import requests
import re  # import regular expressions to remove stray numbers in string that might interfere with date finding
import json  # import json to read project info stored in json file
from project import Project
from shared import CSC_MIRROR

import datefinder  # another date finding library
from datetime import timedelta

class macports(Project):
    """macports class"""
    # checker: gets the timestamp of the file inside the directory at the specified URL and returns it as a string
    @staticmethod
    def checker(directory_URL, file_name):
        page = requests.get(directory_URL).text
        file_index = page.find(file_name)
        end_index = page[file_index:].find("</tr>") + file_index

        # The CSC mirror does not use tr tags, so end_index will be set to the end of the file
        if end_index == (file_index - 1):
            end_index = len(page) - 1

        # remove stray numbers (file size numbers in particular) that might interfere with date finding
        segment_clean = re.sub(r'\s\d+\s', ' ', page[file_index:end_index])  # removes numbers for size
        segment_clean = re.sub(r'\s\d+\w*\s', ' ', page[file_index:end_index])  # removes numbers + size unit. e.x. 50kb

        # finds the dates in the segment after the file name
        # notes: a generator will be returned by the datefinder module. I'm typecasting it to a list. Please read the note of caution provided at the bottom.
        matches = list(datefinder.find_dates(segment_clean))

        return matches[0]
    
    @classmethod
    def check(cls, data, project, current_time):
        """Check if project packages are up-to-date"""
        csc_url = CSC_MIRROR + data[project]["csc"]
        upstream_url = data[project]["upstream"]
        file_name = data[project]["file"]
        
        upstreamDate = cls.checker(csc_url, file_name)
        downstreamDate = cls.checker(upstream_url, file_name)

        if (upstreamDate < downstreamDate):
            timeDiff = downstreamDate - upstreamDate
        else:
            timeDiff = upstreamDate - downstreamDate

        # MacPorts are updated so often that we want to make sure we are 
        #   at most 6 hours out of date
        return timeDiff < timedelta(hours=6)