import time, os
from luma.core.interface.serial import i2c
from luma.oled.device import ssd1306
from PIL import Image, ImageDraw, ImageFont

serial = i2c(port=1, address=0x3C)
device = ssd1306(serial)
font = ImageFont.truetype('/usr/share/fonts/truetype/dejavu/DejaVuSans.ttf', 10)
font_big = ImageFont.truetype('/usr/share/fonts/truetype/dejavu/DejaVuSans-Bold.ttf', 16)
device.cleanup = lambda: None


def get_cpu():
    with open('/proc/loadavg') as f:
        parts = f.read().split()
    load = float(parts[0])
    cores = os.cpu_count() or 4
    percent = (load / cores) * 100
    return min(percent, 100), load


def get_ram():
    with open('/proc/meminfo') as f:
        lines = f.readlines()
    mem_total = int([l for l in lines if 'MemTotal' in l][0].split()[1])
    mem_avail = int([l for l in lines if 'MemAvailable' in l][0].split()[1])
    used = mem_total - mem_avail
    return used / mem_total * 100, used // 1024, mem_total // 1024


def get_temp():
    try:
        with open('/sys/class/thermal/thermal_zone0/temp') as f:
            return int(f.read()) / 1000
    except:
        return 0


while True:
    cpu_pct, load = get_cpu()
    ram_pct, used_mb, total_mb = get_ram()
    temp = get_temp()

    img = Image.new('1', device.size, 'black')
    draw = ImageDraw.Draw(img)

    draw.rectangle((0, 0, 127, 63), outline='white', fill='black')

    bar_w = 90
    bar_h = 12

    # CPU bar
    draw.rectangle((32, 4, 32 + bar_w, 4 + bar_h), outline='white', fill='black')
    fill_w = int(bar_w * cpu_pct / 100)
    if fill_w > 0:
        draw.rectangle((32 + 1, 4 + 1, 32 + fill_w, 4 + bar_h - 1), fill='white')
    draw.text((2, 5), 'CPU', font=font, fill='white')
    draw.text((32 + bar_w + 4, 3), f'{cpu_pct:.0f}%', font=font_big, fill='white')
    draw.text((2, 20), f'Load: {load:.2f}', font=font, fill='white')

    # RAM bar
    draw.rectangle((32, 36, 32 + bar_w, 36 + bar_h), outline='white', fill='black')
    fill_w2 = int(bar_w * ram_pct / 100)
    if fill_w2 > 0:
        draw.rectangle((32 + 1, 36 + 1, 32 + fill_w2, 36 + bar_h - 1), fill='white')
    draw.text((2, 38), 'RAM', font=font, fill='white')
    draw.text((32 + bar_w + 4, 36), f'{ram_pct:.0f}%', font=font_big, fill='white')

    # Temp and PID at bottom
    draw.text((2, 52), f'Temp: {temp:.1f}C', font=font, fill='white')
    draw.text((72, 52), f'PID: {os.getpid()}', font=font, fill='white')

    device.display(img)
    time.sleep(1)