#!/usr/bin/python3

#----------------------------------------------------------------------
# Backend utilities for the Klimatanalys Norr project (import source layers)
# Copyright © 2024-2025 Guilhem Moulin <info@guilhem.se>
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program 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 General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <https://www.gnu.org/licenses/>.
#----------------------------------------------------------------------

# pylint: disable=invalid-name, missing-module-docstring, fixme

import logging
import tempfile
import re
from fnmatch import fnmatchcase
from pathlib import Path
from typing import Any, Optional

from osgeo import gdal, ogr, osr
from osgeo.gdalconst import (
    OF_ALL as GDAL_OF_ALL,
    OF_READONLY as GDAL_OF_READONLY,
    OF_UPDATE as GDAL_OF_UPDATE,
    OF_VERBOSE_ERROR as GDAL_OF_VERBOSE_ERROR,
    DCAP_CREATE as GDAL_DCAP_CREATE,
)
from osgeo import gdalconst

from common import BadConfiguration, escape_identifier, escape_literal_str
from common_gdal import gdalSetOpenExArgs, gdalGetMetadataItem, formatTZFlag

def openOutputDS(def_dict : dict[str, Any]) -> gdal.Dataset:
    """Open and return the output DS.  It is created if create=False or
    create-options is a non-empty dictionary."""

    path = def_dict['path']
    kwargs, drv = gdalSetOpenExArgs(def_dict, flags=GDAL_OF_UPDATE|GDAL_OF_VERBOSE_ERROR)
    try:
        logging.debug('OpenEx(%s, %s)', path, str(kwargs))
        return gdal.OpenEx(path, **kwargs)
    except RuntimeError as e:
        if not (gdal.GetLastErrorType() >= gdalconst.CE_Failure and
                gdal.GetLastErrorNo() == gdalconst.CPLE_OpenFailed):
            # not an open error
            raise e

        dso2 = None
        try:
            dso2 = gdal.OpenEx(path, nOpenFlags=GDAL_OF_ALL | GDAL_OF_UPDATE)
        except RuntimeError:
            pass
        if dso2 is not None:
            # path exists but can't be open with OpenEx(path, **kwargs)
            raise e

        try:
            dso2 = gdal.OpenEx(path, nOpenFlags=GDAL_OF_ALL)
        except RuntimeError:
            pass
        if dso2 is not None:
            # path exists but can't be open with OpenEx(path, **kwargs)
            raise e

        dsco = def_dict.get('create-options', None)
        if not def_dict.get('create', False) and dsco is None:
            # not configured for creation
            raise e
        if drv is None or not gdalGetMetadataItem(drv, GDAL_DCAP_CREATE):
            # not capable of creation
            raise e

    if 'open_options' in kwargs:
        # like ogr2ogr(1)
        logging.warning('Destination\'s open options ignored '
                        'when creating the output datasource')

    kwargs2 = { 'eType': gdalconst.GDT_Unknown }
    if dsco is not None:
        kwargs2['options'] = [ k + '=' + str(v) for k, v in dsco.items() ]

    logging.debug('Create(%s, %s, eType=%s%s)', drv.ShortName, path, kwargs2['eType'],
                  ', options=' + str(kwargs2['options']) if 'options' in kwargs2 else '')
    # XXX racy, a GDAL equivalent of O_EXCL would be nice
    return drv.Create(path, 0, 0, 0, **kwargs2)

def createOutputLayer(ds : gdal.Dataset,
                      layername : str,
                      srs : Optional[osr.SpatialReference] = None,
                      options : dict[str, Any]|None = None) -> ogr.Layer:
    """Create output layer."""

