import java.util.*
import kotlin.math.abs
import kotlin.properties.Delegates

//Character is the one who entered next turn
//Returned value indicates whether this listener can be removed
typealias NextTurnListener = (Character) -> Boolean

abstract class Character {
    //basic info
    abstract val name: String
    abstract val id: Int
    abstract val deck: Deck

    var damageAddition: Int = 0
    var damageMultiplier: Int = 1
    var life: Int by Delegates.observable(0) {_, old, new ->
        val diff = abs(old-new)
        if (new < old) {
            println("${this.name} 受到 $diff 點傷害")
        } //heal description is provided in HealCard
    }
        protected set //This line of code belong's to life property

    //This describe whether the character can be damaged by non_SP attack
    var isInvincible = false

    var poisoned: Boolean by Delegates.observable(false) {_, _, new ->
        if(new) {
            println("${this.name} 中毒了")
        } else {
            println("${this.name} 毒性解除")
        }
    }
    var hand: Cards = emptyList<Card>().toMutableList()

    lateinit var enemy: Character //This will be set in GameLoop.init
    lateinit var endGameAsLoser: () -> Unit //This will be set in GameLoop.init
    //listeners inside this will be called immediately after character enter next turn
    var nextTurnListeners: MutableList<NextTurnListener> = emptyList<NextTurnListener>().toMutableList()

    var turn = 0

    var effectBuffer: Array<Effect> by Delegates.observable(emptyArray()) { _, old, new ->
        if(new.isNotEmpty() /* been clean*/ &&
                old.map { it.reverseEffect }.toTypedArray().contentNotEquals(new) /*tmp effect of reverse*/) {
            val defensiveInHand = hand.filter { it is DefensiveCard }
            if (defensiveInHand.isNotEmpty()) {
                println("請選擇要使用的防禦卡片，或是打0放棄")
                println(defensiveInHand.filterIndexed { index,_ ->
                    if (index != 0) {
                        defensiveInHand[index].name != defensiveInHand[index-1].name
                    } else {
                        true
                    }
                })
                val scanner = Scanner(System.`in`)
                var id = scanner.nextInt()
                while(id != 0) {
                    if(defensiveInHand.indexOfFirst { it.id == id } == -1){
                        id = scanner.nextInt()
                        continue
                    } else {
                        val index = hand.indexOfFirst { it.id == id }
                        hand[index].startSkill()
                        hand.removeAt(index)
                        break
                    }
                }
            }
        }
    }
    var attackingCard: Card? = null

    fun drawFromDeck(num: Int = 1) {
        for (i in 1..num) {
             try {
                val card = deck.firstCard
                println("${this.name}抽到了 ${card.id}. ${card.name}")
                hand.add(card)
                println("牌組剩餘 ${deck.size} 張牌")
            } catch (e: NoSuchElementException) {
                 println("牌庫已空，你抽到了死神")
                 life = -9999
                 endGameAsLoser()
            }
        }
    }

    fun chooseFromCards(cards: Cards) {
        println("請選擇一張")
        cards.forEach { println("${it.id}. ${it.name} ") }
        val scanner = Scanner(System.`in`)
        while(true) {
            val id = scanner.nextInt()
            val card = try {
                cards.filter { it.id == id }[0]
            } catch (e: IndexOutOfBoundsException) {
                continue
            }
            println("${this.name} 選擇了 ${card.name}")
            hand.add(card)
            break
        }
    }

    fun nextTurn() {
        turn++
        nextTurnListeners.forEach {listener ->
            val result = listener(this)
            if(result) { //listener can be removed
                nextTurnListeners.remove(listener)
            }
        }
        println("${this.name} 的第 $turn 回合")
        if (this.poisoned) {
            println("中毒，扣1滴血")
            this.life--
        }
        println("生命值: $life")
        println("請出牌:(或輸入0放棄)")
        println(this.hand.filter { !(it is DefensiveCard) })
        val scanner = Scanner(System.`in`)
        var id = scanner.nextInt()
        while (id != 0) {
            val index = hand.indexOfFirst {
                it.id == id
            }
            if (index == -1) {
                println("請出牌:(或輸入0放棄)")
                id = scanner.nextInt()
                continue
            } else {
                if (hand[index] is DefensiveCard) {
                    println("請出牌:(或輸入0放棄)")
                    id = scanner.nextInt()
                    continue
                } else {
                    hand[index].startSkill()
                    hand.removeAt(index)
                    drawFromDeck()
                    break
                }
            }
        }
    }

    fun gotDamage(point: Int, defendable: Boolean = true) {
        if (defendable && this.isInvincible) {
            return
        }
        val damage = point * damageMultiplier + damageAddition
        life -= damage
    }

    fun heal(point: Int) {
        life += point
    }

    override fun toString() = this.name
}

fun <T> Array<T>.contentNotEquals(array: Array<out T>) = !this.contentEquals(array)

class Deck(cards: Cards) {
    var cards: Cards = cards
        private set
    val size: Int
        get() = cards.size
    val firstCard: Card
        get() {
            val card = cards.first()
            cards.removeAt(0)
            return card
        }

    fun shuffle() = cards.shuffle()
}

typealias Cards = MutableList<Card>

interface Card {
    val owner: Character
    val name: String
    val id: Int
    val activeString: String
    //This must be a calculated property instead of a stored value
    //in order to prevent StackOverflowError
    val effects: Array<Effect>

    fun startSkill()
}

abstract class Effect {
    abstract val subjects: Array<out Character> //The structure of subjects will defined by the concrete classes
    abstract val reverseEffect: Effect
    abstract val id: Int

    abstract fun apply()

    override fun toString(): String = this.javaClass.name

    override fun equals(other: Any?): Boolean {
        return if(other is Effect) {
            this.id == other.id
        } else {
            false
        }
    }

    override fun hashCode() = this.id
}