//
//  ViewController.swift
//  TicTacToe
//
//  Created by Dannel Albert on 3/22/18.
//  Copyright © 2018 Dannel Albert. All rights reserved.
//

import UIKit
import ReSwift

class ViewController: UIViewController, StoreSubscriber {
    @IBOutlet weak var button0: UIButton!
    @IBOutlet weak var button1: UIButton!
    @IBOutlet weak var button2: UIButton!
    @IBOutlet weak var button3: UIButton!
    @IBOutlet weak var button4: UIButton!
    @IBOutlet weak var button5: UIButton!
    @IBOutlet weak var button6: UIButton!
    @IBOutlet weak var button7: UIButton!
    @IBOutlet weak var button8: UIButton!
    @IBOutlet weak var playAgainButton: UIButton!
    @IBOutlet weak var winnerLabel: UILabel!

    var buttons: [UIButton]!

    override func viewDidLoad() {
        super.viewDidLoad()
        setupButtons()
        TicTacToe.store.subscribe(self)
    }

    func newState(state: TicTacToe.State) {
        DispatchQueue.main.async {
            self.render(state: state)
        }

        if state.currentPlayer == .o {
            DispatchQueue.global(qos: .background).async {
                self.computerMove(state: state)
            }
        }
    }

    func render(state: TicTacToe.State) {
        let thereIsAWinner = state.winner != nil
        let hasMovesLeft = state.board.filter { $0 == nil }.count > 0

        playAgainButton.isHidden = !thereIsAWinner && hasMovesLeft
        winnerLabel.isHidden = !thereIsAWinner && hasMovesLeft

        for (i, player) in state.board.enumerated() {
            if let player = player {
                buttons[i].setTitle(player.rawValue, for: .normal)
            } else {
                buttons[i].setTitle(nil, for: .normal)
            }

            if state.winner?.path.contains(i) == true {
                buttons[i].backgroundColor = .green
            } else {
                buttons[i].backgroundColor = .lightGray
            }
        }

        if let winner = state.winner {
            winnerLabel.text = "\(winner.player.rawValue) Won!"
        } else if !hasMovesLeft {
            winnerLabel.text = "It's a draw!"
        }

        for button in buttons {
            button.isEnabled = state.currentPlayer == .x && !thereIsAWinner && hasMovesLeft
        }

        #if DEBUG
        renderTextBoard(state: state)
        #endif
    }

    func renderTextBoard(state: TicTacToe.State) {
        let board = state.board.map { $0?.rawValue ?? " " }
        print()
        print(" \(board[0]) | \(board[1]) | \(board[2])")
        print("-----------")
        print(" \(board[3]) | \(board[4]) | \(board[5])")
        print("-----------")
        print(" \(board[6]) | \(board[7]) | \(board[8])")
        if let winner = state.winner {
            print("\(winner.player.rawValue) Won!")
        }
        print()
    }

    private func setupButtons() {
        buttons = [
            button0, button1, button2,
            button3, button4, button5,
            button6, button7, button8
        ]
    }

    func computerMove(state: TicTacToe.State) {
        if state.winner != nil {
            return
        }

        let emptyLocations = state.board
            .enumerated()
            .map { (player: $1, location: $0) }
            .filter { $0.player == nil }
            .map { $0.location }

        if emptyLocations.count == 0 {
            return
        }

        let location = emptyLocations[Int(arc4random_uniform(UInt32(emptyLocations.count)))]
        TicTacToe.store.dispatch(
            TicTacToe.Action.move(location: location)
        )
    }

    @IBAction func button0Pressed(_ sender: Any) {
        TicTacToe.store.dispatch(TicTacToe.Action.move(location: 0))
    }

    @IBAction func button1Pressed(_ sender: Any) {
        TicTacToe.store.dispatch(TicTacToe.Action.move(location: 1))
    }
    
    @IBAction func button2Pressed(_ sender: Any) {
        TicTacToe.store.dispatch(TicTacToe.Action.move(location: 2))
    }

    @IBAction func button3Pressed(_ sender: Any) {
        TicTacToe.store.dispatch(TicTacToe.Action.move(location: 3))
    }

    @IBAction func button4Pressed(_ sender: Any) {
        TicTacToe.store.dispatch(TicTacToe.Action.move(location: 4))
    }

    @IBAction func button5Pressed(_ sender: Any) {
        TicTacToe.store.dispatch(TicTacToe.Action.move(location: 5))
    }

    @IBAction func button6Pressed(_ sender: Any) {
        TicTacToe.store.dispatch(TicTacToe.Action.move(location: 6))
    }

    @IBAction func button7Pressed(_ sender: Any) {
        TicTacToe.store.dispatch(TicTacToe.Action.move(location: 7))
    }

    @IBAction func button8Pressed(_ sender: Any) {
        TicTacToe.store.dispatch(TicTacToe.Action.move(location: 8))
    }

    @IBAction func playAgain(_ sender: Any) {
        TicTacToe.store.dispatch(TicTacToe.Action.reset)
    }

    deinit {
        TicTacToe.store.unsubscribe(self)
    }
}