// Replays every scenario in test/scenarios with the TypeScript engine and
// compares the result with what the filius-ipad Swift engine produced for the
// same file (<name>.swift.json, written by tools/swift-oracle/run.sh).
// Every trace event must match: identity, time, node, headers, detail.

import { readdirSync, readFileSync } from 'node:fs';
import { dirname, join } from 'node:path';
import { fileURLToPath } from 'node:url';
import { describe, expect, it } from 'vitest';
import {
  deviceConfiguration,
  firewallConfiguration,
  firewallRule,
  interfaceKey,
  NetworkRuntimeEngine,
  portSnapshot,
  switchConfiguration,
  topologySnapshot,
  type FirewallConfiguration,
  type IPv4DeliveryResult,
  type IcmpObservation,
  type ManualRoute,
  type NodeKind,
  type TopologySnapshot,
  type TraceEvent,
} from '../src/index.js';

const scenarioDirectory = join(dirname(fileURLToPath(import.meta.url)), 'scenarios');

interface Scenario {
  seed: number;
  speedPercent?: number;
  nodes: { id: string; kind: NodeKind; ports: { id: string; label: string; mac?: string }[] }[];
  links: { id: string; sourceNode: string; sourcePort: string; targetNode: string; targetPort: string }[];
  devices?: Record<string, { ip: string; mask: string; gateway?: string; dns?: string }>;
  interfaces?: { node: string; port: string; ip: string; mask: string }[];
  routes?: Record<string, { destination: string; mask: string; gateway: string; interface: string }[]>;
  switches?: Record<string, { ssid: string; retention?: number }>;
  firewalls?: Record<
    string,
    {
      active?: boolean;
      defaultPolicy?: 'accept' | 'drop';
      dropIcmp?: boolean;
      synOnly?: boolean;
      filterUdp?: boolean;
      rules?: {
        source?: string;
        sourceMask?: string;
        destination?: string;
        destinationMask?: string;
        port?: number;
        protocol?: 'all' | 'icmp' | 'tcp' | 'udp';
        action?: 'accept' | 'drop';
      }[];
    }
  >;
  steps: {
    op: string;
    from?: string;
    node?: string;
    target?: string;
    ttl?: number;
    identifier?: number;
    sequence?: number;
    maxTtl?: number;
    to?: number;
    enabled?: boolean;
    percent?: number;
    // UDP: a socket is named by the id bindUdp returned.
    port?: number;
    localIp?: string;
    remoteIp?: string;
    remotePort?: number;
    socket?: string;
    payload?: string;
    timeout?: number;
  }[];
}

function snapshotOf(scenario: Scenario): TopologySnapshot {
  const firewalls = new Map<string, FirewallConfiguration>();
  for (const [node, config] of Object.entries(scenario.firewalls ?? {})) {
    firewalls.set(
      node,
      firewallConfiguration({
        isActive: config.active ?? false,
        defaultPolicy: config.defaultPolicy ?? 'drop',
        dropIcmp: config.dropIcmp ?? false,
        filterSynSegmentsOnly: config.synOnly ?? true,
        filterUdp: config.filterUdp ?? true,
        rules: (config.rules ?? []).map((rule) =>
          firewallRule({
            sourceIPAddress: rule.source ?? '',
            sourceSubnetMask: rule.sourceMask ?? '',
            destinationIPAddress: rule.destination ?? '',
            destinationSubnetMask: rule.destinationMask ?? '',
            ...(rule.port === undefined ? {} : { port: rule.port }),
            protocol: rule.protocol ?? 'tcp',
            action: rule.action ?? 'drop',
          }),
        ),
      }),
    );
  }
  return topologySnapshot({
    nodes: scenario.nodes.map((node) => ({
      id: node.id,
      kind: node.kind,
      ports: node.ports.map((port) => portSnapshot(port.id, port.label, port.mac)),
    })),
    links: scenario.links.map((link) => ({
      id: link.id,
      sourceNodeId: link.sourceNode,
      sourcePortId: link.sourcePort,
      targetNodeId: link.targetNode,
      targetPortId: link.targetPort,
    })),
    deviceConfigurations: new Map(
      Object.entries(scenario.devices ?? {}).map(([node, device]) => [
        node,
        deviceConfiguration(device.ip, device.mask, device.gateway ?? '', device.dns ?? ''),
      ]),
    ),
    interfaceConfigurations: new Map(
      (scenario.interfaces ?? []).map((item) => [
        interfaceKey(item.node, item.port),
        { ipAddress: item.ip, subnetMask: item.mask },
      ]),
    ),
    manualRoutesByNodeId: new Map(
      Object.entries(scenario.routes ?? {}).map(([node, rows]) => [
        node,
        rows.map(
          (row): ManualRoute => ({
            destinationNetwork: row.destination,
            subnetMask: row.mask,
            gateway: row.gateway,
            interfaceIPAddress: row.interface,
          }),
        ),
      ]),
    ),
    switchConfigurationsByNodeId: new Map(
      Object.entries(scenario.switches ?? {}).map(([node, config]) => [
        node,
        config.retention === undefined ? switchConfiguration(config.ssid) : switchConfiguration(config.ssid, config.retention),
      ]),
    ),
    firewallConfigurationsByNodeId: firewalls,
  });
}

