#!/usr/bin/python3.11
# SPDX-License-Identifier: MPL-2.0
"""Narrow stdio-to-socket adapter for the Android CameraService broker."""
import os
import json
import socket
import sys

SOCKET = '/work/camera-ipc/camera.sock'

def read_exact(stream, size):
    data = bytearray()
    while len(data) < size:
        chunk = stream.recv(size - len(data))
        if not chunk:
            raise EOFError('Camera broker closed the session')
        data.extend(chunk)
    return bytes(data)

def forward(sock, target, size):
    header = read_exact(sock, size)
    target.write(header); target.flush()
    return header

def packet(sock, output):
    header = read_exact(sock, 4)
    size = int.from_bytes(header, 'little')
    if size > 65536:
        raise ValueError('Camera broker sent an oversized response')
    payload = read_exact(sock, size)
    output.write(header + payload); output.flush()
    return json.loads(payload.decode('utf-8'))

def main():
    client = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
    client.connect(SOCKET)
    output = os.fdopen(os.dup(1), 'wb', buffering=0)
    try:
        client.sendall(b'start\n')
        header = forward(client, output, 4)
        length = int.from_bytes(header, 'little')
        if not 0 < length <= 65536:
            return 2
        forward(client, output, length)
        while True:
            command = sys.stdin.buffer.readline(2049)
            if not command or len(command) > 2048:
                break
            client.sendall(command)
            if command.strip() == b'frame':
                header = forward(client, output, 8)
                length = int.from_bytes(header[4:], 'little')
                if length > 320 * 240 * 3 // 2:
                    return 3
                if length:
                    forward(client, output, length)
            elif command.strip() == b'stop':
                packet(client, output)
                break
            else:
                response = packet(client, output)
                jpeg = response.get('jpegLength', 0)
                if isinstance(jpeg, int) and 0 < jpeg <= 32 * 1024 * 1024:
                    forward(client, output, jpeg)
    except (BrokenPipeError, ConnectionError, EOFError):
        return 0
    finally:
        client.close(); output.close()
    return 0

if __name__ == '__main__':
    sys.exit(main())