using System;
using System.Collections.Generic;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.Windows.Forms;

namespace CSharpGraphicsApp
{
    public class DoubleBufferedPanel : Panel
    {
        public DoubleBufferedPanel() { DoubleBuffered = true; }
    }

    public class Task20_FinalProject : Form
    {
        private readonly Panel graphPanel;
        private readonly Panel imagePanel;
        private readonly Panel animPanel;
        private readonly Timer animTimer = new Timer();
        private float animAngle = 0;
        private int animX = 0;

        public Task20_FinalProject()
        {
            Text = "Задание 20 — Итоговый проект";
            Size = new Size(700, 500);
            BackColor = Color.White;

            var menu = new MenuStrip();
            var mGraph = new ToolStripMenuItem("График");
            var mImage = new ToolStripMenuItem("Изображение");
            var mAnim  = new ToolStripMenuItem("Анимация");

            mGraph.Click += (s, e) => ShowPanel(graphPanel);
            mImage.Click += (s, e) => ShowPanel(imagePanel);
            mAnim.Click  += (s, e) => ShowPanel(animPanel);

            menu.Items.AddRange(new ToolStripItem[] { mGraph, mImage, mAnim });
            MainMenuStrip = menu;
            Controls.Add(menu);

            graphPanel = CreateGraphPanel();
            imagePanel = CreateImagePanel();
            animPanel  = CreateAnimPanel();

            graphPanel.Location = imagePanel.Location = animPanel.Location
                = new Point(0, menu.Height);
            Controls.Add(graphPanel);
            Controls.Add(imagePanel);
            Controls.Add(animPanel);

            ShowPanel(graphPanel);

            animTimer.Interval = 50;
            animTimer.Tick += AnimTimer_Tick;
            animTimer.Start();

            Resize += (s, e) => ResizePanels(menu.Height);
            FormClosed += (s, e) => animTimer.Stop();
            ResizePanels(menu.Height);
        }

        private void ResizePanels(int top)
        {
            var size = new Size(ClientSize.Width, ClientSize.Height - top);
            graphPanel.Size = imagePanel.Size = animPanel.Size = size;
        }

        private void ShowPanel(Panel panel)
        {
            graphPanel.Visible = imagePanel.Visible = animPanel.Visible = false;
            panel.Visible = true;
            panel.Invalidate();
        }

        private Panel CreateGraphPanel()
        {
            var p = new DoubleBufferedPanel { BackColor = Color.White };
            p.Paint += (s, e) =>
            {
                var g = e.Graphics;
                int oy = p.ClientSize.Height / 2;
                int ox = p.ClientSize.Width  / 2;
                g.DrawLine(Pens.Black, 30, oy, p.ClientSize.Width - 30, oy);
                g.DrawLine(Pens.Black, ox, 30, ox, p.ClientSize.Height - 30);

                var pts = new List<PointF>();
                for (float x = -(float)Math.PI * 2; x <= Math.PI * 2; x += 0.05f)
                {
                    float y = (float)Math.Sin(x);
                    pts.Add(new PointF(ox + x * 40, oy - y * 60));
                }
                using (var pen = new Pen(Color.Red, 2))
                    g.DrawLines(pen, pts.ToArray());
                g.DrawString("График sin(x)",
                    new Font("Segoe UI", 12, FontStyle.Bold), Brushes.DarkRed, 20, 20);
            };
            return p;
        }

        private Panel CreateImagePanel()
        {
            var p = new DoubleBufferedPanel { BackColor = Color.White };
            p.Paint += (s, e) =>
            {
                var g = e.Graphics;
                var rect = new Rectangle(50, 50, 200, 120);
                using (var lgb = new LinearGradientBrush(rect, Color.Blue, Color.Yellow, 45f))
                    g.FillRectangle(lgb, rect);

                var tex = new Bitmap(32, 32);
                using (var tg = Graphics.FromImage(tex))
                {
                    tg.Clear(Color.LightGray);
                    tg.DrawLine(Pens.DarkGray, 0, 0, 32, 32);
                    tg.DrawLine(Pens.DarkGray, 32, 0, 0, 32);
                }
                using (var tb = new TextureBrush(tex))
                    g.FillEllipse(tb, 300, 50, 180, 100);

                g.DrawString("Градиент + Текстура",
                    new Font("Segoe UI", 12, FontStyle.Bold), Brushes.Black, 20, 20);
            };
            return p;
        }

        private Panel CreateAnimPanel()
        {
            var p = new DoubleBufferedPanel { BackColor = Color.White };
            p.Paint += (s, e) =>
            {
                var g = e.Graphics;
                g.SmoothingMode = SmoothingMode.AntiAlias;
                g.FillEllipse(Brushes.Orange, animX, 100, 40, 40);

                g.TranslateTransform(300, 200);
                g.RotateTransform(animAngle);
                using (var brush = new SolidBrush(Color.FromArgb(120, Color.Green)))
                    g.FillRectangle(brush, -30, -20, 60, 40);
                g.ResetTransform();

                g.DrawString("Анимация: движение + вращение",
                    new Font("Segoe UI", 12, FontStyle.Bold), Brushes.Black, 20, 20);
            };
            return p;
        }

        private void AnimTimer_Tick(object sender, EventArgs e)
        {
            animAngle += 4;
            animX += 4;
            if (animX > ClientSize.Width) animX = -40;
            animPanel.Invalidate();
        }
    }
}