import os
import numpy

#Establish file path for directory containing OpenPIV output, count files in directory
pivOutputPath = r'/run/user/1000/gvfs/sftp:host=isoptera.lcsc.edu,user=jamcdonald/home/jamcdonald/reu/OpenPIV_Out'
fileCount = 0
fileList = os.listdir(pivOutputPath)
for fileName in fileList:
    fileCount = fileCount + 1

#Create array to hold average velocity values
videoAvgVelocity = []

#Begin loop to loop through file directory
for i in range(0, fileCount - 1):
    #Find and open file
    filePath = pivOutputPath + "\\piv%4d.txt" % i
    file = open(filePath)

    #Read through file to obtain line count, then return to beginning
    lineCount = len(file.readlines())
    print(str(lineCount) + " lines in file.")
    file.seek(0, 0)

    #Create array to hold all velocity values in the file
    velocityList = []

    #Read the file data line by line
    for j in range(0, lineCount - 1):
        line = file.readline()
        lineInfo = line.split("\t")
        x = float(lineInfo[0])
        y = float(lineInfo[1])
        u = float(lineInfo[2])
        v = float(lineInfo[3])

        #Calculate speed for each line and append to array
        speed = ((u**2)+(v**2))**0.5
        print("The speed at point (" + str(x) + ", " + str(y) + ") is " + str(speed) + " pixels per second.")
        velocityList.append(speed)
        print("Vector " + str(j + 1) + " of " + str(lineCount) + " appended.")
    listLength = len(velocityList)
    print(str(listLength) + " velocity vectors.")

    #Find the average velocity, standard deviation, and median
    avgVelocity = numpy.mean(velocityList)
    stdDev = numpy.std(velocityList)
    medVelocity = numpy.median(velocityList)
    print("Average velocity is " + str(avgVelocity) + " pixels per second.")

    #Add file average to overall average array
    videoAvgVelocity.append(avgVelocity)

    #Close file
    file.close()

#Find the average overall velocity of the waves.
listLength = len(videoAvgVelocity)
total = sum(videoAvgVelocity)
avgOverallVelocity = total / listLength
print("Average velocity over " + str(listLength) + " frames is " + str(avgOverallVelocity) + " pixels per second.")