#!/usr/bin/python
# -*- coding: utf-8 -*-
import datetime
import math
import cv2
import numpy as np

width = 0
height = 0
EntranceCounter = 0
ExitCounter = 0
MinCountourArea = 3000
BinarizationThreshold = 70
OffsetRefLines = 150


def CheckEntranceLineCrossing(y, CoorYEntranceLine, CoorYExitLine):
    AbsDistance = abs(y - CoorYEntranceLine)
    if AbsDistance <= 2 and y < CoorYExitLine:
        return 1
    else:
        return 0


def CheckExitLineCrossing(y, CoorYEntranceLine, CoorYExitLine):
    AbsDistance = abs(y - CoorYExitLine)

    if AbsDistance <= 2 and y > CoorYEntranceLine:
        return 1
    else:
        return 0


camera = cv2.VideoCapture(0)

camera.set(3, 640)
camera.set(4, 480)

ReferenceFrame = None

for i in range(0, 20):
    (grabbed, Frame) = camera.read()

while True:
    (grabbed, Frame) = camera.read()
    height = np.size(Frame, 0)
    width = np.size(Frame, 1)

    if not grabbed:
        break

    GrayFrame = cv2.cvtColor(Frame, cv2.COLOR_BGR2GRAY)
    GrayFrame = cv2.GaussianBlur(GrayFrame, (21, 21), 0)

    if ReferenceFrame is None:
        ReferenceFrame = GrayFrame
        continue

    FrameDelta = cv2.absdiff(ReferenceFrame, GrayFrame)
    FrameThresh = cv2.threshold(FrameDelta, BinarizationThreshold, 255,
                                cv2.THRESH_BINARY)[1]

    FrameThresh = cv2.dilate(FrameThresh, None, iterations=2)
    (_, cnts, _) = cv2.findContours(FrameThresh.copy(),
                                    cv2.RETR_EXTERNAL,
                                    cv2.CHAIN_APPROX_SIMPLE)

    QttyOfContours = 0

    CoorYEntranceLine = height / 2 - OffsetRefLines
    CoorYExitLine = height / 2 + OffsetRefLines
    cv2.line(Frame, (0, CoorYEntranceLine), (width, CoorYEntranceLine),
             (255, 0, 0), 2)
    cv2.line(Frame, (0, CoorYExitLine), (width, CoorYExitLine), (0, 0,
             255), 2)

    for c in cnts:
        if cv2.contourArea(c) < MinCountourArea:
            continue

        QttyOfContours = QttyOfContours + 1

        (x, y, w, h) = cv2.boundingRect(c)
        cv2.rectangle(Frame, (x, y), (x + w, y + h), (0, 255, 0), 2)

        CoordXCentroid = (x + x + w) / 2
        CoordYCentroid = (y + y + h) / 2
        ObjectCentroid = (CoordXCentroid, CoordYCentroid)
        cv2.circle(Frame, ObjectCentroid, 1, (0, 0, 0), 5)

        if CheckEntranceLineCrossing(CoordYCentroid, CoorYEntranceLine,
                CoorYExitLine):
            EntranceCounter += 1

        if CheckExitLineCrossing(CoordYCentroid, CoorYEntranceLine,
                                 CoorYExitLine):
            ExitCounter += 1

    print 'Total countours found: ' + str(QttyOfContours)

    cv2.putText(
        Frame,
        'Entrances: {}'.format(str(EntranceCounter)),
        (10, 50),
        cv2.FONT_HERSHEY_SIMPLEX,
        0.5,
        (250, 0, 1),
        2,
        )
    cv2.putText(
        Frame,
        'Exits: {}'.format(str(ExitCounter)),
        (10, 70),
        cv2.FONT_HERSHEY_SIMPLEX,
        0.5,
        (0, 0, 255),
        2,
        )
    cv2.imshow('Original Frame', Frame)
    cv2.waitKey(1)

camera.release()
cv2.destroyAllWindows()