import assert from 'node:assert/strict'
import test from 'node:test'

import { createStepQueue } from '../static/tetris/step-queue.js'

const step = (side, number, raceElapsedMs = number) => ({
  side, step: number, race_elapsed_ms: raceElapsedMs, game: { pieces: number },
})

test('a short race keeps every step on two independent boards', () => {
  const queue = createStepQueue()
  for (let number = 1; number <= 40; number += 1) {
    assert.equal(queue.enqueueStep('left', step('left', number)), true)
    assert.equal(queue.enqueueStep('right', step('right', number)), true)
  }
  assert.equal(queue.enqueueStep('left', step('left', 40)), false)

  const left = []
  const right = []
  let processed = 0
  let now = 0
  while (queue.hasPending()) {
    const frame = queue.nextFrame(now)
    if (frame.steps.left) left.push(frame.steps.left.step)
    if (frame.steps.right) right.push(frame.steps.right.step)
    processed += frame.processed
    now += 16
  }
  assert.equal(processed, 80)
  assert.equal(left.at(-1), 40)
  assert.equal(right.at(-1), 40)
  assert.ok(left.every((value, index) => index === 0 || value > left[index - 1]))
  assert.ok(right.every((value, index) => index === 0 || value > right[index - 1]))
})

test('a line clear survives when a later step replaces its board in the same frame', () => {
  const queue = createStepQueue()
  queue.enqueueStep('left', {
    ...step('left', 1, 10), cleared_rows: [19],
  }, 0)
  queue.enqueueStep('left', {
    ...step('left', 2, 10), cleared_rows: [],
  }, 0)
  queue.enqueueStep('right', {
    ...step('right', 1, 10), cleared_rows: [],
  }, 0)

  const frame = queue.nextFrame(0)
  assert.equal(frame.steps.left.step, 2)
  assert.equal(frame.steps.right.step, 1)
  assert.equal(frame.lineClears.left, 1)
  assert.equal(frame.lineClears.right, 0)
})

test('a 2,000-step-per-side burst finishes visual replay within a bounded interval', () => {
  const queue = createStepQueue()
  for (let number = 1; number <= 2_000; number += 1) {
    queue.enqueueStep('left', step('left', number, number / 3), 0)
    queue.enqueueStep('right', step('right', number, number / 3), 0)
  }
  queue.finishSide('left', { score: 10 }, 670, 0)
  queue.finishSide('right', { score: 20 }, 675, 0)
  const left = []
  const right = []
  let processed = 0
  let now = 0
  const finishedAt = {}
  while (queue.hasPending()) {
    const frame = queue.nextFrame(now)
    if (frame.steps.left) left.push(frame.steps.left.step)
    if (frame.steps.right) right.push(frame.steps.right.step)
    if (frame.finished) finishedAt[frame.finished.side] = now
    processed += frame.processed
    now += 16
  }
  assert.equal(processed, 4_002)
  assert.equal(left.at(-1), 2_000)
  assert.equal(right.at(-1), 2_000)
  assert.ok(finishedAt.left < finishedAt.right)
  assert.ok(now <= 1_200, `4,000 decisions replayed in ${now} ms`)
})

test('a completed 120-step-per-side race does not incur a frame per decision', () => {
  const queue = createStepQueue()
  for (let number = 1; number <= 120; number += 1) {
    queue.enqueueStep('left', step('left', number, number * 5), 0)
    queue.enqueueStep('right', step('right', number, number * 5), 0)
  }
  queue.finishSide('left', { score: 10 }, 605, 0)
  queue.finishSide('right', { score: 20 }, 610, 0)
  let now = 0
  let processed = 0
  const last = { left: 0, right: 0 }
  while (queue.hasPending()) {
    const frame = queue.nextFrame(now)
    processed += frame.processed
    for (const side of ['left', 'right']) {
      if (frame.steps[side]) last[side] = frame.steps[side].step
    }
    now += 16
  }
  assert.equal(processed, 242)
  assert.deepEqual(last, { left: 120, right: 120 })
  assert.ok(now <= 900, `240 decisions replayed in ${now} ms`)
})

test('terminal cards follow actual finish order and wait for each last board frame', () => {
  const queue = createStepQueue()
  for (let number = 1; number <= 3; number += 1) {
    queue.enqueueStep('left', step('left', number, number * 10), 0)
  }
  queue.enqueueStep('right', step('right', 1, 15), 0)
  queue.finishSide('left', { score: 10 }, 40, 0)
  queue.finishSide('right', { score: 20 }, 50, 0)

  const frames = []
  for (let now = 0; queue.hasPending(); now += 16) frames.push(queue.nextFrame(now))
  assert.equal(frames[0].steps.left.step, 1)
  assert.equal(frames[1].steps.right.step, 1)
  assert.equal(frames[0].finished, null)
  assert.equal(frames[2].steps.left.step, 3)
  assert.deepEqual(frames[2].finished, { side: 'left', result: { score: 10 } })
  assert.deepEqual(frames[3].finished, { side: 'right', result: { score: 20 } })
})

test('snapshot recovery applies the server finish order before rendering cards', () => {
  const queue = createStepQueue()
  queue.setFinishOrder(['right', 'left'])
  queue.finishSide('left', { score: 10 })
  queue.finishSide('right', { score: 20 })
  assert.equal(queue.nextFrame(0).finished.side, 'right')
  assert.equal(queue.nextFrame(16).finished.side, 'left')
  assert.equal(queue.hasPending(), false)
})

test('a completed replay keeps a large finish gap without dropping decisions', () => {
  const queue = createStepQueue()
  for (let number = 1; number <= 4; number += 1) {
    queue.enqueueStep('left', step('left', number, number * 25), 0)
    queue.enqueueStep('right', step('right', number, number * 10_000), 0)
  }
  queue.finishSide('left', { score: 10 }, 125, 0)
  queue.finishSide('right', { score: 20 }, 41_000, 0)

  const latest = { left: 0, right: 0 }
  const finishedAt = {}
  let processed = 0
  for (let now = 0; queue.hasPending() && now <= 2400; now += 16) {
    const frame = queue.nextFrame(now)
    for (const side of ['left', 'right']) {
      if (frame.steps[side]) latest[side] = frame.steps[side].step
    }
    processed += frame.processed
    if (frame.finished) finishedAt[frame.finished.side] = now
  }
  assert.deepEqual(latest, { left: 4, right: 4 })
  assert.equal(processed, 10)
  assert.ok(finishedAt.left < finishedAt.right - 1000)
  assert.ok(finishedAt.right <= 2000)
  assert.equal(queue.hasPending(), false)
})