import path from "node:path";
import { statSync } from "node:fs";
import {
  createAuthenticationConfigProvider,
  type AuthenticationConfigProvider,
  type AuthMode,
} from "./auth/config.js";
import { createProjectedAuthenticationConfigProvider } from "./auth/runtime-projection.js";
import type { WorkspaceRegistryConfig } from "./workspaces/types.js";
import type { CatalogConnectionConfig } from "./catalog/repository.js";

export interface AppConfig {
  host: string; port: number; harnessDir: string; thtBin: string; piBin: string;
  authMode: AuthMode;
  authConfigFile: string;
  authStateRoot: string;
  authentication?: AuthenticationConfigProvider;
  publicExposure: boolean;
  sessionStorage: {
    mode: "local" | "postgres";
    host?: string; port?: number; database?: string; runtimeUser?: string;
    runtimePasswordFile?: string; sslmode?: "verify-ca" | "verify-full"; sslrootcert?: string;
  };
  /** Installation-local metadata catalog. Omitted installations expose an unavailable admin surface. */
  catalogDatabase?: CatalogConnectionConfig;
  defaults: { provider?: string; model?: string; thinking?: string };
  maxPiProcesses: number;
  settingsFile: string;
  maintenanceFile: string;
  dataRoot?: string;
  ollamaEnsureTimeoutMs: number;
  piManagementTimeoutMs: number;
  secretsFile?: string;
  installationConfigFile?: string;
  piAuthFile?: string;
  secretFiles: Readonly<Record<string, string | undefined>>;
  modelApiKeyFile?: string;
  /**
   * Local-only: when true, POST /sessions probes DWH reachability (`tht db ping`) and
   * refuses to create a session if it is down. Off by default so containers/CI never
   * pay the probe; the local dev launcher (run-stack.sh) opts in via THT_DWH_PRECHECK.
   */
  dwhPrecheck: boolean;
  /** Explicit compatibility mode for old loopback clients that send `workspace` in POST /sessions. */
  legacyWorkspaceMode: boolean;
  workspaceDiagnosticTimeoutMs: number;
  catalogSyncTimeoutMs: number;
  workspaceRegistry: WorkspaceRegistryConfig;
  workspaceSecretStoreRoot: string;
  workspaceSecretRuntimeRoot: string;
  internalQdrantUrl: string;
  internalEmbeddingUrl: string;
  internalEmbeddingModel: string;
  internalEmbeddingDimensions: number;
}

export const MAX_WORKSPACE_DIAGNOSTIC_TIMEOUT_MS = 10_000;

function requiredRegistryValue(value: string, label: string): string {
  if (value.length === 0 || value.trim() !== value || value.includes("\0")) {
    throw new Error(`workspace registry ${label} configuration is invalid`);
  }
  return value;
}

function absoluteRegistryPath(value: string, label: string): string {
  const pathValue = requiredRegistryValue(value, label);
  if (!path.isAbsolute(pathValue)) {
    throw new Error(`workspace registry ${label} must be absolute`);
  }
  return pathValue;
}

function absoluteAuthPath(value: string, label: string): string {
  if (value.length === 0 || value.trim() !== value || value.includes("\0") || !path.isAbsolute(value)) {
    throw new Error(`authentication ${label} configuration is invalid`);
  }
  return value;
}

function authConfigFileExists(file: string): boolean {
  try {
    if (!statSync(file).isFile()) throw new Error("authentication configuration is invalid");
    return true;
  } catch (error: any) {
    if (error?.code === "ENOENT") return false;
    throw new Error("authentication configuration is invalid");
  }
}

function refSafeGitBranch(value: string): string {
  const branch = requiredRegistryValue(value, "branch");
  if (
    branch === "@"
    || branch === "HEAD"
    || branch.startsWith("-")
    || branch.startsWith("/")
    || branch.endsWith("/")
    || branch.endsWith(".")
    || branch.includes("..")
    || branch.includes("@{")
    || branch.includes("//")
    || branch.split("/").some((component) => component.startsWith(".") || component.endsWith(".lock"))
    || /[\p{Cc} ~^:?*\[\\]/u.test(branch)
  ) {
    throw new Error("workspace registry branch configuration is invalid");
  }
  return branch;
}

