"""
Extract functions for space time raster, 3d raster and vector datasets

(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 .core import (
    get_tgis_message_interface,
    get_current_mapset,
    SQLDatabaseInterfaceConnection,
)
from .abstract_map_dataset import AbstractMapDataset
from .open_stds import open_old_stds, check_new_stds, open_new_stds
from .datetime_math import create_suffix_from_datetime
from .datetime_math import create_time_suffix
from .datetime_math import create_numeric_suffix
from multiprocessing import Process
import grass.script as gscript
from grass.exceptions import CalledModuleError

############################################################################


def extract_dataset(
    input,
    output,
    type,
    where,
    expression,
    base,
    time_suffix,
    nprocs=1,
    register_null=False,
    layer=1,
    vtype="point,line,boundary,centroid,area,face",
):
    """Extract a subset of a space time raster, raster3d or vector dataset

    A mapcalc expression can be provided to process the temporal extracted
    maps.
    Mapcalc expressions are supported for raster and raster3d maps.

    :param input: The name of the input space time raster/raster3d dataset
    :param output: The name of the extracted new space time raster/raster3d
                  dataset
    :param type: The type of the dataset: "raster", "raster3d" or vector
    :param where: The temporal SQL WHERE statement for subset extraction
    :param expression: The r(3).mapcalc expression or the v.extract where
                      statement
    :param base: The base name of the new created maps in case a mapclac
                expression is provided
    :param time_suffix: string to choose which suffix to use: gran, time, num%*
                       (where * are digits)
    :param nprocs: The number of parallel processes to be used for mapcalc
                  processing
    :param register_null: Set this number True to register empty maps
                         (only raster and raster3d maps)
    :param layer: The vector layer number to be used when no timestamped
           layer is present, default is 1
    :param vtype: The feature type to be extracted for vector maps, default
           is point,line,boundary,centroid,area and face
    """

    # Check the parameters
    msgr = get_tgis_message_interface()

    if expression and not base:
        msgr.fatal(_("You need to specify the base name of new created maps"))

    mapset = get_current_mapset()

    dbif = SQLDatabaseInterfaceConnection()
    dbif.connect()

    sp = open_old_stds(input, type, dbif)
    # Check the new stds
    new_sp = check_new_stds(output, type, dbif, gscript.overwrite())
    if type == "vector":
        rows = sp.get_registered_maps("id,name,mapset,layer", where, "start_time", dbif)
    else:
        rows = sp.get_registered_maps("id", where, "start_time", dbif)

    new_maps = {}
    if rows:
        num_rows = len(rows)

        msgr.percent(0, num_rows, 1)

        # Run the mapcalc expression
        if expression:
            count = 0
            proc_count = 0
            proc_list = []

            for row in rows:
                count += 1

                if count % 10 == 0:
                    msgr.percent(count, num_rows, 1)

                if sp.get_temporal_type() == "absolute" and time_suffix == "gran":
                    old_map = sp.get_new_map_instance(row["id"])
                    old_map.select(dbif)
                    suffix = create_suffix_from_datetime(
                        old_map.temporal_extent.get_start_time(), sp.get_granularity()
                    )
                    map_name = "{ba}_{su}".format(ba=base, su=suffix)
                elif sp.get_temporal_type() == "absolute" and time_suffix == "time":
                    old_map = sp.get_new_map_instance(row["id"])
                    old_map.select(dbif)
                    suffix = create_time_suffix(old_map)
                    map_name = "{ba}_{su}".format(ba=base, su=suffix)
                else:
                    map_name = create_numeric_suffix(base, count, time_suffix)

                # We need to modify the r(3).mapcalc expression
                if type != "vector":
                    expr = expression
                    expr = expr.replace(sp.base.get_map_id(), row["id"])
                    expr = expr.replace(sp.base.get_name(), row["id"])

                    expr = "%s = %s" % (map_name, expr)

                    # We need to build the id
                    map_id = AbstractMapDataset.build_id(map_name, mapset)
                else:
                    map_id = AbstractMapDataset.build_id(map_name, mapset, row["layer"])

                new_map = sp.get_new_map_instance(map_id)

                # Check if new map is in the temporal database
                if new_map.is_in_db(dbif):
                    if gscript.overwrite():
                        # Remove the existing temporal database entry
                        new_map.delete(dbif)
                        new_map = sp.get_new_map_instance(map_id)
                    else:
                        msgr.error(
                            _(
                                "Map <%s> is already in temporal database"
                                ", use overwrite flag to overwrite"
                            )
                            % (new_map.get_map_id())
                        )
                        continue

