import { randomBytes } from "node:crypto";
import { existsSync, mkdirSync, readFileSync, writeFileSync } from "node:fs";
import { join } from "node:path";

import { isValidOrgSlug } from "@executor-js/api";
import {
  missingPublicOriginWarning,
  resolvePublicOrigin,
  shouldWarnMissingPublicOrigin,
} from "@executor-js/sdk/public-origin";

// ---------------------------------------------------------------------------
// Self-host server config — a single typed surface parsed from the
// environment. Slice 1 keeps this a plain loader with safe defaults; it can
// graduate to Effect-Schema validation without changing call sites.
// ---------------------------------------------------------------------------

export const SELF_HOST_NAMESPACE = "executor_selfhost";
export const SELF_HOST_SCHEMA_VERSION = "1.0.0";

export interface SelfHostConfig {
  /** Bind address. Defaults to loopback. */
  readonly host: string;
  readonly port: number;
  /** Absolute path to the SQLite database file. */
  readonly dbPath: string;
  /** Public base URL used by core tools that build absolute links. */
  readonly webBaseUrl: string;
  /** Browser origins allowed to send cookie-authenticated requests. */
  readonly trustedOrigins: readonly string[];
  /**
   * Whether sandboxed code may reach loopback/private network addresses.
   * Defaults to false — adversarial LLM code should not hit the host's
   * internal network unless an operator opts in.
   */
  readonly allowLocalNetwork: boolean;
  // Better Auth session secret. Always resolved (env, else generated + persisted
  // under the data dir) so a single-container deploy boots with no env; the auth
  // layer still validates an explicitly-set env secret is long enough.
  readonly authSecret: string;
  readonly bootstrapAdminEmail: string | undefined;
  readonly bootstrapAdminPassword: string | undefined;
  readonly bootstrapAdminName: string;
  /** The single organization every self-host user belongs to. */
  readonly organizationName: string;
  /** URL slug for org-prefixed console paths (`/<slug>/policies`). */
  readonly orgSlug: string;
  /**
   * Sandbox execution budget passed to the QuickJS runtime, or undefined for
   * the runtime's own default (5 minutes). An operator knob in principle, but
   * its real consumer is the e2e harness, which shrinks it to seconds so the
   * sandbox-deadline scenario proves its race without waiting out real
   * minutes (the same pattern as MCP_PAUSED_SESSION_IDLE_TIMEOUT_MS on cloud).
   */
  readonly sandboxTimeoutMs: number | undefined;
  /**
   * How long an MCP session may sit idle before the in-process store evicts it,
   * or undefined for the store's own default (30 minutes). 0 disables eviction.
   */
  readonly mcpSessionIdleTtlMs: number | undefined;
  /**
   * How long a connection's persisted remote tool catalog stays fresh, in ms.
   * `undefined` takes the SDK default (15 minutes); `null` disables time-based
   * re-sync, leaving stale-marking and config revision as the only triggers.
   */
  readonly toolsSyncTtlMs: number | null | undefined;
}

export const resolveDataDir = (): string =>
  process.env.EXECUTOR_DATA_DIR ?? join(process.cwd(), ".executor-selfhost");

let cachedSecretKey: string | undefined;

/**
 * Master key for the encrypted secret provider. Prefers EXECUTOR_SECRET_KEY;
 * otherwise generates and persists a random key under the data dir on first
 * boot (so a single-container deploy is encrypted-by-default without manual
 * setup). Memoized so repeated per-request reads are cheap.
 */
export const resolveSecretKey = (): string => {
  if (cachedSecretKey) return cachedSecretKey;
  const fromEnv = process.env.EXECUTOR_SECRET_KEY?.trim();
  if (fromEnv) {
    cachedSecretKey = fromEnv;
    return fromEnv;
  }
  const keyPath = join(resolveDataDir(), "secret.key");
  if (existsSync(keyPath)) {
    cachedSecretKey = readFileSync(keyPath, "utf8").trim();
    return cachedSecretKey;
  }
  mkdirSync(resolveDataDir(), { recursive: true });
  const generated = randomBytes(32).toString("base64");
  writeFileSync(keyPath, generated, { mode: 0o600 });
  console.warn(
    `[executor] generated a secret-encryption key at ${keyPath}. Set EXECUTOR_SECRET_KEY to manage it explicitly (and to keep secrets readable across data-dir changes).`,
  );
  cachedSecretKey = generated;
  return generated;
};

let cachedAuthSecret: string | undefined;

