import * as fs from 'node:fs';
import * as os from 'node:os';
import * as path from 'node:path';
import { pathToFileURL } from 'node:url';

import type { MatrixActor } from '@open-matrix/core/core/MatrixActor.js';
import { RequestReply } from '@open-matrix/core/engine/remoting/RequestReply.js';
import { MatrixRuntime } from '@open-matrix/core/runtime/MatrixRuntime.js';
import { NatsTransport } from '@open-matrix/core/transport/NatsTransport.js';
import { connect as natsConnect, jwtAuthenticator, type NatsConnection } from 'nats';

import { loadMatrixServiceManifest, type ILoadedMatrixServiceManifest } from '../utils/service-manifest.js';
import { createRunnerSecurityRealm } from '../utils/runner-security.js';

export interface IActorRunCommandOptions {
  readonly natsUrl?: string;
  readonly root?: string;
  readonly space?: string;
  readonly jwt?: string;
  readonly seed?: string;
  readonly home?: string;
  readonly export?: string;
  readonly mount?: string;
  readonly json?: boolean;
  readonly props?: string;
  readonly checkOp?: string;
  readonly checkPayload?: string;
}

export interface IBrokerRunConfig {
  readonly natsUrl: string;
  readonly root: string;
  readonly jwt?: string;
  readonly seed?: string;
  readonly checked: readonly string[];
}

type ActorConstructor = {
  new (): MatrixActor;
  readonly accepts?: Record<string, unknown>;
  readonly emits?: Record<string, unknown>;
  readonly subscribes?: Record<string, unknown>;
  readonly name: string;
};

type PackageBootstrapFunction = (...args: readonly unknown[]) => Promise<unknown> | unknown;

export interface IPackageRunCommandOptions extends IActorRunCommandOptions {
  readonly entry?: string;
  readonly overrides?: string;
}

export interface IPackageRunSpec {
  readonly packageDir: string;
  readonly packageName: string;
  readonly manifestPath: string;
  readonly entryPath: string;
  readonly exportName: string;
  readonly mount: string;
  readonly actorId: string;
  readonly packageId: string;
  readonly runtimeId: string;
  readonly accepts: Record<string, unknown>;
  readonly emits: Record<string, unknown>;
  readonly subscribes: Record<string, unknown>;
  readonly overrides: Record<string, unknown>;
  readonly serviceInstance: ILoadedMatrixServiceManifest['serviceInstance'];
}

export async function actorRunCommand(
  entry: string,
  options: IActorRunCommandOptions,
): Promise<void> {
  const entryPath = path.resolve(entry);
  if (!fs.existsSync(entryPath)) {
    throw new Error(`Actor entry not found: ${entryPath}`);
  }
  const exportName = options.export?.trim() || 'default';
  const ActorClass = await loadActorConstructor(entryPath, exportName);
  const mount = options.mount?.trim() || inferMountFromEntry(entryPath);
  if (!mount) {
    throw new Error('matrix actor run requires --mount <mount> when it cannot infer a mount from the entry file');
  }
  const broker = resolveActorRunBroker(options);
  const connection = await connectActorNats(broker);
  const transport = new NatsTransport(connection, { root: broker.root });
  const runtime = new MatrixRuntime({
    transport,
    logging: false,
    allowDynamicCompilation: false,
    securityRealm: createRunnerSecurityRealm(),
  });

  const props = parseProps(options.props);
  await runtime.createSupervised(ActorClass, mount, props);
  await transport.flush();
  const check = await runOptionalActorCheck(runtime, mount, options);

  const result = {
    ok: true,
    mode: 'standalone-actor-runner',
    entry: entryPath,
    export: exportName,
    actor: ActorClass.name,
    mount,
    root: broker.root,
    effectiveMount: `${broker.root}.${mount}`,
    natsUrl: broker.natsUrl,
    authMode: broker.jwt ? 'jwt' : 'none',
    hostStateWritten: false,
    ...(check ? { check } : {}),
  };

  if (options.json) {
    console.log(JSON.stringify(result, null, 2));
  } else {
    console.log('Actor mounted:');
    console.log(`  logical:   ${result.mount}`);
    console.log(`  root:      ${result.root}`);
    console.log(`  effective: ${result.effectiveMount}`);
    console.log(`  broker:    ${result.natsUrl}`);
    console.log('Press Ctrl+C to stop.');
  }

