import fs from 'node:fs';

const MAX_SAFE_DEV_MEMORY = 4 * 1024 * 1024 * 1024;
const MAX_SAFE_DEV_CPUS = 4;
const MAX_SAFE_DEV_PIDS = 256;

const positive = (value) => typeof value === 'number' ? value > 0 : Number(value) > 0;

export const validateComposeModel = (model, mode) => {
  const errors = [];
  const runtime = model?.services?.runtime;
  if (!runtime) return ['runtime service is missing'];
  const builder = model?.services?.builder;
  const caddy = model?.services?.caddy;
  if (!builder) errors.push('builder service is missing');
  if (!caddy) errors.push('caddy service is missing');

  const requiredImageEnvironment = {
    GATEWAY_IMAGE_UPLOAD_SECRET_FILE: '/run/secrets/image_upload_core2026_secret',
    GAME_IMAGE_UPLOAD_SECRET_FILE: '/run/secrets/image_upload_core2026_secret',
    IMAGE_SYNC_SECRET_FILE: '/run/secrets/image_sync_core2026_secret',
  };
  for (const [key, expected] of Object.entries(requiredImageEnvironment)) {
    if (runtime.environment?.[key] !== expected) errors.push(`${key} must be ${expected}`);
  }
  for (const key of [
    'GATEWAY_IMAGE_UPLOAD_URL',
    'GATEWAY_SHARED_ICON_PUBLIC_URL',
    'GATEWAY_USER_ICON_PUBLIC_URL',
    'GAME_IMAGE_UPLOAD_URL',
    'GAME_CONTENT_IMAGE_PUBLIC_URL',
    'IMAGE_SYNC_URL',
    'VITE_IMAGE_PUBLIC_URL',
    'VITE_GATEWAY_USER_ICON_BASE_URL',
  ]) {
    if (!runtime.environment?.[key]) errors.push(`${key} must be configured`);
  }
  const mounts = Array.isArray(runtime.volumes) ? runtime.volumes : [];
  for (const target of [
    '/run/secrets/image_upload_core2026_secret',
    '/run/secrets/image_sync_core2026_secret',
  ]) {
    const mount = mounts.find((candidate) => candidate?.target === target);
    if (!mount || mount.type !== 'bind' || mount.read_only !== true) {
      errors.push(`${target} must be a read-only bind mount`);
    }
  }
  const artifactMount = mounts.find((candidate) => candidate?.target === '/srv/frontend-artifacts');
  if (!artifactMount || artifactMount.read_only === true) {
    errors.push('/srv/frontend-artifacts must be a writable runtime volume');
  }
  const caddyArtifactMount = (Array.isArray(caddy?.volumes) ? caddy.volumes : []).find(
    (candidate) => candidate?.target === '/srv/frontend-artifacts',
  );
  if (!caddyArtifactMount || caddyArtifactMount.read_only !== true) {
    errors.push('/srv/frontend-artifacts must be a read-only Caddy volume');
  }

  if (!positive(runtime.mem_limit)) errors.push('runtime memory limit must be positive');
  if (!positive(runtime.memswap_limit)) errors.push('runtime memory+swap limit must be positive');
  if (Number(runtime.memswap_limit) !== Number(runtime.mem_limit)) {
    errors.push('runtime memory+swap limit must equal its memory limit');
  }
  if (!positive(runtime.cpus)) errors.push('runtime CPU limit must be positive');
  if (!positive(runtime.pids_limit)) errors.push('runtime PID limit must be positive');

  const nodeOptions = runtime.environment?.NODE_OPTIONS ?? '';
  const heapMatch = /(?:^|\s)--max-old-space-size=(\d+)(?:\s|$)/.exec(nodeOptions);
  const heapMiB = Number(heapMatch?.[1] ?? 0);
  if (!heapMatch || heapMiB < 512 || heapMiB > 2048) {
    errors.push('runtime Node heap limit must be between 512 and 2048 MiB');
  }
  const turnDaemonNodeOptions = runtime.environment?.TURN_DAEMON_NODE_OPTIONS ?? '';
  const turnDaemonHeapMatch = /(?:^|\s)--max-old-space-size=(\d+)(?:\s|$)/.exec(turnDaemonNodeOptions);
  const turnDaemonHeapMiB = Number(turnDaemonHeapMatch?.[1] ?? 0);
  if (!turnDaemonHeapMatch || turnDaemonHeapMiB < 512 || turnDaemonHeapMiB > 4096) {
    errors.push('turn daemon Node heap limit must be between 512 and 4096 MiB');
  }
  if (turnDaemonHeapMiB * 1024 * 1024 >= Number(runtime.mem_limit)) {
    errors.push('turn daemon Node heap limit must stay below the runtime memory limit');
  }
  const rayonThreads = Number(runtime.environment?.RAYON_NUM_THREADS ?? 0);
  if (!Number.isInteger(rayonThreads) || rayonThreads < 1 || rayonThreads > 4) {
    errors.push('runtime Rayon thread count must be between 1 and 4');
  }

