import { expect, test } from "vitest"

import { MinHeap } from "#Source/timer/index.ts"

test("MinHeap size returns the current node count", () => {
  const heap = new MinHeap<"alpha" | "beta">()

  expect(heap.size()).toBe(0)

  heap.push({ name: "alpha", endAt: 3 })
  heap.push({ name: "beta", endAt: 1 })

  expect(heap.size()).toBe(2)
})

test("MinHeap peek returns the smallest endAt without removing it", () => {
  const heap = new MinHeap<"alpha" | "beta" | "gamma">()

  expect(heap.peek()).toBeUndefined()

  heap.push({ name: "alpha", endAt: 5 })
  heap.push({ name: "beta", endAt: 2 })
  heap.push({ name: "gamma", endAt: 4 })

  expect(heap.peek()).toEqual({ name: "beta", endAt: 2 })
  expect(heap.size()).toBe(3)
})

test("MinHeap push maintains heap order for later reads", () => {
  const heap = new MinHeap<"alpha" | "beta" | "gamma">()

  heap.push({ name: "alpha", endAt: 7 })
  heap.push({ name: "beta", endAt: 3 })
  heap.push({ name: "gamma", endAt: 5 })

  expect(heap.peek()).toEqual({ name: "beta", endAt: 3 })
  expect(heap.pop()).toEqual({ name: "beta", endAt: 3 })
  expect(heap.pop()).toEqual({ name: "gamma", endAt: 5 })
  expect(heap.pop()).toEqual({ name: "alpha", endAt: 7 })
})

test("MinHeap remove deletes the named node and keeps the remaining order valid", () => {
  const heap = new MinHeap<"alpha" | "beta" | "gamma" | "delta" | "missing">()

  heap.push({ name: "alpha", endAt: 7 })
  heap.push({ name: "beta", endAt: 3 })
  heap.push({ name: "gamma", endAt: 5 })
  heap.push({ name: "delta", endAt: 1 })

  heap.remove("beta")
  heap.remove("missing")

  expect(heap.pop()).toEqual({ name: "delta", endAt: 1 })
  expect(heap.pop()).toEqual({ name: "gamma", endAt: 5 })
  expect(heap.pop()).toEqual({ name: "alpha", endAt: 7 })
})

test("MinHeap pop removes and returns nodes in ascending endAt order", () => {
  const heap = new MinHeap<"alpha" | "beta" | "gamma">()

  expect(heap.pop()).toBeUndefined()

  heap.push({ name: "alpha", endAt: 4 })
  heap.push({ name: "beta", endAt: 2 })
  heap.push({ name: "gamma", endAt: 6 })

  expect(heap.pop()).toEqual({ name: "beta", endAt: 2 })
  expect(heap.pop()).toEqual({ name: "alpha", endAt: 4 })
  expect(heap.pop()).toEqual({ name: "gamma", endAt: 6 })
  expect(heap.pop()).toBeUndefined()
})