/*

    Copyright (C) 2016 Apple Inc. All Rights Reserved.

    See LICENSE.txt for this sample’s licensing information

    Abstract:

    An option set used for categorizing physics bodies in SpriteKit's physics world.

*/

import SpriteKit

import GameplayKit

struct ColliderType: OptionSet, Hashable, CustomDebugStringConvertible {

    // MARK: Static properties

    /// A dictionary to specify which `ColliderType`s should be notified of contacts with other `ColliderType`s.

    static var requestedContactNotifications = [ColliderType: [ColliderType]]()

    /// A dictionary of which `ColliderType`s should collide with other `ColliderType`s.

    static var definedCollisions = [ColliderType: [ColliderType]]()

    // MARK: Properties

    let rawValue: UInt32

    // MARK: Options

    static var Obstacle: ColliderType  { return self.init(rawValue: 1 << 0) }

    static var PlayerBot: ColliderType { return self.init(rawValue: 1 << 1) }

    static var TaskBot: ColliderType   { return self.init(rawValue: 1 << 2) }

    // MARK: Hashable

    var hashValue: Int {

        return Int(rawValue)

    }

    // MARK: CustomDebugStringConvertible

    var debugDescription: String {

        switch self.rawValue {

            case ColliderType.Obstacle.rawValue:

                return "ColliderType.Obstacle"

            case ColliderType.PlayerBot.rawValue:

                return "ColliderType.PlayerBot"

            case ColliderType.TaskBot.rawValue:

                return "ColliderType.TaskBot"

            default:

                return "UnknownColliderType(\(self.rawValue))"

        }

    }

    // MARK: SpriteKit Physics Convenience

    /// A value that can be assigned to a 'SKPhysicsBody`'s `categoryMask` property.

    var categoryMask: UInt32 {

        return rawValue

    }

    /// A value that can be assigned to a 'SKPhysicsBody`'s `collisionMask` property.

    var collisionMask: UInt32 {

        // Combine all of the collision requests for this type using a bitwise or.

        let mask = ColliderType.definedCollisions[self]?.reduce(ColliderType()) { initial, colliderType in

            return initial.union(colliderType)

        }

        // Provide the rawValue of the resulting mask or 0 (so the object doesn't collide with anything).

        return mask?.rawValue ?? 0

    }

    /// A value that can be assigned to a 'SKPhysicsBody`'s `contactMask` property.

    var contactMask: UInt32 {

        // Combine all of the contact requests for this type using a bitwise or.

        let mask = ColliderType.requestedContactNotifications[self]?.reduce(ColliderType()) { initial, colliderType in

            return initial.union(colliderType)

        }

        // Provide the rawValue of the resulting mask or 0 (so the object doesn't need contact callbacks).

        return mask?.rawValue ?? 0

    }

    // MARK: ContactNotifiableType Convenience

    /**

        Returns `true` if the `ContactNotifiableType` associated with this `ColliderType` should be

        notified of contact with the passed `ColliderType`.

    */

    func notifyOnContactWith(_ colliderType: ColliderType) -> Bool {

        if let requestedContacts = ColliderType.requestedContactNotifications[self] {

            return requestedContacts.contains(colliderType)

        }

        return false

    }

}