  if (check) {
    await runtime.shutdown();
    await transport.disconnect();
    if (!connection.isClosed()) {
      await connection.close();
    }
    return;
  }

  await waitForActorShutdown(async () => {
    await runtime.shutdown();
    await transport.disconnect();
    if (!connection.isClosed()) {
      await connection.close();
    }
  });
}

export async function packageRunCommand(
  packageDir: string,
  options: IPackageRunCommandOptions,
): Promise<void> {
  const spec = resolvePackageRunSpec(packageDir, options);
  const broker = resolveActorRunBroker(options);
  const connection = await connectActorNats(broker);
  const transport = new NatsTransport(connection, { root: broker.root });
  const runtime = new MatrixRuntime({
    transport,
    logging: false,
    allowDynamicCompilation: false,
    securityRealm: createRunnerSecurityRealm(),
  });

  const bootstrap = await loadPackageBootstrap(spec.entryPath, spec.exportName);
  const bootstrapResult = await bootstrap(
    spec.overrides,
    { runtime },
    undefined,
    {
      packageName: spec.packageName,
      packageDir: spec.packageDir,
      manifestPath: spec.manifestPath,
      entryPath: spec.entryPath,
      exportName: spec.exportName,
      root: broker.root,
      mount: spec.mount,
      instance: spec.serviceInstance,
      serviceInstance: spec.serviceInstance,
    },
  );
  await transport.flush();
  const check = await runOptionalActorCheck(runtime, spec.mount, options);

  const result = {
    ok: true,
    mode: 'standalone-package-runner',
    packageDir: spec.packageDir,
    packageName: spec.packageName,
    manifest: spec.manifestPath,
    entry: spec.entryPath,
    export: spec.exportName,
    mount: spec.mount,
    root: broker.root,
    effectiveMount: `${broker.root}.${spec.mount}`,
    natsUrl: broker.natsUrl,
    authMode: broker.jwt ? 'jwt' : 'none',
    hostStateWritten: false,
    ...(check ? { check } : {}),
  };

  if (options.json) {
    console.log(JSON.stringify(result, null, 2));
  } else {
    console.log('Package actor mounted:');
    console.log(`  package:   ${result.packageName}`);
    console.log(`  logical:   ${result.mount}`);
    console.log(`  root:      ${result.root}`);
    console.log(`  effective: ${result.effectiveMount}`);
    console.log(`  broker:    ${result.natsUrl}`);
    console.log('Press Ctrl+C to stop.');
  }

  if (check) {
    await shutdownPackageBootstrapResult(bootstrapResult, runtime);
    await runtime.shutdown();
    await transport.disconnect();
    if (!connection.isClosed()) {
      await connection.close();
    }
    return;
  }

  await waitForActorShutdown(async () => {
    await shutdownPackageBootstrapResult(bootstrapResult, runtime);
    await runtime.shutdown();
    await transport.disconnect();
    if (!connection.isClosed()) {
      await connection.close();
    }
  });
}

export function resolveActorRunBroker(options: IActorRunCommandOptions): IBrokerRunConfig {
  const candidateHomes = resolveCandidateHomes(options.home);
  const files = candidateHomes.flatMap((home) => [
    {
      label: `${formatHomeLabel(home)}/credentials/matrix-broker.json`,
      value: readBrokerCredentialFile(path.join(home, 'credentials', 'matrix-broker.json')),
    },
    {
      label: `${formatHomeLabel(home)}/credentials/matrix-nats.json`,
      value: readBrokerCredentialFile(path.join(home, 'credentials', 'matrix-nats.json')),
    },
    {
      label: `${formatHomeLabel(home)}/config.json`,
      value: readBrokerConfigFile(path.join(home, 'config.json')),
    },
  ]);

  const natsUrl = readOptionalString(options.natsUrl)
    ?? readOptionalString(process.env.MATRIX_NATS_URL)
    ?? readOptionalString(process.env.NATS_URL)
    ?? firstConfigured(files, 'natsUrl');
  const root = readOptionalString(options.root)
    ?? readOptionalString(options.space)
    ?? readOptionalString(process.env.MATRIX_ROOT)
    ?? readOptionalString(process.env.MATRIX_SPACE)
    ?? firstConfigured(files, 'root')
    ?? firstConfigured(files, 'space');
  const jwt = readOptionalString(options.jwt)
    ?? readOptionalString(process.env.MATRIX_NATS_JWT)
    ?? readOptionalString(process.env.NATS_JWT)
    ?? firstConfigured(files, 'jwt');
  const seed = readOptionalString(options.seed)
    ?? readOptionalString(process.env.MATRIX_NATS_SEED)
    ?? readOptionalString(process.env.NATS_SEED)
    ?? firstConfigured(files, 'seed');