function safeInstallationId(value: string): string {
  const installationId = requiredRegistryValue(value, "installation ID");
  if (/\p{Cc}/u.test(installationId)) {
    throw new Error("workspace registry installation ID configuration is invalid");
  }
  return installationId;
}

function positiveImportLimit(value: string | undefined, fallback: number): number {
  const limit = Number(value ?? fallback);
  if (!Number.isSafeInteger(limit) || limit <= 0) {
    throw new Error("workspace limit configuration is invalid");
  }
  return limit;
}

function diagnosticTimeout(value: string | undefined): number {
  const timeout = Number(value ?? 5_000);
  if (!Number.isSafeInteger(timeout) || timeout < 1 || timeout > MAX_WORKSPACE_DIAGNOSTIC_TIMEOUT_MS) {
    throw new Error("workspace diagnostic timeout configuration is invalid");
  }
  return timeout;
}

function catalogSyncTimeout(value: string | undefined): number {
  const timeout = Number(value ?? 600_000);
  if (!Number.isSafeInteger(timeout) || timeout < 1_000 || timeout > 3_600_000) {
    throw new Error("catalog synchronization timeout configuration is invalid");
  }
  return timeout;
}

function piManagementTimeout(value: string | undefined): number {
  const timeout = Number(value ?? 8_000);
  if (!Number.isSafeInteger(timeout) || timeout < 1 || timeout > 30_000) {
    throw new Error("Pi management timeout configuration is invalid");
  }
  return timeout;
}

function loopbackHost(host: string): boolean {
  return host === "::1"
    || host === "127.0.0.1"
    || /^127(?:\.\d{1,3}){3}$/.test(host);
}

function internalServiceUrl(
  value: string | undefined,
  fallback: string,
  label: string,
  allowedHosts: readonly string[],
): string {
  const raw = value ?? fallback;
  let parsed: URL;
  try {
    parsed = new URL(raw);
  } catch {
    throw new Error(`${label} configuration is invalid`);
  }
  if (
    parsed.protocol !== "http:"
    || parsed.username.length > 0
    || parsed.password.length > 0
    || parsed.pathname !== "/"
    || parsed.search.length > 0
    || parsed.hash.length > 0
    || (!allowedHosts.includes(parsed.hostname) && !loopbackHost(parsed.hostname))
  ) {
    throw new Error(`${label} configuration is invalid`);
  }
  return parsed.toString().replace(/\/$/, "");
}

function positiveDimension(value: string | undefined, fallback: number): number {
  const parsed = Number(value ?? fallback);
  if (!Number.isSafeInteger(parsed) || parsed <= 0) {
    throw new Error("internal embedding dimensions configuration is invalid");
  }
  return parsed;
}

function catalogDatabase(env: Record<string, string | undefined>): CatalogConnectionConfig | undefined {
  const value = env.THT_CATALOG_DATABASE_URL;
  if (value !== undefined) {
    try {
      const parsed = new URL(value);
      if ((parsed.protocol !== "postgres:" && parsed.protocol !== "postgresql:")
        || !parsed.hostname || !parsed.pathname.slice(1) || parsed.hash || parsed.search) throw new Error();
      return { connectionString: value };
    } catch {
      throw new Error("catalog database configuration is invalid");
    }
  }
  const host = env.THT_CATALOG_DB_HOST;
  if (host === undefined) return undefined;
  const port = Number(env.THT_CATALOG_DB_PORT ?? 5432);
  const database = env.THT_CATALOG_DB_NAME;
  const user = env.THT_CATALOG_RUNTIME_USER;
  const passwordFile = env.THT_CATALOG_RUNTIME_PASSWORD_FILE;
  try {
    if (!host.trim() || !database?.trim() || !user?.trim() || !passwordFile
      || !path.isAbsolute(passwordFile) || !Number.isInteger(port) || port < 1 || port > 65_535) throw new Error();
    return { host, port, database, user, passwordFile };
  } catch {
    throw new Error("catalog database configuration is invalid");
  }
}

