import test from 'node:test'
import assert from 'node:assert/strict'
import { freeCells, spawnApple, tick, newGame } from '../src/spawn.js'
import { advance } from '../src/rules.js'
import { loadFixture, freeze } from './helpers.js'

const fixtureTests = (name, f) => {
  const fx = loadFixture(name)
  fx.cases.forEach((c) =>
    test(`m04 ${fx.function}: ${c.name}`, () => assert.deepStrictEqual(f(...freeze(c.args)), c.expected)))
}

fixtureTests('m04-free-cells', freeCells)
fixtureTests('m04-spawn', spawnApple)
fixtureTests('m04-new-game', newGame)
fixtureTests('m04-tick', tick)

// 3x2 board, one-cell snake, about to eat the apple at (1,0)
const eating = freeze({
  width: 3, height: 2, snake: [{ x: 0, y: 0 }], dir: 'Right', nextDir: 'Right',
  apple: { x: 1, y: 0 }, seed: 0, score: 0, status: 'Playing', frame: 0,
})

test('m04 tick: eating the apple spawns a new one in the same step', () => {
  // snake becomes [(1,0),(0,0)]; free cells are (2,0),(0,1),(1,1),(2,1); seed 0 draws 1144304738 % 4 = 2 -> (1,1)
  assert.deepStrictEqual(tick(eating), {
    ...eating, snake: [{ x: 1, y: 0 }, { x: 0, y: 0 }], apple: { x: 1, y: 1 }, score: 1, seed: 1831565813,
  })
})

test('m04 tick is spawnApple after advance', () => assert.deepStrictEqual(tick(eating), spawnApple(advance(eating))))

test('m04 tick leaves the seed alone when no apple needs spawning', () => {
  const s = freeze({ ...eating, apple: { x: 2, y: 1 } })
  assert.equal(tick(s).seed, 0)
})

test('m04 newGame is reproducible: same seed, same game', () => assert.deepStrictEqual(newGame(42), newGame(42)))