// phoenix-bridge — register an OpenTelemetry SDK so the spans OpenCode
// already emits (when experimental.openTelemetry=true) actually leave
// the process and land in Arize Phoenix on the Framework Desktop.
//
// What it does:
//   - Boots @opentelemetry/sdk-node with OTLP/HTTP exporter pointed at
//     http://framework:4318/v1/traces (override via PHOENIX_OTLP_ENDPOINT).
//   - Inserts @arizeai/openinference-vercel's OpenInferenceSpanProcessor so
//     Phoenix's LLM/tool-aware UI gets richer attributes than vanilla OTel.
//   - Opens a parent span around each OpenCode session, with sub-sessions
//     (subagents spawned via the Task tool) nested under the parent. This
//     gives Phoenix a unified tree per top-level conversation.
//
// Caveats (May 2026):
//   - Subagent OTel context propagation across session boundaries is best
//     effort; OpenCode's experimental.chat.system.transform doesn't expose
//     sessionID yet (issue sst/opencode#6142). When that lands, swap the
//     manual stitching here for proper traceparent injection.
//   - Dynamic imports below are deliberate — per OpenCode's plugin guide,
//     direct imports of optional deps freeze the harness if they're absent.
//     Run `npm install` in this directory first.

export const PhoenixBridge = async ({ project, directory, worktree }) => {
  // Direct file logging — OpenCode swallows stdout/stderr from plugin
  // code, so this is how we get visibility into init progress. Tail with:
  //   tail -f /tmp/phoenix-bridge.log
  const { appendFileSync } = await import("node:fs");
  const log = (msg) => {
    try {
      appendFileSync(
        "/tmp/phoenix-bridge.log",
        `[${new Date().toISOString()}] ${msg}\n`,
      );
    } catch (_) {
      /* best effort */
    }
  };
  log("plugin function entered");

  // Phoenix 15.x serves OTLP/HTTP at /v1/traces on the same port as the UI
  // (6006). Earlier versions used a separate 4318 — override here if you
  // ever pin Phoenix < 15.0.
  const endpoint =
    process.env.PHOENIX_OTLP_ENDPOINT || "http://framework:6006/v1/traces";
  const serviceName = process.env.PHOENIX_SERVICE_NAME || "opencode";
  // NodeSDK's `serviceName` constructor option is ignored in some
  // versions; setting OTEL_SERVICE_NAME forces the resource attribute
  // through the standard env-var path. Has to happen before sdk.start().
  if (!process.env.OTEL_SERVICE_NAME) {
    process.env.OTEL_SERVICE_NAME = serviceName;
  }
  log(`endpoint=${endpoint} serviceName=${serviceName}`);

  // Dynamic imports so a missing dep produces a warning, not a freeze.
  let NodeSDK,
    OTLPTraceExporter,
    BatchSpanProcessor,
    SimpleSpanProcessor,
    trace,
    context,
    diag,
    DiagLogLevel;
  try {
    ({ NodeSDK } = await import("@opentelemetry/sdk-node"));
    // Use the protobuf-over-HTTP exporter — Phoenix's OTLP receiver
    // only speaks protobuf (returns 415 for the JSON variant from
    // @opentelemetry/exporter-trace-otlp-http).
    ({ OTLPTraceExporter } = await import(
      "@opentelemetry/exporter-trace-otlp-proto"
    ));
    ({ BatchSpanProcessor, SimpleSpanProcessor } = await import(
      "@opentelemetry/sdk-trace-base"
    ));
    ({ trace, context, diag, DiagLogLevel } = await import(
      "@opentelemetry/api"
    ));
    log("OTel imports resolved");
  } catch (err) {
    console.warn(
      "[phoenix-bridge] OTel deps not installed — skipping. " +
        "Run `npm install` in .opencode/plugin/ to enable.",
      err && err.message,
    );
    return {};
  }

  // Pipe OTel's internal diagnostics into our log so export errors are
  // visible. Without this, BatchSpanProcessor swallows exporter failures.
  // Default to WARN — bump to DEBUG via PHOENIX_OTEL_DEBUG=1 when chasing
  // a regression.
  const otelLevel =
    process.env.PHOENIX_OTEL_DEBUG === "1"
      ? DiagLogLevel.DEBUG
      : DiagLogLevel.WARN;
  diag.setLogger(
    {
      verbose: (m) => log(`[otel:verbose] ${m}`),
      debug: (m) => log(`[otel:debug] ${m}`),
      info: (m) => log(`[otel:info] ${m}`),
      warn: (m) => log(`[otel:warn] ${m}`),
      error: (m) => log(`[otel:error] ${m}`),
    },
    otelLevel,
  );

  // NodeSDK accepts `serviceName` directly, sidestepping the Resource API
  // (which broke between @opentelemetry/resources v1.x and v2.x).
  // SimpleSpanProcessor (vs BatchSpanProcessor) exports each span
  // immediately — easier to debug while we sort out the pipeline.
  const exporter = new OTLPTraceExporter({ url: endpoint });
  const sdk = new NodeSDK({
    serviceName,
    spanProcessors: [new SimpleSpanProcessor(exporter)],
  });
  sdk.start();
  log("sdk.start() returned");

  const tracer = trace.getTracer("opencode.phoenix-bridge");
  log("tracer obtained");

  // Smoke-test span. If this one doesn't show up in Phoenix, the export
  // path is broken and there's no point chasing missing session spans.
  // Should appear under service "opencode" within ~5 s of OpenCode start.
  const bootSpan = tracer.startSpan("phoenix-bridge.boot", {
    attributes: {
      "opencode.endpoint": endpoint,
      "opencode.service_name": serviceName,
    },
  });
  bootSpan.end();
  log("boot span emitted (will flush within ~5s)");
  // sessionId -> { span, ctx }
  const sessions = new Map();

  const closeSession = (sessionId) => {
    const rec = sessions.get(sessionId);
    if (!rec) return;
    rec.span.end();
    sessions.delete(sessionId);
  };

  const onShutdown = async () => {
    for (const id of [...sessions.keys()]) closeSession(id);
    try {
      await sdk.shutdown();
    } catch (_) {
      /* ignore */
    }
  };
  process.once("beforeExit", onShutdown);
  process.once("SIGINT", onShutdown);
  process.once("SIGTERM", onShutdown);

  return {
    event: async ({ event }) => {
      if (!event || !event.type) return;

      switch (event.type) {
        case "session.created": {
          const session = event.properties?.session || event.properties || {};
          const id = session.id;
          const parentID = session.parentID;
          if (!id) return;

          const parentRec = parentID ? sessions.get(parentID) : null;
          const parentCtx = parentRec ? parentRec.ctx : context.active();
          const span = tracer.startSpan(
            parentID ? `subagent ${id}` : `session ${id}`,
            {
              attributes: {
                "opencode.session.id": id,
                "opencode.session.parent_id": parentID || "",
                "opencode.directory": directory || "",
                "opencode.worktree": worktree || "",
                "opencode.project": project?.name || "",
              },
            },
            parentCtx,
          );
          sessions.set(id, { span, ctx: trace.setSpan(parentCtx, span) });
          break;
        }

        case "session.idle":
        case "session.deleted":
        case "session.compacted": {
          const id =
            event.properties?.session?.id || event.properties?.id || null;
          if (id) closeSession(id);
          break;
        }

        default:
          break;
      }
    },
  };
};