export function loadConfig(
  env: Record<string, string | undefined>,
  options: { surface?: "application" | "workspace-maintenance" } = {},
): AppConfig {
  const applicationSurface = options.surface !== "workspace-maintenance";
  const defaultAuthConfigFile = "/run/thothii-auth/auth.yaml";
  const authConfigFile = absoluteAuthPath(env.THT_AUTH_CONFIG_FILE ?? defaultAuthConfigFile, "file");
  const authStateRoot = absoluteAuthPath(env.THT_AUTH_STATE_ROOT ?? "/data/auth", "state root");
  const runtimeProjectionRoot = env.THT_AUTH_RUNTIME_PROJECTION_ROOT;
  let hasAuthenticationConfig = false;
  let authentication: AuthenticationConfigProvider | undefined;
  if (runtimeProjectionRoot !== undefined) {
    let projectionRoot: string;
    try {
      projectionRoot = absoluteAuthPath(runtimeProjectionRoot, "runtime projection root");
    } catch {
      throw new Error("authentication configuration is invalid");
    }
    if (env.THT_AUTH_CONFIG_FILE !== undefined && env.THT_AUTH_CONFIG_FILE !== defaultAuthConfigFile) {
      throw new Error("authentication configuration is invalid");
    }
    authentication = createProjectedAuthenticationConfigProvider(projectionRoot);
    hasAuthenticationConfig = true;
  } else {
    hasAuthenticationConfig = authConfigFileExists(authConfigFile);
    authentication = hasAuthenticationConfig ? createAuthenticationConfigProvider(authConfigFile) : undefined;
  }
  if (hasAuthenticationConfig && env.AUTH_MODE !== undefined) {
    throw new Error("authentication configuration and AUTH_MODE cannot both be set");
  }
  let authMode: AuthMode;
  if (authentication) {
    authMode = authentication.current().value.mode;
  } else {
    const requestedMode = env.AUTH_MODE ?? "none";
    if (!(["none", "mock", "upstream"] as const).includes(requestedMode as "none" | "mock" | "upstream")) {
      throw new Error(`unsupported AUTH_MODE=${requestedMode}; use none, mock, or upstream`);
    }
    const nodeEnvironment = env.NODE_ENV ?? process.env.NODE_ENV;
    if (applicationSurface && (requestedMode === "none" || requestedMode === "mock")
      && nodeEnvironment !== "development" && nodeEnvironment !== "test") {
      throw new Error("production requires auth.yaml or AUTH_MODE=upstream");
    }
    authMode = requestedMode as "none" | "mock" | "upstream";
  }
  const publicExposure = applicationSurface && env.THOTH_PUBLIC_EXPOSURE === "true";
  if (publicExposure && authMode !== "oidc" && authMode !== "upstream") {
    throw new Error("public exposure requires AUTH_MODE=upstream or configured OIDC behind a trusted proxy");
  }
  const sessionStorageMode = env.THT_SESSION_STORAGE ?? "local";
  if (sessionStorageMode !== "local" && sessionStorageMode !== "postgres") {
    throw new Error("session storage configuration is invalid");
  }
  if (sessionStorageMode === "local" && publicExposure) {
    throw new Error("local session storage requires loopback-only deployment");
  }
  const legacyWorkspaceMode = env.THT_LEGACY_WORKSPACE_MODE;
  if (legacyWorkspaceMode !== undefined && legacyWorkspaceMode !== "local") {
    throw new Error("legacy workspace mode configuration is invalid");
  }
  if (legacyWorkspaceMode === "local" && sessionStorageMode !== "local") {
    throw new Error("legacy workspace mode requires local session storage");
  }
  const sessionStorage: AppConfig["sessionStorage"] = { mode: sessionStorageMode };
