#!/usr/bin/env -S bun --no-env-file --config=/dev/null
/**
 * gstack-gbrain-detect — emit current gbrain/gstack-brain state as JSON.
 *
 * Rewritten from bash to TypeScript in v{X.Y.Z.0} to share the engine-status
 * classifier with bin/gstack-gbrain-sync.ts. Single source of truth via
 * lib/gbrain-local-status.ts. Filename and exec semantics unchanged: callers
 * just shell out to the file path; the bun shebang resolves at runtime.
 *
 * Output (always valid JSON, even when every check is false):
 *   {
 *     "gbrain_on_path": true|false,
 *     "gbrain_version": "0.18.2" | null,
 *     "gbrain_config_exists": true|false,
 *     "gbrain_engine": "pglite"|"postgres" | null,
 *     "gbrain_doctor_ok": true|false,
 *     "gbrain_mcp_mode": "local-stdio"|"remote-http"|"none",
 *     "gstack_brain_sync_mode": "off"|"artifacts-only"|"full",
 *     "gstack_brain_git": true|false,
 *     "gstack_artifacts_remote": "https://..." | "",
 *     "gbrain_local_status": "ok"|"no-cli"|"missing-config"|"broken-config"|"broken-db"|"engine-locked"|"timeout"|"db-unreachable"|"thin-client",
 *     "gbrain_pooler_mode": "transaction"|"session"|null
 *   }
 *
 * Backward compatibility (per plan codex #5): the 9 pre-existing fields stay
 * identical in name + type + value semantics. One new field added:
 * gbrain_local_status. Key order may differ from the bash version's `jq -n`
 * output — downstream parsers must not depend on key order (none currently do).
 *
 * Env:
 *   GSTACK_HOME      — override ~/.gstack for state lookups (used by tests).
 *   HOME             — effective user home (drives ~/.gbrain/config.json path).
 *   GSTACK_DETECT_NO_CACHE=1 — bypass the 60s local-status cache.
 */

import { execFileSync } from "child_process";
import { existsSync, readFileSync } from "fs";
import { homedir } from "os";
import { join } from "path";

import {
  localEngineStatus,
  localEngineStatusDetail,
  resolveGbrainBin,
  readGbrainVersion,
} from "../lib/gbrain-local-status";
import { gbrainConfigDir, isTransactionModePooler } from "../lib/gbrain-exec";
import { classifyGbrainMcpEntry, classifyGbrainMcpListLine, type GbrainMcpEntry } from "../lib/gbrain-mcp-locality";
import { resolveStateRoot } from "../lib/state-root";

const STATE_DIR = resolveStateRoot();
const SCRIPT_DIR = __dirname;
const CONFIG_BIN = join(SCRIPT_DIR, "gstack-config");
// Honors GBRAIN_HOME with gbrain's own configDir() semantics (#2521:
// GBRAIN_HOME is a parent dir, `.gbrain` is appended) — must stay consistent
// with lib/gbrain-local-status's config resolution, or the detect JSON
// reports gbrain_local_status "ok" alongside gbrain_config_exists false for
// relocated-home users. Both route through gbrainConfigDir.
const GBRAIN_CONFIG = join(gbrainConfigDir(), "config.json");
const CLAUDE_JSON = join(userHome(), ".claude.json");

function userHome(): string {
  return process.env.HOME || homedir();
}

function tryExec(cmd: string, args: string[], timeoutMs = 5_000): string | null {
  try {
    return execFileSync(cmd, args, {
      encoding: "utf-8",
      timeout: timeoutMs,
      stdio: ["ignore", "pipe", "ignore"],
    }).trim();
  } catch {
    return null;
  }
}

function tryReadJSON(path: string): unknown | null {
  if (!existsSync(path)) return null;
  try {
    return JSON.parse(readFileSync(path, "utf-8"));
  } catch {
    return null;
  }
}

// --- gbrain binary presence + version ---
// Uses the shared memoized resolvers from lib/gbrain-local-status.ts so
// detect and the classifier share probe results within one process.
function detectGbrain(): { onPath: boolean; version: string | null } {
  const bin = resolveGbrainBin();
  if (!bin) return { onPath: false, version: null };
  const verRaw = readGbrainVersion();
  if (!verRaw) return { onPath: true, version: null };
  // Match bash behavior: head -1 | tr -d '[:space:]'
  const version = verRaw.split("\n")[0].replace(/\s+/g, "") || null;
  return { onPath: true, version };
}

// --- gbrain config existence + engine kind ---
function detectConfig(): { exists: boolean; engine: "pglite" | "postgres" | null } {
  if (!existsSync(GBRAIN_CONFIG)) return { exists: false, engine: null };
  const parsed = tryReadJSON(GBRAIN_CONFIG) as { engine?: string } | null;
  if (!parsed) return { exists: true, engine: null };
  if (parsed.engine === "pglite" || parsed.engine === "postgres") {
    return { exists: true, engine: parsed.engine };
  }
  return { exists: true, engine: null };
}

