import Foundation

public struct PeerId: Hashable, CustomStringConvertible, Comparable {
    public typealias Namespace = Int32
    public typealias Id = Int32
    
    public let namespace: Namespace
    public let id: Id
    
    public init(namespace: Namespace, id: Id) {
        self.namespace = namespace
        self.id = id
    }
    
    public init(_ n: Int64) {
        self.namespace = Int32((n >> 32) & 0xffffffff)
        self.id = Int32(n & 0xffffffff)
    }
    
    public func toInt64() -> Int64 {
        return (Int64(self.namespace) << 32) | Int64(self.id)
    }
    
    public static func encodeArrayToBuffer(array: [PeerId], buffer: WriteBuffer) {
        var length: Int32 = Int32(array.count)
        buffer.write(&length, offset: 0, length: 4)
        for id in array {
            var value = id.toInt64()
            buffer.write(&value, offset: 0, length: 8)
        }
    }
    
    public static func decodeArrayFromBuffer(buffer: ReadBuffer) -> [PeerId] {
        var length: Int32 = 0
        memcpy(&length, buffer.memory, 4)
        buffer.offset += 4
        var i = 0
        var array: [PeerId] = []
        array.reserveCapacity(Int(length))
        while i < Int(length) {
            var value: Int64 = 0
            buffer.read(&value, offset: 0, length: 8)
            array.append(PeerId(value))
            i++
        }
        return array
    }
    
    public var hashValue: Int {
        get {
            return Int(self.id)
        }
    }
    
    public var description: String {
        get {
            return "\(namespace):\(id)"
        }
    }
    
    public init(_ buffer: ReadBuffer) {
        
        var namespace: Int32 = 0
        var id: Int32 = 0
        memcpy(&namespace, buffer.memory, 4)
        self.namespace = namespace
        memcpy(&id, buffer.memory + 4, 4)
        self.id = id
    }
    
    public func encodeToBuffer(buffer: WriteBuffer) {
        var namespace = self.namespace
        var id = self.id
        buffer.write(&namespace, offset: 0, length: 4);
        buffer.write(&id, offset: 0, length: 4);
    }
}

public func ==(lhs: PeerId, rhs: PeerId) -> Bool {
    return lhs.id == rhs.id && lhs.namespace == rhs.namespace
}

public func <(lhs: PeerId, rhs: PeerId) -> Bool {
    if lhs.namespace != rhs.namespace {
        return lhs.namespace < rhs.namespace
    }
    
    if lhs.id != rhs.id {
        return lhs.id < rhs.id
    }
    
    return false
}

public protocol Peer: Coding {
    var id: PeerId { get }
    
    func equalsTo(other: Peer) -> Bool
}