import io
from flask import Flask, Response
from picamera2 import Picamera2
from PIL import Image

WIDTH, HEIGHT = 640, 400

cam = Picamera2()
cam.configure(cam.create_video_configuration(
    main={"size": (WIDTH, HEIGHT), "format": "YUV420"},
    controls={"FrameRate": 30}))
cam.start()

app = Flask(__name__)


def frames():
    while True:
        gray = cam.capture_array("main")[:HEIGHT, :WIDTH]   # Y plane = greyscale image
        buf = io.BytesIO()
        Image.fromarray(gray).save(buf, format="JPEG", quality=70)
        yield b"--frame\r\nContent-Type: image/jpeg\r\n\r\n" + buf.getvalue() + b"\r\n"


@app.route("/")
def index():
    return ('<html><body style="margin:0;background:#111">'
            '<img src="/stream" style="width:100%"></body></html>')


@app.route("/stream")
def stream():
    return Response(frames(), mimetype="multipart/x-mixed-replace; boundary=frame")


if __name__ == "__main__":
    try:
        app.run(host="0.0.0.0", port=8000, threaded=True)
    finally:
        cam.stop()