    if options is None or len(options) < 1:
        raise BadConfiguration(f'Missing schema for new output layer "{layername}"')

    logging.info('Creating new destination layer "%s"', layername)
    geom_type = options['geometry-type']
    lco = options.get('options', None)

    drv = ds.GetDriver()
    if geom_type != ogr.wkbNone and drv.ShortName == 'PostgreSQL':
        # “Important to set to 2 for 2D layers as it has constraints on the geometry
        # dimension during loading.”
        # — https://gdal.org/drivers/vector/pg.html#layer-creation-options
        if ogr.GT_HasM(geom_type):
            if ogr.GT_HasZ(geom_type):
                dim = 'XYZM'
            else:
                dim = 'XYM'
        elif ogr.GT_HasZ(geom_type):
            dim = '3'
        else:
            dim = '2'
        if lco is None:
            lco = []
        lco = ['dim=' + dim] + lco # prepend dim=

    kwargs = { 'geom_type': geom_type }
    if srs is not None:
        kwargs['srs'] = srs
    if lco is not None:
        kwargs['options'] = lco
    logging.debug('CreateLayer(%s, geom_type="%s"%s%s)', layername,
        ogr.GeometryTypeToName(geom_type),
        ', srs="' + kwargs['srs'].GetName() + '"' if 'srs' in kwargs else '',
        ', options=' + str(kwargs['options']) if 'options' in kwargs else '')
    lyr = ds.CreateLayer(layername, **kwargs)
    if lyr is None:
        raise RuntimeError(f'Could not create destination layer "{layername}"')
    # TODO use CreateLayerFromGeomFieldDefn() from ≥v3.9 as it's not
    # possible to toggle the geomfield's nullable property after fact
    # otherwise

    fields = options['fields']
    if len(fields) > 0 and not lyr.TestCapability(ogr.OLCCreateField):
        raise RuntimeError(f'Destination layer "{layername}" lacks field creation capability')

    # set up output schema
    for fld in fields:
        fldName = fld['Name']
        defn = ogr.FieldDefn()
        defn.SetName(fldName)

        if 'AlternativeName' in fld:
            v = fld['AlternativeName']
            logging.debug('Set AlternativeName="%s" on output field "%s"', str(v), fldName)
            defn.SetAlternativeName(v)

        if 'Comment' in fld:
            v = fld['Comment']
            logging.debug('Set Comment="%s" on output field "%s"', str(v), fldName)
            defn.SetComment(v)

        if 'Type' in fld:
            v = fld['Type']
            logging.debug('Set Type=%d (%s) on output field "%s"',
                v, ogr.GetFieldTypeName(v), fldName)
            defn.SetType(v)

        if 'SubType' in fld:
            v = fld['SubType']
            logging.debug('Set SubType=%d (%s) on output field "%s"',
                v, ogr.GetFieldSubTypeName(v), fldName)
            defn.SetSubType(v)

        if 'TZFlag' in fld:
            v = fld['TZFlag']
            logging.debug('Set TZFlag=%d (%s) on output field "%s"',
                v, formatTZFlag(v), fldName)
            defn.SetTZFlag(v)

        if 'Precision' in fld:
            v = fld['Precision']
            logging.debug('Set Precision=%d on output field "%s"', v, fldName)
            defn.SetPrecision(v)

        if 'Width' in fld:
            v = fld['Width']
            logging.debug('Set Width=%d on output field "%s"', v, fldName)
            defn.SetWidth(v)

        if 'Default' in fld:
            v = fld['Default']
            logging.debug('Set Default=%s on output field "%s"', v, fldName)
            defn.SetDefault(v)

        if 'Nullable' in fld:
            v = fld['Nullable']
            logging.debug('Set Nullable=%s on output field "%s"', v, fldName)
            defn.SetNullable(v)

        if 'Unique' in fld:
            v = fld['Unique']
            logging.debug('Set Unique=%s on output field "%s"', v, fldName)
            defn.SetUnique(v)

        if lyr.CreateField(defn, approx_ok=False) != gdalconst.CE_None:
            raise RuntimeError('Could not create field "{fldName}"')
        logging.debug('Added field "%s" to output layer "%s"', fldName, layername)

    # sync before calling StartTransaction() so we're not trying to rollback changes
    # on a non-existing table
    lyr.SyncToDisk()
    return lyr

# pylint: disable-next=too-many-branches
def validateOutputLayer(lyr : ogr.Layer,
                        srs : Optional[osr.SpatialReference] = None,
                        options : Optional[dict[str, Any]] = None) -> bool:
    """Validate the output layer against the provided SRS and creation options."""
    ok = True

