// FILIUS' own examples run as Java FILIUS runs them (the acceptance of F2).
// tools/java-oracle's ExampleRun opened each file in Java FILIUS as FILIUS
// opens it, started it as the action mode does, played a story and wrote
// every frame each card saw, the capture's tables, the story's calls and the
// hosts' addresses (examples/<story>.java.json). Here the file is read with
// this package's reader and run in the core (projectSnapshot); each card's
// capture must hold the same frames at about the same times with the same
// table rows (javaRun.ts, cards by their MAC address from the file), the
// calls must return the same, the hosts must end with the same addresses.

import { describe, expect, it } from 'vitest';
import { interfaceKey, NetworkRuntimeEngine, stableMacAddress, type DnsAddressResolution, type Id, type IPv4DeliveryResult } from '@mdg-filius/core';
import { projectSnapshot } from '../src/index.js';
import { exampleCards, exampleRecording, namesInJavaOrder, openExample } from './exampleRun.js';
import {
  engineText,
  expectSameCaptures,
  GAP_TOLERANCE_MILLISECONDS,
  gaps,
  javaFrames,
  withClientPortText,
  type JavaFrame,
  type JavaTables,
  type SeenFrame,
} from '../../core/test/javaRun.js';

const SEED = 14;

interface JavaRun extends JavaTables {
  frames: Record<string, JavaFrame[]>;
  events: [number, string][];
  devices: Record<string, [string, string, string, string]>;
  /** Each card's MAC address in Java and its node's name with the card's index, `name/index`. */
  cards: Record<string, string>;
}

type Call = (label: string, run: () => string) => void;

interface Story {
  readonly file: string;
  /**
   * Hosts that start their DHCP clients together: which sends first is up to
   * Java's threads, and its log loses some of their frames (dhcpJava.test.ts).
   * Compared per client instead of per card: its own frames and the
   * server's answers to it, the long waits at about the same distances. Which address a
   * client gets follows the order the server hears them in: an address of
   * the server's range (`dhcpRange`) is a placeholder, and the hosts must
   * end with the same addresses, in any order.
   */
  readonly dhcpClients?: readonly string[];
  readonly dhcpRange?: RegExp;
  /**
   * When the story's calls begin (the engine's time), after the DHCP clients
   * are done: the clients are compared before it, each card from it on, both
   * counted from the first call.
   */
  readonly storyStart?: number;
  readonly play: (engine: NetworkRuntimeEngine, node: (name: string) => Id, call: Call) => void;
}

const ICMP_CODES: Record<string, string> = { timeExceeded: '11/0', destinationNetworkUnreachable: '3/0', destinationHostUnreachable: '3/1' };

/** A ping in Java's words (ICMP.sendProbe): the answer's type, code and sender, or null. */
function ping(engine: NetworkRuntimeEngine, from: Id, target: string, sequenceNumber: number): string {
  const result: IPv4DeliveryResult = engine.sendIcmpEcho(from, target, { sequenceNumber, identifier: 1 });
  const observations = engine.state.icmpObservationsByNodeId.get(from) ?? [];
  if (result.type === 'icmpError') {
    const error = observations.findLast((observation) => observation.message.kind === result.kind);
    return `ICMP ${ICMP_CODES[result.kind]} from ${error?.packet.senderIPAddress ?? '?'}`;
  }
  const reply = observations.find((observation) => observation.message.kind === 'echoReply' && observation.message.sequenceNumber === sequenceNumber);
  return reply === undefined ? 'null' : `ICMP 0/0 from ${reply.packet.senderIPAddress}`;
}

/** A lookup in Java's words (Resolver): the address, null, or the exception. */
function lookup(resolution: DnsAddressResolution): string {
  return resolution.type === 'timedOut' ? 'failed TimeOutException' : `returned ${resolution.address ?? 'null'}`;
}

