"""$ fio load"""


from functools import partial
import logging

import click
import cligj

import fiona
from fiona.fio import options, with_context_env
from fiona.schema import FIELD_TYPES_MAP_REV
from fiona.transform import transform_geom


def _cb_key_val(ctx, param, value):
    """
    click callback to validate `--opt KEY1=VAL1 --opt KEY2=VAL2` and collect
    in a dictionary like the one below, which is what the CLI function receives.
    If no value or `None` is received then an empty dictionary is returned.

        {
            'KEY1': 'VAL1',
            'KEY2': 'VAL2'
        }

    Note: `==VAL` breaks this as `str.split('=', 1)` is used.

    """
    if not value:
        return {}
    else:
        out = {}
        for pair in value:
            if "=" not in pair:
                raise click.BadParameter(
                    "Invalid syntax for KEY=VAL arg: {}".format(pair)
                )
            else:
                k, v = pair.split("=", 1)
                k = k.lower()
                v = v.lower()
                out[k] = None if v.lower() in ["none", "null", "nil", "nada"] else v
        return out


@click.command(short_help="Load GeoJSON to a dataset in another format.")
@click.argument('output', required=True)
@click.option('-f', '--format', '--driver', 'driver', required=True,
              help="Output format driver name.")
@options.src_crs_opt
@click.option('--dst-crs', '--dst_crs',
              help="Destination CRS.  Defaults to --src-crs when not given.")
@cligj.features_in_arg
@click.option(
    "--layer",
    metavar="INDEX|NAME",
    callback=options.cb_layer,
    help="Load features into specified layer.  Layers use "
    "zero-based numbering when accessed by index.",
)
@click.option(
    "--co",
    "--profile",
    "creation_options",
    metavar="NAME=VALUE",
    multiple=True,
    callback=_cb_key_val,
    help="Driver specific creation options. See the documentation for the selected output driver for more information.",
)
@click.pass_context
@with_context_env
def load(ctx, output, driver, src_crs, dst_crs, features, layer, creation_options):
    """Load features from JSON to a file in another format.

    The input is a GeoJSON feature collection or optionally a sequence of
    GeoJSON feature objects.

    """
    logger = logging.getLogger(__name__)

    dst_crs = dst_crs or src_crs

    if src_crs and dst_crs and src_crs != dst_crs:
        transformer = partial(transform_geom, src_crs, dst_crs,
                              antimeridian_cutting=True, precision=-1)
    else:
        def transformer(x):
            return x

    def feature_gen():
        for feat in features:
            feat['geometry'] = transformer(feat['geometry'])
            yield feat

    try:
        source = feature_gen()

        # Use schema of first feature as a template.
        # TODO: schema specified on command line?
        first = next(source)
        schema = {'geometry': first['geometry']['type']}
        schema['properties'] = dict([
            (k, FIELD_TYPES_MAP_REV.get(type(v)) or 'str')
            for k, v in first['properties'].items()])

        with fiona.open(
            output,
            "w",
            driver=driver,
            crs=dst_crs,
            schema=schema,
            layer=layer,
            **creation_options
        ) as dst:
            dst.write(first)
            dst.writerecords(source)

    except Exception:
        logger.exception("Exception caught during processing")
        raise click.Abort()