from tkinter import *
from tkinter import messagebox as mb

CANVAS_HEIGHT = 500
CANVAS_WIDTH = 500

points = list()
counter = 0
scale_const_y = 1
scale_const_x = 1

def fill_header():

    Label(info_frame, text='#', relief=SUNKEN, width=5).grid(row=0, column=0)
    Label(info_frame, text='X', relief=SUNKEN, width=5).grid(row=0, column=1)
    Label(info_frame, text='Y', relief=SUNKEN, width=5).grid(row=0, column=2)

def add_point():

    global counter
    changed = False
    x = entry_x.get()
    y = entry_y.get()

    try:
        float(x), float(y)

    except ValueError:
        mb.messagebox("Неверный тип координат точек.")
        return -1

    for i in range(counter):
        if points[i][0] == float(x) and points[i][1] == float(y):
            mb.showerror("Предупреждение", "Эта точка уже была введена.")
            return -2

    fill_table_row(counter, x, y)
    points.append([float(x), float(y)])

    max_x = points[0][0]
    max_y = points[0][1]

    for point in points[1:]:

        max_x = max_x if max_x > abs(point[0]) else abs(point[0])
        max_y = max_y if max_y > abs(point[1]) else abs(point[1])

    max_x = max(max_x, CANVAS_WIDTH)
    max_y = max(max_y, CANVAS_HEIGHT)

    if float(x) > max_x:
        scale_coords(x=x / max_x)
        changed = True

    if float(y) > max_y:
        scale_coords(y=y / max_y)
        changed = True

    if changed:
        redraw_canvas()

    new_coords = transform_coordinates(float(x), float(y))
    canvas.create_oval(new_coords, new_coords[0] + 2, new_coords[1] + 2, fill='green')

    counter += 1

def redraw_canvas():

    canvas.delete("all")
    for point in points:
        canvas.create_oval(point, point)

def find_solution():

    if len(points) < 3:
        mb.showerror("Недостаточно точек для построения решения.")
        return -1

    delta_min = len(points)
    line = None

    for i in range(len(points)):
        for j in range(len(points)):
            delta = 0
            if i != j:
                a = points[i][1] - points[j][1]
                b = points[j][0] - points[i][0]
                c = points[i][0] * points[j][1] - points[j][0] * points[i][1]
                for k in range(len(points)):
                    if k != j and k != i:
                        if a * points[k][0] + b * points[k][1] + c > 0: delta += 1
                        elif a * points[k][0] + b * points[k][1] + c < 0: delta -= 1


                if abs(delta) < delta_min:
                    delta_min = abs(delta)

                    first_point = (- b * CANVAS_WIDTH / 2 - c) / a if a != 0 else points[i][0]
                    second_point = ( b * CANVAS_WIDTH / 2 - c) / a if a != 0 else points[j][0]

                    line = [transform_coordinates(first_point, CANVAS_HEIGHT / 2),
                          transform_coordinates(second_point, - CANVAS_HEIGHT / 2)]

    canvas.delete('line')
    canvas.create_line(line, fill='blue', tag='line')

def transform_coordinates(x, y):

    x = x + CANVAS_WIDTH // 2
    y = -y + CANVAS_HEIGHT // 2

    return [x, y]

def scale_coords(scale_x=scale_const_x, scale_y=scale_const_y):

    global points
    scale_const_x = scale_x
    scale_const_y = scale_y

    for point in points:
        points[0] *= scale_x
        points[1] *= scale_y

def fill_table_row(counter, a, b):

    cols = 3
    table_row = list()
    table_row.append(Label(info_frame,
                           text=str(counter + 1),
                           relief=SUNKEN,
                           width=5))

    table_row.append(Label(info_frame,
                           text=a,
                           relief=SUNKEN,
                           width=5))

    table_row.append(Label(info_frame,
                           text=b,
                           relief=SUNKEN,
                           width=5))

    for j in range(cols):
        table_row[j].grid(row=counter + 1, column=j)


window = Tk()
info_frame = Frame(window)
interface_frame = Frame(window)
canvas = Canvas(window, width=CANVAS_WIDTH, height=CANVAS_HEIGHT)

btn_solute = Button(interface_frame,
                 text="Найти решение:",
                 width=15,
                 command=find_solution).pack()

btn_points = Button(interface_frame,
                 text="Добавить точку:",
                 width=15,
                 command=add_point).pack()

upper_frame = Frame(interface_frame)
bottom_frame = Frame(interface_frame)

label_x = Label(upper_frame, width=6, text='X')
label_y = Label(upper_frame, width=6, text='Y')
entry_x = Entry(bottom_frame, width=6)
entry_y = Entry(bottom_frame, width=6)

label_x.pack(side=LEFT)
label_y.pack(side=RIGHT)
entry_x.pack(side=LEFT)
entry_y.pack(side=RIGHT)
upper_frame.pack()
bottom_frame.pack()

interface_frame.pack(side=LEFT)
canvas.pack(side = RIGHT)
info_frame.pack(side=LEFT)

fill_header()

window.mainloop()