// Optional Sentry error monitoring for the server process.
//
// Activated only when the backend DSN resolves to a value — see
// `resolveSentryDsns` in `sentry-dsn.ts` for the precedence between
// `SENTRY_DSN_BACKEND` and the legacy `SENTRY_DSN` fallback. When it
// resolves to `null`, no Sentry package is loaded at all.
//
// The import is dynamic and the package is an optional runtime dependency —
// operators who want server-side error monitoring install `@sentry/node`
// themselves. That keeps Sentry off the default dependency graph and avoids
// forcing a lockfile bump for an opt-in feature. This gate mirrors the
// OpenTelemetry gate in `instrumentation.ts`.
//
// OpenTelemetry keeps ownership of trace setup: the initializer passes
// `skipOpenTelemetrySetup: true` and `tracesSampleRate: 0`, so this module
// adds error monitoring only and starts no span or trace behavior of its
// own.
//
// `serverName`: the initializer sets this to the host name of the process,
// with `os.hostname()`. The `@sentry/node` client already falls back to the
// same host name when the caller omits this option, so this line makes an
// existing default explicit instead of changing captured event content. An
// explicit value stays correct if a future SDK version changes its default.
//
// An operator can still send a different value in place of the host name.
// When the environment variable `SENTRY_NAME` holds a non-empty string, the
// initializer uses that value instead. This keeps the same order the
// `@sentry/node` client itself uses when the caller omits `serverName`.
//
// Default-integration privacy note: `sendDefaultPii: false` filters values
// by name, inside the `RequestData` integration only. Three other default
// integrations copy raw values past that filter, so the initializer removes
// or narrows them with built-in Sentry options — no custom filter code:
//   - `Console` turns a `console.*` call into a breadcrumb with the raw
//     arguments. The initializer drops it.
//   - `ContextLines` reads local source lines around each stack frame off
//     the host disk. The initializer drops it.
//   - `Http` records a breadcrumb for each outbound request, with its URL
//     and query string. The initializer keeps the integration (`RequestData`
//     and request isolation need it) and turns the breadcrumb off with the
//     integration's own `breadcrumbs` option.
//
// `onUnhandledRejectionIntegration` defaults to `mode: "warn"`, which
// registers a `process.on("unhandledRejection")` listener. Node cancels its
// own crash-on-unhandled-rejection behavior when any listener is registered.
// The server relies on that crash today, so the initializer passes
// `mode: "strict"`: Sentry still captures the event, then exits the process,
// so the existing crash-and-restart behavior stays.
//
// Before it imports the package, the bootstrap checks the installed
// `@sentry/node` version against the exact version this manifest's
// `peerDependencies` declares — the same audited version documented in
// `doc/observability.md`. A missing or a mismatched version logs one
// diagnostic and leaves the server running without error monitoring; it
// never throws. This gate mirrors the OpenTelemetry gate in
// `instrumentation.ts`.

import os from "node:os";
import { AdapterStopTimeoutError } from "./services/adapter-stop-timeout.js";
import type { RunFailureDiagnostics } from "./services/run-failure-diagnostics.js";
import { readBuildCommit } from "./build-commit.js";
import { checkExactPeerVersions } from "./peer-version-check.js";
import { resolveSentryDsns } from "./sentry-dsn.js";

const { backend: dsn, legacyFallbackUsed } = resolveSentryDsns();

if (legacyFallbackUsed) {
  // eslint-disable-next-line no-console
  console.warn(
    "[paperclip] SENTRY_DSN_FRONTEND or SENTRY_DSN_BACKEND is not set. " +
      "The server uses the legacy SENTRY_DSN value for the affected " +
      "component. Set SENTRY_DSN_FRONTEND and SENTRY_DSN_BACKEND to send " +
      "each component to its own Sentry project.",
  );
}

/** Event-local context accepted by the optional Sentry package. */
interface SentryCaptureContext {
  tags: Record<string, string>;
  contexts: Record<string, Record<string, unknown>>;
  fingerprint: string[];
}

/** The subset of the `@sentry/node` client surface this gate calls. */
interface SentryHandle {
  captureException(error: unknown, context?: SentryCaptureContext): string;
  close(timeout?: number): Promise<boolean>;
}

let sentryHandle: SentryHandle | null = null;
let shutdownPromise: Promise<void> | null = null;

/**
 * Resolves once the Sentry SDK has started, or once bootstrap has failed and
 * logged, or at once when the backend DSN resolves to `null`. No caller
 * needs to await this before calling `captureException` — it is a no-op
 * until ready — but `index.ts` awaits it at startup so the first real error
 * has a live client.
 */
export const sentryReady: Promise<void> = dsn ? bootstrapSentry(dsn) : Promise.resolve();