  if (sessionStorageMode === "postgres") {
    const host = env.THT_SESSION_DB_HOST;
    const database = env.THT_SESSION_DB_NAME;
    const runtimeUser = env.THT_SESSION_RUNTIME_USER;
    const runtimePasswordFile = env.THT_SESSION_RUNTIME_PASSWORD_FILE;
    const sslmode = env.THT_SESSION_DB_SSLMODE;
    const sslrootcert = env.THT_SESSION_DB_SSLROOTCERT;
    const port = Number(env.THT_SESSION_DB_PORT ?? 5432);
    if (
      (authMode !== "upstream" && authMode !== "oidc")
      || !host || !database || !runtimeUser
      || !runtimePasswordFile || !path.isAbsolute(runtimePasswordFile)
      || (sslmode !== "verify-ca" && sslmode !== "verify-full")
      || !sslrootcert || !path.isAbsolute(sslrootcert)
      || !Number.isInteger(port) || port < 1 || port > 65535
    ) {
      if (authMode !== "upstream" && authMode !== "oidc") {
        throw new Error("server session storage requires AUTH_MODE=upstream or configured OIDC");
      }
      throw new Error("server session storage configuration is invalid");
    }
    sessionStorage.host = host;
    sessionStorage.port = port;
    sessionStorage.database = database;
    sessionStorage.runtimeUser = runtimeUser;
    sessionStorage.runtimePasswordFile = runtimePasswordFile;
    sessionStorage.sslmode = sslmode;
    sessionStorage.sslrootcert = sslrootcert;
  }
  const modelApiKeyFile = env.THT_MODEL_API_KEY_FILE;
  if (modelApiKeyFile !== undefined && (
    modelApiKeyFile.trim() !== modelApiKeyFile
    || modelApiKeyFile.length === 0
    || modelApiKeyFile.includes("\0")
    || !path.isAbsolute(modelApiKeyFile)
  )) {
    throw new Error("model credential configuration is invalid");
  }
  const secretsFile = env.THT_SECRETS_FILE;
  if (secretsFile !== undefined && (
    secretsFile.trim() !== secretsFile || secretsFile.length === 0 || secretsFile.includes("\0")
    || !path.isAbsolute(secretsFile)
  )) throw new Error("secret bundle configuration is invalid");
  const installationConfigFile = env.THT_INSTALLATION_CONFIG_FILE;
  if (installationConfigFile !== undefined && (
    installationConfigFile.trim() !== installationConfigFile
    || installationConfigFile.length === 0
    || installationConfigFile.includes("\0")
    || !path.isAbsolute(installationConfigFile)
  )) throw new Error("installation configuration is invalid");
  const piAuthFile = env.THT_PI_AUTH_FILE;
  if (piAuthFile !== undefined && (
    piAuthFile.trim() !== piAuthFile || piAuthFile.length === 0 || piAuthFile.includes("\0")
    || !path.isAbsolute(piAuthFile)
  )) throw new Error("Pi authentication source configuration is invalid");
  const secretFiles: Record<string, string | undefined> = {};
  for (const name of [
    "THT_MODEL_API_KEY_SECRET_FILE", "THT_DWH_API_KEY_SECRET_FILE", "THT_VEC_API_KEY_SECRET_FILE",
    "THT_VEC_WRITE_API_KEY_SECRET_FILE", "THT_CA_SECRET_FILE", "THT_VECTOR_BOOTSTRAP_PASSWORD_SECRET_FILE",
    "THT_VECTOR_MIGRATOR_PASSWORD_SECRET_FILE", "THT_VECTOR_READER_PASSWORD_SECRET_FILE",
    "THT_VECTOR_WRITER_PASSWORD_SECRET_FILE",
  ]) secretFiles[name] = env[name];
  const registryRoot = absoluteRegistryPath(
    env.THT_WORKSPACE_REGISTRY_ROOT ?? "/data/workspace-registry",
    "root",
  );
  const registryBranch = refSafeGitBranch(env.THT_WORKSPACE_GIT_BRANCH ?? "main");
  const installationId = safeInstallationId(
    env.THT_WORKSPACE_INSTALLATION_ID ?? "local",
