using System;
using System.Drawing;
using System.Windows.Forms;

namespace NeuralNetworkPrediction
{
    public class MainPanel : Panel
    {
        // Константы
        private const int N = 300;
        private const double TAU = 0.01;
        private const double TAU_STEP = 0.01;
        private const double D_H = 0.05;
        private const double ALPHA = 0.01;
        private const int R = 10;
        private const double START_X = -10.0;
        private const double END_X = 5.0;

        private const double A0 = 4.5;
        private const double A1 = 0.6;
        private const double A2 = -23.2;
        private const double A3 = 108.6;
        private const double A4 = -147.7;
        private const double A5 = 38;

        // Переменные нейросети
        private double c_x;
        private double[] u_t;
        private double[] u;
        private double[] u_n;
        private double[] g;
        private int n_t;
        private int step;
        private int err;
        private double learningPercentage;

        // Графические параметры
        private double graphW, graphH, graphDx, graphBx, graphRx;

        private Timer timer;

        public MainPanel()
        {
            // Инициализация переменных
            c_x = START_X;
            u_t = new double[N];
            u = new double[N];
            u_n = new double[N];
            g = new double[R];

            for (int i = 0; i < N; i++)
            {
                u[i] = 0.0;
                u_t[i] = 0.0;
                u_n[i] = 0.0;
            }
            for (int i = 0; i < R; i++)
            {
                g[i] = 0.0;
            }
            n_t = N / 2 + 1;
            step = 1;
            err = 0;
            learningPercentage = 0.0;

            // Настройка панели
            DoubleBuffered = true;

            // Запуск таймера
            timer = new Timer();
            timer.Interval = 1;
            timer.Tick += Timer_Tick;
            timer.Start();
        }

        private double Sign(double x)
        {
            if (x > 0) return 1.0;
            else if (x < 0) return -1.0;
            return 0.0;
        }

        private double F(double x)
        {
            return A0 * Math.Pow(x, 5) + A1 * Math.Pow(x, 4) + A2 * Math.Pow(x, 3)
                + A3 * Math.Pow(x, 2) + A4 * x + A5;
        }

        private void Teach(double[] u, double[] g, int n_t, double delta)
        {
            double[] delta_g = new double[R];
            for (int r = 0; r < R; r++)
            {
                double x_r = u[n_t - 1 - r];
                delta_g[r] = ALPHA * Sign(x_r) * Sign(delta);
            }
            for (int r = 0; r < R; r++)
            {
                g[r] += delta_g[r];
            }
            err++;
        }

        private void CalculateLearningPercentage()
        {
            double totalError = 0.0;
            double minVal = u[0], maxVal = u[0];
            for (int i = 0; i < N; i++)
            {
                totalError += Math.Abs(u_n[i] - u_t[i]);
                if (u[i] < minVal) minVal = u[i];
                if (u[i] > maxVal) maxVal = u[i];
            }
            double avgError = totalError / N;
            double range = maxVal - minVal;
            if (range < 1e-9) range = 1.0;
            learningPercentage = 100 * (1 - avgError / range);
            if (learningPercentage < 0) learningPercentage = 0;
            if (learningPercentage > 100) learningPercentage = 100;
        }

        private void NewStep()
        {
            for (int i = 0; i < N; i++)
            {
                u_n[i] = F(c_x + i * TAU);
            }
            c_x += TAU_STEP;

            if (c_x > END_X)
            {
                c_x = START_X;
            }

            for (int i = 0; i < N; i++)
            {
                u_t[i] = 0.0;
            }
            for (int i = R; i < N; i++)
            {
                for (int r = 0; r < R; r++)
                {
                    u_t[i] += g[r] * u[i - 1 - r];
                }
            }
            for (int i = 0; i < R; i++)
            {
                u_t[i] = u[i];
            }

            double d_u = u_n[n_t] - u_t[n_t];
            if (d_u < -D_H || d_u > D_H)
            {
                Teach(u, g, n_t, d_u);
            }
            step++;
        }

        private void UpdateVars()
        {
            NewStep();
            for (int i = 0; i < N; i++)
            {
                u[i] = u_n[i];
            }
            CalculateLearningPercentage();
        }

        protected override void OnPaint(PaintEventArgs e)
        {
            base.OnPaint(e);
            Graphics g2 = e.Graphics;

