refactor: split config module

src/config/paths.ts

@@ -0,0 +1,69 @@
+import os from "node:os";
+import path from "node:path";
+
+import type { ClawdisConfig } from "./types.js";
+
+/**
+ * Nix mode detection: When CLAWDIS_NIX_MODE=1, the gateway is running under Nix.
+ * In this mode:
+ * - No auto-install flows should be attempted
+ * - Missing dependencies should produce actionable Nix-specific error messages
+ * - Config is managed externally (read-only from Nix perspective)
+ */
+export function resolveIsNixMode(
+  env: NodeJS.ProcessEnv = process.env,
+): boolean {
+  return env.CLAWDIS_NIX_MODE === "1";
+}
+
+export const isNixMode = resolveIsNixMode();
+
+/**
+ * State directory for mutable data (sessions, logs, caches).
+ * Can be overridden via CLAWDIS_STATE_DIR environment variable.
+ * Default: ~/.clawdis
+ */
+export function resolveStateDir(
+  env: NodeJS.ProcessEnv = process.env,
+  homedir: () => string = os.homedir,
+): string {
+  const override = env.CLAWDIS_STATE_DIR?.trim();
+  if (override) return override;
+  return path.join(homedir(), ".clawdis");
+}
+
+export const STATE_DIR_CLAWDIS = resolveStateDir();
+
+/**
+ * Config file path (JSON5).
+ * Can be overridden via CLAWDIS_CONFIG_PATH environment variable.
+ * Default: ~/.clawdis/clawdis.json (or $CLAWDIS_STATE_DIR/clawdis.json)
+ */
+export function resolveConfigPath(
+  env: NodeJS.ProcessEnv = process.env,
+  stateDir: string = resolveStateDir(env, os.homedir),
+): string {
+  const override = env.CLAWDIS_CONFIG_PATH?.trim();
+  if (override) return override;
+  return path.join(stateDir, "clawdis.json");
+}
+
+export const CONFIG_PATH_CLAWDIS = resolveConfigPath();
+
+export const DEFAULT_GATEWAY_PORT = 18789;
+
+export function resolveGatewayPort(
+  cfg?: ClawdisConfig,
+  env: NodeJS.ProcessEnv = process.env,
+): number {
+  const envRaw = env.CLAWDIS_GATEWAY_PORT?.trim();
+  if (envRaw) {
+    const parsed = Number.parseInt(envRaw, 10);
+    if (Number.isFinite(parsed) && parsed > 0) return parsed;
+  }
+  const configPort = cfg?.gateway?.port;
+  if (typeof configPort === "number" && Number.isFinite(configPort)) {
+    if (configPort > 0) return configPort;
+  }
+  return DEFAULT_GATEWAY_PORT;
+}