import os
import tempfile
import logging
import pyqrcode
import time

# Created by Francesco Mangiacrapa
# francesco.mangiacrapa@isti.cnr.it
# ISTI-CNR Pisa (ITALY)

CATALINA_HOME = 'CATALINA_HOME'
log = logging.getLogger(__name__)

temp_dir = None
qr_code_dir = None
qr_code_dir_name = "qr_code_for_catalogue"


class D4S_QrCode():
    def __init__(self, qr_code_url=None):
        self._qr_code_url = qr_code_url
        global temp_dir
        if temp_dir is None:
            D4S_QrCode.init_temp_dir()
            if temp_dir is None:
                raise Exception('No temp directory found!')

    def get_qrcode_path(self):
        image_name = self._qr_code_url.rsplit('/', 1)[-1]
        image_name+=".svg"
        image_path = os.path.join(qr_code_dir, image_name)
        # ONLY IF QRCODE DOES NOT EXIST THEN IT WILL BE CREATED
        if not os.path.isfile(image_path):
            url = pyqrcode.create(self._qr_code_url)
            url.svg(image_path, scale=3)
            log.debug("Created QRCode image: " + image_name)

        attempt = 0
        while not os.path.exists(image_path) and attempt < 3:
            time.sleep(1)
            attempt += 1

        if os.path.isfile(image_path):
            log.info("QRcode image exists at: " + image_path)
        else:
            log.error("%s isn't a file!" % image_path)

        return image_path

    @classmethod
    def init_temp_dir(cls):
        global temp_dir
        global qr_code_dir_name
        global qr_code_dir
        try:
            temp_dir = str(os.environ[CATALINA_HOME])
            temp_dir = os.path.join(temp_dir, "temp")
        except KeyError as error:
            log.error("No environment variable for: %s" % CATALINA_HOME)

        if temp_dir is None:
            temp_dir = tempfile.gettempdir()  # using system tmp dir

        log.debug("Temp dir is: %s" % temp_dir)

        qr_code_dir = os.path.join(temp_dir, qr_code_dir_name)

        if not os.path.exists(qr_code_dir):
            os.makedirs(qr_code_dir)

    def get_temp_directory(self):
        return temp_dir

    def get_qr_code_dir(self):
        return qr_code_dir


# D4S_QrCode.init_temp_dir()
#qr_code = D4S_QrCode("http://data.d4science.org/ctlg/BiodiversityLab/distribution_of_the_giant_squid_architeuthis")
#print qr_code.get_qrcode_path()