const upper = (id: string) => id.toUpperCase();

function traceJson(event: TraceEvent): Record<string, unknown> {
  return {
    id: event.id,
    time: event.timeMilliseconds,
    node: upper(event.nodeId),
    direction: event.direction,
    layer: event.layer,
    operation: event.operation,
    before: event.beforeHeaders.map((field) => [field.name, field.value]),
    after: event.afterHeaders.map((field) => [field.name, field.value]),
    ...(event.frameIdentity === undefined ? {} : { frame: event.frameIdentity }),
    ...(event.packetIdentity === undefined ? {} : { packet: event.packetIdentity }),
    ...(event.interfaceId === undefined ? {} : { interface: upper(event.interfaceId) }),
    ...(event.detail === undefined ? {} : { detail: event.detail }),
  };
}

function deliveryJson(result: IPv4DeliveryResult): Record<string, unknown> {
  switch (result.type) {
    case 'delivered':
      return { type: 'delivered', packet: result.packetIdentity, node: upper(result.nodeId) };
    case 'icmpError':
      return { type: 'icmpError', packet: result.packetIdentity, node: upper(result.nodeId), kind: result.kind };
    case 'dropped':
      return {
        type: 'dropped',
        packet: result.packetIdentity,
        ...(result.nodeId === undefined ? {} : { node: upper(result.nodeId) }),
      };
  }
}

function observationJson(item: IcmpObservation): Record<string, unknown> {
  return {
    kind: item.message.kind,
    identifier: item.message.identifier,
    sequence: item.message.sequenceNumber,
    sender: item.packet.senderIPAddress,
  };
}

function run(scenario: Scenario): Record<string, unknown> {
  const engine = new NetworkRuntimeEngine(scenario.seed);
  if (scenario.speedPercent !== undefined) engine.setSimulationSpeed(scenario.speedPercent);
  engine.handle({ type: 'start', snapshot: snapshotOf(scenario), seed: scenario.seed, initialTimeMilliseconds: 0 });

  const results: unknown[] = [];
  for (const step of scenario.steps) {
    switch (step.op) {
      case 'ping':
        results.push(
          deliveryJson(
            engine.sendIcmpEcho(step.from!, step.target!, {
              timeToLive: step.ttl ?? 64,
              identifier: step.identifier ?? 1,
              sequenceNumber: step.sequence ?? 1,
            }),
          ),
        );
        break;
      case 'traceroute':
        results.push(
          engine
            .traceIcmpEcho(step.from!, step.target!, {
              maximumTimeToLive: step.maxTtl ?? 64,
              identifier: step.identifier ?? 1,
            })
            .map(observationJson),
        );
        break;
      case 'resolveMac':
        results.push(engine.resolveMacAddress(step.node!, step.target!) ?? null);
        break;
      case 'advance':
        engine.handle({ type: 'advance', toMilliseconds: step.to! });
        results.push(engine.state.currentTimeMilliseconds);
        break;
      case 'packetLoss':
        engine.setGlobalPacketLossEnabled(step.enabled!);
        results.push(engine.state.globalPacketLossEnabled);
        break;
      case 'sat':
        results.push(
          engine.switchSatEntries(step.node!).map((entry) => ({
            mac: entry.macAddress,
            port: entry.portLabel,
            updated: entry.updatedAtMilliseconds,
          })),
        );
        break;
      case 'speed':
        engine.setSimulationSpeed(step.percent!);
        results.push(engine.simulationSpeed.percent);
        break;
      case 'bindUdp':
        results.push(
          engine.bindUdpSocket(step.node!, {
            ...(step.port === undefined ? {} : { localPort: step.port }),
            ...(step.localIp === undefined ? {} : { localIPAddress: step.localIp }),
            ...(step.remoteIp === undefined ? {} : { remoteIPAddress: step.remoteIp }),
            ...(step.remotePort === undefined ? {} : { remotePort: step.remotePort }),
          }) ?? null,
        );
        break;
      case 'sendUdp': {
        const result = engine.sendUdp(step.socket!, new TextEncoder().encode(step.payload ?? ''), {
          ...(step.target === undefined ? {} : { ipAddress: step.target }),
          ...(step.port === undefined ? {} : { port: step.port }),
        });
        results.push(result === undefined ? null : deliveryJson(result));
        break;
      }
      case 'receiveUdp': {
        const item = engine.receiveUdp(step.socket!, step.timeout ?? 0);
        results.push(
          item === undefined
            ? null
            : {
                sender: item.senderIPAddress,
                receiver: item.receiverIPAddress,
                sourcePort: item.datagram.sourcePort,
                destinationPort: item.datagram.destinationPort,
                payload: new TextDecoder().decode(item.datagram.payload),
                at: item.receivedAtMilliseconds,
              },
        );
        break;
      }
      case 'closeSocket':
        engine.closeSocket(step.socket!);
        results.push(!engine.state.socketsById.has(step.socket!));
        break;
      default:
        throw new Error(`unknown step ${step.op}`);
    }
  }

