import org.junit.jupiter.api.Test;
import org.junit.jupiter.api.AfterEach;
import org.junit.jupiter.api.DisplayName;

import static org.junit.jupiter.api.Assertions.assertAll;
import static org.junit.jupiter.api.Assertions.assertEquals;
import static org.junit.jupiter.api.Assertions.assertThrows;
import static org.junit.jupiter.api.Assertions.assertTrue;

import java.io.EOFException;
import java.io.StringReader;
import java.io.StringWriter;
import java.io.UncheckedIOException;
import java.util.Arrays;
import java.util.LinkedList;

public class GameTest {

    private StringReader in;
    private StringWriter out;
    private Game game;

    // TODO See if it's possible to initialize test data in a more readable way.
    // e.g.
    //   playerGets(Card)
    //   playerGets(Card)
    //   playerDoes(String)
    //   playerGets(Card)
    //   playerDoes(String)
    //   initGame(g) // Creates the deck and initializes 'in' based on values accumulated from prior calls to playerGets and playerDoes.

    private void givenStubGame() {
        in = new StringReader("");
        out = new StringWriter();
        UserIo userIo = new UserIo(in, out);
        Deck deck = new Deck((cards) -> cards);
        game = new Game(deck, userIo);
    }

    private void givenInput(String input) {
        in = new StringReader(input);
        out = new StringWriter();
        UserIo userIo = new UserIo(in, out);
        Deck deck = new Deck((cards) -> cards);
        game = new Game(deck, userIo);
    }

    private void givenInput(String input, Card... customCards) {
        in = new StringReader(input);
        out = new StringWriter();
        UserIo userIo = new UserIo(in, out);
        LinkedList<Card> cardList = new LinkedList<>();
        cardList.addAll(Arrays.asList(customCards));
        Deck deck = new Deck((cards) -> cardList);
        game = new Game(deck, userIo);
    }

    @AfterEach
    private void printOutput() {
        System.out.println(out.toString());
    }

    @Test
    public void shouldQuitOnCtrlD() {
        // Given
        givenInput("\u2404"); // U+2404 is "End of Transmission" sent by CTRL+D (or CTRL+Z on Windows)

        // When
        Exception e = assertThrows(UncheckedIOException.class, game::run);

        // Then
        assertTrue(e.getCause() instanceof EOFException);
        assertEquals("!END OF INPUT", e.getMessage());
    }

    @Test
    @DisplayName("play() should end on STAY")
    public void playEndOnStay(){
        // Given
        Player player = new Player(1);
        player.dealCard(new Card(3, Card.Suit.CLUBS));
        player.dealCard(new Card(2, Card.Suit.SPADES));
        givenInput("S\n"); // "I also like to live dangerously."

        // When
        game.play(player);

        // Then
        assertEquals("PLAYER 1 ? ", out.toString());
    }

    @Test
    @DisplayName("play() should allow HIT until BUST")
    public void playHitUntilBust() {
        // Given
        Player player = new Player(1);
        player.dealCard(new Card(10, Card.Suit.HEARTS));
        player.dealCard(new Card(10, Card.Suit.SPADES));

        givenInput("H\nH\nH\n",
            new Card(1, Card.Suit.SPADES), // 20
            new Card(1, Card.Suit.HEARTS), // 21
            new Card(1, Card.Suit.CLUBS)); // 22 - D'oh!

        // When
        game.play(player);

        // Then
        assertTrue(out.toString().contains("BUSTED"));
    }

    @Test
    @DisplayName("Should allow double down on initial turn")
    public void playDoubleDown(){
        // Given
        Player player = new Player(1);
        player.setCurrentBet(100);
        player.dealCard(new Card(10, Card.Suit.HEARTS));
        player.dealCard(new Card(4, Card.Suit.SPADES));

        givenInput("D\n", new Card(7, Card.Suit.SPADES));

        // When
        game.play(player);

        // Then
        assertTrue(player.getCurrentBet() == 200);
        assertTrue(player.getHand().size() == 3);
    }

    @Test
    @DisplayName("Should NOT allow double down after initial deal")
    public void playDoubleDownLate(){
        // Given
        Player player = new Player(1);
        player.setCurrentBet(100);
        player.dealCard(new Card(10, Card.Suit.HEARTS));
        player.dealCard(new Card(2, Card.Suit.SPADES));

        givenInput("H\nD\nS\n", new Card(7, Card.Suit.SPADES));

        // When
        game.play(player);

        // Then
        assertTrue(out.toString().contains("TYPE H, OR S, PLEASE"));
    }

    @Test
    @DisplayName("scoreHand should sum non-ace values normally")
    public void scoreHandNormally() {
        // Given
        givenStubGame();
        LinkedList<Card> hand = new LinkedList<>();
        hand.add(new Card(4, Card.Suit.SPADES));
        hand.add(new Card(6, Card.Suit.SPADES));
        hand.add(new Card(10, Card.Suit.SPADES));

        // When
        int result = game.scoreHand(hand);

