"""
Alumno: Nava Villagrana Brian Ulises
No. Control: 19211692
Practica: Menu OLED
"""
from machine import Pin, I2C
from os import listdir
from ssd1306 import SSD1306_I2C
from time import sleep

# I2C variables
id = 0
sda = Pin(0)
scl = Pin(1)
i2c = I2C(id=id, scl=scl, sda=sda)

# Screen Variables
width = 128
height = 64
line = 1
highlight = 1
shift = 0
list_length = 0
total_lines = 6

# create the display
oled = SSD1306_I2C(width=width, height=height, i2c=i2c)
oled.init_display()

# Setup the buttons
button_next = Pin(16, Pin.IN, Pin.PULL_UP)  # Button to navigate to the next item
button_prev = Pin(17, Pin.IN, Pin.PULL_UP)  # Button to navigate to the previous item
button_select = Pin(18, Pin.IN, Pin.PULL_UP)  # Button to select an item

# for tracking the button state
button_down = False

def get_files():
    """ Get a list of Python files in the root folder of the Pico """
    files = listdir()
    menu = []
    for file in files:
        if file.endswith(".py"):
            menu.append(file)
    return menu

def show_menu(menu):
    """ Shows the menu on the screen"""
    global line, highlight, shift, list_length

    # Clear the display
    oled.fill_rect(0, 0, width, height, 0)

    # Shift the list of files so that it shows on the display
    list_length = len(menu)
    short_list = menu[shift:shift + total_lines]

    for idx, item in enumerate(short_list, 1):
        if highlight == idx:
            oled.fill_rect(0, (idx - 1) * 10, width, 10, 1)
            oled.text(">", 0, (idx - 1) * 10, 0)
            oled.text(item, 10, (idx - 1) * 10, 0)
        else:
            oled.text(item, 10, (idx - 1) * 10, 1)
    oled.show()

def launch(filename):
    """ Launch the Python script <filename> """
    global file_list
    # Clear the screen
    oled.fill_rect(0, 0, width, height, 0)
    oled.text("Launching", 1, 10)
    oled.text(filename, 1, 20)
    oled.show()
    sleep(3)
    exec(open(filename).read())
    show_menu(file_list)

# Get the list of Python files and display the menu
file_list = get_files()
show_menu(file_list)

# Repeat forever
while True:
    if button_next.value() == False:
        if highlight < total_lines and highlight < len(file_list) - shift:
            highlight += 1
        elif shift + total_lines < len(file_list):
            shift += 1
        show_menu(file_list)

    if button_prev.value() == False:
        if highlight > 1:
            highlight -= 1
        elif shift > 0:
            shift -= 1
        show_menu(file_list)

    if button_select.value() == False and not button_down:
        button_down = True
        if 0 < highlight <= len(file_list) - shift:
            print("Launching", file_list[highlight - 1 + shift])
            # execute script
            launch(file_list[highlight - 1 + shift])
            print("Returned from launch")

    # Debounce button
    if button_select.value() == True and button_down:
        button_down = False