/**
 * Better Auth session secret. Prefers BETTER_AUTH_SECRET / AUTH_SECRET;
 * otherwise generates and persists a strong random secret under the data dir on
 * first boot (so a single-container deploy boots with no env and keeps sessions
 * valid across restarts). Memoized; mirrors {@link resolveSecretKey}.
 */
export const resolveAuthSecret = (): string => {
  if (cachedAuthSecret) return cachedAuthSecret;
  const fromEnv = (process.env.BETTER_AUTH_SECRET ?? process.env.AUTH_SECRET)?.trim();
  if (fromEnv) {
    cachedAuthSecret = fromEnv;
    return fromEnv;
  }
  const keyPath = join(resolveDataDir(), "auth-secret.key");
  if (existsSync(keyPath)) {
    cachedAuthSecret = readFileSync(keyPath, "utf8").trim();
    return cachedAuthSecret;
  }
  mkdirSync(resolveDataDir(), { recursive: true });
  const generated = randomBytes(32).toString("base64");
  writeFileSync(keyPath, generated, { mode: 0o600 });
  console.warn(
    `[executor] generated a session secret at ${keyPath}. Set BETTER_AUTH_SECRET to manage it explicitly (rotating it signs everyone out).`,
  );
  cachedAuthSecret = generated;
  return generated;
};

let warnedNoPublicUrl = false;

// The public origin used to build absolute links (OAuth redirects, MCP OAuth
// metadata, the connect-card URL). Priority via the shared resolver: an explicit
// EXECUTOR_WEB_BASE_URL, then a platform-injected origin (zero-config on
// Railway/Render/Fly/…), then a localhost fallback for local dev. NEVER derived
// from the request `Host` — that's spoofable and would let host-header injection
// poison those links (the request origin is only trusted for the CSRF/
// `trustedOrigins` check, which is same-origin-safe; see better-auth.ts).
const resolveWebBaseUrl = (port: number): string => {
  const resolved = resolvePublicOrigin({
    explicit: process.env.EXECUTOR_WEB_BASE_URL,
    env: process.env,
  });
  if (resolved) return resolved;
  const fallback = `http://localhost:${port}`;
  // A deployed instance with no detectable origin mints localhost links — warn
  // once (unless local dev/test) so the operator sets the variable.
  if (!warnedNoPublicUrl && shouldWarnMissingPublicOrigin(process.env.NODE_ENV)) {
    warnedNoPublicUrl = true;
    console.warn(missingPublicOriginWarning({ varName: "EXECUTOR_WEB_BASE_URL", fallback }));
  }
  return fallback;
};

export const loadConfig = (): SelfHostConfig => {
  const port = Number.parseInt(process.env.PORT ?? "4788", 10);
  const dataDir = resolveDataDir();
  const webBaseUrl = resolveWebBaseUrl(port);
  return {
    host: process.env.EXECUTOR_HOST ?? "127.0.0.1",
    port,
    dbPath: process.env.EXECUTOR_DB_PATH ?? join(dataDir, "data.db"),
    webBaseUrl,
    trustedOrigins: resolveTrustedOrigins(webBaseUrl),
    allowLocalNetwork: process.env.EXECUTOR_ALLOW_LOCAL_NETWORK === "true",
    authSecret: resolveAuthSecret(),
    bootstrapAdminEmail: process.env.EXECUTOR_BOOTSTRAP_ADMIN_EMAIL,
    bootstrapAdminPassword: process.env.EXECUTOR_BOOTSTRAP_ADMIN_PASSWORD,
    bootstrapAdminName: process.env.EXECUTOR_BOOTSTRAP_ADMIN_NAME ?? "Admin",
    organizationName: process.env.EXECUTOR_ORG_NAME ?? "Default",
    orgSlug: resolveOrgSlug(),
    sandboxTimeoutMs: resolveSandboxTimeoutMs(),
    mcpSessionIdleTtlMs: resolveMcpSessionIdleTtlMs(),
    toolsSyncTtlMs: resolveToolsSyncTtlMs(),
  };
};