const STORIES: Record<string, Story> = {
  routing: {
    file: 'internetwork_komplett.fls',
    play: (engine, node, call) => {
      call('sendProbe 141.99.5.10', () => ping(engine, node('Notebook 1.10'), '141.99.5.10', 1));
      call('sendProbe 141.99.5.10', () => ping(engine, node('Notebook 1.11'), '141.99.5.10', 2));
    },
  },
  dhcp: {
    file: 'einfaches_rechnernetz_komplett.fls',
    dhcpClients: ['Notebook 1', 'Notebook 2', 'Notebook 3', 'Notebook 4'],
    dhcpRange: /192\.168\.0\.2\d/g,
    play: () => {},
  },
  dns: {
    file: 'dns_server.fls',
    play: (engine, node, call) => {
      call('holeIPAdresse www.filius.de', () => lookup(engine.resolveDnsAddress(node('Notebook'), 'www.filius.de')));
      call('holeIPAdresseMailServer filius.de', () => lookup(engine.resolveDnsMailServer(node('Notebook'), 'filius.de')));
    },
  },
  firewall: {
    file: 'Internet_Komplett_mit_eMail_Webserver_Intranet_Portforwarding_Firewall_DHCP_DE.fls',
    dhcpClients: ['Notebook', 'Notebook#2', 'Heimrouter', 'Notebook#3', 'iPad 1', 'iPad 2', 'iPad 3', 'iPad 4'],
    dhcpRange: /10\.50\.50\.\d+/g,
    storyStart: 8_000,
    play: (engine, node, call) => {
      engine.handle({ type: 'advance', toMilliseconds: 8_000 });
      call('sendProbe 130.100.200.25', () => ping(engine, node('iPad 1'), '130.100.200.25', 1));
      call('sendProbe 130.100.200.25', () => ping(engine, node('Notebook'), '130.100.200.25', 2));
      call('sendProbe 42.0.0.10', () => ping(engine, node('mail.gmx.de (130.100.200.25)'), '42.0.0.10', 3));
    },
  },
  nat: {
    file: 'nat_with_mapped_port.fls',
    play: (engine, node, call) => {
      call('sendProbe 141.99.4.10', () => ping(engine, node('Notebook 1.10'), '141.99.4.10', 1));
      call('sendProbe 141.99.5.10', () => ping(engine, node('Notebook 1.10'), '141.99.5.10', 2));
    },
  },
};

/**
 * Where Java errs, per story: its run corrected, as Java means it.
 *
 * routing: Notebook 1.11 has no gateway; Java's sendProbe fails with a
 * NullPointerException (no route), the engine answers network unreachable
 * from the notebook itself, as a router does.
 *
 * nat: both pings leave with identifier 1. Java's Heimrouter Paul keeps one
 * entry per LAN endpoint, for its first remote end (natJava.test.ts,
 * udpTwoRemotes): the echo reply of the second, Heimrouter Vincent, finds no
 * entry and stays at Paul's WAN card. The engine adds an entry for the second
 * remote end: the reply goes on through Paul's LAN card to the notebook, a
 * cable later.
 */
const JAVA_BUGS: Record<string, (java: JavaRun) => JavaRun> = {
  routing: (java) => ({
    ...java,
    events: java.events.map(([time, event]) => [time, event === 'sendProbe 141.99.5.10 failed NullPointerException' ? 'sendProbe 141.99.5.10 returned ICMP 3/0 from 141.99.1.11' : event]),
  }),
  nat: (java) => {
    const card = (name: string) => Object.entries(java.cards).find(([, each]) => each === name)![0];
    const [paulWan, paulLan, notebook] = [card('Heimrouter Paul/0'), card('Heimrouter Paul/1'), card('Notebook 1.10/0')];
    const reply = java.frames[paulWan]!.find((frame) => frame.icmp === 0 && frame.sourceIp === '141.99.5.10')!;
    const request = java.frames[paulLan]!.find((frame) => frame.icmp === 8 && frame.destinationIp === '141.99.5.10')!;
    const onLan: JavaFrame = { ...reply, time: reply.time + 1, source: request.destination, destination: request.source, destinationIp: request.sourceIp! };
    const called = java.events.findIndex(([, event]) => event === 'sendProbe 141.99.5.10 called');
    return {
      ...java,
      frames: { ...java.frames, [paulLan]: [...java.frames[paulLan]!, onLan], [notebook]: [...java.frames[notebook]!, { ...onLan, time: onLan.time + 55 }] },
      events: java.events.map(([time, event], index) =>
        index === called + 1 ? [onLan.time + 55, 'sendProbe 141.99.5.10 returned ICMP 0/0 from 141.99.5.10'] : [time, event],
      ),
    };
  },
};

describe("FILIUS' examples as Java FILIUS runs them", () => {
  it('corrects Java only where it errs', () => {
    for (const [name, correct] of Object.entries(JAVA_BUGS)) {
      const java = exampleRecording<JavaRun>(name);
      expect(JSON.stringify(correct(java)), name).not.toBe(JSON.stringify(java));
    }
  });

  for (const [name, story] of Object.entries(STORIES)) {
    it(`${name}: ${story.file}`, () => {
      const measured = exampleRecording<JavaRun>(name);
      const java = JAVA_BUGS[name]?.(measured) ?? measured;
      const project = openExample(story.file);
      const names = namesInJavaOrder(project);
      const engine = new NetworkRuntimeEngine(SEED);
      engine.handle({ type: 'start', snapshot: projectSnapshot(project), seed: SEED, initialTimeMilliseconds: 0 });
      engine.handle({ type: 'advance', toMilliseconds: 500 });

      const events: [number, string][] = [];
      story.play(engine, (nodeName) => names.get(nodeName)!, (label, run) => {
        events.push([engine.state.currentTimeMilliseconds, `${label} called`]);
        events.push([engine.state.currentTimeMilliseconds, `${label} ${run().replace(/^(?!returned |failed )/, 'returned ')}`]);
      });
      const last = Math.max(...Object.values(java.frames).flat().map((frame) => frame.time), ...java.events.map(([time]) => time));
      engine.handle({ type: 'advance', toMilliseconds: Math.max(engine.state.currentTimeMilliseconds, last) + 1_000 });

