import { describe, it, expect } from "vitest";
import {
  parseRecord,
  isFailure,
  groupByCorrelation,
  buildCorrelationTree,
  type TelemetryRecord,
} from "../telemetry";

const env = (messageId: string, causationId: string, correlationId = "c1") => ({
  messageId,
  causationId,
  correlationId,
});

describe("parseRecord", () => {
  it("parses a JSON string with a kind", () => {
    const r = parseRecord('{"kind":"action.completed","durationMs":3}');
    expect(r?.kind).toBe("action.completed");
    expect(r?.durationMs).toBe(3);
  });
  it("accepts an already-parsed object", () => {
    expect(parseRecord({ kind: "event.published" })?.kind).toBe("event.published");
  });
  it("returns null for invalid json, missing kind, or non-object", () => {
    expect(parseRecord("not json")).toBeNull();
    expect(parseRecord('{"no":"kind"}')).toBeNull();
    expect(parseRecord(42)).toBeNull();
  });
});

describe("isFailure", () => {
  it("flags failure kinds + anything carrying an error", () => {
    expect(isFailure({ kind: "action.failed" })).toBe(true);
    expect(isFailure({ kind: "dlq.recorded" })).toBe(true);
    expect(isFailure({ kind: "external.call.failed" })).toBe(true);
    expect(isFailure({ kind: "action.completed", error: { name: "E", message: "x" } })).toBe(true);
  });
  it("does not flag success kinds", () => {
    expect(isFailure({ kind: "action.completed" })).toBe(false);
    expect(isFailure({ kind: "event.published" })).toBe(false);
  });
});

describe("groupByCorrelation", () => {
  it("buckets by correlationId; envelope-less under ''", () => {
    const recs: TelemetryRecord[] = [
      { kind: "a", envelope: env("m1", "m1", "c1") },
      { kind: "b", envelope: env("m2", "m1", "c1") },
      { kind: "c", envelope: env("m3", "m3", "c2") },
      { kind: "hook.step" },
    ];
    const g = groupByCorrelation(recs);
    expect(g.get("c1")).toHaveLength(2);
    expect(g.get("c2")).toHaveLength(1);
    expect(g.get("")).toHaveLength(1);
  });
});

describe("buildCorrelationTree", () => {
  it("roots the chain head and nests children by causationId", () => {
    const recs: TelemetryRecord[] = [
      { kind: "action.dispatched", envelope: env("m1", "m1") }, // head (self-caused)
      { kind: "event.published", envelope: env("m2", "m1") }, //   child of m1
      { kind: "listener.fired", envelope: env("m3", "m2") }, //    child of m2
    ];
    const roots = buildCorrelationTree(recs);
    expect(roots).toHaveLength(1);
    expect(roots[0]!.record.kind).toBe("action.dispatched");
    expect(roots[0]!.children[0]!.record.kind).toBe("event.published");
    expect(roots[0]!.children[0]!.children[0]!.record.kind).toBe("listener.fired");
  });
  it("treats an orphan (parent not present) as a root, and skips envelope-less records", () => {
    const recs: TelemetryRecord[] = [
      { kind: "orphan", envelope: env("m9", "m-missing") },
      { kind: "no-envelope" },
    ];
    const roots = buildCorrelationTree(recs);
    expect(roots).toHaveLength(1);
    expect(roots[0]!.record.kind).toBe("orphan");
  });
  it("keeps the first record per messageId (multi-stage dispatch)", () => {
    const recs: TelemetryRecord[] = [
      { kind: "action.dispatched", envelope: env("m1", "m1") },
      { kind: "action.completed", envelope: env("m1", "m1") },
    ];
    const roots = buildCorrelationTree(recs);
    expect(roots).toHaveLength(1);
    expect(roots[0]!.record.kind).toBe("action.dispatched");
  });
});