#!/usr/bin/env python3
# -*- coding: utf-8 -*-
# ******************************************************************************
#  $Id$
#
#  Project:  GDAL
#  Purpose:  Generate the extent of each raster tile in a overview as a vector layer
#  Author:   Even Rouault, <even dot rouault at spatialys dot com>
#
# ******************************************************************************
#  Copyright (c) 2019, Even Rouault, <even dot rouault at spatialys dot com>
#
# SPDX-License-Identifier: MIT
# ******************************************************************************

import sys

from osgeo import gdal, ogr
from osgeo_utils.auxiliary.util import GetOutputDriverFor


def Usage():
    print("Usage:  tile_extent_from_raster.py [-f format] [-ovr level] in.tif out.shp")
    return 2


def main(argv=sys.argv):
    i = 1
    output_format = None
    in_filename = None
    out_filename = None
    ovr_level = None
    while i < len(argv):
        if argv[i] == "-f":
            output_format = argv[i + 1]
            i = i + 1
        elif argv[i] == "-ovr":
            ovr_level = int(argv[i + 1])
            i = i + 1
        elif argv[i][0] == "-":
            return Usage()
        elif in_filename is None:
            in_filename = argv[i]
        elif out_filename is None:
            out_filename = argv[i]
        else:
            return Usage()

        i = i + 1

    if out_filename is None:
        return Usage()
    if output_format is None:
        output_format = GetOutputDriverFor(out_filename, is_raster=False)

    src_ds = gdal.Open(in_filename)
    out_ds = gdal.GetDriverByName(output_format).Create(
        out_filename, 0, 0, 0, gdal.GDT_Unknown
    )
    first_band = src_ds.GetRasterBand(1)
    main_gt = src_ds.GetGeoTransform()

    for i in (
        [ovr_level]
        if ovr_level is not None
        else range(1 + first_band.GetOverviewCount())
    ):
        src_band = first_band if i == 0 else first_band.GetOverview(i - 1)
        out_lyr = out_ds.CreateLayer(
            "main_image" if i == 0 else ("overview_%d" % i),
            geom_type=ogr.wkbPolygon,
            srs=src_ds.GetSpatialRef(),
        )
        blockxsize, blockysize = src_band.GetBlockSize()
        nxblocks = (src_band.XSize + blockxsize - 1) // blockxsize
        nyblocks = (src_band.YSize + blockysize - 1) // blockysize
        gt = [
            main_gt[0],
            main_gt[1] * first_band.XSize / src_band.XSize,
            0,
            main_gt[3],
            0,
            main_gt[5] * first_band.YSize / src_band.YSize,
        ]
        for y in range(nyblocks):
            ymax = gt[3] + y * blockysize * gt[5]
            ymin = ymax + blockysize * gt[5]
            for x in range(nxblocks):
                xmin = gt[0] + x * blockxsize * gt[1]
                xmax = xmin + blockxsize * gt[1]
                f = ogr.Feature(out_lyr.GetLayerDefn())
                wkt = (
                    "POLYGON((%.18g %.18g,%.18g %.18g,%.18g %.18g,%.18g %.18g,%.18g %.18g))"
                    % (xmin, ymin, xmin, ymax, xmax, ymax, xmax, ymin, xmin, ymin)
                )
                f.SetGeometryDirectly(ogr.CreateGeometryFromWkt(wkt))
                out_lyr.CreateFeature(f)
    out_ds = None
    return 0


if __name__ == "__main__":
    sys.exit(main(sys.argv))