using System.ComponentModel;
using System.Drawing.Drawing2D;
using System.Runtime.InteropServices;
using SuzuMagnifier.Dtos;
using static System.Windows.Forms.Design.AxImporter;

namespace SuzuMagnifier
{
    public partial class Form1 : Form
    {
        [StructLayout(LayoutKind.Sequential)]
        public struct POINT
        {
            public int X;
            public int Y;
        }

        [DllImport("user32.dll")]
        private static extern bool GetCursorPos(out POINT lpPoint);

        public static Point GetMousePosition()
        {
            GetCursorPos(out var p);
            return new Point(p.X, p.Y);
        }


        private readonly System.Windows.Forms.Timer _timer = new();
        private Bitmap? _bitmap;
        private string jsonfigFilename;


        public Form1()
        {
            InitializeComponent();

            this.BackColor = Color.Black;
            this.DoubleBuffered = true;
            this.SetStyle(ControlStyles.AllPaintingInWmPaint | ControlStyles.UserPaint | ControlStyles.OptimizedDoubleBuffer, true);
            this.Text = Application.ProductName;

            _timer.Interval = this.UpdateFrequency;
            _timer.Tick += (sender, e) =>
            {
                UpdateMagnifier();
            };
        }

        protected async override void OnLoad(EventArgs e)
        {
            base.OnLoad(e);

            var args = GetCommandLine()!;

            jsonfigFilename = args.Where(x => (x.Key.Equals("o") || x.Key.Equals("open"))).Select(x => x.Value).FirstOrDefault();
            if (string.IsNullOrWhiteSpace(jsonfigFilename))
            {
                jsonfigFilename = Path.ChangeExtension(Application.ExecutablePath, "jsonfig");
            }

            if (System.IO.File.Exists(jsonfigFilename))
            {
                var newSettings = await LoadSettings(jsonfigFilename);
                if (newSettings == null)
                {
                    newSettings = new SavedOptions();
                }

                this.HighQuality = newSettings.HighQuality;
                this.ZoomFactor = newSettings.ZoomFactor;
                //this.UpdateFrequency = newSettings.UpdateFrequency;
                this.ShowCrosshair = newSettings.ShowCrosshair;
                this.CrosshairSize = newSettings.CrosshairSize;
                this.CrosshairColour = newSettings.CrosshairColour;
            }
        }

        protected override void OnShown(EventArgs e)
        {
            base.OnShown(e);

            //_timer.Start();
        }

        protected override void OnPaint(PaintEventArgs e)
        {
            base.OnPaint(e);

            var g = e.Graphics;

            if (!_timer.Enabled)
            {
                TextRenderer.DrawText(g, "Press [Space] To Start", this.Font, this.ClientRectangle, this.ForeColor, TextFormatFlags.HorizontalCenter | TextFormatFlags.VerticalCenter | TextFormatFlags.NoPadding);
            }

            if (_bitmap == null)
            {
                return;
            }

            if (this.HighQuality)
            {
                g.InterpolationMode = InterpolationMode.HighQualityBicubic;
                g.PixelOffsetMode = PixelOffsetMode.HighQuality;
                g.SmoothingMode = SmoothingMode.HighQuality;
            }
            else
            {
                g.InterpolationMode = InterpolationMode.NearestNeighbor;
                g.PixelOffsetMode = PixelOffsetMode.None;
                g.SmoothingMode = SmoothingMode.None;
            }

            g.DrawImage(_bitmap, this.ClientRectangle);

            // Draw center crosshair
            if (this.ShowCrosshair)
            {
                var cx = Divide(this.Width, 2);
                var cy = Divide(this.Height, 2);

                g.DrawLine(new Pen(this.CrosshairColour), cx - this.CrosshairSize, cy, cx + this.CrosshairSize, cy);
                g.DrawLine(new Pen(this.CrosshairColour), cx, cy - this.CrosshairSize, cx, cy + this.CrosshairSize);
            }
        }

        protected override void OnPreviewKeyDown(PreviewKeyDownEventArgs e)
        {
            base.OnPreviewKeyDown(e);

            if (e.Control)
            {
                switch (e.KeyCode)
                {
                    //case Keys.D0:
                    //    this.ZoomFactor = 1;
                    //    break;
                    //case Keys.OemMinus:
                    //    this.ZoomFactor--;
                    //    break;
                    //case Keys.Oemplus:
                    //    this.ZoomFactor++;
                    //    break;
                    //case Keys.F11:
                    //    toolStripMenuItem5_Click(null, null);
                    //    break;
                    default:
                        break;
                }
            }
            else
            {
                switch (e.KeyCode)
                {
                    case Keys.Space:
                        if (_timer.Enabled)
                        {
                            _timer.Stop();
                        }
                        else
                        {
                            _timer.Start();
                        }

