import test from "node:test";
import assert from "node:assert/strict";

import { beginSession, finishSession, pauseSession, resumeSession } from "../src/session_control.js";

test("beginSession resets pause/timing bookkeeping for a fresh start", () => {
  const session = { status: "ready", pausedAt: 999, totalPausedMs: 5000, followUpPausedMs: 2000 };
  beginSession(session, 1000);
  assert.equal(session.status, "running");
  assert.equal(session.startedAt, 1000);
  assert.equal(session.pausedAt, null);
  assert.equal(session.totalPausedMs, 0);
  assert.equal(session.followUpPausedMs, 0);
});

test("pauseSession only takes effect on a running session", () => {
  const session = { status: "running" };
  assert.equal(pauseSession(session, 1000), true);
  assert.equal(session.status, "paused");
  assert.equal(session.pausedAt, 1000);

  assert.equal(pauseSession({ status: "paused" }, 1000), false, "already paused");
  assert.equal(pauseSession({ status: "ready" }, 1000), false, "not started yet");
});

test("resumeSession accumulates paused duration across multiple pause/resume cycles", () => {
  const session = { status: "running", startedAt: 0, totalPausedMs: 0 };
  pauseSession(session, 1000);
  resumeSession(session, 3000); // paused 2000ms
  assert.equal(session.totalPausedMs, 2000);
  assert.equal(session.pausedAt, null);
  assert.equal(session.status, "running");

  pauseSession(session, 5000);
  resumeSession(session, 5750); // paused another 750ms
  assert.equal(session.totalPausedMs, 2750, "second pause segment adds to the running total, not replaces it");
});

test("resumeSession also folds the pause into an active follow-up period", () => {
  const session = { status: "running", followUpStartedAt: 4000, followUpPausedMs: 0, totalPausedMs: 0 };
  pauseSession(session, 4500);
  resumeSession(session, 5200); // paused 700ms during follow-up
  assert.equal(session.totalPausedMs, 700);
  assert.equal(session.followUpPausedMs, 700);
});

test("finishSession while paused folds the still-open pause segment into totalPausedMs instead of dropping it", () => {
  const session = { status: "paused", startedAt: 0, pausedAt: 10000, totalPausedMs: 2000 };
  finishSession(session, 13000); // was paused for 3000ms when finished
  assert.equal(session.status, "finished");
  assert.equal(session.endedAt, 13000);
  assert.equal(session.pausedAt, null);
  assert.equal(session.totalPausedMs, 5000, "the 3000ms final pause segment is added to the 2000ms already accumulated");
});

test("finishSession on a running (not paused) session leaves totalPausedMs untouched", () => {
  const session = { status: "running", startedAt: 0, totalPausedMs: 1500 };
  finishSession(session, 20000);
  assert.equal(session.totalPausedMs, 1500);
  assert.equal(session.endedAt, 20000);
});