  );
  const remoteUrl = env.THT_WORKSPACE_GIT_REMOTE === undefined
    ? undefined
    : requiredRegistryValue(env.THT_WORKSPACE_GIT_REMOTE, "remote");
  const secretRoots = (env.THT_WORKSPACE_SECRET_ROOTS ?? "")
    .split(",")
    .filter((root) => root.length > 0)
    .map((root) => absoluteRegistryPath(root, "secret root"));
  const workspaceRegistry: WorkspaceRegistryConfig = {
    root: registryRoot,
    remoteUrl,
    branch: registryBranch,
    installationId,
    secretRoots,
    dataRoot: env.THT_DATA_ROOT,
    maxEvidenceEntries: positiveImportLimit(env.THT_WORKSPACE_MAX_EVIDENCE_ENTRIES, 4096),
    maxEvidenceBytes: positiveImportLimit(env.THT_WORKSPACE_MAX_EVIDENCE_BYTES, 64 * 1024 * 1024),
    maxEvidenceFileBytes: positiveImportLimit(env.THT_WORKSPACE_MAX_EVIDENCE_FILE_BYTES, 8 * 1024 * 1024),
    maxEvidencePathBytes: positiveImportLimit(env.THT_WORKSPACE_MAX_EVIDENCE_PATH_BYTES, 4096),
    maxEvidenceManifestBytes: positiveImportLimit(env.THT_WORKSPACE_MAX_EVIDENCE_MANIFEST_BYTES, 1024 * 1024),
  };
  const workspaceSecretStoreRoot = absoluteRegistryPath(
    env.THT_WORKSPACE_SECRET_STORE_ROOT ?? path.join(path.dirname(registryRoot), "workspace-secrets"),
    "secret store root",
  );
  const workspaceSecretRuntimeRoot = absoluteRegistryPath(
    env.THT_WORKSPACE_SECRET_RUNTIME_ROOT ?? "/tmp/thothii-workspace-secrets",
    "secret runtime root",
  );
  const settingsFile = env.SETTINGS_FILE ?? "data/settings.json";
  const internalQdrantUrl = internalServiceUrl(
    env.THT_INTERNAL_QDRANT_URL,
    "http://qdrant:6333",
    "internal Qdrant URL",
    ["qdrant", "localhost"],
  );
  const internalEmbeddingUrl = internalServiceUrl(
    env.THT_INTERNAL_EMBEDDING_URL,
    "http://embedding:11434",
    "internal embedding URL",
    ["embedding", "localhost"],
  );
  return {
    host: env.HOST ?? "127.0.0.1",
    port: Number(env.PORT ?? 8787),
    harnessDir: env.THT_HARNESS_DIR ?? "../harness",
    thtBin: env.THT_BIN ?? "tht",
    piBin: env.PI_BIN ?? "pi",
    authMode,
    authConfigFile,
    authStateRoot,
    authentication,
    publicExposure,
    sessionStorage,
    catalogDatabase: catalogDatabase(env),
    defaults: { provider: env.PI_PROVIDER, model: env.PI_MODEL, thinking: env.PI_THINKING },
    maxPiProcesses: Number(env.MAX_PI_PROCESSES ?? 4),
    settingsFile,
    maintenanceFile: env.THT_MAINTENANCE_FILE ?? path.join(path.dirname(settingsFile), "maintenance.json"),
    dataRoot: env.THT_DATA_ROOT,
    ollamaEnsureTimeoutMs: Number(env.OLLAMA_ENSURE_TIMEOUT_MS ?? 60000),
    piManagementTimeoutMs: piManagementTimeout(env.PI_MANAGEMENT_TIMEOUT_MS),
    secretsFile,
    installationConfigFile,
    piAuthFile,
    secretFiles,
    modelApiKeyFile,
    dwhPrecheck: env.THT_DWH_PRECHECK === "true" || env.THT_DWH_PRECHECK === "1",
    legacyWorkspaceMode: legacyWorkspaceMode === "local",
    workspaceDiagnosticTimeoutMs: diagnosticTimeout(env.THT_WORKSPACE_DIAGNOSTIC_TIMEOUT_MS),
    catalogSyncTimeoutMs: catalogSyncTimeout(env.THT_CATALOG_SYNC_TIMEOUT_MS),
    workspaceRegistry,
    workspaceSecretStoreRoot,
    workspaceSecretRuntimeRoot,
    internalQdrantUrl,
    internalEmbeddingUrl,
    internalEmbeddingModel: env.THT_INTERNAL_EMBEDDING_MODEL ?? "qwen3-embedding:0.6b",
    internalEmbeddingDimensions: positiveDimension(env.THT_INTERNAL_EMBEDDING_DIMENSIONS, 1024),
  };
}