package net.pterodactylus.rhynodge.filters.webpages.epicgames

import net.pterodactylus.rhynodge.Merger
import net.pterodactylus.rhynodge.states.StateManagerTest.TestState
import org.hamcrest.MatcherAssert.assertThat
import org.hamcrest.Matchers.contains
import org.hamcrest.Matchers.empty
import org.hamcrest.Matchers.equalTo
import org.hamcrest.Matchers.instanceOf
import org.junit.Assert.assertThrows
import org.junit.Test
import java.time.Instant

class EpicGamesMergerTest {

	@Test
	fun `merger implements Merger interface`() {
		assertThat(merger, instanceOf(Merger::class.java))
	}

	@Test
	fun `merger throws exception if previous state is not a free games state`() {
		assertThrows(IllegalArgumentException::class.java) { merger.mergeStates(TestState(), emptyState) }
	}

	@Test
	fun `merger throws exception if current state is not a free games state`() {
		assertThrows(IllegalArgumentException::class.java) { merger.mergeStates(emptyState, TestState()) }
	}

	@Test
	fun `merger given two empty free game states returns an empty state`() {
		val mergedState = merger.mergeStates(emptyState, emptyState) as FreeGamesState
		assertThat(mergedState.games, empty())
	}

	@Test
	fun `merging two empty states results in not-triggered state`() {
		val mergedState = merger.mergeStates(emptyState, emptyState) as FreeGamesState
		assertThat(mergedState.triggered(), equalTo(false))
	}

	@Test
	fun `merging state without games into state with games returns state without games`() {
		val mergedState = merger.mergeStates(stateWithOneGame, emptyState) as FreeGamesState
		assertThat(mergedState.games, empty())
	}

	@Test
	fun `merging state without games into state with games returns not-triggered state`() {
		val mergedState = merger.mergeStates(stateWithOneGame, emptyState) as FreeGamesState
		assertThat(mergedState.triggered(), equalTo(false))
	}

	@Test
	fun `merging state with games into state without games returns state with games`() {
		val mergedState = merger.mergeStates(emptyState, stateWithOneGame) as FreeGamesState
		assertThat(mergedState.games, contains(game1))
	}

	@Test
	fun `merging state with games into state without games returns a triggered state`() {
		val mergedState = merger.mergeStates(emptyState, stateWithOneGame) as FreeGamesState
		assertThat(mergedState.triggered(), equalTo(true))
	}

	@Test
	fun `merge state with more games into state with less games returns a triggered state`() {
		val mergedState = merger.mergeStates(stateWithOneGame, stateWithTwoGames) as FreeGamesState
		assertThat(mergedState.triggered(), equalTo(true))
	}

	@Test
	fun `merge state with less games into state with more games does not return a triggered state`() {
		val mergedState = merger.mergeStates(stateWithTwoGames, stateWithOneGame) as FreeGamesState
		assertThat(mergedState.triggered(), equalTo(false))
	}

	private val merger = EpicGamesMerger()

}

private val emptyState = FreeGamesState(emptySet())
private val game1 = FreeGame("1", "i", Instant.now(), Instant.now())
private val game2 = FreeGame("2", "i", Instant.now(), Instant.now())
private val stateWithOneGame = FreeGamesState(setOf(game1))
private val stateWithTwoGames = FreeGamesState(setOf(game1, game2))