package razorvine.examplemachines

import razorvine.ksim65.Bus
import razorvine.ksim65.Cpu6502
import razorvine.ksim65.IVirtualMachine
import razorvine.ksim65.Version
import razorvine.ksim65.components.*
import java.io.File
import javax.swing.ImageIcon

/**
 * A virtual computer constructed from the various virtual components
 */
class VirtualMachine(title: String) : IVirtualMachine {
    override val bus = Bus()
    override val cpu = Cpu6502(false)
    val ram = Ram(0x0000, 0xffff)
    private val rtc = RealTimeClock(0xd100, 0xd108)
    private val timer = Timer(0xd200, 0xd203, cpu)

    private val debugWindow = DebugWindow(this)
    private val hostDisplay = MainWindow(title)
    private val display = Display(
        0xd000, 0xd00a, hostDisplay,
        ScreenDefs.SCREEN_WIDTH_CHARS, ScreenDefs.SCREEN_HEIGHT_CHARS,
        ScreenDefs.SCREEN_WIDTH, ScreenDefs.SCREEN_HEIGHT
    )
    private val mouse = Mouse(0xd300, 0xd305, hostDisplay)
    private val keyboard = Keyboard(0xd400, 0xd400, hostDisplay)
    private var paused = false

    init {
        hostDisplay.iconImage = ImageIcon(javaClass.getResource("/icon.png")).image
        debugWindow.iconImage = hostDisplay.iconImage
        debugWindow.setLocation(hostDisplay.location.x + hostDisplay.width, hostDisplay.location.y)

        ram[Cpu6502.RESET_vector] = 0x00
        ram[Cpu6502.RESET_vector + 1] = 0x10
        ram.loadPrg(javaClass.getResourceAsStream("/vmdemo.prg"), null)

        bus += rtc
        bus += timer
        bus += display
        bus += mouse
        bus += keyboard
        bus += ram
        bus += cpu
        bus.reset()

        debugWindow.isVisible = true
        hostDisplay.isVisible = true
        hostDisplay.start()
    }

    override fun getZeroAndStackPages(): Array<UByte> = ram.getPages(0, 2)

    override fun loadFileInRam(file: File, loadAddress: Address?) {
        if (file.extension == "prg" && loadAddress == null)
            ram.loadPrg(file.inputStream(), null)
        else
            ram.load(file.readBytes(), loadAddress!!)
    }

    override fun pause(paused: Boolean) {
        this.paused = paused
    }

    override fun step() {
        // step a full single instruction
        while (cpu.instrCycles > 0) bus.clock()
        bus.clock()
        while (cpu.instrCycles > 0) bus.clock()
    }

    fun start() {
        javax.swing.Timer(10) {
            debugWindow.updateCpu(cpu, bus)
        }.start()

        // busy waiting loop, averaging cpu speed to ~1 Mhz:
        var numInstructionsteps = 600
        val targetSpeedKhz = 1000
        while (true) {
            if (paused) {
                Thread.sleep(100)
            } else {
                cpu.startSpeedMeasureInterval()
                Thread.sleep(0, 1000)
                repeat(numInstructionsteps) { step() }
                val speed = cpu.measureAvgIntervalSpeedKhz()
                if (speed < targetSpeedKhz - 50)
                    numInstructionsteps++
                else if (speed > targetSpeedKhz + 50)
                    numInstructionsteps--
            }
        }
    }
}

fun main(args: Array<String>) {
    val machine = VirtualMachine("KSim65 demo virtual machine - using ksim65 v${Version.version}")
    machine.start()
}