import os
from itertools import product
import rasterio as rio
import rasterio.mask as mask
from rasterio import windows
import os


def split(ds, width, height):
    nols, nrows = ds.meta['width'], ds.meta['height']
    offsets = product(range(0, nols, width), range(0, nrows, height))
    big_window = windows.Window(col_off=0, row_off=0, width=nols, height=nrows)
    for col_off, row_off in  offsets:
        window =windows.Window(col_off=col_off, row_off=row_off, width=width, height=height).intersection(big_window)
        transform = windows.transform(window, ds.transform)
        yield window, transform



def get_tiles(args):

    input_path, out_dir, patch_size = args['input_path'], args['out_dir'], args['patch_size']
    
    id = os.path.basename(input_path).replace('.tiff', '')
    output_filename = '{id}_{col}-{row}.tiff'
    tile_width, tile_height = patch_size, patch_size

    with rio.open(input_path) as inds:

        meta = inds.meta.copy()

        for window, transform in split(inds, tile_width, tile_height):
            if window.width != patch_size or window.height != patch_size:
                continue

            print(window)
            meta['transform'] = transform
            meta['width'], meta['height'] = window.width, window.height

            outpath = os.path.join(out_dir,output_filename.format(id = id, col=int(window.col_off), row=int(window.row_off)))
            if os.path.exists(outpath):
                continue
            with rio.open(outpath, 'w', **meta) as outds:
                data = inds.read(window=window)
                #out_image, out_transform = mask.mask(outds, [geometry], crop=True)
                outds.write(data)