  const checked = [
    '--nats-url',
    '--root',
    '--space',
    '--jwt',
    '--seed',
    'MATRIX_NATS_URL',
    'MATRIX_ROOT',
    'MATRIX_SPACE',
    'MATRIX_NATS_JWT',
    'MATRIX_NATS_SEED',
    'NATS_URL',
    'NATS_JWT',
    'NATS_SEED',
    ...files.map((entry) => entry.label),
  ];

  if (!natsUrl) {
    throw new Error(`MATRIX_NATS_URL_REQUIRED: matrix actor/package run requires --nats-url or configured broker URL. Checked: ${checked.join(', ')}`);
  }
  if (!root) {
    throw new Error('MATRIX_ROOT_REQUIRED: matrix actor/package run requires --root, --space, MATRIX_ROOT, MATRIX_SPACE, or configured root');
  }
  if ((jwt && !seed) || (!jwt && seed)) {
    throw new Error('MATRIX_NATS_JWT_SEED_PAIR_REQUIRED: provide both JWT and seed, or neither for an unauthenticated local broker');
  }

  return {
    natsUrl,
    root,
    ...(jwt ? { jwt } : {}),
    ...(seed ? { seed } : {}),
    checked,
  };
}

export function resolvePackageRunSpec(packageDir: string, options: IPackageRunCommandOptions): IPackageRunSpec {
  const loaded = loadMatrixServiceManifest(packageDir);
  const entryPath = options.entry
    ? resolvePackageEntryPath(loaded.packageDir, options.entry)
    : loaded.entryPath;
  const exportName = options.export?.trim() || loaded.exportName;
  const mount = options.mount?.trim() || loaded.mount;
  if (!mount) {
    throw new Error('matrix package run requires --mount <mount> when the package descriptor does not declare one');
  }
  const binding = resolvePackageBindingForMount(loaded, mount);
  const componentType = binding?.type ?? loaded.serviceInstance.componentType ?? loaded.serviceInstance.class;
  const actorId = componentType || mount;
  const runtimeId = `standalone-package:${process.pid}:${sanitizeRuntimeIdPart(loaded.packageName)}:${sanitizeRuntimeIdPart(mount)}`;
  return {
    packageDir: loaded.packageDir,
    packageName: loaded.packageName,
    manifestPath: loaded.manifestPath,
    entryPath,
    exportName,
    mount,
    actorId,
    packageId: loaded.packageName,
    runtimeId,
    accepts: acceptsArrayToRecord(binding?.accepts ?? []),
    emits: {},
    subscribes: {},
    overrides: parseOverrides(options.overrides),
    serviceInstance: loaded.serviceInstance,
  };
}

async function connectActorNats(input: IBrokerRunConfig): Promise<NatsConnection> {
  const encoder = new TextEncoder();
  return await natsConnect({
    servers: [input.natsUrl],
    name: `matrix-actor-run-${input.root}-${process.pid}`,
    timeout: 5_000,
    ...(input.jwt && input.seed
      ? {
          authenticator: jwtAuthenticator(
            () => input.jwt!,
            () => encoder.encode(input.seed!),
          ),
        }
      : {}),
  });
}

export async function loadActorConstructor(entryPath: string, exportName: string): Promise<ActorConstructor> {
  const moduleUrl = `${pathToFileURL(entryPath).href}?matrix_actor_run=${Date.now()}-${Math.random().toString(16).slice(2)}`;
  const mod = await import(moduleUrl) as Record<string, unknown>;
  const requested = actorConstructorFromExport(mod[exportName]);
  if (requested) {
    return requested;
  }
  const available = Object.entries(mod)
    .filter(([, value]) => actorConstructorFromExport(value))
    .map(([name]) => name);
  throw new Error(`No actor class found as export "${exportName}". Available exports: ${available.join(', ') || '(none)'}`);
}

