import numpy as np

##  Some polygon converted to an array
class ShapeArray:
    def __init__(self, arr, offset_x, offset_y, scale = 1):
        self.arr = arr
        self.offset_x = offset_x
        self.offset_y = offset_y
        self.scale = scale

    @classmethod
    def from_polygon(cls, vertices, scale = 1):
        # scale
        vertices = vertices * scale
        # offset
        offset_y = int(np.amin(vertices[:, 0]))
        offset_x = int(np.amin(vertices[:, 1]))
        # normalize to 0
        vertices[:, 0] = np.add(vertices[:, 0], -offset_y)
        vertices[:, 1] = np.add(vertices[:, 1], -offset_x)
        shape = [int(np.amax(vertices[:, 0])), int(np.amax(vertices[:, 1]))]
        arr = cls.array_from_polygon(shape, vertices)
        return cls(arr, offset_x, offset_y)

    ##  Return indices that mark one side of the line, used by array_from_polygon
    #   Uses the line defined by p1 and p2 to check array of
    #   input indices against interpolated value

    #   Returns boolean array, with True inside and False outside of shape
    #   Originally from: http://stackoverflow.com/questions/37117878/generating-a-filled-polygon-inside-a-numpy-array
    @classmethod
    def _check(cls, p1, p2, base_array):
        """
        """
        if p1[0] == p2[0] and p1[1] == p2[1]:
            return
        idxs = np.indices(base_array.shape)  # Create 3D array of indices

        p1 = p1.astype(float)
        p2 = p2.astype(float)

        if p2[0] == p1[0]:
            sign = np.sign(p2[1] - p1[1])
            return idxs[1] * sign

        if p2[1] == p1[1]:
            sign = np.sign(p2[0] - p1[0])
            return idxs[1] * sign

        # Calculate max column idx for each row idx based on interpolated line between two points

        max_col_idx = (idxs[0] - p1[0]) / (p2[0] - p1[0]) * (p2[1] - p1[1]) + p1[1]
        sign = np.sign(p2[0] - p1[0])
        return idxs[1] * sign <= max_col_idx * sign

    @classmethod
    def array_from_polygon(cls, shape, vertices):
        """
        Creates np.array with dimensions defined by shape
        Fills polygon defined by vertices with ones, all other values zero

        Only works correctly for convex hull vertices
        """
        base_array = np.zeros(shape, dtype=float)  # Initialize your array of zeros

        fill = np.ones(base_array.shape) * True  # Initialize boolean array defining shape fill

        # Create check array for each edge segment, combine into fill array
        for k in range(vertices.shape[0]):
            fill = np.all([fill, cls._check(vertices[k - 1], vertices[k], base_array)], axis=0)

        # Set all values inside polygon to one
        base_array[fill] = 1

        return base_array


class Arrange:
    def __init__(self, x, y, offset_x, offset_y, scale=1):
        self.shape = (y, x)
        self._priority = np.zeros((x, y), dtype=np.int32)
        self._occupied = np.zeros((x, y), dtype=np.int32)
        self._scale = scale  # convert input coordinates to arrange coordinates
        self._offset_x = offset_x
        self._offset_y = offset_y

    ##  Fill priority, take offset as center. lower is better
    def centerFirst(self):
        self._priority = np.fromfunction(
            lambda i, j: abs(self._offset_x-i)+abs(self._offset_y-j), self.shape)

    ##  Return the amount of "penalty points" for polygon, which is the sum of priority
    #   999999 if occupied
    def check_shape(self, x, y, shape_arr):
        x = int(self._scale * x)
        y = int(self._scale * y)
        offset_x = x + self._offset_x + shape_arr.offset_x
        offset_y = y + self._offset_y + shape_arr.offset_y
        occupied_slice = self._occupied[
            offset_y:offset_y + shape_arr.arr.shape[0],
            offset_x:offset_x + shape_arr.arr.shape[1]]
        if np.any(occupied_slice[np.where(shape_arr.arr == 1)]):
            return 999999
        prio_slice = self._priority[
            offset_y:offset_y + shape_arr.arr.shape[0],
            offset_x:offset_x + shape_arr.arr.shape[1]]
        return np.sum(prio_slice[np.where(shape_arr.arr == 1)])

    ##  Slower but better (it tries all possible locations)
    def bestSpot2(self, shape_arr):
        best_x, best_y, best_points = None, None, None
        min_y = max(-shape_arr.offset_y, 0) - self._offset_y
        max_y = self.shape[0] - shape_arr.arr.shape[0] - self._offset_y
        min_x = max(-shape_arr.offset_x, 0) - self._offset_x
        max_x = self.shape[1] - shape_arr.arr.shape[1] - self._offset_x
        for y in range(min_y, max_y):
            for x in range(min_x, max_x):
                penalty_points = self.check_shape(x, y, shape_arr)
                if best_points is None or penalty_points < best_points:
                    best_points = penalty_points
                    best_x, best_y = x, y
        return best_x, best_y, best_points

    ##  Faster
    def bestSpot(self, shape_arr):
        min_y = max(-shape_arr.offset_y, 0) - self._offset_y
        max_y = self.shape[0] - shape_arr.arr.shape[0] - self._offset_y
        min_x = max(-shape_arr.offset_x, 0) - self._offset_x
        max_x = self.shape[1] - shape_arr.arr.shape[1] - self._offset_x

        for prio in range(200):
            tryout_idx = np.where(self._priority == prio)
            for idx in range(len(tryout_idx[0])):
                x = tryout_idx[0][idx]
                y = tryout_idx[1][idx]
                projected_x = x - self._offset_x
                projected_y = y - self._offset_y
                if projected_x < min_x or projected_x > max_x or projected_y < min_y or projected_y > max_y:
                    continue
                # array to "world" coordinates
                penalty_points = self.check_shape(projected_x, projected_y, shape_arr)
                if penalty_points != 999999:
                    return projected_x, projected_y, penalty_points
        return None, None, None  # No suitable location found :-(

    def place(self, x, y, shape_arr):
        x = int(self._scale * x)
        y = int(self._scale * y)
        offset_x = x + self._offset_x + shape_arr.offset_x
        offset_y = y + self._offset_y + shape_arr.offset_y
        occupied_slice = self._occupied[
            offset_y:offset_y + shape_arr.arr.shape[0],
            offset_x:offset_x + shape_arr.arr.shape[1]]
        occupied_slice[np.where(shape_arr.arr == 1)] = 1