// A malformed value is refused rather than silently ignored: an operator who
// sets the knob and typos it should find out at boot, not by watching a
// runaway execution use the 5-minute default.
const resolveSandboxTimeoutMs = (): number | undefined => {
  const raw = process.env.EXECUTOR_SANDBOX_TIMEOUT_MS;
  if (!raw) return undefined;
  const parsed = Number(raw);
  if (!Number.isFinite(parsed) || parsed <= 0) {
    // oxlint-disable-next-line executor/no-try-catch-or-throw, executor/no-error-constructor -- boundary: refuse to boot on a malformed operator knob
    throw new Error(
      `EXECUTOR_SANDBOX_TIMEOUT_MS ${JSON.stringify(raw)} is not a positive number of milliseconds`,
    );
  }
  return Math.floor(parsed);
};

// How long an MCP session may sit idle before the store evicts it. 0 disables
// eviction, which restores the old behaviour of holding every session for the
// lifetime of the process — only useful for diagnosing a client that cannot
// tolerate re-initializing.
const resolveMcpSessionIdleTtlMs = (): number | undefined => {
  const raw = process.env.EXECUTOR_MCP_SESSION_IDLE_TTL_MS;
  if (!raw) return undefined;
  const parsed = Number(raw);
  if (!Number.isFinite(parsed) || parsed < 0) {
    // oxlint-disable-next-line executor/no-try-catch-or-throw, executor/no-error-constructor -- boundary: refuse to boot on a malformed operator knob
    throw new Error(
      `EXECUTOR_MCP_SESSION_IDLE_TTL_MS ${JSON.stringify(raw)} is not a non-negative number of milliseconds`,
    );
  }
  return Math.floor(parsed);
};

// EXECUTOR_TRUSTED_ORIGINS — extra browser origins allowed to send
// cookie-authenticated requests when one instance is deliberately reachable
// under more than one address (a LAN IP as well as a domain, say).
//
// This list widens ONLY Better Auth's origin/CSRF check. `webBaseUrl` stays the
// single canonical origin for OAuth callbacks, MCP metadata, and every other
// generated link, so an alias can never redirect a callback somewhere else.
//
// Entries must be exact origins. A path, query, fragment, credential, wildcard
// host, or non-http(s) scheme is refused rather than trimmed off: an operator
// who writes `https://*.example.com` means a pattern, and silently accepting it
// as the literal host would leave them believing a wildcard is in force. Like
// the other knobs here, a malformed value refuses to boot instead of quietly
// leaving the browser locked out with an "Invalid origin" page.
const normalizeTrustedOrigin = (value: string): string => {
  if (!URL.canParse(value)) {
    // oxlint-disable-next-line executor/no-try-catch-or-throw, executor/no-error-constructor -- boundary: refuse to boot on a malformed operator knob
    throw new Error(
      `EXECUTOR_TRUSTED_ORIGINS contains ${JSON.stringify(value)}, which is not a valid URL origin`,
    );
  }
  const url = new URL(value);
  if (
    (url.protocol !== "http:" && url.protocol !== "https:") ||
    url.username.length > 0 ||
    url.password.length > 0 ||
    url.hostname.includes("*") ||
    (url.pathname !== "" && url.pathname !== "/") ||
    url.search.length > 0 ||
    url.hash.length > 0
  ) {
    // oxlint-disable-next-line executor/no-try-catch-or-throw, executor/no-error-constructor -- boundary: refuse to boot on a malformed operator knob
    throw new Error(
      `EXECUTOR_TRUSTED_ORIGINS entry ${JSON.stringify(value)} must be an exact http(s) origin (scheme, host, and optional port only)`,
    );
  }
  return url.origin;
};

