import curses


class FieldPad:
    
    
    
    def __init__(self, size=(1,1), charSize=1, colours=False):
        self.pad = curses.newpad(size[1]+1, (size[0]+1)*charSize)
        self.size = size
        self.charSize = charSize
        self.center = (0, 0)
        self.colours = colours
        self.changed = False
        self.lastView = None
    
    def resize(self, width, height):
        self.size = (width, height)
        self.pad.resize(height+1, width*self.charSize+1)
    
    def changeCell(self, x, y, char, colour=None, bgcolour=0):
        if colour != None and self.colours:
            self.pad.addstr(y, x*self.charSize, char, self.colours.get(colour, bgcolour))
        else:
            self.pad.addstr(y, x*self.charSize, char)
        self.changed = True
    
    def setCenter(self, pos):
        self.center = pos
    
    def getWidth(self):
        return self.size[0]*self.charSize
    
    def getHeight(self):
        return self.size[1]
    
    def roundWidth(self, x):
        return x // self.charSize * self.charSize
    
    def update(self, screen, x, y, xmax, ymax, force=False):
        if not self.changed and (x, y, xmax, ymax) == self.lastView or xmax <= x or ymax <= y and not force:
            return
        self.lastView = (x, y, xmax, ymax)
        self.changed = False
        width = xmax-x
        height = ymax-y
        self.pad.noutrefresh(
            max(0, min(self.getHeight()-height, self.center[1] - int(height/2))),
            max(0, min(
                self.roundWidth(self.getWidth()-width),
                self.roundWidth(self.center[0]*self.charSize - int(width/2)))),
            y,
            x,
            ymax-1,
            xmax-1)