"""
Sampling functions for space time datasets

Usage:

.. code-block:: python

    import grass.temporal as tgis

    tgis.register_maps_in_space_time_dataset(type, name, maps)

(C) 2012-2013 by the GRASS Development Team
This program is free software under the GNU General Public
License (>=v2). Read the file COPYING that comes with GRASS
for details.

:authors: Soeren Gebbert
"""
from __future__ import print_function
from .core import get_current_mapset, get_tgis_message_interface, SQLDatabaseInterfaceConnection
from .datetime_math import time_delta_to_relative_time
from .factory import dataset_factory


def sample_stds_by_stds_topology(intype, sampletype, inputs, sampler, header,
                                 separator, method, spatial=False,
                                 print_only=True):
    """Sample the input space time datasets with a sample
       space time dataset, return the created map matrix and optionally
       print the result to stdout

        In case multiple maps are located in the current granule,
        the map names are separated by comma.

        In case a layer is present, the names map ids are extended
        in this form: "name:layer@mapset"

        Attention: Do not use the comma as separator for printing

        :param intype: Type of the input space time dataset (strds, stvds or
                       str3ds)
        :param sampletype: Type of the sample space time datasets (strds,
                           stvds or str3ds)
        :param inputs: Name or comma separated names of space time datasets or
                       a list of map names
        :param sampler: Name of a space time dataset used for temporal sampling
        :param header: Set True to print column names
        :param separator: The field separator character between the columns
        :param method: The method to be used for temporal sampling
                       (start,during,contain,overlap,equal) as comma separated
                       string or as a list of methods
        :param spatial: Perform spatial overlapping check
        :param print_only: If set True (default) then the result of the
                           sampling will be printed to stdout, if set to False
                           the resulting map matrix will be returned.

        :return: The map matrix or None if nothing found
    """
    mapset = get_current_mapset()
    msgr = get_tgis_message_interface()

    # Make a method list
    if not issubclass(type(method), type([])):
        method = method.split(",")

    # Split the inputs
    if not issubclass(type(inputs), type([])):
        inputs = inputs.split(",")

    sts = []

    for input in inputs:
        if input.find("@") >= 0:
            id = input
        else:
            id = input + "@" + mapset

        st = dataset_factory(intype, id)
        sts.append(st)

    if sampler.find("@") >= 0:
        sid = sampler
    else:
        sid = sampler + "@" + mapset

    sst = dataset_factory(sampletype, sid)

    dbif = SQLDatabaseInterfaceConnection()
    dbif.connect()

    for st in sts:
        if st.is_in_db(dbif) is False:
            msgr.fatal(_("Dataset <%s> not found in temporal database")
                       % (st.get_id()))
        st.select(dbif)

    if sst.is_in_db(dbif) is False:
        msgr.fatal(_("Dataset <%s> not found in temporal database") % (sid))

    sst.select(dbif)

    if separator is None or separator == "" or separator.find(",") >= 0:
        separator = " | "

    mapmatrizes = []
    for st in sts:
        mapmatrix = st.sample_by_dataset(sst, method, spatial, dbif)
        if mapmatrix and len(mapmatrix) > 0:
            mapmatrizes.append(mapmatrix)

    if len(mapmatrizes) > 0:

        # Simply return the map matrix
        if not print_only:
            dbif.close()
            return mapmatrizes

        if header:
            string = ""
            string += "%s%s" % (sst.get_id(), separator)
            for st in sts:
                string += "%s%s" % (st.get_id(), separator)
            string += "%s%s" % ("start_time", separator)
            string += "%s%s" % ("end_time", separator)
            string += "%s%s" % ("interval_length", separator)
            string += "%s" % ("distance_from_begin")
            print(string)

        first_time, dummy = mapmatrizes[0][0]["granule"].get_temporal_extent_as_tuple()

        for i in range(len(mapmatrizes[0])):
            mapname_list = []
            for mapmatrix in mapmatrizes:
                mapnames = ""
                count = 0
                entry = mapmatrix[i]
                for sample in entry["samples"]:
                    if count == 0:
                        mapnames += str(sample.get_id())
                    else:
                        mapnames += ",%s" % str(sample.get_id())
                    count += 1
                mapname_list.append(mapnames)

            entry = mapmatrizes[0][i]
            map = entry["granule"]

            start, end = map.get_temporal_extent_as_tuple()
            if end:
                delta = end - start
            else:
                delta = None
            delta_first = start - first_time

            if map.is_time_absolute():
                if end:
                    delta = time_delta_to_relative_time(delta)
                delta_first = time_delta_to_relative_time(delta_first)

            string = ""
            string += "%s%s" % (map.get_id(), separator)
            for mapnames in mapname_list:
                string += "%s%s" % (mapnames, separator)
            string += "%s%s" % (start, separator)
            string += "%s%s" % (end, separator)
            string += "%s%s" % (delta, separator)
            string += "%s" % (delta_first)
            print(string)

    dbif.close()
    if len(mapmatrizes) > 0:
        return mapmatrizes

    return None
