//
//  Array+Rotation.swift
//  TetrisKit
//
//  Created by Shadowfacts on 10/13/19.
//  Copyright © 2019 Shadowfacts. All rights reserved.
//

import Foundation

extension Array where Element: RandomAccessCollection, Element: MutableCollection, Element.Index == Int {
    mutating func rotateClockwise() {
        guard allSatisfy({ $0.count == self.count }) else { return }
        
        let layerCount = self.count / 2
        
        for layer in 0..<layerCount {
            let first = layer
            let last = self.count - first - 1
            
            for element in first..<last {
                let offset = element - first
                
                let top = self[first][element]
                let rightSide = self[element][last]
                let bottom = self[last][last - offset]
                let leftSide = self[last - offset][first]
                
                self[first][element] = leftSide
                self[element][last] = top
                self[last][last - offset] = rightSide
                self[last - offset][first] = bottom
            }
        }
    }
    
    mutating func rotateCounterclockwise() {
        guard allSatisfy({ $0.count == self.count }) else { return }

        let layerCount = self.count / 2
        
        for layer in 0..<layerCount {
            let first = layer
            let last = self.count - first - 1
            
            for element in first..<last {
                let offset = element - first
                
                let top = self[first][element]
                let rightSide = self[element][last]
                let bottom = self[last][last - offset]
                let leftSide = self[last - offset][first]
                
                self[first][element] = rightSide
                self[element][last] = bottom
                self[last][last - offset] = leftSide
                self[last - offset][first] = top
            }
        }
    }
}