# -*- coding: utf-8 -*-
# imageio is distributed under the terms of the (new) BSD License.

""" Plugin for reading gdal files.
"""
from __future__ import absolute_import, print_function, division

from .. import formats
from ..core import Format, has_module

_gdal = None  # lazily loaded in load_lib()


def load_lib():
    global _gdal
    try:
        import osgeo.gdal as _gdal
    except ImportError:
        raise ImportError("The GDAL format relies on the GDAL package."
                          "Please refer to http://www.gdal.org/"
                          "for further instructions.")
    return _gdal


GDAL_FORMATS = ('.tiff', ' .tif', '.img', '.ecw', '.jpg', '.jpeg')


class GdalFormat(Format):

    """

    Parameters for reading
    ----------------------
    None

    """

    def _can_read(self, request):
        if request.extension in ('.ecw', ):
            return True
        if has_module('osgeo.gdal'):
            return request.extension in self.extensions

    def _can_write(self, request):
        return False

    # --

    class Reader(Format.Reader):

        def _open(self):
            if not _gdal:
                load_lib()
            self._ds = _gdal.Open(self.request.get_local_filename())

        def _close(self):
            del self._ds

        def _get_length(self):
            return 1

        def _get_data(self, index):
            if index != 0:
                raise IndexError('Gdal file contains only one dataset')
            return self._ds.ReadAsArray(), self._get_meta_data(index)

        def _get_meta_data(self, index):
            return self._ds.GetMetadata()


# Add this format
formats.add_format(GdalFormat(
    'gdal', 'Geospatial Data Abstraction Library',
    ' '.join(GDAL_FORMATS), 'iIvV'))
