//
//  Overrides.swift
//  FruitMachine
//
//  Created by Christopher Rohl on 7/27/17.
//  Copyright © 2017 Christopher Rohl. All rights reserved.
//

import Cocoa

class PIAOverrides: NSObject {
    static let writeDSP = WriteOverride(start: 0xD012, end: 0xD012, writeAnyway: false, action: PIAOverrides.actionWriteDSP)
    static func actionWriteDSP(terminal: AnyObject, byte: UInt8?) -> UInt8? {
        //TODO: implement actual 6520 PIA behavior
        
        //Writing to DSP sets DSP.7
        AppleI.sharedInstance.pia["display"]!.data = byte! | 0x80
        
        //Output our character to the terminal
        AppleI.sharedInstance.terminal.putCharacter(charIndex: byte!)
        
        AppleI.sharedInstance.pia["display"]!.data = byte! & ~(0x80)
        return nil;
    }
    
    static let readDSP = ReadOverride(start: 0xD012, end: 0xD012, readAnyway: false, action: PIAOverrides.actionReadDSP)
    static func actionReadDSP(terminal: AnyObject, byte: UInt8?) -> UInt8? {
        
        //DSP.7 is unset when the character is accepted by the terminal
        return AppleI.sharedInstance.pia["display"]!.data
    }
    /* */
    
    static let readKBDCR = ReadOverride(start: 0xD011, end: 0xD011, readAnyway: false, action: PIAOverrides.actionReadKBDCR)
    static func actionReadKBDCR(terminal: AnyObject, byte: UInt8?) -> UInt8? {
        return AppleI.sharedInstance.pia["keyboard"]!.control
    }
    
    /* */
    static let readKBD = ReadOverride(start: 0xD010, end: 0xD010, readAnyway: false, action: PIAOverrides.actionReadKBD)
    static func actionReadKBD(terminal: AnyObject, byte: UInt8?) -> UInt8? {
        //Reading KBD clears KBDCR.7
        AppleI.sharedInstance.pia["keyboard"]!.control = AppleI.sharedInstance.pia["keyboard"]!.control & ~(0x80)
        
        //KBD.7 is tied to +5V
        return AppleI.sharedInstance.pia["keyboard"]!.data | 0x80
    }
    
}