// --- pooler mode detection (#1435) ---
//
// Reads DATABASE_URL from ~/.gbrain/config.json and checks whether it targets
// a PgBouncer transaction-mode pooler (port 6543). Surfaced so /sync-gbrain
// and /setup-gbrain can advise users when search may require GBRAIN_PREPARE.
function detectPoolerMode(): "transaction" | "session" | "unknown" | null {
  const parsed = tryReadJSON(GBRAIN_CONFIG) as { database_url?: string } | null;
  if (!parsed?.database_url) return null;
  return isTransactionModePooler(parsed.database_url) ? "transaction" : "session";
}

// --- gbrain doctor health (any nonzero exit or non-"ok"/"warnings" status → false) ---
//
// Uses --fast to avoid hanging on a dead DB. Per the local-status classifier
// (which probes DB directly via `gbrain sources list`), gbrain_doctor_ok is a
// coarse health summary, not engine-reachability — that's gbrain_local_status.
function detectDoctor(onPath: boolean): boolean {
  if (!onPath) return false;
  const out = tryExec("gbrain", ["doctor", "--json", "--fast"], 3_000);
  if (!out) return false;
  try {
    const parsed = JSON.parse(out) as { status?: string };
    return parsed.status === "ok" || parsed.status === "warnings";
  } catch {
    return false;
  }
}

// --- artifacts sync mode ---
function detectSyncMode(): "off" | "artifacts-only" | "full" {
  if (!existsSync(CONFIG_BIN)) return "off";
  const out = tryExec(CONFIG_BIN, ["get", "artifacts_sync_mode"], 2_000);
  if (out === "off" || out === "artifacts-only" || out === "full") return out;
  return "off";
}

// --- gstack-brain git repo present? ---
function detectBrainGit(): boolean {
  return existsSync(join(STATE_DIR, ".git"));
}

// --- MCP mode: local-stdio | remote-http | none ---
//
// Defense-in-depth fallback chain (same ordering as the bash version):
//   1. `claude mcp get gbrain --json` — public CLI surface, structured output
//   2. `claude mcp list` text-grep    — older claude versions without --json
//   3. `~/.claude.json` jq read       — last resort if `claude` isn't on PATH
//
// #3539: an HTTP entry on a loopback host whose local gbrain config has an
// engine and no remote_mcp marker is a resident `gbrain serve --http` of this
// machine's own brain. It reports "local-stdio" (the local-engine mode every
// consumer already understands: memory ingest imports, sync-gbrain skips the
// remote trust-policy question) rather than a new value.
type McpMode = "local-stdio" | "remote-http";
function classify(entry: GbrainMcpEntry): McpMode | null {
  const c = classifyGbrainMcpEntry(entry);
  return c === "remote" ? "remote-http" : c === "local" ? "local-stdio" : null;
}

function detectMcpMode(): McpMode | "none" {
  const claudeOnPath = tryExec("sh", ["-c", "command -v claude"], 1_000) !== null;
  if (claudeOnPath) {
    // Tier 1: `claude mcp get gbrain --json`
    const get = tryExec("claude", ["mcp", "get", "gbrain", "--json"], 3_000);
    if (get) {
      try {
        const parsed = JSON.parse(get) as {
          type?: string;
          transport?: string;
          command?: string;
          url?: string;
        };
        const c = classify(parsed);
        if (c) return c;
      } catch {
        // fall through
      }
    }
    // Tier 2: `claude mcp list` text-grep. Name-pattern generalized (#2051):
    // a gbrain server registered as e.g. "gbrain-remote" or "gbrain_work"
    // still counts. Anchored to the gbrain token so unrelated servers can't
    // false-positive. The exact `gbrain:` line wins over a variant, the same
    // order as tier 3 (and memory-ingest, which reads mcpServers.gbrain):
    // {gbrain-a: loopback, gbrain: remote} is remote-http.
    const list = tryExec("claude", ["mcp", "list"], 3_000);
    if (list) {
      const lines = list.split("\n");
      const line =
        lines.find((l) => l.startsWith("gbrain:")) ?? lines.find((l) => /^gbrain[-_][\w-]*:/.test(l));
      if (line) {
        // The list line carries the URL for HTTP and SSE servers
        // ("gbrain: http://127.0.0.1:3131/mcp (HTTP) - ✓ Connected"), so the
        // loopback rule (#3539) applies here too. The whole URL token is
        // classified, never cut at ")"; an HTTP or SSE line without a usable
        // URL keeps the old remote-http answer.
        return classifyGbrainMcpListLine(line) === "local" ? "local-stdio" : "remote-http";
      }
    }
  }
  // Tier 3: read ~/.claude.json directly
  const cj = tryReadJSON(CLAUDE_JSON) as
    | { mcpServers?: Record<string, GbrainMcpEntry> }
    | null;
  const servers = cj?.mcpServers || {};
  const exact = servers["gbrain"];
  if (exact) {
    const c = classify(exact);
    if (c) return c;
  }
  // #2051 generalization, deterministic identifiers first:
  // (a) a server whose url matches the config's remote_mcp.mcp_url is THE
  //     thin-client brain regardless of its registered name (URL-path
  //     heuristics are impossible — gbrain mounts at the generic /mcp);
  // (b) name pattern gbrain[-_]* ;
  // (c) a stdio server whose command mentions gbrain.
  const remoteMcpUrl = readRemoteMcpUrl();
  for (const [name, entry] of Object.entries(servers)) {
    if (remoteMcpUrl && entry.url && entry.url === remoteMcpUrl) return "remote-http";
    if (/^gbrain([-_][\w-]*)?$/.test(name)) {
      const c = classify(entry);
      if (c) return c;
    }
    if (entry.command && /\bgbrain\b/.test(entry.command)) return "local-stdio";
  }
  return "none";
}

