using System;
using System.Collections.Generic;
using System.Text;

using dotnes.Core;

namespace dotnes
{
    namespace Nes
    {
        struct Constants
        {
            public const float ClockDivider = 12;
            public const int CyclesPerScanline = (int)(1364 / ClockDivider);
        }
    }

    class Machine : IMachine
    {
        private CPU cpu;
        private Cartridge image;
        bool vblanking;
        private int currentCycles;

        public Machine()
        {
            cpu = new CPU(this);
            
            vblanking = false;
            currentCycles = Nes.Constants.CyclesPerScanline;
        }

        void LoadImage(Cartridge img)
        {
            image = img;
        }

        void DoFrame()
        {
            // do each visible scanline (hblank), vblank, and then non-visible
            for (int line = 0; line < 262; line++)
            {
                switch (line)
                {
                    case 241:
                        {
                            vblanking = true;
                            currentCycles -= cpu.Execute(7);

                            cpu.Interrupt(InterruptType.NMI);

                            break;
                        }
                    case 261:
                        vblanking = false;
                        break;
                }

                if (currentCycles > 0)
                    currentCycles -= cpu.Execute(currentCycles);

                currentCycles += Nes.Constants.CyclesPerScanline;

            }   
        }

        //--------------------------------------------------------------------
        // IMachine implementation
        //--------------------------------------------------------------------
        byte IMachine.Read(UInt16 address)
        {
            return 0;
        }

        void IMachine.Write(UInt16 address, byte value)
        {
        }

        void IMachine.BadOp(byte op)
        {
        }

        InterruptType IMachine.CheckInterrupt()
        {
            return InterruptType.None;
        }

        void IMachine.Debug()
        {
        }
    }
}