// The canonical origin always leads the list, so the unset case reproduces the
// previous `[webBaseUrl]` exactly and an operator who repeats it in the env var
// does not get a duplicate.
const resolveTrustedOrigins = (webBaseUrl: string): readonly string[] => {
  const additional = (process.env.EXECUTOR_TRUSTED_ORIGINS ?? "")
    .split(",")
    .map((value) => value.trim())
    .filter((value) => value.length > 0)
    .map(normalizeTrustedOrigin);
  return [...new Set([webBaseUrl, ...additional])];
};

// The org slug doubles as a URL segment (`/<slug>/policies`), so an
// operator-set value must fit the shared grammar and avoid reserved root
// segments (api, mcp, login, …) — a colliding slug would shadow real routes.
const resolveOrgSlug = (): string => {
  const slug = process.env.EXECUTOR_ORG_SLUG;
  if (!slug) return "default";
  if (!isValidOrgSlug(slug) && slug !== "default") {
    // oxlint-disable-next-line executor/no-try-catch-or-throw, executor/no-error-constructor -- boundary: a colliding org slug would shadow app routes; refuse to boot
    throw new Error(
      `EXECUTOR_ORG_SLUG ${JSON.stringify(slug)} is not usable as a URL slug (2-48 chars of [a-z0-9-], not a reserved path segment like "api" or "login")`,
    );
  }
  return slug;
};

// EXECUTOR_TOOLS_SYNC_TTL_MS — how long a remote tool catalog (an MCP server's
// tool set, which changes server-side with no executor-visible signal) stays
// fresh before the next tools read re-lists it. Unset takes the SDK default of
// 15 minutes.
//
// The value forwards to the SDK's `toolsSyncTtlMs` verbatim, so `0` keeps the
// SDK's meaning — every catalog is expired on every read. "off", "null" and
// "false" disable time-based re-sync (the SDK's `null` sentinel), since
// operators reach for all three spellings. The comparison is case-insensitive:
// "OFF" and "False" are the same intent typed by a different operator.
//
// Like the other knobs here a malformed or negative value is refused rather
// than silently ignored: an operator who sets the TTL and typos it should find
// out at boot, not by wondering months later why catalogs never refresh.
const TOOLS_SYNC_TTL_DISABLE_TOKENS = new Set(["off", "null", "false"]);

const resolveToolsSyncTtlMs = (): number | null | undefined => {
  const raw = process.env.EXECUTOR_TOOLS_SYNC_TTL_MS?.trim();
  if (!raw) return undefined;
  if (TOOLS_SYNC_TTL_DISABLE_TOKENS.has(raw.toLowerCase())) return null;
  const parsed = Number(raw);
  // `isSafeInteger`, not `isInteger`: past 2^53 a decimal literal silently
  // rounds to a nearby representable value, so an operator's typo'd digit
  // would boot as a TTL they never wrote. Refuse it instead.
  if (!Number.isSafeInteger(parsed)) {
    // oxlint-disable-next-line executor/no-try-catch-or-throw, executor/no-error-constructor -- boundary: refuse to boot on a malformed operator knob
    throw new Error(
      `EXECUTOR_TOOLS_SYNC_TTL_MS ${JSON.stringify(raw)} is not an exactly representable whole number of milliseconds ("off", "null" or "false" disable time-based re-sync)`,
    );
  }
  if (parsed < 0) {
    // oxlint-disable-next-line executor/no-try-catch-or-throw, executor/no-error-constructor -- boundary: refuse to boot on a malformed operator knob
    throw new Error(
      `EXECUTOR_TOOLS_SYNC_TTL_MS ${JSON.stringify(raw)} must not be negative (use "off" to disable time-based re-sync)`,
    );
  }
  return parsed;
};