async function loadPackageBootstrap(entryPath: string, exportName: string): Promise<PackageBootstrapFunction> {
  const moduleUrl = `${pathToFileURL(entryPath).href}?matrix_package_run=${Date.now()}-${Math.random().toString(16).slice(2)}`;
  const mod = await import(moduleUrl) as Record<string, unknown>;
  const bootstrap = mod[exportName];
  if (typeof bootstrap !== 'function') {
    throw new Error(`Package run export "${exportName}" was not found in ${entryPath}`);
  }
  return bootstrap as PackageBootstrapFunction;
}

function actorConstructorFromExport(value: unknown): ActorConstructor | null {
  if (typeof value !== 'function') {
    return null;
  }
  const candidate = value as ActorConstructor;
  return candidate.prototype ? candidate : null;
}

function inferMountFromEntry(entryPath: string): string {
  return path.basename(entryPath, path.extname(entryPath))
    .replace(/Actor$/i, '')
    .replace(/([a-z0-9])([A-Z])/g, '$1-$2')
    .toLowerCase()
    .replace(/[^a-z0-9._-]+/g, '-')
    .replace(/-+/g, '-')
    .replace(/^-|-$/g, '');
}

function parseProps(value: string | undefined): Record<string, unknown> | undefined {
  const text = value?.trim();
  if (!text) {
    return undefined;
  }
  const parsed = JSON.parse(text) as unknown;
  if (!parsed || typeof parsed !== 'object' || Array.isArray(parsed)) {
    throw new Error('matrix actor run --props must be a JSON object');
  }
  return parsed as Record<string, unknown>;
}

function parseOverrides(value: string | undefined): Record<string, unknown> {
  const text = value?.trim();
  if (!text) {
    return {};
  }
  const parsed = JSON.parse(text) as unknown;
  if (!parsed || typeof parsed !== 'object' || Array.isArray(parsed)) {
    throw new Error('matrix package run --overrides must be a JSON object');
  }
  return parsed as Record<string, unknown>;
}

async function runOptionalActorCheck(
  runtime: MatrixRuntime,
  mount: string,
  options: IActorRunCommandOptions,
): Promise<{ readonly op: string; readonly result: unknown } | null> {
  const op = options.checkOp?.trim();
  if (!op) {
    return null;
  }
  const payload = parseCheckPayload(options.checkPayload);
  const result = await RequestReply.execute<Record<string, unknown>, unknown>(
    runtime.getRootContext(),
    mount,
    op,
    payload,
    { timeoutMs: 5_000 },
  );
  return { op, result };
}

function parseCheckPayload(value: string | undefined): Record<string, unknown> {
  const text = value?.trim();
  if (!text) {
    return {};
  }
  const parsed = JSON.parse(text) as unknown;
  if (!parsed || typeof parsed !== 'object' || Array.isArray(parsed)) {
    throw new Error('matrix actor/package run --check-payload must be a JSON object');
  }
  return parsed as Record<string, unknown>;
}

function resolvePackageEntryPath(packageDir: string, entry: string): string {
  const trimmed = entry.trim();
  if (!trimmed) {
    throw new Error('matrix package run --entry must be a non-empty path');
  }
  const entryPath = path.resolve(packageDir, trimmed);
  if (!fs.existsSync(entryPath)) {
    throw new Error(`matrix package run entry does not exist: ${trimmed}`);
  }
  return entryPath;
}

function resolvePackageBindingForMount(
  loaded: ILoadedMatrixServiceManifest,
  mount: string,
): ILoadedMatrixServiceManifest['packageComponents'][number] | ILoadedMatrixServiceManifest['packageRoot'] | undefined {
  if (loaded.packageRoot?.mount === mount) {
    return loaded.packageRoot;
  }
  return loaded.packageComponents.find((entry) => entry.mount === mount);
}

function acceptsArrayToRecord(accepts: readonly string[]): Record<string, unknown> {
  const result: Record<string, unknown> = {};
  for (const op of accepts) {
    result[op] = {};
  }
  return result;
}

function sanitizeRuntimeIdPart(value: string): string {
  return value
    .replace(/^@/u, '')
    .replace(/[^a-zA-Z0-9._-]+/gu, '-')
    .replace(/-+/gu, '-')
    .replace(/^-|-$/gu, '')
    || 'package';
}

