import {
  INITIAL_PROTOCOL_MISMATCH_SNAPSHOT,
  newestProtocolMismatchSnapshot,
  type ProtocolMismatchSnapshot,
} from "../src/lib/protocolMismatch.ts";

const assertEquals = <T>(actual: T, expected: T, message: string) => {
  if (JSON.stringify(actual) !== JSON.stringify(expected)) {
    throw new Error(
      `${message}: expected ${JSON.stringify(expected)}, got ${JSON.stringify(actual)}`,
    );
  }
};

Deno.test("delayed bootstrap snapshot cannot overwrite a newer mismatch event", () => {
  const delayedQuery = INITIAL_PROTOCOL_MISMATCH_SNAPSHOT;
  const event: ProtocolMismatchSnapshot = {
    revision: 1,
    mismatch: { observed: 7, expected: 8 },
  };

  const afterEvent = newestProtocolMismatchSnapshot(
    INITIAL_PROTOCOL_MISMATCH_SNAPSHOT,
    event,
  );
  assertEquals(
    newestProtocolMismatchSnapshot(afterEvent, delayedQuery),
    event,
    "delayed query must lose to event",
  );
});

Deno.test("new runtime generation clears an older mismatch", () => {
  const mismatch: ProtocolMismatchSnapshot = {
    revision: 4,
    mismatch: { observed: null, expected: 8 },
  };
  const cleared: ProtocolMismatchSnapshot = { revision: 5, mismatch: null };

  assertEquals(
    newestProtocolMismatchSnapshot(mismatch, cleared),
    cleared,
    "new generation clear must win",
  );
});