    # ensure the output SRS is equivalent
    if srs is not None:
        srs2 = lyr.GetSpatialRef()
        # cf. apps/ogr2ogr_lib.cpp
        srs_options = [
            'IGNORE_DATA_AXIS_TO_SRS_AXIS_MAPPING=YES',
            'CRITERION=EQUIVALENT'
        ]
        if not srs.IsSame(srs2, srs_options):
            logging.warning('Output layer "%s" has SRS %s,\nexpected %s',
                lyr.GetName(),
                srs2.ExportToPrettyWkt(),
                srs.ExportToPrettyWkt())
            ok = False

    if options is None:
        return ok

    layerDefn = lyr.GetLayerDefn()
    n = layerDefn.GetGeomFieldCount()
    if n != 1:
        logging.warning('Output layer "%s" has %d != 1 geometry fields', lyr.GetName(), n)

    geom_type1 = lyr.GetGeomType()
    geom_type2 = options['geometry-type']
    if geom_type1 != geom_type2:
        logging.warning('Output layer "%s" has geometry type #%d (%s), expected #%d (%s)',
            lyr.GetName(),
            geom_type1, ogr.GeometryTypeToName(geom_type1),
            geom_type2, ogr.GeometryTypeToName(geom_type2))
        ok = False

    fields = options.get('fields', None)
    if fields is not None:
        for fld in fields:
            fldName = fld['Name']

            idx = layerDefn.GetFieldIndex(fldName)
            if idx < 0:
                logging.warning('Output layer "%s" has no field named "%s"',
                    lyr.GetName(), fldName)
                ok = False
                continue
            defn = layerDefn.GetFieldDefn(idx)

            if 'AlternativeName' in fld:
                v1 = defn.GetAlternativeName()
                v2 = fld['AlternativeName']
                if v1 != v2:
                    logging.warning('Field "%s" has AlternativeName="%s", expected "%s"',
                        fldName, v1, v2)
                    ok = False

            if 'Comment' in fld:
                v1 = defn.GetComment()
                v2 = fld['Comment']
                if v1 != v2:
                    logging.warning('Field "%s" has Comment="%s", expected "%s"',
                        fldName, v1, v2)
                    ok = False

            if 'Type' in fld:
                v1 = defn.GetType()
                v2 = fld['Type']
                if v1 != v2:
                    logging.warning('Field "%s" has Type=%d (%s), expected %d (%s)',
                        fldName,
                        v1, ogr.GetFieldTypeName(v1),
                        v2, ogr.GetFieldTypeName(v2))
                    ok = False

            if 'SubType' in fld:
                v1 = defn.GetSubType()
                v2 = fld['SubType']
                if v1 != v2:
                    logging.warning('Field "%s" has SubType=%d (%s), expected %d (%s)',
                        fldName,
                        v1, ogr.GetFieldSubTypeName(v1),
                        v2, ogr.GetFieldSubTypeName(v2))
                    ok = False

            if 'TZFlag' in fld:
                v1 = defn.GetTZFlag()
                v2 = fld['TZFlag']
                if v1 != v2:
                    logging.warning('Field "%s" has TZFlag=%d (%s), expected %d (%s)',
                        fldName, v1, formatTZFlag(v1), v2, formatTZFlag(v2))
                    ok = False

            if 'Precision' in fld:
                v1 = defn.GetPrecision()
                v2 = fld['Precision']
                if v1 != v2:
                    logging.warning('Field "%s" has Precision=%d, expected %d',
                        fldName, v1, v2)
                    ok = False

            if 'Width' in fld:
                v1 = defn.GetWidth()
                v2 = fld['Width']
                if v1 != v2:
                    logging.warning('Field "%s" has Width=%d, expected %d',
                        fldName, v1, v2)
                    ok = False

            if 'Default' in fld:
                v1 = defn.GetDefault()
                v2 = fld['Default']
                if v1 != v2:
                    logging.warning('Field "%s" has Default="%s", expected "%s"',
                        fldName, v1, v2)
                    ok = False

