# SPDX-FileCopyrightText: 2017 Tony DiCola for Adafruit Industries
# SPDX-FileCopyrightText: 2017 James DeVito for Adafruit Industries
# SPDX-License-Identifier: MIT

# This example is for use on (Linux) computers that are using CPython with
# Adafruit Blinka to support CircuitPython libraries. CircuitPython does
# not support PIL/pillow (python imaging library)!

import time
import subprocess

from board import SCL, SDA
import busio
from PIL import Image, ImageDraw, ImageFont
import adafruit_ssd1306

# Create the I2C interface.
i2c = busio.I2C(SCL, SDA)

# Create the SSD1306 OLED class.
# The first two parameters are the pixel width and pixel height.  Change these
# to the right size for your display!
disp = adafruit_ssd1306.SSD1306_I2C(128, 32, i2c)

# Clear display.
disp.fill(0)
disp.show()

# Adjust contrast between 0 and 255
disp.contrast(20)

# Create blank image for drawing.
# Make sure to create image with mode '1' for 1-bit color.
width = disp.width
height = disp.height
image = Image.new("1", (width, height))

# Get drawing object to draw on image.
draw = ImageDraw.Draw(image)

# Draw a black filled box to clear the image.
draw.rectangle((0, 0, width, height), outline=0, fill=0)

# Draw some shapes.
# First define some constants to allow easy resizing of shapes.
padding = -2
top = padding
bottom = height - padding
# Move left to right keeping track of the current x position for drawing shapes.
x = 0

# Load default font.
font = ImageFont.load_default()

# Alternatively load a TTF font.  Make sure the .ttf font file is in the
# same directory as the python script!
# Some other nice fonts to try: http://www.dafont.com/bitmap.php
# font = ImageFont.truetype('/usr/share/fonts/truetype/dejavu/DejaVuSans.ttf', 9)

while True:
    
    # Draw a black filled box to clear the image.
    draw.rectangle((0,0,width,height), outline=0, fill=0)

    # Shell scripts for system monitoring from here : https://unix.stackexchange.com/questions/119126/command-to-display-memory-usage-disk-usage-and-cpu-load
    cmd = "hostname -i | tr -d '\n'"
    ip = subprocess.check_output(cmd, shell = True )
    cmd = "top -bn1 | grep load | tr ',' '.' | awk '{printf \"Load %.2f\", $(NF-2)}'"
    cpu = subprocess.check_output(cmd, shell = True )
    cmd = "free -m | awk 'NR==2{printf \"%0.2f/%0.2fGB %.1f%%\", $3/1024,$2/1024,$3*100/$2 }'"
    memUsage = subprocess.check_output(cmd, shell = True )
    cmd = "df -h | awk '$NF==\"/\"{printf \"%d/%dGB %s\", $3,$2,$5}'"
    disk = subprocess.check_output(cmd, shell = True )
    cmd = "vcgencmd measure_temp | tr -d '\n' | cut -d'=' -f2"
    temp = subprocess.check_output(cmd, shell = True )

    # Write 4 lines of text.

    draw.text((x, top),    "CPU "+str(cpu.decode())+' '+str(temp.decode()), font=font, fill=255)
    draw.text((x, top+8),  "Mem "+str(memUsage.decode()),  font=font, fill=255)
    draw.text((x, top+16), "Disk "+str(disk.decode()),  font=font, fill=255)
    draw.text((x, top+25), "IP " + str(ip.decode()),  font=font, fill=255)

    # Display image.
    disp.image(image)
    disp.show()
    time.sleep(0.1)