        // Then
        assertEquals(20, result);
    }

    @Test
    @DisplayName("scoreHand should treat face cards as 10")
    public void scoreHandFaceCards() {
        // Given
        givenStubGame();
        LinkedList<Card> hand = new LinkedList<>();
        hand.add(new Card(11, Card.Suit.SPADES));
        hand.add(new Card(12, Card.Suit.SPADES));
        hand.add(new Card(13, Card.Suit.SPADES));

        // When
        int result = game.scoreHand(hand);

        // Then
        assertEquals(30, result);
    }

    @Test
    @DisplayName("scoreHand should score aces as 11 when possible")
    public void scoreHandSoftAce() {
        // Given
        givenStubGame();
        LinkedList<Card> hand = new LinkedList<>();
        hand.add(new Card(10, Card.Suit.SPADES));
        hand.add(new Card(1, Card.Suit.SPADES));

        // When
        int result = game.scoreHand(hand);

        // Then
        assertEquals(21, result);
    }

    @Test
    @DisplayName("scoreHand should score aces as 1 when using 11 would bust")
    public void scoreHandHardAce() {
        // Given
        givenStubGame();
        LinkedList<Card> hand = new LinkedList<>();
        hand.add(new Card(10, Card.Suit.SPADES));
        hand.add(new Card(9, Card.Suit.SPADES));
        hand.add(new Card(1, Card.Suit.SPADES));

        // When
        int result = game.scoreHand(hand);

        // Then
        assertEquals(20, result);
    }

    @Test
    @DisplayName("scoreHand should score 3 aces as 13")
    public void scoreHandMultipleAces() {
        // Given
        givenStubGame();
        LinkedList<Card> hand = new LinkedList<>();
        hand.add(new Card(1, Card.Suit.SPADES));
        hand.add(new Card(1, Card.Suit.CLUBS));
        hand.add(new Card(1, Card.Suit.HEARTS));

        // When
        int result = game.scoreHand(hand);

        // Then
        assertEquals(13, result);
    }

    @Test
    @DisplayName("compareHands should return 1 meaning A beat B, 20 to 12")
    public void compareHandsAWins() {

        givenStubGame();
        LinkedList<Card> handA = new LinkedList<>();
        handA.add(new Card(10, Card.Suit.SPADES));
        handA.add(new Card(10, Card.Suit.CLUBS));

        LinkedList<Card> handB = new LinkedList<>();
        handB.add(new Card(1, Card.Suit.SPADES));
        handB.add(new Card(1, Card.Suit.CLUBS));

        int result = game.compareHands(handA,handB);

        assertEquals(1, result);
    }

    @Test
    @DisplayName("compareHands should return -1 meaning B beat A, 18 to 4")
    public void compareHandsBwins() {
        givenStubGame();
        LinkedList<Card> handA = new LinkedList<>();
        handA.add(new Card(2, Card.Suit.SPADES));
        handA.add(new Card(2, Card.Suit.CLUBS));

        LinkedList<Card> handB = new LinkedList<>();
        handB.add(new Card(5, Card.Suit.SPADES));
        handB.add(new Card(6, Card.Suit.HEARTS));
        handB.add(new Card(7, Card.Suit.CLUBS));

        int result = game.compareHands(handA,handB);

        assertEquals(-1, result);
    }

    @Test
    @DisplayName("compareHands should return 1 meaning A beat B, natural Blackjack to Blackjack")
    public void compareHandsAWinsWithNaturalBlackJack() {
        //Hand A wins with natural BlackJack, B with Blackjack
        givenStubGame();
        LinkedList<Card> handA = new LinkedList<>();
        handA.add(new Card(10, Card.Suit.SPADES));
        handA.add(new Card(1, Card.Suit.CLUBS));

        LinkedList<Card> handB = new LinkedList<>();
        handB.add(new Card(6, Card.Suit.SPADES));
        handB.add(new Card(7, Card.Suit.HEARTS));
        handB.add(new Card(8, Card.Suit.CLUBS));

        int result = game.compareHands(handA,handB);

        assertEquals(1, result);
    }

    @Test
    @DisplayName("compareHands should return -1 meaning B beat A, natural Blackjack to Blackjack")
    public void compareHandsBWinsWithNaturalBlackJack() {
        givenStubGame();
        LinkedList<Card> handA = new LinkedList<>();
        handA.add(new Card(6, Card.Suit.SPADES));
        handA.add(new Card(7, Card.Suit.HEARTS));
        handA.add(new Card(8, Card.Suit.CLUBS));
        
        LinkedList<Card> handB = new LinkedList<>();
        handB.add(new Card(10, Card.Suit.SPADES));
        handB.add(new Card(1, Card.Suit.CLUBS));

        int result = game.compareHands(handA,handB);

        assertEquals(-1, result);
    }

    @Test
    @DisplayName("compareHands should return 0, hand A and B tied with a Blackjack")
    public void compareHandsTieBothBlackJack() {
        givenStubGame();
        LinkedList<Card> handA = new LinkedList<>();
        handA.add(new Card(11, Card.Suit.SPADES));
        handA.add(new Card(10, Card.Suit.CLUBS));
        
