#!/usr/bin/env python3
#-*- coding:utf-8 -*-

'''
        Autor: Joao Bernardo Vianna
        Data: 12/03/2011
'''

from tkinter import Tk, Frame, Button, Label, Entry, LEFT, TOP, RIGHT
import serial


MAX_NUM = 255
INCREMENTO = 10

porta_serial = '/dev/ttyUSB0'
tempo = 5
taxa = 115200



class Programa:

    def __init__(self, serial_dic):
        self.janela = Tk()
        self.janela.title('Controle de Volume')
        self.janela['padx'] = 60
        self.janela['pady'] = 20

        self.serial_dic = serial_dic
        try:
            self.serial = serial.Serial(**serial_dic)
        except serial.SerialException:
            self.serial = None

        self.fr = Frame(self.janela)
        self.fr.pack()

        if self.serial:
            txt = 'Conectado a '
        else:
            txt = 'Impossivel conectar a '

        txt += self.serial_dic['port']
        Label(self.fr, text=txt+'\n').pack(side=TOP)

        Label(self.fr, text='Volume\n\n').pack(side=TOP)

        fr_caixa = Frame(self.fr)
        fr_caixa.pack(side=TOP)
        self.caixa = Entry(fr_caixa, width=5)
        self.caixa.insert(0, '0')
        self.caixa.pack(side=LEFT)
        Label(fr_caixa, text=' ', font='sans').pack(side=LEFT)
        Button(fr_caixa, text='Enviar', command=self.enviar).pack(side=RIGHT)

        fr_btn = Frame(self.fr)
        fr_btn.pack(side=TOP)
        Label(fr_btn, text='\n').pack(side=TOP)
        Button(fr_btn, text='+', command=self.aumentar, font='sans').pack(side=LEFT)
        Button(fr_btn, text='-', command=self.diminuir, font='sans').pack(side=LEFT)


    def verifica_num(self, valor):
        try:
            num = int(self.caixa.get())
            if num < 0:
                raise ValueError
            return num
        except ValueError:
            return -1


    def enviar(self):
        num = self.verifica_num(self.caixa.get())
        if num > MAX_NUM:
            num = MAX_NUM
        if num < 0:
            num = 0

        self.caixa.delete(0, 1000)
        self.caixa.insert(0, str(num))
        self.envia_serial(num)


    def aumentar(self, direcao=True):
        num = self.verifica_num(self.caixa.get())

        if num >= 0:
            if direcao:
                num += INCREMENTO
            else:
                num -= INCREMENTO
        else:
            num = 0

        if num > MAX_NUM:
            num = MAX_NUM
        if num < 0:
            num = 0

        self.caixa.delete(0, 1000)
        self.caixa.insert(0, str(num))

        self.envia_serial(num)

    def diminuir(self):
        self.aumentar(False)


    def envia_serial(self, valor):
        if self.serial:
            self.serial.write(bytes(str(valor), 'utf8'))

    def executar(self):
        self.janela.mainloop()



if __name__ == '__main__':
    s = {'port': porta_serial, 'baudrate': taxa, 'timeout': tempo}
    Programa(s).executar()