                # Add process to the process list
                if type == "raster":
                    msgr.verbose(_('Applying r.mapcalc expression: "%s"') % expr)
                    proc_list.append(Process(target=run_mapcalc2d, args=(expr,)))
                elif type == "raster3d":
                    msgr.verbose(_('Applying r3.mapcalc expression: "%s"') % expr)
                    proc_list.append(Process(target=run_mapcalc3d, args=(expr,)))
                elif type == "vector":
                    msgr.verbose(
                        _('Applying v.extract where statement: "%s"') % expression
                    )
                    if row["layer"]:
                        proc_list.append(
                            Process(
                                target=run_vector_extraction,
                                args=(
                                    row["name"] + "@" + row["mapset"],
                                    map_name,
                                    row["layer"],
                                    vtype,
                                    expression,
                                ),
                            )
                        )
                    else:
                        proc_list.append(
                            Process(
                                target=run_vector_extraction,
                                args=(
                                    row["name"] + "@" + row["mapset"],
                                    map_name,
                                    layer,
                                    vtype,
                                    expression,
                                ),
                            )
                        )

                proc_list[proc_count].start()
                proc_count += 1

                # Join processes if the maximum number of processes are
                # reached or the end of the loop is reached
                if proc_count == nprocs or count == num_rows:
                    proc_count = 0
                    exitcodes = 0
                    for proc in proc_list:
                        proc.join()
                        exitcodes += proc.exitcode
                    if exitcodes != 0:
                        dbif.close()
                        msgr.fatal(_("Error in computation process"))

                    # Empty process list
                    proc_list = []

                # Store the new maps
                new_maps[row["id"]] = new_map

        msgr.percent(0, num_rows, 1)

        temporal_type, semantic_type, title, description = sp.get_initial_values()
        new_sp = open_new_stds(
            output,
            type,
            sp.get_temporal_type(),
            title,
            description,
            semantic_type,
            dbif,
            gscript.overwrite(),
        )

        # collect empty maps to remove them
        empty_maps = []

        # Register the maps in the database
        count = 0
        for row in rows:
            count += 1

            if count % 10 == 0:
                msgr.percent(count, num_rows, 1)

            old_map = sp.get_new_map_instance(row["id"])
            old_map.select(dbif)

            if expression:
                # Register the new maps
                if row["id"] in new_maps:
                    new_map = new_maps[row["id"]]

                    # Read the raster map data
                    new_map.load()

                    # In case of a empty map continue, do not register empty
                    # maps
                    if type == "raster" or type == "raster3d":
                        if (
                            new_map.metadata.get_min() is None
                            and new_map.metadata.get_max() is None
                        ):
                            if not register_null:
                                empty_maps.append(new_map)
                                continue
                    elif type == "vector":
                        if (
                            new_map.metadata.get_number_of_primitives() == 0
                            or new_map.metadata.get_number_of_primitives() is None
                        ):
                            if not register_null:
                                empty_maps.append(new_map)
                                continue

                    # Set the time stamp
                    new_map.set_temporal_extent(old_map.get_temporal_extent())

                    if type == "raster":
                        # Set the semantic label
                        semantic_label = old_map.metadata.get_semantic_label()
                        if semantic_label is not None:
                            new_map.set_semantic_label(semantic_label)

                    # Insert map in temporal database
                    new_map.insert(dbif)

                    new_sp.register_map(new_map, dbif)
            else:
                new_sp.register_map(old_map, dbif)

        # Update the spatio-temporal extent and the metadata table entries
        new_sp.update_from_registered_maps(dbif)

        msgr.percent(num_rows, num_rows, 1)

        # Remove empty maps
        if len(empty_maps) > 0:
            names = ""
            count = 0
            for map in empty_maps:
                if count == 0:
                    names += "%s" % (map.get_name())
                else:
                    names += ",%s" % (map.get_name())
                count += 1
            if type == "raster":
                gscript.run_command(
                    "g.remove", flags="f", type="raster", name=names, quiet=True
                )
            elif type == "raster3d":
                gscript.run_command(
                    "g.remove", flags="f", type="raster_3d", name=names, quiet=True
                )
            elif type == "vector":
                gscript.run_command(
                    "g.remove", flags="f", type="vector", name=names, quiet=True
                )

    dbif.close()


###############################################################################


def run_mapcalc2d(expr):
    """Helper function to run r.mapcalc in parallel"""
    try:
        gscript.run_command(
            "r.mapcalc", expression=expr, overwrite=gscript.overwrite(), quiet=True
        )
    except CalledModuleError:
        exit(1)


def run_mapcalc3d(expr):
    """Helper function to run r3.mapcalc in parallel"""
    try:
        gscript.run_command(
            "r3.mapcalc", expression=expr, overwrite=gscript.overwrite(), quiet=True
        )
    except CalledModuleError:
        exit(1)


def run_vector_extraction(input, output, layer, type, where):
    """Helper function to run r.mapcalc in parallel"""
    try:
        gscript.run_command(
            "v.extract",
            input=input,
            output=output,
            layer=layer,
            type=type,
            where=where,
            overwrite=gscript.overwrite(),
            quiet=True,
        )
    except CalledModuleError:
        exit(1)