/**
 * Report an error to Sentry. A no-op before the gate opens, when the gate
 * never opens (the backend DSN resolves to `null`), or when bootstrap
 * failed. Never throws — observability must not change control flow.
 */
export function captureException(error: unknown): void {
  if (!sentryHandle) return;
  try {
    if (error instanceof AdapterStopTimeoutError) {
      // Event-local, fixed-shape context: no ambient scope or raw error fields.
      const exception = new Error(error.message);
      exception.stack = error.stack;
      sentryHandle.captureException(exception, {
        tags: { error_code: "adapter_stop_unconfirmed" },
        contexts: { adapter_stop: { ...error.diagnostics } },
        fingerprint: ["{{ default }}"],
      });
    } else {
      sentryHandle.captureException(error);
    }
  } catch (err) {
    // eslint-disable-next-line no-console
    console.error("[paperclip] Sentry captureException failed", err);
  }
}

/** The run status values that mark a run as a genuine terminal failure. */
export type RunFailureStatus = "failed" | "timed_out" | "cancelled";

/**
 * The diagnostic values `captureRunFailure` sends with a terminal-failure
 * event. `errorCode` is `null` when the run holds no error code.
 */
export interface RunFailureEvent {
  /** The task UUID the run belongs to. */
  taskId: string;
  /** The `heartbeat_runs` row id. */
  runId: string;
  /** The redacted error message. */
  errorMessage: string;
  /** The run's error code, or `null` when the run holds none. */
  errorCode: string | null;
  /** The agent's adapter type, or `"unknown"` when the agent row is absent. */
  agentAdapter: string;
  /** The run status that triggered this report. */
  runStatus: RunFailureStatus;
  /** Bounded, redacted diagnostics selected by the run failure reporter. */
  diagnostics?: RunFailureDiagnostics;
  /** Recorded process exit evidence, when available. Validated before capture. */
  exitCode?: number | null;
  signal?: string | null;
}

function normalizeRunExitCode(value: unknown): number | null {
  // Match the persisted PostgreSQL integer. Do not coerce adapter-supplied text.
  return typeof value === "number" &&
    Number.isInteger(value) &&
    value >= -2147483648 &&
    value <= 2147483647
    ? value
    : null;
}

function normalizeRunSignal(value: unknown): string | null {
  if (value == null) return null;
  // Only host signal constants may leave the process; arbitrary adapter text
  // can contain output or credentials even when stored in the signal column.
  return typeof value === "string" && Object.hasOwn(os.constants.signals, value)
    ? value
    : "unknown";
}

/**
 * Report one terminal run failure to Sentry. A no-op before the gate opens
 * or when the gate never opens. Never throws — observability must not
 * change run control flow.
 *
 * Sets the fingerprint to `[errorCode, agentAdapter]`, in that order, so
 * Sentry groups events by error code and adapter. The error message stays
 * out of the fingerprint — it still travels as the exception message and as
 * a field of the `run_failure` context.
 */
export function captureRunFailure(event: RunFailureEvent): void {
  if (!sentryHandle) return;
  const handle = sentryHandle;
  try {
    const errorCode = event.errorCode ?? "unknown";
    // Sentry's async scope isolation is absent when OTel setup is skipped.
    // A withScope mutation can then persist into unrelated later captures.
    // Pass these fields on this event only; do not mutate the ambient scope.
    const diagnostics = event.diagnostics;
    const contexts: Record<string, Record<string, unknown>> = {};
    if (diagnostics) {
      contexts.run_execution = { ...diagnostics.execution, truncatedFields: diagnostics.truncatedFields };
      if (Object.keys(diagnostics.adapter).length) contexts.adapter_failure = diagnostics.adapter;
      if (Object.keys(diagnostics.provider).length) contexts.provider_failure = diagnostics.provider;
      diagnostics.exceptions.forEach(({ name, code, status, requestId }, index) => {
        contexts[`run_exception_${index}`] = { name, code, status, requestId };
      });
    }
    // Rebuild only sanitized exception fields. Passing a raw SDK Error can
    // serialize its request/response, headers, or other enumerable properties.
    let cause: Error | undefined;
    for (const entry of [...(diagnostics?.exceptions ?? [])].reverse()) {
      const error: Error = new Error(entry.message ?? event.errorMessage, cause ? { cause } : undefined);
      error.name = entry.name ?? "Error";
      error.stack = entry.stack;
      cause = error;
    }
    const exception = cause ?? new Error(event.errorMessage);
    if (!cause) {
      // A saved adapter result is not a thrown Error. Do not pretend that the
      // reporter's own stack is the failure location.
      exception.stack = typeof diagnostics?.adapter.stackPreview === "string"
        ? diagnostics.adapter.stackPreview : undefined;
    }
    handle.captureException(exception, {
      tags: {
        run_id: event.runId,
        task_id: event.taskId,
        error_code: errorCode,
        agent_adapter: event.agentAdapter,
        run_status: event.runStatus,
      },
      contexts: {
        ...contexts,
        run_failure: {
          taskId: event.taskId,
          runId: event.runId,
          errorMessage: event.errorMessage,
          errorCode,
          agentAdapter: event.agentAdapter,
          exitCode: normalizeRunExitCode(event.exitCode),
          signal: normalizeRunSignal(event.signal),
        },
      },
      fingerprint: [errorCode, event.agentAdapter],
    });
  } catch (err) {
    // eslint-disable-next-line no-console
    console.error("[paperclip] Sentry captureRunFailure failed", err);
  }
}