        LinkedList<Card> handB = new LinkedList<>();
        handB.add(new Card(10, Card.Suit.SPADES));
        handB.add(new Card(11, Card.Suit.CLUBS));

        int result = game.compareHands(handA,handB);

        assertEquals(0, result);
    }

    @Test
    @DisplayName("compareHands should return 0, hand A and B tie without a Blackjack")
    public void compareHandsTieNoBlackJack() {
        givenStubGame();
        LinkedList<Card> handA = new LinkedList<>();
        handA.add(new Card(10, Card.Suit.DIAMONDS));
        handA.add(new Card(10, Card.Suit.HEARTS));
        
        LinkedList<Card> handB = new LinkedList<>();
        handB.add(new Card(10, Card.Suit.SPADES));
        handB.add(new Card(10, Card.Suit.CLUBS));

        int result = game.compareHands(handA,handB);

        assertEquals(0, result);
    }

    @Test
    @DisplayName("play() should end on STAY after split")
    public void playSplitEndOnStay(){
        // Given
        Player player = new Player(1);
        player.dealCard(new Card(1, Card.Suit.CLUBS));
        player.dealCard(new Card(1, Card.Suit.SPADES));
        givenInput("/\nS\nS\n"); 

        // When
        game.play(player);

        // Then
        assertTrue(out.toString().contains("FIRST HAND RECEIVES"));
        assertTrue(out.toString().contains("SECOND HAND RECEIVES"));
    }

    @Test
    @DisplayName("play() should allow HIT until BUST after split")
    public void playSplitHitUntilBust() {
        // Given
        Player player = new Player(1);
        player.dealCard(new Card(10, Card.Suit.HEARTS));
        player.dealCard(new Card(10, Card.Suit.SPADES));

        givenInput("/\nH\nS\n",
            new Card(12, Card.Suit.SPADES), // First hand has 20. Player hits.
            new Card(12, Card.Suit.HEARTS), // First hand busted
            new Card(10, Card.Suit.HEARTS)); // Second hand gets a 10. Player stays.

        // When
        game.play(player);

        // Then
        assertTrue(out.toString().contains("BUSTED"));
    }

    @Test
    @DisplayName("play() should allow HIT on split hand until BUST")
    public void playSplitHitUntilBustHand2() {
        // Given
        Player player = new Player(1);
        player.dealCard(new Card(10, Card.Suit.HEARTS));
        player.dealCard(new Card(10, Card.Suit.SPADES));

        givenInput("/\nS\nH\nH\n",
            new Card(1, Card.Suit.CLUBS), // Dealt to first split hand. Player stays.
            new Card(12, Card.Suit.SPADES), // Split hand = 20
            new Card(12, Card.Suit.HEARTS)); // Split hand busted

        // When
        game.play(player);

        // Then
        assertTrue(out.toString().contains("BUSTED"));
    }

    @Test
    @DisplayName("play() should allow double down on split hands")
    public void playSplitDoubleDown(){
        // Given
        Player player = new Player(1);
        player.setCurrentBet(100);
        player.dealCard(new Card(9, Card.Suit.HEARTS));
        player.dealCard(new Card(9, Card.Suit.SPADES));

        givenInput("/\nD\nD\n", 
            new Card(5, Card.Suit.DIAMONDS),
            new Card(6, Card.Suit.HEARTS),
            new Card(7, Card.Suit.CLUBS));

        // When
        game.play(player);

        // Then
        assertAll(
            () -> assertEquals(200, player.getCurrentBet(), "Current bet should be doubled"),
            () -> assertEquals(200, player.getSplitBet(), "Split bet should be doubled"),
            () -> assertEquals(3, player.getHand(1).size(), "First hand should have exactly three cards"),
            () -> assertEquals(3, player.getHand(2).size(), "Second hand should have exactly three cards")
        );
    }

    @Test
    @DisplayName("play() should NOT allow re-splitting first split hand")
    public void playSplitTwice(){
        // Given
        Player player = new Player(1);
        player.setCurrentBet(100);
        player.dealCard(new Card(1, Card.Suit.HEARTS));
        player.dealCard(new Card(1, Card.Suit.SPADES));

        givenInput("/\n/\nS\nS\n",
            new Card(13, Card.Suit.CLUBS),
            new Card(13, Card.Suit.SPADES));

        // When
        game.play(player);

        // Then
        assertTrue(out.toString().contains("TYPE H, S OR D, PLEASE"));
    }

    @Test
    @DisplayName("play() should NOT allow re-splitting second split hand")
    public void playSplitTwiceHand2(){
        // Given
        Player player = new Player(1);
        player.setCurrentBet(100);
        player.dealCard(new Card(1, Card.Suit.HEARTS));
        player.dealCard(new Card(1, Card.Suit.SPADES));

        givenInput("/\nS\n/\nS\n", 
            new Card(13, Card.Suit.SPADES),
            new Card(13, Card.Suit.SPADES));

        // When
        game.play(player);

        // Then
        assertTrue(out.toString().contains("TYPE H, S OR D, PLEASE"));
    }
}