import numpy as np
import tabulate as tb

class Simplex:
    def __init__(self, source):
        m, n = source.shape
        self.table = np.zeros((m, n + m - 1))
        self.basis = []

        for i in range(m):
            for j in range(self.table.shape[1]):
                if j < n:
                    self.table[i, j] = source[i, j]
                else:
                    self.table[i, j] = 0

            if (n + i) < self.table.shape[1]:
                self.table[i, n + i] = 1
                self.basis.append(n + i)

        self.m = m
        self.n = self.table.shape[1]

    def calculate(self, result):
        counter = 0
        while not self.is_it_end() and counter < 10:
            main_col = self.find_main_col()
            main_row = self.find_main_row(main_col)
            self.basis[main_row] = main_col

            new_table = np.zeros((self.m, self.n))

            for j in range(self.n):
                new_table[main_row, j] = self.table[main_row, j] / self.table[main_row, main_col]

            for i in range(self.m):
                if i == main_row:
                    continue

                for j in range(self.n):
                    new_table[i, j] = self.table[i, j] - self.table[i, main_col] * new_table[main_row, j]

            self.table = new_table

            counter += 1
            print("Main col: " + str(main_col))
            print("Main row: " + str(main_row))
            print("Basis: ")
            for i in self.basis:
                print(self.basis.index(i), i)
            print(tb.tabulate(self.table))

        for i in range(len(result)):
            k = self.basis.index(i + 1) if i + 1 in self.basis else -1
            result[i] = self.table[k, 0] if k != -1 else 0

        return self.table

    def is_it_end(self):
        return np.all(self.table[self.m - 1, 1:] >= 0)

    def find_main_col(self):
        main_col = 1

        for j in range(2, self.n):
            if self.table[self.m - 1, j] > self.table[self.m - 1, main_col]:
                main_col = j

        return main_col

    def find_main_row(self, main_col):
        main_row = 0

        for i in range(self.m - 1):
            if self.table[i, main_col] > 0:
                main_row = i
                break

        for i in range(main_row + 1, self.m - 1):
            if self.table[i, main_col] > 0 and (self.table[i, 0] / self.table[i, main_col]) < (
                    self.table[main_row, 0] / self.table[main_row, main_col]):
                main_row = i

        return main_row

if __name__ == "__main__":
    table = np.array([[7, 1, 1, 1, -1, 1, 0],
                      [2, 1, -1, 1, -1, 0, -1],
                      [-5, 3, -1, -2, 2, 0, 0],
                      [0, -1, 2, -3, 3, 0, 0]])

    result = np.zeros(6)
    S = Simplex(table)
    table_result = S.calculate(result)

    print("Resulting simplex table")
    print(tb.tabulate(table_result))

    print("\nResult:")
    print(f"X[max] = {result}")
    print(f"F[max] = {-1 * table_result[-1][0]:.2f}")