      expect(events.map(([, event]) => event)).toEqual(java.events.map(([, event]) => event));
      const { cards, withEngineMacs } = exampleCards(project, names, java.cards);
      const javaStoryStart = java.events[0]?.[0];
      if (story.storyStart !== undefined) {
        expectSameCaptures(engine, cards, java.frames, {
          text: (text) => withClientPortText(withEngineMacs(text)).replace(/ID=\d+/g, 'ID=x'),
          cell: withEngineMacs,
          tables: measured,
          from: javaStoryStart!,
          starts: { java: javaStoryStart!, engine: story.storyStart },
        });
      }
      if (story.dhcpClients === undefined) {
        expectSameCaptures(engine, cards, java.frames, {
          text: (text) => withClientPortText(withEngineMacs(text)).replace(/ID=\d+/g, 'ID=x'),
          cell: withEngineMacs,
          tables: measured,
        });
      } else {
        // Each frame where it first shows on any card. Java's log loses some of a client's own frames at
        // its card, and four clients' broadcasts queue on the cables: a frame reaches the cards up to some
        // 450 ms apart, so the same text within a second is the same frame (a client repeats a message
        // only after a round trip, 2750 ms).
        const engineFrames = new Map<number, SeenFrame>();
        for (const { portId } of cards) {
          for (const each of engine.capture.frames(portId)) {
            if (!engineFrames.has(each.frame.identity)) engineFrames.set(each.frame.identity, { time: each.timeMilliseconds, text: engineText(each.frame) });
          }
        }
        const allEngine = [...engineFrames.values()].filter((frame) => frame.time < (story.storyStart ?? Infinity)).sort((lhs, rhs) => lhs.time - rhs.time);
        const allJava = javaFrames(java.frames, 1_000)
          .filter((frame) => story.storyStart === undefined || frame.time < javaStoryStart!).map((frame) => ({ ...frame, text: withEngineMacs(frame.text) }));
        for (const client of story.dhcpClients) {
          const port = project.graph.nodes.find((node) => node.id === names.get(client))!.ports[0]!;
          const mac = (port.importedMacAddress ?? stableMacAddress(port.id)).toUpperCase();
          const own = (frames: readonly SeenFrame[]) =>
            gaps(
              frames
                .filter((frame) => frame.text.startsWith(`${mac} >`) || frame.text.includes(`chaddr=${mac}`))
                .map((frame) => ({ ...frame, text: frame.text.replace(story.dhcpRange!, 'leased') })),
            );
          const [expected, actual] = [own(allJava), own(allEngine)];
          for (let index = 0; index < Math.max(expected.length, actual.length); index += 1) {
            expect(actual[index]?.text, `${client} frame #${index + 1}`).toBe(expected[index]?.text);
            // The server serves clients that come together one after the other, in the order Java's
            // threads happen to send, and their broadcasts queue on the cables: a short step depends on
            // how many frames are ahead (measured: up to some 550 ms with eight clients). Only the long
            // waits (a round trip) are compared, as tightly as elsewhere.
            if (expected[index]!.gap < 1_000) continue;
            expect(Math.abs(actual[index]!.gap - expected[index]!.gap), `${client} gap before frame #${index + 1}`).toBeLessThanOrEqual(GAP_TOLERANCE_MILLISECONDS);
          }
        }
      }

      // Java's addresses of a host's card (ScenarioNetwork.writeDevices: the first card of every node with
      // an IP stack); a router without a gateway has only its cards' settings in the model.
      const snapshot = engine.state.topologySnapshot;
      const devices = Object.fromEntries(
        [...names].flatMap(([nodeName, id]) => {
          const device = snapshot.deviceConfigurations.get(id);
          if (device !== undefined) return [[nodeName, [device.ipAddress, device.subnetMask, device.defaultGateway, device.dnsServer]]];
          const node = project.graph.nodes.find((each) => each.id === id)!;
          const card = node.ports[0] === undefined ? undefined : snapshot.interfaceConfigurations.get(interfaceKey(id, node.ports[0].id));
          return card === undefined || node.kind === 'networkSwitch' ? [] : [[nodeName, [card.ipAddress, card.subnetMask, '', '']]];
        }),
      );
      if (story.dhcpRange === undefined) {
        expect(devices).toEqual(java.devices);
      } else {
        const leased = (byName: Record<string, string[]>) =>
          Object.values(byName)
            .map((device) => device.join(' '))
            .sort();
        expect(leased(devices)).toEqual(leased(java.devices));
        expect(Object.keys(devices).sort()).toEqual(Object.keys(java.devices).sort());
      }
    });
  }
});