            if 'Nullable' in fld:
                v1 = bool(defn.IsNullable())
                v2 = fld['Nullable']
                if v1 != v2:
                    logging.warning('Field "%s" has Nullable=%s, expected %s',
                        fldName, v1, v2)
                    ok = False

            if 'Unique' in fld:
                v1 = bool(defn.IsUnique())
                v2 = fld['Unique']
                if v1 != v2:
                    logging.warning('Field "%s" has Unique=%s, expected %s',
                        fldName, v1, v2)
                    ok = False

    return ok

def clearLayer(ds : gdal.Dataset, lyr : ogr.Layer) -> None:
    """Clear the given layer (wipe all its features)"""
    n = -1
    if lyr.TestCapability(ogr.OLCFastFeatureCount):
        n = lyr.GetFeatureCount(force=0)
        if n == 0:
            # nothing to clear, we're good
            return
    layername_esc = escape_identifier(lyr.GetName())

    # XXX GDAL <3.9 doesn't have lyr.GetDataset() so we pass the DS along with the layer
    drv = ds.GetDriver()
    if drv.ShortName == 'PostgreSQL':
        # https://www.postgresql.org/docs/15/sql-truncate.html
        query = 'TRUNCATE TABLE {table} CONTINUE IDENTITY RESTRICT'
        op = 'Truncating'
    else:
        query = 'DELETE FROM {table}'
        op = 'Clearing'
    logging.info('%s table %s (former feature count: %s)', op,
        layername_esc, str(n) if n >= 0 else 'unknown')
    ds.ExecuteSQL(query.format(table=layername_esc))

def extractArchive(path : Path, destdir : str,
                   fmt : str|None = None,
                   patterns : list[str]|None = None,
                   exact_matches : list[str]|None = None) -> None:
    """Extract an archive file into the given destination directory."""
    if fmt is None:
        suffix = path.suffix
        if suffix is None or suffix == '' or not suffix.startswith('.'):
            raise RuntimeError(f'Could not infer archive format from "{path}"')
        fmt = suffix.removeprefix('.')

    fmt = fmt.lower()
    logging.debug('Unpacking %s archive %s into %s', fmt, path, destdir)

    if fmt == 'zip':
        import zipfile # pylint: disable=import-outside-toplevel
        logging.debug('Opening %s as ZipFile', path)
        with zipfile.ZipFile(path, mode='r') as z:
            namelist = listArchiveMembers(z.namelist(),
                                          patterns=patterns,
                                          exact_matches=exact_matches)
            z.extractall(path=destdir, members=namelist)
    else:
        raise RuntimeError(f'Unknown archive format "{fmt}"')

def listArchiveMembers(namelist : list[str],
                       patterns : list[str]|None = None,
                       exact_matches : list[str]|None = None) -> list[str]:
    """List archive members matching the given parterns and/or exact matches."""
    if patterns is None and exact_matches is None:
        # if neither patterns nor exact_matches are given we'll extract the entire archive
        return namelist
    if patterns is None:
        patterns = []
    if exact_matches is None:
        exact_matches = []

    members = []
    for name in namelist:
        ok = False
        if name in exact_matches:
            # try exact matches first
            logging.debug('Listed archive member %s (exact match)', name)
            members.append(name)
            ok = True
            continue
        # if there are no exact matches, try patterns one by one in the supplied order
        for pat in patterns:
            if fnmatchcase(name, pat):
                logging.debug('Listed archive member %s (matching pattern "%s")', name, pat)
                members.append(name)
                ok = True
                break
        if not ok:
            logging.debug('Ignoring archive member %s', name)
    return members

def getSourceCacheKey(source : dict[str,Any]) -> tuple[str,str,str]:
    """Get the unique triplet (source_path, archive_member, layername)
    for the layer source which can be used for attribute filters and
    lookups."""
    importdef = source['import']
    sourcedef = source['source']
    source_path = sourcedef['path']
    archive_member = importdef['path'] if sourcedef.get('unar', None) is not None else ''
    layername = importdef.get('layername', '')
    return (source_path, archive_member, layername)

