// Tests for the Claude context shaper.  node test/context.test.mjs
import assert from "node:assert/strict";
import { trimContext } from "../agent/context.mjs";

let failures = 0;
function test(name, fn) {
  try {
    fn();
    console.log(`PASS  ${name}`);
  } catch (e) {
    failures++;
    console.log(`FAIL  ${name}  —  ${e && e.message}`);
  }
}

const u = (content = "hi") => ({ role: "user", content });
const a = (content = "hi") => ({ role: "assistant", content });

test("drops a leading assistant turn (API needs user first)", () => {
  assert.deepEqual(trimContext([a("greeting"), u("q"), a("ans")]), [u("q")]);
});

test("drops a trailing assistant turn (no prefill under thinking)", () => {
  // The 400 case: newest message we can see is our own reply.
  assert.deepEqual(trimContext([u("q"), a("ans")]), [u("q")]);
});

test("keeps a conversation that already ends on a user turn", () => {
  const c = [u("a"), a("b"), u("c")];
  assert.deepEqual(trimContext(c), c);
});

test("all-assistant collapses to empty (caller falls back to a hello)", () => {
  assert.deepEqual(trimContext([a(), a()]), []);
});

test("trims both ends at once", () => {
  assert.deepEqual(trimContext([a(), u("x"), a("y"), u("z"), a("w")]), [u("x"), a("y"), u("z")]);
});

test("empty / nullish input is safe and returns a fresh array", () => {
  assert.deepEqual(trimContext([]), []);
  assert.deepEqual(trimContext(null), []);
  const src = [u("x")];
  assert.notEqual(trimContext(src), src); // never mutates or aliases the caller's array
});

console.log(failures === 0 ? "\nALL PASSED" : `\n${failures} FAILED`);
process.exit(failures === 0 ? 0 : 1);