' ? api.inspectForMonitoring : api.rconForMonitoring;
        const request = kind === 'inspect' ? api.inspect : api.rcon;
        const field = kind === 'inspect' ? 'container_checked_at' : 'last_checked_at';
        await call(server);
        vi.setSystemTime(now + 1000);
        api.database.prepare(`UPDATE servers SET ${field}=? WHERE name=?`).run(new Date(now + 1000).toISOString(), server);
        await call(server);
        expect(request).toHaveBeenCalledTimes(2);
    });

    it('rejects a previous generation completing after replacement without discarding the new generation cache', async () => {
        const api = await setup();
        const { instanceId } = await native(api);
        const pending = deferred<typeof healthy>();
        api.inspect.mockReturnValueOnce(pending.promise);
        const old = api.inspectForMonitoring(server);
        const rejected = expect(old).rejects.toThrow('Server changed');
        await Promise.resolve();
        api.database.prepare('UPDATE native_instances SET generation=2 WHERE id=?').run(instanceId);
        const current = await api.inspectForMonitoring(server);
        pending.resolve(healthy); await rejected;
        expect(await api.inspectForMonitoring(server)).toEqual(current);
        expect(api.inspect).toHaveBeenCalledTimes(2);
    });

    it('rejects a result when a lifecycle request arrives while its probe is in flight', async () => {
        const api = await setup();
        const pending = deferred<typeof playing>();
        api.rcon.mockReturnValueOnce(pending.promise);
        const old = api.rconForMonitoring(server);
        const rejected = expect(old).rejects.toThrow('Server changed');
        await Promise.resolve();
        api.database.prepare('INSERT INTO restart_rollout(server,requested_at) VALUES(?,?)').run(server, new Date(now + 1).toISOString());
        pending.resolve(playing); await rejected;
        await api.rconForMonitoring(server);
        expect(api.rcon).toHaveBeenCalledTimes(2);
    });

    it('discards a slow result when a newer manual observation was saved during the request', async () => {
        const api = await setup();
        const pending = deferred<typeof playing>();
        api.rcon.mockReturnValueOnce(pending.promise);
        const old = api.rconForMonitoring(server);
        const rejected = expect(old).rejects.toBeInstanceOf(api.MonitoringChangedError);
        await Promise.resolve();
        vi.setSystemTime(now + 1000);
        api.database.prepare('UPDATE servers SET last_checked_at=? WHERE name=?').run(new Date().toISOString(), server);
        pending.resolve(playing); await rejected;
        await api.rconForMonitoring(server);
        expect(api.rcon).toHaveBeenCalledTimes(2);
    });

    it('discards cached native success while its host is offline and probes again after reconnecting', async () => {
        const api = await setup();
        const { host, hosts } = await native(api);
        await api.inspectForMonitoring(server);
        api.database.prepare('UPDATE ec_hosts SET last_heartbeat=NULL WHERE id=?').run(host.id);
        await expect(api.inspectForMonitoring(server)).rejects.toThrow('Host agent is offline');
        expect(api.inspect).toHaveBeenCalledTimes(1);
        hosts.heartbeat(host.id, { protocolVersion: 1 });
        await api.inspectForMonitoring(server);
        expect(api.inspect).toHaveBeenCalledTimes(2);
    });

    it('rejects an otherwise successful result if the native host went offline during the probe', async () => {
        const api = await setup();
        const { host } = await native(api);
        const pending = deferred<typeof healthy>();
        api.inspect.mockReturnValueOnce(pending.promise);
        const observation = api.inspectForMonitoring(server);
        const rejected = expect(observation).rejects.toThrow('Host agent is offline');
        await Promise.resolve();
        api.database.prepare('UPDATE ec_hosts SET last_heartbeat=NULL WHERE id=?').run(host.id);
        pending.resolve(healthy); await rejected;
    });
});