#!/usr/bin/env python3
"""
Local camera CORS proxy for OCR app.
Run this script on the computer that accesses the OCR app (same network as camera).
Then paste  http://localhost:8108/snapshot.cgi  into the IP Camera URL field.
"""
import urllib.request, base64
from http.server import HTTPServer, BaseHTTPRequestHandler

CAMERA_IP   = '192.168.1.108'   # camera IP (port 80 for HTTP snapshot/stream)
CAMERA_USER = 'admin'
CAMERA_PASS = 'admin123'
PORT        = 8108

_AUTH = base64.b64encode(f'{CAMERA_USER}:{CAMERA_PASS}'.encode()).decode()


class Proxy(BaseHTTPRequestHandler):

    def _cors(self):
        self.send_header('Access-Control-Allow-Origin', '*')
        self.send_header('Access-Control-Allow-Private-Network', 'true')
        self.send_header('Access-Control-Allow-Methods', 'GET, OPTIONS')
        self.send_header('Access-Control-Allow-Headers', '*')

    def do_OPTIONS(self):
        self.send_response(204)
        self._cors()
        self.end_headers()

    def do_GET(self):
        try:
            url = f'http://{CAMERA_IP}{self.path or "/"}'
            req = urllib.request.Request(url, headers={
                'User-Agent':    'Mozilla/5.0',
                'Authorization': f'Basic {_AUTH}',
            })
            r  = urllib.request.urlopen(req, timeout=6)
            ct = r.headers.get('Content-Type', 'image/jpeg')

            if 'multipart' in ct:
                # MJPEG stream — extract first complete JPEG frame
                raw = b''
                while len(raw) < 600_000:
                    chunk = r.read(65536)
                    if not chunk:
                        break
                    raw += chunk
                    s = raw.find(b'\xff\xd8')
                    if s == -1:
                        continue
                    e = raw.find(b'\xff\xd9', s + 2)
                    if e == -1:
                        continue
                    data = raw[s:e + 2]
                    ct   = 'image/jpeg'
                    self._send(ct, data)
                    return
                self.send_response(502); self._cors(); self.end_headers()
            else:
                data = r.read(2_000_000)
                self._send(ct, data)

        except Exception as ex:
            self.send_response(502)
            self._cors()
            self.end_headers()
            print(f'  Error: {ex}')

    def _send(self, ct, data):
        self.send_response(200)
        self._cors()
        self.send_header('Content-Type', ct)
        self.send_header('Content-Length', str(len(data)))
        self.end_headers()
        self.wfile.write(data)

    def log_message(self, fmt, *args):
        print(f'  {self.address_string()} — {fmt % args}')


print(f'\n  Camera CORS proxy started')
print(f'  Camera : http://{CAMERA_IP}  (user: {CAMERA_USER})')
print(f'  Proxy  : http://localhost:{PORT}')
print(f'\n  Paste into OCR app IP Camera field:')
print(f'    http://localhost:{PORT}/snapshot.cgi')
print(f'  or try:')
print(f'    http://localhost:{PORT}/video\n')
HTTPServer(('0.0.0.0', PORT), Proxy).serve_forever()