# pylint: disable-next=dangerous-default-value
def importSources(lyr_dst : ogr.Layer,
                  dso : gdal.Dataset,
                  sources : dict[str,Any] = {},
                  cachedir : Path|None = None,
                  mtimes : dict[str, int|None]|None = None,
                  lyr_sourcecache : ogr.Layer|None = None,
                  extent : ogr.Geometry|None = None) -> bool:
    """Import source layers."""
    bChanged = False
    for source in sources:
        _importSource(lyr_dst, **source['source'],
                      args=source['import'],
                      cachedir=cachedir,
                      extent=extent)

        # force the PG driver to call EndCopy() to detect errors and trigger a rollback if needed
        # TODO [3.9] use lyr_dst.GetDataset().FlushCache() instead
        dso.FlushCache()

        if lyr_sourcecache is None:
            bChanged = True
            continue

        source_path, archive_member, layername = getSourceCacheKey(source)
        attributeFilter = ('(source_path,archive_member,layername) = ('
                              + escape_literal_str(source_path) + ','
                              + escape_literal_str(archive_member) + ','
                              + escape_literal_str(layername) + ')')
        lyr_sourcecache.SetAttributeFilter(attributeFilter)

        feature = lyr_sourcecache.GetNextFeature()
        if feature is not None:
            logging.debug('Updating existing feature in source cache for %s', attributeFilter)
            update = True
            assert lyr_sourcecache.GetNextFeature() is None
        else:
            logging.debug('Creating new feature in source cache for %s', attributeFilter)
            update = False
            feature = ogr.Feature(lyr_sourcecache.GetLayerDefn())
            feature.SetFieldString(0, source_path)
            feature.SetFieldString(1, archive_member)
            feature.SetFieldString(2, layername)

        mtime_ns = mtimes[source_path]
        if mtime_ns is None:
            feature.SetFieldNull(3)
        else:
            feature.SetFieldInteger64(3, mtime_ns)

        if update:
            # TODO with gdal 3.7 and OLCUpdateFeature capability, use UpdateFeature() instead
            if lyr_sourcecache.SetFeature(feature) != ogr.OGRERR_NONE:
                raise RuntimeError('Could not update feature in sourcecache')
        else:
            if lyr_sourcecache.CreateFeature(feature) != ogr.OGRERR_NONE:
                raise RuntimeError('Could not create new feature in sourcecache')

        # TODO [3.9] use lyr_sourcecache.GetDataset().FlushCache() instead
        dso.FlushCache()
        bChanged = True # TODO fingerprint the features to detect changes

    return bChanged

# pylint: disable-next=dangerous-default-value
def _importSource(lyr : ogr.Layer,
                  path : str = '/nonexistent',
                  unar : dict[str,Any]|None = None,
                  args : dict[str,Any] = {},
                  cachedir : Path|None = None,
                  extent : ogr.Geometry|None = None) -> None:
    """Import a source layer"""
    if unar is None:
        return _importSource2(lyr, path, args=args,
                              basedir=cachedir, extent=extent)

    ds_srcpath = Path(args['path'])
    if ds_srcpath.is_absolute():
        # treat absolute paths as relative to the archive root
        logging.warning('%s is absolute, removing leading anchor', ds_srcpath)
        ds_srcpath = ds_srcpath.relative_to(ds_srcpath.anchor)

    ds_srcpath = str(ds_srcpath)
    with tempfile.TemporaryDirectory() as tmpdir:
        logging.debug('Created temporary directory %s', tmpdir)
        extractArchive(Path(path) if cachedir is None else cachedir.joinpath(path),
                       tmpdir,
                       fmt=unar.get('format', None),
                       patterns=unar.get('patterns', None),
                       exact_matches=[ds_srcpath])
        return _importSource2(lyr, ds_srcpath, args=args,
                              basedir=Path(tmpdir), extent=extent)

