# copyright 2003-2015 LOGILAB S.A. (Paris, FRANCE), all rights reserved.

# contact http://www.logilab.fr/ -- mailto:contact@logilab.fr

#

# This file is part of CubicWeb.

#

# CubicWeb is free software: you can redistribute it and/or modify it under the

# terms of the GNU Lesser General Public License as published by the Free

# Software Foundation, either version 2.1 of the License, or (at your option)

# any later version.

#

# CubicWeb is distributed in the hope that it will be useful, but WITHOUT

# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS

# FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public License for more

# details.

#

# You should have received a copy of the GNU Lesser General Public License along

# with CubicWeb.  If not, see <http://www.gnu.org/licenses/>.

"""Functions to help importing CSV data"""

from __future__ import absolute_import, print_function

import codecs

import csv as csvmod

from six import PY2, PY3, string_types

from logilab.common import shellutils

def count_lines(stream_or_filename):

    if isinstance(stream_or_filename, string_types):

        f = open(stream_or_filename)

    else:

        f = stream_or_filename

        f.seek(0)

    i = 0  # useful is f is an empty file

    for i, line in enumerate(f):

        pass

    f.seek(0)

    return i + 1

def ucsvreader_pb(stream_or_path, encoding='utf-8', delimiter=',', quotechar='"',

                  skipfirst=False, withpb=True, skip_empty=True):

    """same as :func:`ucsvreader` but a progress bar is displayed as we iter on rows"""

    if isinstance(stream_or_path, string_types):

        stream = open(stream_or_path, 'rb')

    else:

        stream = stream_or_path

    rowcount = count_lines(stream)

    if skipfirst:

        rowcount -= 1

    if withpb:

        pb = shellutils.ProgressBar(rowcount, 50)

    for urow in ucsvreader(stream, encoding, delimiter, quotechar,

                           skipfirst=skipfirst, skip_empty=skip_empty):

        yield urow

        if withpb:

            pb.update()

    print(' %s rows imported' % rowcount)

def ucsvreader(stream, encoding='utf-8', delimiter=',', quotechar='"',

               skipfirst=False, ignore_errors=False, skip_empty=True):

    """A csv reader that accepts files with any encoding and outputs unicode

    strings

    if skip_empty (the default), lines without any values specified (only

    separators) will be skipped. This is useful for Excel exports which may be

    full of such lines.

    """

    if PY3:

        stream = codecs.getreader(encoding)(stream)

    it = iter(csvmod.reader(stream, delimiter=delimiter, quotechar=quotechar))

    if not ignore_errors:

        if skipfirst:

            next(it)

        for row in it:

            if PY2:

                decoded = [item.decode(encoding) for item in row]

            else:

                decoded = row

            if not skip_empty or any(decoded):

                yield decoded

    else:

        if skipfirst:

            try:

                row = next(it)

            except csvmod.Error:

                pass

        # Safe version, that can cope with error in CSV file

        while True:

            try:

                row = next(it)

            # End of CSV, break

            except StopIteration:

                break

            # Error in CSV, ignore line and continue

            except csvmod.Error:

                continue

            if PY2:

                decoded = [item.decode(encoding) for item in row]

            else:

                decoded = row

            if not skip_empty or any(decoded):

                yield decoded