#!/usr/bin/env python3

# This script can be used together with the virtual_imgdev to simulate an
# image based fingerprint reader.
#
# To use, set the FP_VIRTUAL_IMAGE environment variable for both the
# libfprint using program (e.g. fprintd) and this script.
#
# Usually this would work by adding it into the systemd unit file. The
# best way of doing so is to create
#  /etc/systemd/system/fprintd.service.d/fprintd-test.conf
#
# [Service]
# RuntimeDirectory=fprint
# Environment=FP_VIRTUAL_IMAGE=/run/fprint/virtimg_sock
# Environment=G_MESSAGES_DEBUG=all
# ReadWritePaths=$RUNTIME_DIR
#
# After that run:
#
#   systemctl daemon-reload
#   systemctl restart fprintd.service
#
# You may also need to disable selinux.
#
# Then run this script with e.g.
# FP_VIRTUAL_IMAGE=/run/fprint/virtimg_sock ./sendvirtimg.py prints/whorl.png



import cairo
import sys
import os
import socket
import struct

if len(sys.argv) != 2:
    sys.stderr.write('You need to pass a PNG with an alpha channel!\n')
    sys.exit(1)

# Just copied from the C file, we could also use the introspection data for
# this. Also, most of them do *not* make any sense.
commands = {
    'retry' : struct.pack('ii', -1, 0),
    'retry-too-short' : struct.pack('ii', -1, 1),
    'retry-center-finger' : struct.pack('ii', -1, 2),
    'retry-remove-finger' : struct.pack('ii', -1, 3),

    'error' : struct.pack('ii', -2, 0),
    'error-not-supported' : struct.pack('ii', -2, 1),
    'error-not-open' : struct.pack('ii', -2, 2),
    'error-already-open' : struct.pack('ii', -2, 3),
    'error-busy' : struct.pack('ii', -2, 4),
    'error-proto' : struct.pack('ii', -2, 5),
    'error-data-invalid' : struct.pack('ii', -2, 6),
    'error-data-not-found' : struct.pack('ii', -2, 7),
    'error-data-full' : struct.pack('ii', -2, 8),
}


if sys.argv[1] in commands:
    command = commands[sys.argv[1]]
else:
    png = cairo.ImageSurface.create_from_png(sys.argv[1])

    # Cairo wants 4 byte aligned rows, so just add a few pixel if necessary
    w = png.get_width()
    h = png.get_height()
    w = (w + 3) // 4 * 4
    h = (h + 3) // 4 * 4
    img = cairo.ImageSurface(cairo.Format.A8, w, h)
    cr = cairo.Context(img)

    cr.set_source_rgba(1, 1, 1, 1)
    cr.paint()

    cr.set_source_rgba(0, 0, 0, 0)
    cr.set_operator(cairo.OPERATOR_SOURCE)

    cr.set_source_surface(png)
    cr.paint()

    mem = img.get_data()
    mem = mem.tobytes()
    assert len(mem) == img.get_width() * img.get_height()

    command = struct.pack('ii', img.get_width(), img.get_height())
    command += mem



def write_dbg_img():
    dbg_img_rgb = cairo.ImageSurface(cairo.Format.RGB24, img.get_width(), img.get_height())
    dbg_cr = cairo.Context(dbg_img_rgb)
    dbg_cr.set_source_rgb(0, 0, 0)
    dbg_cr.paint()
    dbg_cr.set_source_rgb(1, 1, 1)
    dbg_cr.mask_surface(img, 0, 0)

    dbg_img_rgb.write_to_png('/tmp/test.png')

#write_dbg_img()

# Send image through socket
sockaddr = os.environ['FP_VIRTUAL_IMAGE']

sock = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
sock.connect(sockaddr)

sock.sendall(command)