def setFieldMapValue(fld : ogr.FieldDefn,
                     idx : int,
                     val : None|int|str|bytes|float) -> None|int|str|bytes|float:
    """Validate field value mapping."""
    if val is None:
        if not fld.IsNullable():
            logging.warning('Field "%s" is not NULLable but remaps NULL', fld.GetName())
        return None

    fldType = fld.GetType()
    if fldType in (ogr.OFTInteger, ogr.OFTInteger64):
        if isinstance(val, int):
            return val
    elif fldType == ogr.OFTString:
        if isinstance(val, str):
            return val
    elif fldType == ogr.OFTBinary:
        if isinstance(val, bytes):
            return val
    elif fldType == ogr.OFTReal:
        if isinstance(val, int):
            return float(val)
        if isinstance(val, float):
            return val

    raise RuntimeError(f'Field "{fld.GetName()}" mapping #{idx} has incompatible type '
                       f'for {ogr.GetFieldTypeName(fldType)}')

# pylint: disable-next=too-many-branches, too-many-locals, too-many-statements
def _importSource2(lyr_dst : ogr.Layer, path : str, args : dict[str,Any],
                   basedir : Path|None, extent : ogr.Geometry|None) -> None:
    """Import a source layer (already extracted)
    This is more or less like ogr2ogr/GDALVectorTranslate() but we roll
    out our own (slower) version because GDALVectorTranslate() insists in
    calling StartTransaction() https://github.com/OSGeo/gdal/issues/3403
    while we want a single transaction for the entire desination layer,
    including truncation, source imports, and metadata changes."""
    kwargs, _ = gdalSetOpenExArgs(args, flags=GDAL_OF_READONLY|GDAL_OF_VERBOSE_ERROR)
    path2 = path if basedir is None else str(basedir.joinpath(path))

    logging.debug('OpenEx(%s, %s)', path2, str(kwargs))
    ds = gdal.OpenEx(path2, **kwargs)
    if ds is None:
        raise RuntimeError(f'Could not open {path2}')

    layername = args.get('layername', None)
    if layername is None:
        idx = 0
        lyr = ds.GetLayerByIndex(idx)
        msg = '#' + str(idx)
        if lyr is not None:
            layername = lyr.GetName()
            msg += ' ("' + layername + '")'
    else:
        lyr = ds.GetLayerByName(layername)
        msg = '"' + layername + '"'
    if lyr is None:
        raise RuntimeError(f'Could not get requested layer {msg} from {path2}')

    logging.info('Importing layer %s from "%s"', msg, path)
    canIgnoreFields = lyr.TestCapability(ogr.OLCIgnoreFields)

    srs = lyr.GetSpatialRef()
    if srs is None:
        raise RuntimeError('Source layer has no SRS')

    srs_dst = lyr_dst.GetSpatialRef()
    if srs_dst is None:
        logging.warning('Destination has no SRS, skipping coordinate transformation')
        ct = None
    elif srs_dst.IsSame(srs):
        logging.debug('Both source and destination have the same SRS (%s), '
                      'skipping coordinate transformation',
            srs_dst.GetName())
        ct = None
    else:
        # TODO Use GetSupportedSRSList() and SetActiveSRS() with GDAL ≥3.7.0
        # when possible, see apps/ogr2ogr_lib.cpp
        logging.debug('Creating transforming from source SRS (%s) to destination SRS (%s)',
            srs.GetName(), srs_dst.GetName())
        ct = osr.CoordinateTransformation(srs, srs_dst)
        if ct is None:
            raise RuntimeError(f'Could not create transformation from source SRS ({srs.GetName()}) '
                               f'to destination SRS ({srs_dst.GetName()})')

    defn = lyr.GetLayerDefn()
    geomFieldCount = defn.GetGeomFieldCount()
    if geomFieldCount != 1: # TODO Add support for multiple geometry fields
        logging.warning('Source layer "%s" has %d != 1 geometry fields', layername, geomFieldCount)

    fieldCount = defn.GetFieldCount()
    fieldMap = [-1] * fieldCount
    fields = args['field-map']
    fieldSet = set()

