import math

import numpy as np

from analyzer.epoint import EPoint, homogenize
from analyzer.grid import transformPoint


class Line():
	def __init__(self,a,b):
		self.a=a
		self.b=b
		self.points={a,b}

	def getSortedPoints(self):
		return tuple(sorted(self.points))

	def computeAngle(self,line):
		ab=self.a-self.b
		cd=line.a-line.b
		alpha=math.atan(ab.y/ab.x)
		gamma=math.atan(cd.y/cd.x)
		fi=max(alpha,gamma)-min(alpha,gamma)
		return min(fi,math.pi-fi)

	def intersect(self,line):
		p=self.toProjective()
		q=line.toProjective()
		return EPoint.fromProjective(np.cross(p,q))

	def toProjective(self):
		return homogenize(np.cross(self.a.toProjective(),self.b.toProjective()))

	def transform(self,matrix):
		a=EPoint.fromProjective(transformPoint(self.a.toProjective(),matrix))
		b=EPoint.fromProjective(transformPoint(self.b.toProjective(),matrix))
		if a is None or b is None: return None
		return Line(a,b)

	def __str__(self): return "({0},{1})".format(self.a,self.b)
	def __repr__(self): return "Line({0},{1})".format(repr(self.a),repr(self.b))


def point2lineDistance(a,b,p):
	# https://en.wikipedia.org/wiki/Point-line_distance#Line_defined_by_two_points
	ab=b-a
	num=abs(ab.y*p.x - ab.x*p.y + b.x*a.y - a.x*b.y)
	denum=math.sqrt(ab.y**2+ab.x**2)
	return num/denum # double_area / side_length == height


def angleDiff(alpha,beta):
	diff=abs(alpha-beta)
	if diff>math.pi: diff=2*math.pi-diff
	return diff