Diff two arrays in swift

Array+Diff.swift

import UIKit

var left:[Int] = [1,1,1,1,1]
var right:[Int] = [1,2,2,2,2,2,2,1]

enum Difference {
    case insert(Int, Any)
    case delete(Int, Any)
}

extension Array where Element:Equatable {
    func diff(_ to:Array<Element>) -> Array<Difference> {
        var first:[Difference] = []
        var second:[Difference] = []

        var temp:[Element] = to
        
        self.enumerated().forEach { (index, value) in
            if let found = temp.firstIndex(of: value) {
                temp.remove(at: found)
                return
            }
            first.append(.delete(index, value))
        }
        
        var new:[Element] = self
        
        first.reversed().forEach { (action) in
            switch action {
            case .delete(let index, _):
                new.remove(at: index)
                break
            default:
                break
            }
        }

        to.enumerated().forEach { (index, value) in
            if new.count == index {
                new.append(value)
                first.append(.insert(index, value))
                return
            }
            
            if new[index] == value {
                return
            }
            
            new.insert(value, at: index)
            first.append(.insert(index, value))
        }

        temp = to
        new.enumerated().forEach { (index, value) in
            if let found = temp.firstIndex(of: value) {
                temp.remove(at: found)
                return
            }
            second.append(.delete(index, value))
        }
        
        second.reversed().forEach { (action) in
            switch action {
            case .delete(let index, _):
                new.remove(at: index)
                break
            default:
                break
            }
        }

        return first + second
    }
}

let actions = left.diff(right).map { (action) -> String in
    switch action {
    case .insert(let index, let value):
        return "+\(index):\(value)"
    case .delete(let index, let value):
        return "-\(index):\(value)"
    }
}

print(actions)