"""
2D bin-packing
"""
from typing import Tuple, List, Set, Sequence

import numpy
from numpy.typing import NDArray, ArrayLike

from ..error import MasqueError


def maxrects_bssf(
        rects: ArrayLike,
        containers: ArrayLike,
        presort: bool = True,
        allow_rejects: bool = True,
        ) -> Tuple[NDArray[numpy.float64], Set[int]]
    """
    sizes should be Nx2
    regions should be Mx4 (xmin, ymin, xmax, ymax)
    """
    regions = numpy.array(containers, copy=False, dtype=float)
    rect_sizes = numpy.array(rects, copy=False, dtype=float)
    rect_locs = numpy.zeros_like(rect_sizes)
    rejected_inds = set()

    if presort:
        rotated_sizes = numpy.sort(rect_sizes, axis=0)  # shortest side first
        rect_order = numpy.lexsort(rotated_sizes.T)[::-1]  # Descending shortest side
        rect_sizes = rect_sizes[rect_order]

    for rect_ind, rect_size in enumerate(rect_sizes):
        ''' Remove degenerate regions '''
        # First remove duplicate regions (but keep one; code below would drop both)
        regions = numpy.unique(regions, axis=0)

        # Now remove regions enclosed in another
        min_more = (regions[None, :, :2] >= regions[:, None, :2]).all(axis=2)   # first axis > second axis
        max_less = (regions[None, :, 2:] <= regions[:, None, 2:]).all(axis=2)   # first axis < second axis
        max_less &= ~numpy.eye(regions.shape[0], dtype=bool)    # exclude self
        degenerate = (min_more & max_less).any(axis=0)
        regions = regions[~degenerate]

        ''' Place the rect '''
        # Best short-side fit (bssf) to pick a region
        bssf_scores = ((regions[:, 2:] - regions[:, :2]) - rect_size).min(axis=1).astype(float)
        bssf_scores[bssf_scores < 0] = numpy.inf        # doesn't fit!
        rr = bssf_scores.argmin()
        if numpy.isinf(bssf_scores[rr]):
            if allow_rejects:
                rejected_inds.add(rect_ind)
                continue
            else:
                raise MasqueError(f'Failed to find a suitable location for rectangle {rect_ind}')

        # Read out location
        loc = regions[rr, :2]
        rect_locs[rect_ind] = loc

        ''' Shatter regions '''
        # Which regions does this rectangle intersect?
        min_over = regions[:, :2] >= loc + rect_size
        max_undr = regions[:, 2:] <= loc
        intersects = ~(min_over | max_undr).any(axis=1)

        # Which sides is there excess on?
        region_past_botleft = intersects[:, None] & (regions[:, :2] < loc)
        region_past_topright = intersects[:, None] & (regions[:, 2:] > loc + rect_size)

        # Create new regions
        r_lft = regions[region_past_botleft[:, 0]].copy()
        r_bot = regions[region_past_botleft[:, 1]].copy()
        r_rgt = regions[region_past_topright[:, 0]].copy()
        r_top = regions[region_past_topright[:, 1]].copy()

        r_lft[:, 2] = loc[0]
        r_bot[:, 3] = loc[1]
        r_rgt[:, 0] = loc[0] + rect_size[0]
        r_top[:, 1] = loc[1] + rect_size[1]

        regions = numpy.vstack((regions[~intersects], r_lft, r_bot, r_rgt, r_top))
    return rect_locs, rejected_inds