using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace DO_Lab1_Rect
{
    internal class SimplexMethod
    {
        private double[,] array;
        private double[,] oldArray;
        private List<int> basis;
        private double[] assistCof;
        public SimplexMethod(double[,] array)
        {
            this.array = array;
            basis = new List<int>();
            assistCof = new double[array.GetLength(0) - 1];
        }
        public SimplexMethod(string path)
        {
            basis = new List<int>();

            string[] task = File.ReadAllLines(path);
            string[] current = task[task.Length - 1].Split(' ');
            array = new double[task.Length, current.Length + task.Length];
            assistCof = new double[array.GetLength(0) - 1];
            int variables = current.Length;
            for (int i = 0; i < array.GetLength(1); i++)
            {
                if (i < current.Length)
                {
                    array[array.GetLength(0) - 1, i] = -double.Parse(current[i]);
                }
                else array[array.GetLength(0) - 1, i] = 0;
            }
            for (int i = 0; i < array.GetLength(0) - 1; i++)
            {
                current = task[i].Split(' ');
                for (int j = 0; j < array.GetLength(1); j++)
                {
                    if (j == variables + i)
                    {
                        array[i, j] = 1;
                    }
                    else if (j == array.GetLength(1) - 1)
                    {
                        array[i, j] = double.Parse(current[current.Length - 1]);
                    }
                    else if (j >= variables)
                    {
                        array[i, j] = 0;
                    }
                    else
                    {
                        array[i, j] = double.Parse(current[j]);
                    }
                }
            }
        }
        private void calcBasis()
        {
            if (basis.Count == 0)
            {
                for (int i = 0; i < array.GetLength(1); i++)
                {
                    int zeroCount = 0;
                    for (int j = 0; j < array.GetLength(0); j++)
                    {
                        if (array[j, i] == 0)
                        {
                            zeroCount++;
                        }
                    }
                    if (zeroCount == array.GetLength(0) - 1)
                    {
                        basis.Add(i + 1);
                    }
                }
            }
            else
            {
                int insertIndex = -1, toInsert = -1;
                for (int i = 0; i < array.GetLength(1); i++)
                {
                    int zeroCount = 0;
                    for (int j = 0; j < array.GetLength(0); j++)
                    {
                        if (array[j, i] == 0)
                        {
                            zeroCount++;
                        }
                    }
                    if (zeroCount != array.GetLength(0) - 1 && basis.Contains(i + 1))
                    {
                        insertIndex = basis.IndexOf(i + 1);
                    }
                    else if (zeroCount == array.GetLength(0) - 1 && !basis.Contains(i + 1))
                    {
                        toInsert = i + 1;
                    }
                }
                basis.RemoveAt(insertIndex);
                basis.Insert(insertIndex, toInsert);
            }
        }
        private void printTable()
        {
            Console.Write("Basis   ");
            for (int i = 0; i < array.GetLength(1) - 1; i++)
            {
                Console.Write($"x{i + 1,-4}");
            }
            Console.Write("Bi   ");
            Console.WriteLine("Bi/mainColumn");
            for (int i = 0; i < array.GetLength(0); i++)
            {
                if (i < basis.Count)
                {
                    Console.Write($"X{basis[i],-7}");
                }
                else
                {
                    Console.Write("{0,-8}", "Q");
                }
                for (int j = 0; j < array.GetLength(1); j++)
                {
                    Console.Write($"{array[i, j],-5}");
                }
                if (i < assistCof.Length)
                {
                    if (assistCof[i] < 0)
                    {
                        Console.WriteLine($"<0");
                    }
                    else
                    {
                        Console.WriteLine($"{assistCof[i]}");
                    }
                }
                else
                {
                    Console.WriteLine();
                }
            }
        }
        private void printFinalTable()
        {
            Console.Write("Basis   ");
            for (int i = 0; i < array.GetLength(1) - 1; i++)
            {
                Console.Write($"x{i + 1,-4}");
            }
            Console.WriteLine("Bi");
            for (int i = 0; i < array.GetLength(0); i++)
            {
                if (i < basis.Count)
                {
                    Console.Write($"X{basis[i],-7}");
                }
                else
                {
                    Console.Write("{0,-8}", "Q");
                }
                for (int j = 0; j < array.GetLength(1); j++)
                {
                    Console.Write($"{array[i, j],-5}");
                }
                Console.WriteLine();
            }
            double[] answer = new double[array.GetLength(1) - 1];
            for (int j = 0; j < answer.Length; j++)
            {
                if (basis.Contains(j + 1))
                {
                    int index = basis.IndexOf(j + 1);
                    answer[j] = array[index, array.GetLength(1) - 1];
                }
                else
                {
                    answer[j] = 0;
                }
            }
            Console.WriteLine("Answer:");
            for (int i = 0; i < answer.Length; i++)
            {
                Console.Write($"X{i + 1} = {answer[i]}    ");
            }
            Console.WriteLine($"\nQ = {array[array.GetLength(0) - 1, array.GetLength(1) - 1]}");
        }
        public void Solve()
        {
            bool isSolved = true;
            for (int i = 0; i < array.GetLength(1); i++)
            {
                if (array[array.GetLength(0) - 1, i] < 0)
                {
                    isSolved = false;
                    break;
                }
            }
            int iter = 0;
            while (!isSolved)
            {
                //Знайдемо базисні елемент
                calcBasis();

