import datetime
import sys
import time
import xml.etree.ElementTree as ET

import requests


# Prepare and send the propfind request return xml string
def propfind(path, auth):
    headers = {"Depth": "1"}
    # This body returns only the timelastmodified and the fileid variable
    data = "<d:propfind  xmlns:d=\"DAV:\" xmlns:oc=\"http://owncloud.org/ns\" xmlns:nc=\"http://nextcloud.org/ns\">" + "<d:prop>" + "<d:getlastmodified />" + "<oc:fileid />" + "</d:prop>" + "</d:propfind>"
    req = r = requests.Request("PROPFIND", path, headers=headers, auth=auth, data=data)
    prepped = req.prepare()

    s = requests.Session()
    resp = s.send(prepped)
    return resp.text


# Function iterates through the given xml which contains all files and folders in the provided path
def search_folder(requestreturn):
    # List to collect path of folders stored in path
    innerfolders = []
    # List to collect path of files with wrong timestamp
    linkswrongtime = []
    # First folder provided in the xml file is always the folder we are currently in.
    # To prevent searching this folder twice, or ending in a loop, we can not store this folder in the folderlist again.
    firstfolder = True
    # Get a xml tree
    tree = ET.ElementTree(ET.fromstring(requestreturn))
    # Find all responses in the tree, those contain the fielpath, lasttimemodified, typeoffile etc.
    for resp in tree.findall('.//{DAV:}response'):
        # Here we can get the filpath out of href and get further information in prop (lastimemodified, typeoffile, etc.)
        for p in resp:
            # In case p.text is not none, it contains the filepath
            if not (p.text is None):
                if (p.text[-1] == '/'):
                    # If the current object is a folder, check it its not first folder
                    if not (firstfolder):
                        innerfolders.append(p.text)
                    else:
                        firstfolder = False
                    break
            # In case p.text is none, it contains the further information
            else:
                for t in p.findall('.//{DAV:}getlastmodified'):
                    # this function converts the given date to unix timestamp
                    lastmodified = time.mktime(
                        datetime.datetime.strptime(t.text, "%a, %d %b %Y %H:%M:%S GMT").timetuple())
                    # 631148400 is the unix timestamp of 01.01.1990 00:00:00, because we know there is no file older than this in our nextcloud system
                    if lastmodified < 631148400:
                        for fileid in p.findall('.//{http://owncloud.org/ns}fileid'):
                            linkswrongtime.append(fileid.text)
    return [innerfolders, linkswrongtime]


# This function returns the fileid of the version of a given fileid with the most current timestamp or None if there are no versions with a timestamp younger than 01.01.1990
def version_check(xmlfile):
    tree = ET.ElementTree(ET.fromstring(xmlfile))
    # Name of files are stored as a string. But we can check the timestamp of the file only after we can check the name,
    # so it needs to be stored temporary in case the timestamp is the most current
    temp = "this is a temporary string"
    # These two variables are used to store the highest/most current timestamp and the associated fileid
    most_current_timestamp = 631148400
    most_current_timestamp_fileid = 0
    for resp in tree.findall('.//{DAV:}response'):
        for p in resp:
            # In case p.text is not none, it contains the filepath
            if not (p.text is None):
                temp = p.text
            else:
                for t in p.findall('.//{DAV:}getlastmodified'):
                    if not (t.text is None):
                        # this function converts the given date to unix timestamp
                        lastmodified = time.mktime(
                            datetime.datetime.strptime(t.text, "%a, %d %b %Y %H:%M:%S GMT").timetuple())
                        #
                        if lastmodified > most_current_timestamp:
                            most_current_timestamp = lastmodified
                            fileid_old_version = temp.split('/')
                            most_current_timestamp_fileid = fileid_old_version[-1]
                    else:
                        break
    # Check if there is another version and a file with a current timestamp
    if most_current_timestamp_fileid != 0:
        return most_current_timestamp_fileid
    else:
        return None


if __name__ == "__main__":
    # Enter username and password to enter nextcloud via webdav
    user = sys.argv[1]
    passw = sys.argv[2]
    auth = requests.auth.HTTPBasicAuth(user, passw)
    # Prepare the path we want to use
    prefix_path = "https://kingsx.cs.uni-saarland.de"
    mainpath = "/remote.php/dav/files/" + user + "/Testrequests/"
    # List of all folderpaths we need to enter
    folders = [mainpath]
    # List of all fileids with wrong time
    wrongtime = []

    # Iterate through all folders and check for wrong timestamps
    while folders:
        path_suffix = folders.pop(0)
        path = prefix_path + str(path_suffix)
        r = propfind(path, auth)
        res = search_folder(r)
        # Append all found folders and files with wrong timestamps to global list
        folders = folders + res[0]
        wrongtime = wrongtime + res[1]
        # Iterate through all fileids with wrong timestamps and check for versions with intact timestamp
        while wrongtime:
            fileid = wrongtime.pop(0)
            version_suffix = "/remote.php/dav/versions/" + user + "/versions/" + fileid
            version_path = prefix_path + version_suffix
            versions = propfind(version_path, auth)
            print(version_check(versions))