#!/usr/bin/env python3
# -*- coding: utf-8 -*-
"""
GEPARD - Gepard-Enabled PARticle Detection
Copyright (C) 2018  Lars Bittrich and Josef Brandt, Leibniz-Institut für 
Polymerforschung Dresden e. V. <bittrich-lars@ipfdd.de>    

This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program, see COPYING.  
If not, see <https://www.gnu.org/licenses/>.
"""
import cv2
from ...errors import InvalidParticleError


class ShapeClassifier(object):
    def __init__(self):
        self.shapeClasses = [Spherule(), Fibre(), Irregular()]
    
    def classifyShape(self, contour, particleHeight):
        newShape = BaseShape()
        newShape.contour = contour
        newShape.height = particleHeight
        newShape.getParticleCharacteristics()
        
        mostFittingCriteria = 0
        bestFittingShape = 'unknown'
        
        for testShape in self.shapeClasses:
            numFits = newShape.fitsOtherShapeCriteria(testShape)
            if numFits > mostFittingCriteria:
                mostFittingCriteria = numFits
                bestFittingShape = testShape.name
        
        return bestFittingShape
    

class BaseShape(object):
    def __init__(self):
        self.name = None
        self.contour = None
                
        self.longSize = None
        self.shortSize = None
        self.height = None        
        
        self.aspectRatio = None
        self.aspectRatioRange = None
        
        self.solidity = None
        self.solidityRange = None

        self.height2AverageLength = None
        self.height2AverageLengthRange = None
    
    def getParticleCharacteristics(self):
        assert self.contour is not None, 'not able to get contour characteristics of NONE contour'
        area = cv2.contourArea(self.contour)
        hull = cv2.convexHull(self.contour)
        hull_area = cv2.contourArea(hull)
        if area == 0 or hull_area == 0:
            raise InvalidParticleError
            
        self.solidity = area/hull_area
        
        long, short = self.getEllipseOrBoxLongAndShortSize()
        self.aspectRatio = long/short
        
        avgLength = (long+short)/2
        self.height2AverageLength = self.height/avgLength
    
    def getEllipseOrBoxLongAndShortSize(self):
        if self.contour.shape[0] >= 5:       ##at least 5 points required for ellipse fitting...
            ellipse = cv2.fitEllipse(self.contour)
            short, long = ellipse[1]
        else:
            rect = cv2.minAreaRect(self.contour)
            long, short = rect[1]
            
        if short>long:
            long, short = short, long
        
        if short == 0.0:
            raise InvalidParticleError
        
        return long, short
    
    def fitsOtherShapeCriteria(self, otherShape):
        assert self.aspectRatio is not None
        assert self.solidity is not None
        
        numFittingCriteria = 0
        if otherShape.aspectRatioRange[0] <= self.aspectRatio <= otherShape.aspectRatioRange[1]:
            numFittingCriteria += 1
            
        if otherShape.solidityRange[0] <= self.solidity <= otherShape.solidityRange[1]:
            numFittingCriteria += 1
            
        if otherShape.height2AverageLengthRange[0] <= self.height2AverageLength <= otherShape.height2AverageLengthRange[1]:
            numFittingCriteria += 1
        
        return numFittingCriteria


class Spherule(BaseShape):
    def __init__(self):
        super(Spherule, self).__init__()
        self.name = 'spherule'
        self.aspectRatioRange = [1.0, 1.2]
        self.solidityRange = [0.95, 1.]
        self.height2AverageLengthRange = [0.4, 1.5]


class Irregular(BaseShape):
    def __init__(self):
        super(Irregular, self).__init__()
        self.name = 'irregular'
        
        self.aspectRatioRange = [1.0, 3]
        self.solidityRange = [0.9, 1.]
        self.height2AverageLengthRange = [0.4, 10]


class Flake(BaseShape):
    def __init__(self):
        super(Flake, self).__init__()
        self.name = 'flake'
        
        self.aspectRatioRange = [1.0, 3]
        self.solidityRange = [0.7, 1.]
        self.height2AverageLengthRange = [0.0, 0.4]


class Fibre(BaseShape):
    def __init__(self):
        super(Fibre, self).__init__()
        self.name = 'fibre'
        self.aspectRatioRange = [5, 1000]
        self.solidityRange = [0.0, 0.4]
        self.height2AverageLengthRange = [0, 1000]