"""
Some utility functions for sets of grid cells.
"""

import debug
from direction import direction
from vector3d import vector3d


def increment_set(curset, direct):
    """
    Return the cells incremented in given direction
    """
    offset = direction.get_offset(direct)
    
    newset = set()
    for c in curset:
        newc = c+offset
        newset.add(newc)
        
    return newset


def remove_border(curset, direct):
    """ 
    Remove the cells on a given border.
    """
    border = get_border(curset, direct)
    curset.difference_update(border)
    

def get_upper_right(curset):
    ur = None
    for p in curset:
        if ur == None or (p.x>=ur.x and p.y>=ur.y):
            ur = p
    return ur

def get_lower_left(curset):
    ll = None
    for p in curset:
        if ll == None or (p.x<=ll.x and p.y<=ll.y):
            ll = p
    return ll

def get_border( curset, direct):
    """
    Return the furthest cell(s) in a given direction.
    """
    
    # find direction-most cell(s)
    maxc = []
    if direct==direction.NORTH:
        for c in curset:
            if len(maxc)==0 or c.y>maxc[0].y:
                maxc = [c]
            elif c.y==maxc[0].y:
                maxc.append(c)
    elif direct==direct.SOUTH:
        for c in curset:
            if len(maxc)==0 or c.y<maxc[0].y:
                maxc = [c]
            elif c.y==maxc[0].y:
                maxc.append(c)
    elif direct==direct.EAST:
        for c in curset:
            if len(maxc)==0 or c.x>maxc[0].x:
                maxc = [c]
            elif c.x==maxc[0].x:
                maxc.append(c)
    elif direct==direct.WEST:
        for c in curset:
            if len(maxc)==0 or c.x<maxc[0].x:
                maxc = [c]
            elif c.x==maxc[0].x:
                maxc.append(c)

    newset = set(maxc)
    return newset

def expand_border(curset, direct):
    """
    Expand the current set of sells in a given direction.
    Only return the contiguous cells.
    """
    border_set = get_border(curset, direct)
    next_border_set = increment_set(border_set, direct)
    return next_border_set
    
def expand_borders(curset):
    """
    Return the expansions in planar directions.
    """
    north_set=expand_border(curset,direction.NORTH)
    south_set=expand_border(curset,direction.SOUTH)
    east_set=expand_border(curset,direction.EAST)
    west_set=expand_border(curset,direction.WEST)
        
    return(north_set, east_set, south_set, west_set)

def inflate_cell(cell, distance):
    """
    Expand the current cell in all directions and return the set.
    """
    newset = set(cell)
    
    if distance==0:
        return(newset)

    # recursively call this based on the distance
    for offset in direction.all_offsets():
        # FIXME: If distance is large this will be inefficient, but it is like 1 or 2
        newset.update(inflate_cell(cell+offset,distance-1))
                      
    return newset

def inflate_set(curset, distance):
    """
    Expand the set in all directions by the given number of grids.
    """
    if distance<=0:
        return curset
    
    newset = curset.copy()
    # Add all my neighbors
    for c in curset:
        newset.update(direction.all_neighbors(c))
    # Recurse with less depth
    return inflate_set(newset,distance-1)

def flatten_set(curset):
    """
    Flatten until we have a set of vector3d objects.
    """
    newset = set()
    for c in curset:
        if isinstance(c,vector3d):
            newset.add(c)
        else:
            newset.update(flatten_set(c))
    return newset