  if (builder) {
    if (!positive(builder.mem_limit)) errors.push('builder memory limit must be positive');
    if (!positive(builder.memswap_limit)) errors.push('builder memory+swap limit must be positive');
    if (Number(builder.memswap_limit) !== Number(builder.mem_limit)) {
      errors.push('builder memory+swap limit must equal its memory limit');
    }
    if (!positive(builder.cpus)) errors.push('builder CPU limit must be positive');
    if (!positive(builder.pids_limit)) errors.push('builder PID limit must be positive');
    const builderNodeOptions = builder.environment?.NODE_OPTIONS ?? '';
    const builderHeapMatch = /(?:^|\s)--max-old-space-size=(\d+)(?:\s|$)/.exec(builderNodeOptions);
    const builderHeapMiB = Number(builderHeapMatch?.[1] ?? 0);
    if (!builderHeapMatch || builderHeapMiB < 512 || builderHeapMiB > 3584) {
      errors.push('builder Node heap limit must be between 512 and 3584 MiB');
    }
    if (builderHeapMiB * 1024 * 1024 >= Number(builder.mem_limit)) {
      errors.push('builder Node heap limit must stay below the builder memory limit');
    }
    const builderRayonThreads = Number(builder.environment?.RAYON_NUM_THREADS ?? 0);
    if (!Number.isInteger(builderRayonThreads) || builderRayonThreads < 1 || builderRayonThreads > 4) {
      errors.push('builder Rayon thread count must be between 1 and 4');
    }
    for (const name of Object.keys(builder.environment ?? {})) {
      if (/(?:SECRET|TOKEN|PASSWORD|DATABASE_URL|REDIS_URL)/i.test(name)) {
        errors.push(`builder must not receive sensitive environment variable ${name}`);
      }
    }
  }

  if (mode === 'development') {
    if (runtime.environment?.RUNTIME_MODE !== 'development') {
      errors.push('development runtime mode must be literal development');
    }
    if (runtime.environment?.CORE_SOURCE_MODE !== 'bind') {
      errors.push('development Core source mode must be bind');
    }
  } else if (runtime.environment?.CORE_SOURCE_MODE !== 'clone') {
    errors.push(`${mode} Core source mode must be clone`);
  } else if (runtime.environment?.RUNTIME_MODE === 'development') {
    errors.push(`${mode} runtime must not use development mode`);
  }
  if (mode !== 'development') {
    if (runtime.environment?.FRONTEND_SERVE_MODE !== 'static') {
      errors.push(`${mode} frontend serve mode must be static`);
    }
    if (runtime.environment?.RELEASE_BUILDER_URL !== 'http://builder:15100') {
      errors.push(`${mode} runtime must use the isolated release builder`);
    }
    if (runtime.environment?.GATEWAY_ACTIVE_RELEASE_GIT_REF !== 'refs/sammo/active-gateway') {
      errors.push(`${mode} runtime must persist the active Gateway release ref`);
    }
  }

  if (mode === 'development' || mode === 'smoke') {
    for (const name of ['postgres', 'redis', 'builder', 'runtime', 'caddy']) {
      if (model?.services?.[name]?.restart !== 'no') errors.push(`${name} ${mode} restart policy must be no`);
    }
    if (Number(runtime.mem_limit) > MAX_SAFE_DEV_MEMORY) errors.push(`${mode} runtime memory limit exceeds 4 GiB`);
    if (Number(runtime.cpus) > MAX_SAFE_DEV_CPUS) errors.push(`${mode} runtime CPU limit exceeds 4`);
    if (Number(runtime.pids_limit) > MAX_SAFE_DEV_PIDS) errors.push(`${mode} runtime PID limit exceeds 256`);
  }

  return errors;
};

if (process.argv[1] && process.argv[1].endsWith('validate-compose-model.mjs')) {
  const mode = process.argv[2];
  const model = JSON.parse(fs.readFileSync(0, 'utf8'));
  const errors = validateComposeModel(model, mode);
  if (errors.length) {
    console.error(`Compose ${mode} safety validation failed:`);
    for (const error of errors) console.error(`- ${error}`);
    process.exitCode = 65;
  } else {
    console.log(`Compose ${mode} safety validation passed.`);
  }
}