    ignoredFieldNames = []
    for i in range(fieldCount):
        fld = defn.GetFieldDefn(i)
        fldName = fld.GetName()
        fieldMap[i] = v = fields.get(fldName, -1)
        fieldSet.add(fldName)

        if v < 0 and canIgnoreFields:
            # call SetIgnored() on unwanted source fields
            logging.debug('Set Ignored=True on output field "%s"', fldName)
            fld.SetIgnored(True)
            ignoredFieldNames.append(fldName)

    count0 = -1
    if lyr.TestCapability(ogr.OLCFastFeatureCount):
        count0 = lyr.GetFeatureCount(force=0)

    if count0 == 0 and len(fieldSet) == 0:
        # skip the below warning in some cases (e.g., GeoJSON source)
        logging.info('Source layer "%s" has no fields nor features, skipping', layername)
        return

    logging.debug('Field map: %s', str(fieldMap))
    for fld in fields:
        if not fld in fieldSet:
            logging.warning('Source layer "%s" has no field named "%s", ignoring', layername, fld)

    count1 = -1
    if args.get('spatial-filter', True) and extent is not None:
        if extent.GetSpatialReference().IsSame(srs):
            extent2 = extent
        else:
            extent2 = extent.Clone()
            if extent2.TransformTo(srs) != ogr.OGRERR_NONE:
                raise RuntimeError(f'Could not transform extent {extent.ExportToWkt()} '
                                   f'to {srs.GetName()}')

        #logging.debug('Applying extent: %s', extent2.ExportToWkt())
        lyr.SetSpatialFilter(extent2)

        if lyr.TestCapability(ogr.OLCFastFeatureCount):
            count1 = lyr.GetFeatureCount(force=0)

    if count0 >= 0:
        if count1 >= 0:
            logging.info('Source layer "%s" has %d features (%d of which intersecting extent)',
                layername, count0, count1)
        else:
            logging.info('Source layer "%s" has %d features', layername, count0)

    logging.info('Ignored fields from source layer: %s',
        '-' if len(ignoredFieldNames) == 0 else ', '.join(ignoredFieldNames))

    # build a list of triplets (field index, replacement_for_null, [(from_value, to_value), …])
    valueMap = []
    for fldName, rules in args.get('value-map', {}).items():
        i = defn.GetFieldIndex(fldName)
        if i < 0:
            raise RuntimeError(f'Source layer "{layername}" has no field named "{fldName}"')
        if fieldMap[i] < 0:
            logging.warning('Ignored source field "%s" has value map', fldName)
            continue

        hasNullReplacement = False
        nullReplacement = None
        mapping = []
        fld = defn.GetFieldDefn(i)
        for idx, (rFrom, rTo) in enumerate(rules):
            # use fld for both 'from' and 'to' (the types must match, casting is not
            # allowed in the mapping)
            if rFrom is None:
                if hasNullReplacement:
                    logging.warning('Field "%s" has duplicate NULL replacement',
                                    fld.GetName())
                else:
                    setFieldMapValue(fld, idx, None) # validate NULL
                    rTo = setFieldMapValue(fld, idx, rTo)
                    hasNullReplacement = True
                    nullReplacement = rTo
            elif isinstance(rFrom, re.Pattern):
                # validate but keep the rFrom regex
                setFieldMapValue(fld, idx, str(rFrom))
                rTo = setFieldMapValue(fld, idx, rTo)
                mapping.append( (rFrom, rTo, 1) )
            else:
                rFrom = setFieldMapValue(fld, idx, rFrom)
                rTo = setFieldMapValue(fld, idx, rTo)
                mapping.append( (rFrom, rTo, 0) )

        if nullReplacement is not None or len(mapping) > 0:
            valueMap.append( (i, nullReplacement, mapping) )

    bValueMap = len(valueMap) > 0
    defn = None

    defn_dst = lyr_dst.GetLayerDefn()
    eGType_dst = defn_dst.GetGeomType()
    eGType_dst_HasZ = ogr.GT_HasZ(eGType_dst)
    eGType_dst_HasM = ogr.GT_HasM(eGType_dst)
    dGeomIsUnknown = ogr.GT_Flatten(eGType_dst) == ogr.wkbUnknown