async function shutdownPackageBootstrapResult(value: unknown, ownedRuntime: MatrixRuntime): Promise<void> {
  if (!value || typeof value !== 'object') {
    return;
  }
  const runtime = (value as { readonly runtime?: unknown }).runtime;
  if (!runtime || typeof runtime !== 'object') {
    return;
  }
  if (runtime === ownedRuntime) {
    return;
  }
  const shutdown = (runtime as { readonly shutdown?: unknown }).shutdown;
  if (typeof shutdown === 'function') {
    await shutdown.call(runtime);
  }
}

function waitForActorShutdown(onShutdown: () => Promise<void>): Promise<void> {
  return new Promise<void>((resolve, reject) => {
    let settled = false;
    const finish = (error?: unknown): void => {
      if (settled) return;
      settled = true;
      process.off('SIGINT', shutdown);
      process.off('SIGTERM', shutdown);
      if (error) {
        reject(error);
        return;
      }
      resolve();
    };
    const shutdown = (): void => {
      void onShutdown().then(() => finish()).catch((error) => finish(error));
    };
    process.on('SIGINT', shutdown);
    process.on('SIGTERM', shutdown);
  });
}

function resolveCandidateHomes(homeOption: string | undefined): readonly string[] {
  const homes = [
    homeOption ? path.resolve(homeOption) : undefined,
    path.resolve(process.cwd(), '.matrix'),
    path.resolve(os.homedir(), '.matrix'),
  ].filter((value): value is string => Boolean(value));
  return [...new Set(homes)];
}

function formatHomeLabel(home: string): string {
  const defaultHome = path.resolve(os.homedir(), '.matrix');
  const cwdHome = path.resolve(process.cwd(), '.matrix');
  if (home === defaultHome) return '~/.matrix';
  if (home === cwdHome) return './.matrix';
  return home;
}

function readBrokerCredentialFile(filePath: string): Record<string, string> {
  const value = readJsonFile(filePath);
  return normalizeBrokerConfig(value);
}

function readBrokerConfigFile(filePath: string): Record<string, string> {
  const value = readJsonFile(filePath);
  const nested = [
    value,
    value?.broker,
    value?.nats,
    value?.transport,
    value?.credentials,
  ].filter((entry): entry is Record<string, unknown> => Boolean(entry && typeof entry === 'object' && !Array.isArray(entry)));
  return nested.reduce<Record<string, string>>((result, entry) => ({
    ...result,
    ...normalizeBrokerConfig(entry),
  }), {});
}

function normalizeBrokerConfig(value: Record<string, unknown> | null): Record<string, string> {
  if (!value) {
    return {};
  }
  return {
    ...(readOptionalString(value.natsUrl) ?? readOptionalString(value.url) ?? readOptionalString(value.brokerUrl) ? { natsUrl: (readOptionalString(value.natsUrl) ?? readOptionalString(value.url) ?? readOptionalString(value.brokerUrl))! } : {}),
    ...(readOptionalString(value.root) ?? readOptionalString(value.space) ?? readOptionalString(value.authorityRoot) ? { root: (readOptionalString(value.root) ?? readOptionalString(value.space) ?? readOptionalString(value.authorityRoot))! } : {}),
    ...(readOptionalString(value.space) ? { space: readOptionalString(value.space)! } : {}),
    ...(readOptionalString(value.jwt) ? { jwt: readOptionalString(value.jwt)! } : {}),
    ...(readOptionalString(value.seed) ? { seed: readOptionalString(value.seed)! } : {}),
  };
}

function firstConfigured(
  files: readonly { readonly value: Record<string, string> }[],
  key: 'natsUrl' | 'root' | 'space' | 'jwt' | 'seed',
): string | undefined {
  for (const file of files) {
    const value = file.value[key];
    if (value) {
      return value;
    }
  }
  return undefined;
}

function readJsonFile(filePath: string): Record<string, unknown> | null {
  if (!fs.existsSync(filePath)) {
    return null;
  }
  try {
    const parsed = JSON.parse(fs.readFileSync(filePath, 'utf8')) as unknown;
    return parsed && typeof parsed === 'object' && !Array.isArray(parsed) ? parsed as Record<string, unknown> : null;
  } catch (error) {
    const message = error instanceof Error ? error.message : String(error);
    throw new Error(`Invalid JSON in ${filePath}: ${message}`);
  }
}

function readOptionalString(value: unknown): string | undefined {
  if (typeof value !== 'string') {
    return undefined;
  }
  const trimmed = value.trim();
  return trimmed.length > 0 ? trimmed : undefined;
}