/**
 * Flush buffered events and close the Sentry client. Idempotent — concurrent
 * callers share one shutdown. A no-op when monitoring is off or bootstrap
 * failed.
 */
export function shutdownSentry(): Promise<void> {
  shutdownPromise ??= (async () => {
    await sentryReady;
    if (!sentryHandle) return;
    try {
      // Awaiting matters: the client flushes buffered events to Sentry
      // during close; exiting before it settles silently drops them.
      await sentryHandle.close(5_000);
    } catch (err) {
      // eslint-disable-next-line no-console
      console.error("[paperclip] Sentry shutdown failed", err);
    }
  })();
  return shutdownPromise;
}

/**
 * The subset of the `@sentry/node` module surface the initializer needs to
 * build its options object. A structural type, not the real Sentry type —
 * the real type is unavailable at compile time because the package is an
 * optional runtime dependency (see the module comment above).
 */
interface SentryModuleLike {
  httpIntegration(options: { breadcrumbs: boolean }): { name: string };
  onUnhandledRejectionIntegration(options: { mode: "strict" }): { name: string };
}

/** The `Sentry.init` options this gate builds. */
export interface SentryInitOptions {
  dsn: string;
  release?: string;
  skipOpenTelemetrySetup: boolean;
  tracesSampleRate: number;
  sendDefaultPii: boolean;
  serverName: string;
  integrations: (defaults: Array<{ name: string }>) => Array<{ name: string }>;
}

/**
 * Build the `Sentry.init` options object. A pure function, split out from
 * `bootstrapSentry` so a test can call it with a real `@sentry/node` module
 * and assert the resolved integration list and the captured-event shape
 * against the true SDK, not a stand-in.
 */
export function buildSentryInitOptions(
  dsn: string,
  Sentry: SentryModuleLike,
): SentryInitOptions {
  return {
    dsn,
    release: process.env.SENTRY_RELEASE?.trim() || readBuildCommit() || undefined,
    skipOpenTelemetrySetup: true,
    tracesSampleRate: 0,
    sendDefaultPii: false,
    serverName: process.env.SENTRY_NAME || os.hostname(),
    integrations: (defaults: Array<{ name: string }>) => {
      const kept = defaults.filter(
        (integration) =>
          integration.name !== "Console" &&
          integration.name !== "ContextLines" &&
          integration.name !== "Http" &&
          integration.name !== "OnUnhandledRejection",
      );
      return [
        ...kept,
        // Keep the rest of the Http integration — RequestData and request
        // isolation need it — but turn the outbound breadcrumb off.
        Sentry.httpIntegration({ breadcrumbs: false }),
        // Keep today's crash-on-unhandled-rejection behavior. See the
        // module comment above for why the default mode cannot stay.
        Sentry.onUnhandledRejectionIntegration({ mode: "strict" }),
      ];
    },
  };
}

async function bootstrapSentry(dsn: string): Promise<void> {
  // Gate on the exact peer version before touching the dynamic import: a
  // package installed at the wrong version can still load and start, which
  // would silently invalidate the privacy audit `doc/observability.md`
  // records against one exact version. Checking first turns that into one
  // precise, fail-open diagnostic.
  const versionCheck = checkExactPeerVersions(["@sentry/node"]);
  if (!versionCheck.ok) {
    // eslint-disable-next-line no-console
    console.warn(
      "[paperclip] The backend Sentry DSN is set, but the @sentry/node " +
        "package is not installed, or is installed at an unsupported " +
        "version. Install the declared version of @sentry/node to enable " +
        "server error monitoring. Continuing without it.",
      versionCheck.detail,
    );
    return;
  }

  try {
    // Dynamic import so type-resolution doesn't require the package to be
    // installed unless the operator actually opts in.
    // @ts-ignore optional peer dep
    const Sentry = await import("@sentry/node");

    Sentry.init(buildSentryInitOptions(dsn, Sentry));

    sentryHandle = {
      captureException: (...args) => Sentry.captureException(...args),
      close: (timeout) => Sentry.close(timeout),
    };
  } catch (err) {
    // The exact-version gate above already confirmed @sentry/node is
    // installed at the declared version, so only a load or init failure
    // after that point reaches this block.
    // eslint-disable-next-line no-console
    console.warn(
      "[paperclip] The backend Sentry DSN is set, and @sentry/node passed " +
        "the version check, but it failed to load or initialize. " +
        "Continuing without error monitoring.",
      err,
    );
  }
}