'use strict';

const test = require('node:test');
const assert = require('node:assert/strict');
const { createState, reconcile, summarize } = require('../src/scheduler');

const options = { maxChannels: 3, startGraceMs: 24 * 60 * 60 * 1000 };

function makeEvent(id, startIso, endIso) {
  return {
    key: id,
    title: id,
    league: 'Jupiler Pro League',
    language: 'nl',
    startAt: new Date(startIso),
    endAt: new Date(endIso),
    sources: [{ streamId: id, name: id, candidates: [`http://upstream/${id}.ts`] }],
    missingCount: 0,
  };
}

function current(...events) {
  return new Map(events.map((event) => [event.key, event]));
}

function slotKeys(state) {
  return state.slots.map((slot) => slot.eventKey);
}

test('fills the first three slots by start time and queues the rest', () => {
  const state = createState(3);
  const events = current(
    makeEvent('A', '2026-11-06T16:00:00Z', '2026-11-06T20:00:00Z'),
    makeEvent('B', '2026-11-06T16:30:00Z', '2026-11-06T20:30:00Z'),
    makeEvent('C', '2026-11-06T17:00:00Z', '2026-11-06T21:00:00Z'),
    makeEvent('D', '2026-11-06T17:30:00Z', '2026-11-06T21:30:00Z'),
    makeEvent('E', '2026-11-06T18:00:00Z', '2026-11-06T22:00:00Z')
  );

  reconcile(state, events, Date.parse('2026-11-06T18:00:00Z'), options);

  assert.deepEqual(slotKeys(state), ['A', 'B', 'C']);
  const summary = summarize(state);
  assert.deepEqual(summary.queue.map((event) => event.key), ['D', 'E']);
});

test('a freed slot is filled by the oldest waiting event', () => {
  const state = createState(3);
  const events = current(
    makeEvent('A', '2026-11-06T16:00:00Z', '2026-11-06T20:00:00Z'),
    makeEvent('B', '2026-11-06T16:30:00Z', '2026-11-06T20:30:00Z'),
    makeEvent('C', '2026-11-06T17:00:00Z', '2026-11-06T21:00:00Z'),
    makeEvent('D', '2026-11-06T17:30:00Z', '2026-11-06T21:30:00Z'),
    makeEvent('E', '2026-11-06T18:00:00Z', '2026-11-06T22:00:00Z')
  );

  reconcile(state, events, Date.parse('2026-11-06T18:00:00Z'), options);
  assert.deepEqual(slotKeys(state), ['A', 'B', 'C']);

  reconcile(state, events, Date.parse('2026-11-06T20:01:00Z'), options);
  assert.deepEqual(slotKeys(state), ['D', 'B', 'C']);
});

test('an existing assignment is not preempted by an earlier event', () => {
  const state = createState(3);
  const events = current(
    makeEvent('A', '2026-11-06T16:00:00Z', '2026-11-06T20:00:00Z'),
    makeEvent('B', '2026-11-06T16:30:00Z', '2026-11-06T20:30:00Z'),
    makeEvent('C', '2026-11-06T17:00:00Z', '2026-11-06T21:00:00Z')
  );
  reconcile(state, events, Date.parse('2026-11-06T18:00:00Z'), options);

  const withEarlier = current(
    ...events.values(),
    makeEvent('X', '2026-11-06T17:45:00Z', '2026-11-06T21:45:00Z')
  );
  reconcile(state, withEarlier, Date.parse('2026-11-06T18:10:00Z'), options);

  assert.deepEqual(slotKeys(state), ['A', 'B', 'C']);
});

test('an assigned event keeps its slot until its end even when it disappears', () => {
  const state = createState(3);
  const a = makeEvent('A', '2026-11-06T16:00:00Z', '2026-11-06T20:00:00Z');
  const b = makeEvent('B', '2026-11-06T16:30:00Z', '2026-11-06T20:30:00Z');
  reconcile(state, current(a, b), Date.parse('2026-11-06T18:00:00Z'), options);
  assert.deepEqual(slotKeys(state), ['A', 'B', null]);

  reconcile(state, current(), Date.parse('2026-11-06T19:00:00Z'), options);
  reconcile(state, current(), Date.parse('2026-11-06T19:30:00Z'), options);
  assert.deepEqual(slotKeys(state), ['A', 'B', null]);

  reconcile(state, current(), Date.parse('2026-11-06T20:31:00Z'), options);
  assert.deepEqual(slotKeys(state), [null, null, null]);
});

test('an unassigned event that disappears twice is dropped from the queue', () => {
  const state = createState(3);
  const events = current(
    makeEvent('A', '2026-11-06T16:00:00Z', '2026-11-06T20:00:00Z'),
    makeEvent('B', '2026-11-06T16:30:00Z', '2026-11-06T20:30:00Z'),
    makeEvent('C', '2026-11-06T17:00:00Z', '2026-11-06T21:00:00Z'),
    makeEvent('D', '2026-11-06T17:30:00Z', '2026-11-06T21:30:00Z'),
    makeEvent('E', '2026-11-06T18:00:00Z', '2026-11-06T22:00:00Z')
  );

  reconcile(state, events, Date.parse('2026-11-06T18:00:00Z'), options);
  const withoutD = current(
    events.get('A'),
    events.get('B'),
    events.get('C'),
    events.get('E')
  );

  reconcile(state, withoutD, Date.parse('2026-11-06T18:20:00Z'), options);
  reconcile(state, withoutD, Date.parse('2026-11-06T18:40:00Z'), options);
  reconcile(state, withoutD, Date.parse('2026-11-06T20:01:00Z'), options);

  assert.deepEqual(slotKeys(state), ['E', 'B', 'C']);
});