from tkinter import *


class MetricConverter:
    def __init__(self):
        self.valid_conversions = {
            ("cm", "inches"): lambda x: round(x / 2.54, 2),
            ("m", "feet"): lambda x: round(x * 3.28084, 2),
            ("km", "miles"): lambda x: round(x * 0.621371, 2),
        }

        self.from_unit = None
        self.to_unit = None

        self.window = Tk()
        self.window.title("Metric Conversion Tool")

        self.main_frame = Frame(self.window, padx=10, pady=10)
        self.main_frame.grid()

        self.heading = Label(self.main_frame, text="Metric Conversion Tool",
                             font=("Arial", 16, "bold"))
        self.heading.grid(row=0)

        self.instructions = Label(self.main_frame,
                                  text="Enter a value and select FROM and TO units:",
                                  wraplength=300, justify="left")
        self.instructions.grid(row=1)

        self.input_entry = Entry(self.main_frame, font=("Arial", 14))
        self.input_entry.grid(row=2, pady=10)

        # FROM unit buttons
        self.from_label = Label(self.main_frame, text="From:")
        self.from_label.grid(row=3, sticky="w")
        self.from_frame = Frame(self.main_frame)
        self.from_frame.grid(row=4, pady=5)

        self.from_buttons = {}
        for i, unit in enumerate(set(key[0] for key in self.valid_conversions.keys())):
            btn = Button(self.from_frame, text=unit, width=10,
                         command=lambda u=unit: self.select_unit("from", u))
            btn.grid(row=0, column=i, padx=5)
            self.from_buttons[unit] = btn

        # TO unit buttons
        self.to_label = Label(self.main_frame, text="To:")
        self.to_label.grid(row=5, sticky="w")
        self.to_frame = Frame(self.main_frame)
        self.to_frame.grid(row=6, pady=5)

        self.to_buttons = {}
        for i, unit in enumerate(set(key[1] for key in self.valid_conversions.keys())):
            btn = Button(self.to_frame, text=unit, width=10,
                         command=lambda u=unit: self.select_unit("to", u))
            btn.grid(row=0, column=i, padx=5)
            self.to_buttons[unit] = btn

        # Convert button
        self.convert_button = Button(self.main_frame, text="Convert",
                                     command=self.convert_value,
                                     bg="#004C99", fg="white",
                                     font=("Arial", 12, "bold"))
        self.convert_button.grid(row=7, pady=10)

        self.result_label = Label(self.main_frame, text="", font=("Arial", 14, "bold"))
        self.result_label.grid(row=8)

        self.error_label = Label(self.main_frame, text="", fg="red")
        self.error_label.grid(row=9)

        self.window.mainloop()

    def select_unit(self, unit_type, unit):
        if unit_type == "from":
            self.from_unit = unit
            for u, btn in self.from_buttons.items():
                if u == unit:
                    btn.config(relief="sunken", bg="#007ACC", fg="white")
                else:
                    btn.config(relief="raised", bg="SystemButtonFace", fg="black")
        elif unit_type == "to":
            self.to_unit = unit
            for u, btn in self.to_buttons.items():
                if u == unit:
                    btn.config(relief="sunken", bg="#007ACC", fg="white")
                else:
                    btn.config(relief="raised", bg="SystemButtonFace", fg="black")

    def convert_value(self):
        self.error_label.config(text="")
        self.result_label.config(text="")

        if self.from_unit is None or self.to_unit is None:
            self.error_label.config(text="Please select both FROM and TO units.")
            return

        if (self.from_unit, self.to_unit) not in self.valid_conversions:
            self.error_label.config(text=f"Cannot convert from {self.from_unit} to {self.to_unit}.")
            return

        try:
            value = float(self.input_entry.get())
            conversion_func = self.valid_conversions[(self.from_unit, self.to_unit)]
            result = conversion_func(value)
            self.result_label.config(text=f"Result: {result} {self.to_unit}")
        except ValueError:
            self.error_label.config(text="Please enter a valid number.")


if __name__ == "__main__":
    MetricConverter()