  const state = engine.state;
  const mapOf = <V>(map: Map<string, V>, convert: (value: V) => unknown) =>
    Object.fromEntries([...map].map(([key, value]) => [upper(key), convert(value)]));
  return {
    results,
    traces: state.packetTraces.map(traceJson),
    time: state.currentTimeMilliseconds,
    pendingEvents: state.pendingEvents.length,
    arp: mapOf(state.arpCachesByNodeId, (cache) =>
      Object.fromEntries([...cache].map(([ip, entry]) => [ip, entry.macAddress])),
    ),
    switchTables: mapOf(state.switchForwardingTablesByNodeId, (table) =>
      Object.fromEntries([...table].map(([mac, port]) => [mac, upper(port)])),
    ),
    icmpObservations: mapOf(state.icmpObservationsByNodeId, (items) => items.map(observationJson)),
    sockets: [...state.socketsById.values()]
      .sort((lhs, rhs) => (upper(lhs.id) < upper(rhs.id) ? -1 : 1))
      .map((socket) => ({
        id: upper(socket.id),
        node: upper(socket.nodeId),
        protocol: socket.protocol,
        localIp: socket.localIPAddress ?? null,
        localPort: socket.localPort,
        remoteIp: socket.remoteIPAddress ?? null,
        remotePort: socket.remotePort ?? null,
        queued: state.udpReceiveQueuesBySocketId.get(socket.id)?.length ?? 0,
      })),
    firewallDecisions: state.firewallDecisions.map((decision) => ({
      packet: decision.packetIdentity,
      node: upper(decision.nodeId),
      accepted: decision.accepted,
      ...(decision.ruleIndex === undefined ? {} : { rule: decision.ruleIndex }),
    })),
  };
}

const scenarioNames = readdirSync(scenarioDirectory)
  .filter((name) => name.endsWith('.scenario.json'))
  .map((name) => name.replace('.scenario.json', ''))
  .sort();

describe('same result as the Swift engine', () => {
  it('has scenarios with Swift results', () => {
    expect(scenarioNames.length).toBeGreaterThan(0);
  });

  for (const name of scenarioNames) {
    it(name, () => {
      const scenario = JSON.parse(readFileSync(join(scenarioDirectory, `${name}.scenario.json`), 'utf8')) as Scenario;
      const expected = JSON.parse(readFileSync(join(scenarioDirectory, `${name}.swift.json`), 'utf8')) as Record<
        string,
        unknown
      >;
      const actual = run(scenario);

      // Traces first and one by one: the first difference is the one that matters.
      const expectedTraces = expected.traces as unknown[];
      const actualTraces = actual.traces as unknown[];
      for (let index = 0; index < Math.max(expectedTraces.length, actualTraces.length); index += 1) {
        expect(actualTraces[index], `trace event #${index + 1}`).toEqual(expectedTraces[index]);
      }
      expect(actual).toEqual(expected);
    });
  }
});