            // Инициализация графических параметров
            graphW = Width;
            graphH = Height;
            graphDx = graphW / N;
            graphBx = (graphW - graphDx * (N - 1)) / 2.0;
            graphRx = graphBx + (N - 1) * graphDx;

            // Масштабирование
            double minVal = u[0], maxVal = u[0];
            for (int i = 1; i < N; i++)
            {
                if (u[i] < minVal) minVal = u[i];
                if (u[i] > maxVal) maxVal = u[i];
            }
            double mid = (maxVal + minVal) / 2.0;
            double diff = maxVal - minVal;
            minVal = mid - diff * 1.5;
            maxVal = mid + diff * 1.5;
            if (Math.Abs(maxVal - minVal) < 1e-9)
            {
                minVal -= 1.0;
                maxVal += 1.0;
            }
            double localMtt = graphH / (maxVal - minVal);
            double y_c = localMtt * maxVal;

            // Рисуем оси
            using (Pen pen = new Pen(Color.Black))
            {
                g2.DrawLine(pen, (float)graphBx, 0, (float)graphBx, (float)graphH);
                g2.DrawLine(pen, (float)graphRx, 0, (float)graphRx, (float)graphH);
                g2.DrawLine(pen, (float)graphBx, 0, (float)graphRx, 0);
                g2.DrawLine(pen, (float)graphBx, (float)graphH, (float)graphRx, (float)graphH);
                g2.DrawLine(pen, (float)graphBx, (float)y_c, (float)graphRx, (float)y_c);

                for (int i = 1; i < N - 1; i++)
                {
                    float x = (float)(graphBx + i * graphDx);
                    g2.DrawLine(pen, x, (float)(y_c - 3), x, (float)(y_c + 3));
                }
                float x_nt = (float)(graphBx + (n_t - 1) * graphDx);
                g2.DrawLine(pen, x_nt, 0, x_nt, (float)graphH);
            }

            // Рисуем кривую u
            using (Pen greenPen = new Pen(Color.Green))
            {
                float oldX = (float)graphBx;
                float oldY = (float)(y_c - localMtt * u[0]);
                for (int i = 1; i < N; i++)
                {
                    float x = (float)(graphBx + i * graphDx);
                    float y = (float)(y_c - localMtt * u[i]);
                    g2.DrawLine(greenPen, oldX, oldY, x, y);
                    oldX = x;
                    oldY = y;
                }
            }

            // Рисуем прогноз u_t
            using (Pen redPen = new Pen(Color.Red))
            {
                float oldX = (float)graphBx;
                float oldY = (float)(y_c - localMtt * u_t[0]);
                for (int i = 1; i < N; i++)
                {
                    float x = (float)(graphBx + i * graphDx);
                    float y = (float)(y_c - localMtt * u_t[i]);
                    g2.DrawLine(redPen, oldX, oldY, x, y);
                    oldX = x;
                    oldY = y;
                }
            }

            // Рисуем текст
            using (Font font = new Font("Arial", 10))
            using (Brush brush = new SolidBrush(Color.Black))
            {
                float textX = 20;
                float textY = 20;
                g2.DrawString($"Step = {step}", font, brush, textX, textY); textY += 16;
                g2.DrawString($"dH = {D_H:F2}", font, brush, textX, textY); textY += 16;
                g2.DrawString($"dG = {ALPHA:F3}", font, brush, textX, textY); textY += 16;
                for (int i = 0; i < R; i++)
                {
                    g2.DrawString($"G[{i}] = {g[i]:F3}", font, brush, textX, textY);
                    textY += 16;
                }
                g2.DrawString($"Learning: {learningPercentage:F2}%", font, brush, textX, textY);
                textY += 16;
                g2.DrawString($"c_x = {c_x:F3}", font, brush, textX, textY);
            }
        }

        protected override Size DefaultSize => new Size(800, 600);

        private void Timer_Tick(object sender, EventArgs e)
        {
            UpdateVars();
            Invalidate();
        }

        [STAThread]
        static void Main()
        {
            Application.EnableVisualStyles();
            Application.SetCompatibleTextRenderingDefault(false);
            Form form = new Form
            {
                Text = "Прогнозирование функции (нейросеть)",
                ClientSize = new Size(800, 600)
            };
            MainPanel panel = new MainPanel();
            form.Controls.Add(panel);
            panel.Dock = DockStyle.Fill;
            form.ShowDialog();
        }
    }
}