                        break;
                    case Keys.Escape:
                        exitiToolStripMenuItem_Click(null, null);
                        break;
                    //case Keys.F11:
                    //    toolStripMenuItem3_Click(null, null);
                    //    break;
                    default:
                        break;
                }
            }
        }

        protected async override void OnFormClosing(FormClosingEventArgs e)
        {
            base.OnFormClosing(e);

            var result = MessageBox.Show("Do you want to save settings to file?", "Save Settings?", MessageBoxButtons.YesNoCancel, MessageBoxIcon.Question);
            if (result == DialogResult.Yes)
            {
                var result2 = await SaveSettings(jsonfigFilename);
                if (result2)
                {
                    return;
                }

                MessageBox.Show("Could not save settings. An error has occurred.", "Save Settings?", MessageBoxButtons.OK, MessageBoxIcon.Error);

                e.Cancel = true;
            }
            else if (result == DialogResult.No)
            {
                // Do nothing
            }
            else
            {
                e.Cancel = true;
            }
        }


        [Browsable(false), EditorBrowsable(EditorBrowsableState.Never), DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden)]
        public bool HighQuality { get; set; } = false;

        [Browsable(false), EditorBrowsable(EditorBrowsableState.Never), DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden)]
        public int ZoomFactor
        {
            get => field;
            set
            {
                if (value < 0)
                {
                    field = 1;
                    return;
                }

                if (value > 20)
                {
                    field = 20;
                    return;
                }

                field = value;
            }
        } = 2;

        [Browsable(false), EditorBrowsable(EditorBrowsableState.Never), DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden)]
        public int UpdateFrequency { get; set; } = 33;

        [Browsable(false), EditorBrowsable(EditorBrowsableState.Never), DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden)]
        public bool ShowCrosshair { get; set; } = true;

        [Browsable(false), EditorBrowsable(EditorBrowsableState.Never), DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden)]
        public int CrosshairSize
        {
            get => field;
            set
            {
                if (value < 5)
                {
                    field = 5;
                    return;
                }

                if (value > 200)
                {
                    field = 200;
                    return;
                }

                field = value;
            }
        } = 20;

        [Browsable(false), EditorBrowsable(EditorBrowsableState.Never), DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden)]
        public Color CrosshairColour { get; set; } = Color.FromArgb(255, 255, 0);


        private void contextMenuStrip1_Opening(object sender, CancelEventArgs e)
        {
            toolStripMenuItem1.Enabled = !_timer.Enabled;
            toolStripMenuItem2.Enabled = _timer.Enabled;

            toolStripMenuItem5.Checked = this.TopMost;

            showToolStripMenuItem.Checked = this.ShowCrosshair;
            smallToolStripMenuItem.Checked = (this.CrosshairSize == 10);
            mediumToolStripMenuItem.Checked = (this.CrosshairSize == 20);
            largeToolStripMenuItem.Checked = (this.CrosshairSize == 50);

            agentaToolStripMenuItem.Checked = this.CrosshairColour == Color.FromArgb(255, 0, 255);
            cyanToolStripMenuItem.Checked = this.CrosshairColour == Color.FromArgb(0, 255, 255);
            yellowToolStripMenuItem.Checked = this.CrosshairColour == Color.FromArgb(255, 255, 0);
            greenToolStripMenuItem.Checked = this.CrosshairColour == Color.FromArgb(0, 255, 0);
            redToolStripMenuItem.Checked = this.CrosshairColour == Color.FromArgb(255, 0, 0);
            blackToolStripMenuItem.Checked = this.CrosshairColour == Color.FromArgb(0, 0, 0);
            whiteToolStripMenuItem.Checked = this.CrosshairColour == Color.FromArgb(255, 255, 255);

            fasterToolStripMenuItem.Checked = !this.HighQuality;
            fasterToolStripMenuItem.Enabled = this.HighQuality;
            highToolStripMenuItem.Checked = this.HighQuality;
            highToolStripMenuItem.Enabled = !this.HighQuality;
        }


