#based on https://towardsdatascience.com/a-beginners-guide-to-building-your-own-face-recognition-system-to-creep-out-your-friends-df3f4c471d55

##install:
# pip3 install cmake
# pip3 install face_recognition
#    or pip3 install boost & pip --no-cache-dir install face_recognition 
# pip3 install numpy
# pip3 install dlib
# pip3 install opencv-python
##

##for ChromeOS Linux
# as per current security limitation web camera is not available on ChromeOS yet: https://support.google.com/chromebook/answer/9145439?hl=en
# but it can be solved with Android Phone with "RTSP Camera Server" (https://play.google.com/store/apps/details?id=com.miv.rtspcamera&hl=en_CA)
# which can be remotely accessed via RTSP protocol and "mounted" locally via ffmpeg
#    eg. ffmpeg -i rtsp://@192.168.0.12:5554/camera -acodec copy -vcodec copy -f v4l2 ~/video1
# or pyton video source can be switched to rtsp stream it self 

#code forked and tweaked from https://github.com/ageitgey/face_recognition/blob/master/examples/facerec_from_webcam_faster.py
#to extend, just add more people into the known_people folder

import face_recognition
import cv2
import numpy as np
import os
import glob

# Get a reference to webcam #0 (the default one)
video_capture = cv2.VideoCapture(0)

#make array of sample pictures with encodings
known_face_encodings = []
known_face_names = []
dirname = os.path.dirname(__file__)
path = os.path.join(dirname, 'known_people/')

#make an array of all the saved jpg files' paths
list_of_files = [f for f in glob.glob(path+'*.jpg')]
#find number of known faces
number_files = len(list_of_files)

names = list_of_files.copy()

for i in range(number_files):
    globals()['image_{}'.format(i)] = face_recognition.load_image_file(list_of_files[i])
    globals()['image_encoding_{}'.format(i)] = face_recognition.face_encodings(globals()['image_{}'.format(i)])[0]
    known_face_encodings.append(globals()['image_encoding_{}'.format(i)])

    # Create array of known names
    names[i] = names[i].replace("known_people/", "")  
    known_face_names.append(names[i])

# Initialize some variables
face_locations = []
face_encodings = []
face_names = []
process_this_frame = True

while True:
    # Grab a single frame of video
    ret, frame = video_capture.read()

    # Resize frame of video to 1/4 size for faster face recognition processing
    small_frame = cv2.resize(frame, (0, 0), fx=0.25, fy=0.25)

    # Convert the image from BGR color (which OpenCV uses) to RGB color (which face_recognition uses)
    rgb_small_frame = small_frame[:, :, ::-1]

    # Only process every other frame of video to save time
    if process_this_frame:
        # Find all the faces and face encodings in the current frame of video
        face_locations = face_recognition.face_locations(rgb_small_frame)
        face_encodings = face_recognition.face_encodings(rgb_small_frame, face_locations)

        face_names = []
        for face_encoding in face_encodings:
            # See if the face is a match for the known face(s)
            matches = face_recognition.compare_faces(known_face_encodings, face_encoding)
            name = "Unknown"

            # # If a match was found in known_face_encodings, just use the first one.
            # if True in matches:
            #     first_match_index = matches.index(True)
            #     name = known_face_names[first_match_index]

            # Or instead, use the known face with the smallest distance to the new face
            face_distances = face_recognition.face_distance(known_face_encodings, face_encoding)
            best_match_index = np.argmin(face_distances)
            if matches[best_match_index]:
                name = known_face_names[best_match_index]

            face_names.append(name)

    process_this_frame = not process_this_frame


    # Display the results
    for (top, right, bottom, left), name in zip(face_locations, face_names):
        # Scale back up face locations since the frame we detected in was scaled to 1/4 size
        top *= 4
        right *= 4
        bottom *= 4
        left *= 4

        # Draw a box around the face
        cv2.rectangle(frame, (left, top), (right, bottom), (0, 0, 255), 2)

        # Draw a label with a name below the face
        cv2.rectangle(frame, (left, bottom - 35), (right, bottom), (0, 0, 255), cv2.FILLED)
        font = cv2.FONT_HERSHEY_DUPLEX
        cv2.putText(frame, name, (left + 6, bottom - 6), font, 1.0, (255, 255, 255), 1)

    # Display the resulting image
    cv2.imshow('Video', frame)

    # Hit 'q' on the keyboard to quit!
    if cv2.waitKey(1) & 0xFF == ord('q'):
        break

# Release handle to the webcam
video_capture.release()
cv2.destroyAllWindows()