import { atom, globalScope, never, skipDuplicates, toProperty } from "./index"
import { expectPropertyEvents, expectStreamEvents, series } from "./test-utils"

const sameSign = (a: number, b: number) => Math.sign(a) === Math.sign(b)

describe("EventStream.skipDuplicates", function () {
  describe("should skip duplicate values based on predicate", () =>
    expectStreamEvents(() => {
      const e = series(1, [1, 2, -1, 2, 3]).pipe(skipDuplicates(sameSign))
      return e
    }, [1, -1, 2]))
  it("toString", () =>
    expect(skipDuplicates(() => false)(never()).toString()).toEqual(
      "EventStreamSeed never.skipDuplicates(fn)"
    ))
})

describe("Property.skipDuplicates", function () {
  describe("should skip duplicate values based on predicate", () =>
    expectPropertyEvents(() => {
      const prop = series(1, [1, 2, -2]).pipe(
        toProperty(0),
        skipDuplicates(sameSign)
      )
      return prop
    }, [0, 1, -2]))
})

describe("Atom.skipDuplicates", () => {
  it("Skips duplicates", () => {
    const root = atom(0)
    const a = root.pipe(skipDuplicates(sameSign, globalScope))

    a.set(1)
    expect(a.get()).toEqual(1)
    a.set(2)
    expect(a.get()).toEqual(1)
    expect(root.get()).toEqual(2) // pass all values in set
    a.set(-1)
    expect(a.get()).toEqual(-1)
    expect(root.get()).toEqual(-1)
  })
})