        #region context menu

        /// <summary>
        /// Start
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void toolStripMenuItem1_Click(object sender, EventArgs e)
        {
            if (_timer.Enabled)
            {
                return;
            }

            _timer.Start();
        }

        /// <summary>
        /// Stop
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void toolStripMenuItem2_Click(object sender, EventArgs e)
        {
            if (!_timer.Enabled)
            {
                return;
            }

            _timer.Stop();
        }

        /// <summary>
        /// Quality, fast
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void fastToolStripMenuItem_Click(object sender, EventArgs e)
        {
            this.HighQuality = false;
        }

        /// <summary>
        /// QUality, high
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void highToolStripMenuItem_Click(object sender, EventArgs e)
        {
            this.HighQuality = true;
        }

        /// <summary>
        /// Zoom, increase
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void toolStripMenuItem7_Click(object sender, EventArgs e)
        {
            this.ZoomFactor++;
        }

        /// <summary>
        /// Zoom, decrease
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void toolStripMenuItem8_Click(object sender, EventArgs e)
        {
            this.ZoomFactor--;
        }

        /// <summary>
        /// Zoom, reset
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void resetToolStripMenuItem_Click(object sender, EventArgs e)
        {
            this.ZoomFactor = 1;
        }

        /// <summary>
        /// Crosshair, colour, magenta
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void agentaToolStripMenuItem_Click(object sender, EventArgs e)
        {
            this.CrosshairColour = Color.FromArgb(255, 0, 255);
        }

        /// <summary>
        /// Crosshair, colour, cyan
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void cyanToolStripMenuItem_Click(object sender, EventArgs e)
        {
            this.CrosshairColour = Color.FromArgb(0, 255, 255);
        }

        /// <summary>
        /// Crosshair, colour, yellow
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void yellowToolStripMenuItem_Click(object sender, EventArgs e)
        {
            this.CrosshairColour = Color.FromArgb(255, 255, 0);
        }

        /// <summary>
        /// Crosshair, colour, green
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void greenToolStripMenuItem_Click(object sender, EventArgs e)
        {
            this.CrosshairColour = Color.FromArgb(0, 255, 0);
        }

        /// <summary>
        /// Crosshair, colour, red
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void redToolStripMenuItem_Click(object sender, EventArgs e)
        {
            this.CrosshairColour = Color.FromArgb(255, 0, 0);
        }

        /// <summary>
        /// Crosshair, colour, black
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void blackToolStripMenuItem_Click(object sender, EventArgs e)
        {
            this.CrosshairColour = Color.FromArgb(0, 0, 0);
        }

        /// <summary>
        /// Crosshair, colour, white
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void whiteToolStripMenuItem_Click(object sender, EventArgs e)
        {
            this.CrosshairColour = Color.FromArgb(255, 255, 255);
        }

        /// <summary>
        /// ALways on top
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void toolStripMenuItem5_Click(object sender, EventArgs e)
        {
            this.TopMost = !this.TopMost;
        }

        /// <summary>
        /// Fullscreen
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void toolStripMenuItem3_Click(object sender, EventArgs e)
        {
            if (this.WindowState == FormWindowState.Normal)
            {
                this.FormBorderStyle = FormBorderStyle.None;
                this.WindowState = FormWindowState.Maximized;
            }
            else
            {
                this.FormBorderStyle = FormBorderStyle.Sizable;
                this.WindowState = FormWindowState.Normal;
            }
        }

        /// <summary>
        /// Exit
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void exitiToolStripMenuItem_Click(object sender, EventArgs e)
        {
            if (_timer.Enabled)
            {
                _timer.Stop();
                _timer.Dispose();
            }

            this.Close();
        }

        /// <summary>
        /// Crosshair, toggle
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void showToolStripMenuItem_Click(object sender, EventArgs e)
        {
            this.ShowCrosshair = !this.ShowCrosshair;
        }