                //Знайдемо ведучий стовпець
                double max = -1;
                int mainColumn = -1;
                for (int j = 0; j < array.GetLength(1); j++)
                {
                    if (array[array.GetLength(0) - 1, j] < 0 && Math.Abs(array[array.GetLength(0) - 1, j]) > max)
                    {
                        max = Math.Abs(array[array.GetLength(0) - 1, j]);
                        mainColumn = j;
                    }
                }

                //Обрахуємо допоміжні коефіцієнти
                for (int i = 0; i < assistCof.Length; i++)
                {
                    if (array[i, mainColumn] == 0)
                    {
                        assistCof[i] = -1;
                    }
                    else
                    {
                        assistCof[i] = array[i, array.GetLength(1) - 1] / array[i, mainColumn];
                    }
                }

                double min = -1;
                int mainRow = -1;
                for (int i = 0; i < assistCof.Length; i++)
                {
                    if (assistCof[i] > 0)
                    {
                        if (min == -1)
                        {
                            min = assistCof[i];
                            mainRow = i;
                        }
                        else
                        {
                            if (assistCof[i] < min)
                            {
                                min = assistCof[i];
                                mainRow = i;
                            }
                        }
                    }
                }

                Console.WriteLine("******************");
                Console.WriteLine($"Table {iter + 1} -- Main row {mainRow + 1} -- Main column {mainColumn + 1} -- Main element {array[mainRow, mainColumn]}");
                Console.WriteLine("******************");
                printTable();

                oldArray = (double[,])array.Clone();
                double mainElement = array[mainRow, mainColumn];
                for (int i = 0; i < array.GetLength(0); i++)
                {
                    if (i == mainRow) continue;
                    for (int j = 0; j < array.GetLength(1); j++)
                    {
                        if (j == mainColumn)
                        {
                            array[i, j] = 0;
                        }
                        else
                        {
                            //array[i, j] = oldArray[i, j] * mainElement - oldArray[mainRow, j] * oldArray[i, mainColumn];
                            array[i, j] = oldArray[i, j] - (oldArray[i, mainColumn] * oldArray[mainRow, j]) / mainElement;
                            //  array[i, j] = oldArray[i, j] - oldArray[mainColumn, j] * oldArray[i, mainRow] / mainElement;
                        }
                    }
                }
                //перевіряємо на вирішеність
                isSolved = true;
                for (int i = 0; i < array.GetLength(1); i++)
                {
                    if (array[array.GetLength(0) - 1, i] < 0)
                    {
                        isSolved = false;
                        break;
                    }
                }
                iter++;
            }

            Console.WriteLine("******************");
            Console.WriteLine($"Table {iter + 1}");
            Console.WriteLine("******************");
            calcBasis();
            printFinalTable();
        }
    }
}