/** remote_mcp.mcp_url from gbrain's own config (thin-client marker, #2051). */
function readRemoteMcpUrl(): string {
  const cfg = tryReadJSON(join(gbrainConfigDir(), "config.json")) as
    | { remote_mcp?: { mcp_url?: string } }
    | null;
  return cfg?.remote_mcp?.mcp_url || "";
}

// --- artifacts remote URL with brain-* fallback during the rename migration window ---
function detectArtifactsRemote(): string {
  const newPath = join(userHome(), ".gstack-artifacts-remote.txt");
  const oldPath = join(userHome(), ".gstack-brain-remote.txt");
  for (const p of [newPath, oldPath]) {
    if (existsSync(p)) {
      try {
        return readFileSync(p, "utf-8").split("\n")[0].trim();
      } catch {
        // fall through
      }
    }
  }
  return "";
}

function main(): void {
  const gbrain = detectGbrain();
  const config = detectConfig();
  const noCache = process.env.GSTACK_DETECT_NO_CACHE === "1";

  // Order MATCHES the bash version's jq output for callers that visually grep
  // (key order doesn't affect JSON parsers, but minimizes review noise).
  const out = {
    gbrain_on_path: gbrain.onPath,
    gbrain_version: gbrain.version,
    gbrain_config_exists: config.exists,
    gbrain_engine: config.engine,
    gbrain_doctor_ok: detectDoctor(gbrain.onPath),
    gbrain_mcp_mode: detectMcpMode(),
    gstack_brain_sync_mode: detectSyncMode(),
    gstack_brain_git: detectBrainGit(),
    gstack_artifacts_remote: detectArtifactsRemote(),
    gbrain_local_status: localEngineStatus({ noCache }),
    gbrain_pooler_mode: detectPoolerMode(),
  };

  // #2051 honesty marker: on a thin client the classifier verified the CONFIG
  // (remote_mcp present), not the remote's reachability — that is checked at
  // use time, where gbrain calls degrade gracefully.
  const withThinClient =
    out.gbrain_local_status === "thin-client"
      ? { ...out, gbrain_thin_client: { probed: false } }
      : out.gbrain_local_status === "db-unreachable"
        ? { ...out, gbrain_local_status_detail: localEngineStatusDetail() }
        : out;

  process.stdout.write(JSON.stringify(withThinClient, null, 2) + "\n");
}

// --is-ok: live engine-status gate. Exits 0 iff gbrain is usable ("ok";
// "timeout" — a slow-but-healthy engine, #1964; "db-unreachable" — a network
// error reaching a configured DB, transient like timeout; "thin-client" — remote-HTTP
// MCP brain with no local engine by design, #2051; or "engine-locked" —
// PGLite is single-writer, so a live `gbrain serve` (typically an MCP
// server) holds the embedded DB, #2456 — gbrain is installed and healthy in
// all four; none must silently suppress brain features), 1 otherwise. Runs
// detection live (never reads the possibly-stale gbrain-detection.json), so
// callers — setup, bin/dev-setup, and `gstack-config gbrain-refresh` — can
// decide whether to render the gbrain :user variant without duplicating the
// JSON grep. Prints nothing on stdout.
if (process.argv.includes("--is-ok")) {
  const noCache = process.env.GSTACK_DETECT_NO_CACHE === "1";
  const status = localEngineStatus({ noCache });
  process.exit(
    status === "ok" || status === "timeout" || status === "db-unreachable" ||
      status === "thin-client" || status === "engine-locked"
      ? 0
      : 1,
  );
}

main();