        /// <summary>
        /// Croisshair, size, small
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void smallToolStripMenuItem_Click(object sender, EventArgs e)
        {
            this.CrosshairSize = 10;
        }

        /// <summary>
        /// Croisshair, size, medium
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void mediumToolStripMenuItem_Click(object sender, EventArgs e)
        {
            this.CrosshairSize = 20;
        }

        /// <summary>
        /// Croisshair, size, large
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void largeToolStripMenuItem_Click(object sender, EventArgs e)
        {
            this.CrosshairSize = 50;
        }

        #endregion


        private void UpdateMagnifier()
        {
            //var mouse = Cursor.Position;
            var mouse = GetMousePosition();

            var w = Divide(this.Width, this.ZoomFactor);
            var h = Divide(this.Height, this.ZoomFactor);

            var cx = Divide(w, 2);
            var cy = Divide(h, 2);
            var x = mouse.X - cx;
            var y = mouse.Y - cy;

            var sourceRect = new Rectangle(x, y, w, h);

            _bitmap?.Dispose();
            _bitmap = null;
            _bitmap = new Bitmap(sourceRect.Width, sourceRect.Height);

            using Graphics g = Graphics.FromImage(_bitmap);
            g.CopyFromScreen(sourceRect.Location, Point.Empty, sourceRect.Size);

            this.Invalidate();
        }

        private int Divide(int x, int y)
        {
            return (int)Math.Floor((decimal)x / y);
        }

        /// <summary>
        /// Get execution arguments.
        /// </summary>
        /// <returns></returns>
        private List<KeyValuePair<string, string>> GetCommandLine()
        {
            var result = new List<KeyValuePair<string, string>>();
            var args = Environment.GetCommandLineArgs() ?? new string[0];
            if (args.Length <= 1)
            {
                return result;
            }

            var key = string.Empty;
            var flag = false;
            for (int i = 1; i < args.Length; i++)
            {
                var text = args[i];
                if (string.IsNullOrWhiteSpace(text))
                {
                    continue;
                }

                if (text.StartsWith("-"))
                {
                    if (flag)
                    {
                        result.Add(new KeyValuePair<string, string>(key, string.Empty));
                    }

                    key = text?.TrimStart('-')?.Trim() ?? string.Empty;
                    flag = true;
                }
                else
                {
                    result.Add(new KeyValuePair<string, string>(key, text?.Trim() ?? string.Empty));
                    flag = false;
                }
            }

            return result;
        }

        private async Task<SavedOptions?> LoadSettings(string filename)
        {
            if (!System.IO.File.Exists(filename))
            {
                return null;
            }

            string sourceCode;
            try
            {
                sourceCode = await System.IO.File.ReadAllTextAsync(filename);
            }
            catch (Exception)
            {
                return null;
            }

            if (string.IsNullOrWhiteSpace(sourceCode))
            {
                return null;
            }

            try
            {
                return System.Text.Json.JsonSerializer.Deserialize<SavedOptions>(sourceCode);
            }
            catch (Exception)
            {
                return null;
            }
        }

        private async Task<bool> SaveSettings(string filename)
        {
            var result = new SavedOptions();
            result.AutoStart = false;
            result.HighQuality = this.HighQuality;
            result.ZoomFactor = this.ZoomFactor;
            result.UpdateFrequency = this.UpdateFrequency;
            result.ShowCrosshair = this.ShowCrosshair;
            result.CrosshairSize = this.CrosshairSize;
            result.CrosshairColour = this.CrosshairColour;

            string sourceCode = "";
            try
            {
                sourceCode = System.Text.Json.JsonSerializer.Serialize(result);
            }
            catch (Exception)
            {
                return false;
            }

            if (string.IsNullOrWhiteSpace(sourceCode))
            {
                return false;
            }

            if (System.IO.File.Exists(filename))
            {
                try
                {
                    System.IO.File.Delete(filename);
                }
                catch (Exception)
                {
                    return false;
                }
            }

            try
            {
                await System.IO.File.WriteAllTextAsync(filename, sourceCode);
            }
            catch (Exception)
            {
                return false;
            }

            return true;
        }

    }
}