#!/usr/bin/env python3
#
# Electron Cash - lightweight Bitcoin client
# Copyright (C) 2019 Axel Gembe <derago@gmail.com>
#
# Permission is hereby granted, free of charge, to any person
# obtaining a copy of this software and associated documentation files
# (the "Software"), to deal in the Software without restriction,
# including without limitation the rights to use, copy, modify, merge,
# publish, distribute, sublicense, and/or sell copies of the Software,
# and to permit persons to whom the Software is furnished to do so,
# subject to the following conditions:
#
# The above copyright notice and this permission notice shall be
# included in all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
# BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
# ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
# CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
# SOFTWARE.

import sys
import ctypes
from enum import IntEnum

from PyQt5.QtMultimedia import QCameraInfo, QCamera, QCameraImageCapture, QVideoFrame, QAbstractVideoBuffer
from PyQt5.QtMultimediaWidgets import QCameraViewfinder
from PyQt5.QtWidgets import QDialog, QVBoxLayout
from PyQt5.QtGui import QImage

from electroncash.i18n import _
from electroncash.util import print_error

if sys.platform == 'darwin':
    name = 'libzbar.dylib'
elif sys.platform in ('windows', 'win32'):
    name = 'libzbar-0.dll'
else:
    name = 'libzbar.so.0'

try:
    libzbar = ctypes.cdll.LoadLibrary(name)
    libzbar.zbar_image_create.restype = ctypes.c_void_p
    libzbar.zbar_image_set_data.argtypes = [ctypes.c_void_p, ctypes.c_void_p, ctypes.c_int]
    libzbar.zbar_image_scanner_create.restype = ctypes.c_void_p
    libzbar.zbar_image_scanner_get_results.restype = ctypes.c_void_p
    libzbar.zbar_symbol_set_first_symbol.restype = ctypes.c_void_p
    libzbar.zbar_symbol_get_data.restype = ctypes.c_void_p
except:
    print_error("Failed to load zbar: {}".format(repr(sys.exc_info()[1])))
    libzbar = None

FOURCC_Y800 = 0x30303859

class ZbarSymbolType(IntEnum):
    EAN2 = 2,
    EAN5 = 5,
    EAN8 = 8,
    UPCE = 9,
    ISBN10 = 10,
    UPCA = 12,
    EAN13 = 13,
    ISBN13 = 14,
    COMPOSITE = 15,
    I25 = 25,
    DATABAR = 34,
    DATABAR_EXP = 35,
    CODABAR = 38,
    CODE39 = 39,
    PDF417 = 57,
    QRCODE = 64,
    SQCODE = 80,
    CODE93 = 93,
    CODE128 = 128

class ZbarConfig(IntEnum):
    ENABLE = 0

class QrCameraDialog(QDialog):
    def __init__(self, parent):
        if libzbar is None:
            raise RuntimeError("Cannot start QR scanner; zbar not available.")

        QDialog.__init__(self, parent=parent)

        self.image_capture = None

        self.setWindowTitle(_("Scan QR Code"))

        vbox = QVBoxLayout()
        self.setLayout(vbox)

        self.viewfinder = QCameraViewfinder()
        vbox.addWidget(self.viewfinder)

        # Set up zbar
        libzbar.zbar_set_verbosity(100)

        self.zbar_image = libzbar.zbar_image_create()
        self.zbar_scanner = libzbar.zbar_image_scanner_create()

        # Disable all symbols
        for sym_type in ZbarSymbolType:
            libzbar.zbar_image_scanner_set_config(self.zbar_scanner, int(sym_type), int(ZbarConfig.ENABLE), 0)

        # Enable only QR codes
        libzbar.zbar_image_scanner_set_config(self.zbar_scanner, int(ZbarSymbolType.QRCODE), int(ZbarConfig.ENABLE), 1)

    def closeEvent(self, e):
        libzbar.zbar_image_scanner_destroy(self.zbar_scanner)
        libzbar.zbar_image_ref(self.zbar_image, -1)

    def scan(self, device=''):
        device_info = None

        for camera in QCameraInfo.availableCameras():
            if camera.deviceName() == device:
                device_info = camera
                break

        if not device_info:
            device_info = QCameraInfo.defaultCamera()

        if not device_info or device_info.isNull():
            # TODO: Error message
            return ''

        camera = QCamera(device_info)
        camera.setViewfinder(self.viewfinder)
        camera.setCaptureMode(QCamera.CaptureStillImage)

        self.image_capture = QCameraImageCapture(camera)
        self.image_capture.setCaptureDestination(QCameraImageCapture.CaptureToBuffer)
        self.image_capture.imageAvailable.connect(self.handle_frame)

        camera.start()

        self.image_capture.capture()

        self.exec()

        camera.stop()

        return ''

    def handle_frame(self, frame_id, frame):
        image_format = QVideoFrame.imageFormatFromPixelFormat(frame.pixelFormat())

        if not frame.map(QAbstractVideoBuffer.ReadOnly):
            # FIXME: Handle
            return

        try:
            if image_format == QImage.Format_Invalid:
                # This frame was a format that can not be converter to an image pixel format
                img = QImage.fromData(frame.bits(), frame.mappedBytes())
            else:
                img = QImage(frame.bits(), frame.width(), frame.height(), image_format).copy()
            img = img.copy()
        finally:
            frame.unmap()

        # Convert to Y800 / GREY FourCC (single 8-bit channel)
        img = img.convertToFormat(QImage.Format_Grayscale8)

        self.handle_image(frame_id, img)

        self.image_capture.capture()

    def handle_image(self, frame_id, image: QImage):
        self.current_image = image
        libzbar.zbar_image_set_sequence(self.zbar_image, frame_id)
        libzbar.zbar_image_set_size(self.zbar_image, image.width(), image.height())
        libzbar.zbar_image_set_format(self.zbar_image, FOURCC_Y800)
        libzbar.zbar_image_set_data(self.zbar_image, image.bits().__int__(), image.byteCount())
        libzbar.zbar_image_scanner_recycle_image(self.zbar_scanner, self.zbar_image)
        libzbar.zbar_scan_image(self.zbar_scanner, self.zbar_image)
        result_set = libzbar.zbar_image_scanner_get_results(self.zbar_scanner)
        libzbar.zbar_image_set_symbols(self.zbar_image, result_set)

        #symbol = libzbar.zbar_symbol_set_first_symbol(result_set)

        detected_symbols = libzbar.zbar_symbol_set_get_size(result_set)
        print_error('detected {} symbol(s) in frame {}'.format(detected_symbols, frame_id))

        #print_error('captured {}'.format(frame_id))