using System;
using System.Drawing;
using System.Drawing.Imaging;
using System.Runtime.InteropServices;
using System.Windows.Forms;
using Core.Cpu;
using Core.Io;
using Core.Memory;

namespace Desktop
{
    public partial class Form1 : Form
    {
        private Z80 _cpu = null!;
        private MemoryBus _memoryBus = null!;
        private SimpleIoBus _simpleIoBus = null!;

        // The 16 physical colors of the ZX Spectrum (ARGB format)
        private readonly int[] SpectrumColors = new int[]
{
    // Normal Colors (Bright = 0)
    unchecked((int)0xFF000000), // 0: Black
    unchecked((int)0xFF0000D7), // 1: Blue
    unchecked((int)0xFFD70000), // 2: Red
    unchecked((int)0xFFD700D7), // 3: Magenta
    unchecked((int)0xFF00D700), // 4: Green
    unchecked((int)0xFF00D7D7), // 5: Cyan
    unchecked((int)0xFFD7D700), // 6: Yellow
    unchecked((int)0xFFD7D7D7), // 7: White
    
    // Bright Colors (Bright = 1)
    unchecked((int)0xFF000000), // 8: Bright Black
    unchecked((int)0xFF0000FF), // 9: Bright Blue
    unchecked((int)0xFFFF0000), // 10: Bright Red
    unchecked((int)0xFFFF00FF), // 11: Bright Magenta
    unchecked((int)0xFF00FF00), // 12: Bright Green
    unchecked((int)0xFF00FFFF), // 13: Bright Cyan
    unchecked((int)0xFFFFFF00), // 14: Bright Yellow
    unchecked((int)0xFFFFFFFF)  // 15: Bright White
};

        public Form1()
        {
            InitializeComponent();
            InitializeEmulator();
        }

        private void InitializeEmulator()
        {
            try
            {
                _memoryBus = new MemoryBus();
                _simpleIoBus = new SimpleIoBus();

                _memoryBus.CrapRAMData();
                byte[] romData = RomLoader.Load("48.rom");
                _memoryBus.LoadRom(romData);

                _cpu = new Z80(_memoryBus, _simpleIoBus);

                // Pass 'this' so the DebuggerForm can talk back to this main window
                DebuggerForm debugger = new DebuggerForm(_cpu, _memoryBus, this);
                debugger.Show();
            }
            catch (Exception ex)
            {
                MessageBox.Show($"Failed to initialize emulator:\n{ex.Message}", "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
            }
        }

        // Public so the Debugger's background thread can call it 50 times a second
        public void RenderScreen()
        {
            int[] pixelData = new int[256 * 192];

            // Loop through the 6144 bytes of Pixel RAM
            for (int offset = 0; offset < 6144; offset++)
            {
                ushort address = (ushort)(0x4000 + offset);
                byte pixels = _memoryBus.Read(address);

                // Unwind the Sinclair interlace
                int y = ((offset & 0x0700) >> 8) |
                        ((offset & 0x00E0) >> 2) |
                        ((offset & 0x1800) >> 5);

                int x = (offset & 0x001F) * 8;

                // Fetch Color Attributes
                int attrRow = y / 8;
                int attrCol = x / 8;
                ushort attrAddress = (ushort)(0x5800 + (attrRow * 32) + attrCol);
                byte attr = _memoryBus.Read(attrAddress);

                int ink = attr & 0x07;
                int paper = (attr >> 3) & 0x07;
                int brightOffset = (attr & 0x40) != 0 ? 8 : 0;

                int inkColor = SpectrumColors[ink + brightOffset];
                int paperColor = SpectrumColors[paper + brightOffset];

                // Draw the 8 pixels
                for (int bit = 0; bit < 8; bit++)
                {
                    bool isPixelSet = (pixels & (1 << (7 - bit))) != 0;
                    pixelData[(y * 256) + (x + bit)] = isPixelSet ? inkColor : paperColor;
                }
            }

            // Blast it to the PictureBox
            Bitmap bmp = new Bitmap(256, 192, PixelFormat.Format32bppArgb);
            BitmapData bmpData = bmp.LockBits(
                new Rectangle(0, 0, 256, 192),
                ImageLockMode.WriteOnly,
                bmp.PixelFormat);

            Marshal.Copy(pixelData, 0, bmpData.Scan0, pixelData.Length);
            bmp.UnlockBits(bmpData);

            if (picScreen.Image != null) picScreen.Image.Dispose();
            picScreen.Image = bmp;
        }
    }
}