    if bValueMap:
        valueMapCounts = [0] * fieldCount

    featureCount = 0
    mismatch = {}
    feature = lyr.GetNextFeature()
    while feature is not None:
        if bValueMap:
            for i, nullReplacement, mapping in valueMap:
                if not feature.IsFieldSet(i):
                    continue
                if feature.IsFieldNull(i):
                    if nullReplacement is not None:
                        # replace NULL with non-NULL value
                        feature.SetField(i, nullReplacement)
                        valueMapCounts[i] += 1
                    continue

                v = feature.GetField(i)
                for rFrom, rTo, rType in mapping:
                    if rType == 0:
                        # literal
                        if v != rFrom:
                            continue
                    elif rType == 1:
                        # regex
                        m = rFrom.fullmatch(v)
                        if m is None:
                            continue
                        if rTo is not None:
                            rTo = rTo.format(*m.groups())
                    else:
                        raise RuntimeError(str(rType))

                    if rTo is None:
                        # replace non-NULL value with NULL
                        feature.SetFieldNull(i)
                    else:
                        # replace non-NULL value with non-NULL value
                        feature.SetField(i, rTo)
                    valueMapCounts[i] += 1
                    break

        feature2 = ogr.Feature(defn_dst)
        feature2.SetFromWithMap(feature, False, fieldMap)

        geom = feature2.GetGeometryRef()
        if geom is None:
            if eGType_dst != ogr.wkbNone:
                logging.warning('Source feature #%d has no geometry, trying to transfer anyway',
                                feature.GetFID())
        else:
            if ct is not None and geom.Transform(ct) != ogr.OGRERR_NONE:
                raise RuntimeError('Could not apply coordinate transformation')

            eGType = geom.GetGeometryType()
            if eGType != eGType_dst and not dGeomIsUnknown:
                # Promote to multi, cf. apps/ogr2ogr_lib.cpp:ConvertType()
                eGType2 = eGType
                if eGType in (ogr.wkbTriangle, ogr.wkbTIN, ogr.wkbPolyhedralSurface):
                    eGType2 = ogr.wkbMultiPolygon
                elif not ogr.GT_IsSubClassOf(eGType, ogr.wkbGeometryCollection):
                    eGType2 = ogr.GT_GetCollection(eGType)

                eGType2 = ogr.GT_SetModifier(eGType2, eGType_dst_HasZ, eGType_dst_HasM)
                if eGType2 == eGType_dst:
                    mismatch[eGType] = mismatch.get(eGType, 0) + 1
                    geom = ogr.ForceTo(geom, eGType_dst)
                    # TODO call MakeValid()?
                else:
                    raise RuntimeError(f'Conversion from {ogr.GeometryTypeToName(eGType)} '
                                       f'to {ogr.GeometryTypeToName(eGType_dst)} not implemented')
                feature2.SetGeometryDirectly(geom)

        if lyr_dst.CreateFeature(feature2) != ogr.OGRERR_NONE:
            raise RuntimeError(f'Could not transfer source feature #{feature.GetFID()}')

        featureCount += 1
        feature = lyr.GetNextFeature()

    if bValueMap:
        valueMapCounts = [ (lyr.GetLayerDefn().GetFieldDefn(i).GetName(), k)
                             for i,k in enumerate(valueMapCounts) if k > 0 ]

    lyr = None
    logging.info('Imported %d features from source layer "%s"', featureCount, layername)

    if bValueMap:
        if len(valueMapCounts) > 0:
            valueMapCounts = ', '.join([ str(k) + '× "' + n + '"' for n,k in valueMapCounts ])
        else:
            valueMapCounts = '-'
        logging.info('Field substitutions: %s', valueMapCounts)

    if len(mismatch) > 0:
        mismatches = [ str(n) + '× ' + ogr.GeometryTypeToName(t)
            for t,n in sorted(mismatch.items(), key=lambda x: x[1]) ]
        logging.info('Forced conversion to %s: %s',
            ogr.GeometryTypeToName(eGType_dst), ', '.join(mismatches))