#!/usr/bin/env python3

"""
This mirror status checker determines whether CSC mirror is up-to-date with upstream
"""

from datetime import datetime, timedelta
import requests

CSC_MIRROR = "http://mirror.csclub.uwaterloo.ca/"
SUCCESS = "Success: {} up-to-date"
FAILURE = "Failure: {} out-of-sync"
ERROR = "Error: {}\n{}"

def get_debian_dt(trace_file_url):
    """Get Debian datetime object from trace file"""
    response_text = requests.get(trace_file_url).text
    time_str = response_text.split('\n')[0]
    return datetime.strptime(time_str, "%a %b %d %H:%M:%S UTC %Y")

def get_kernel_line_count(checksum_file_url):
    """Get Kernel line count of checksum file"""
    response_text = requests.get(checksum_file_url).text
    return len(response_text.split('\n'))

def get_openbsd_sec(timestamp_file_url):
    """Get OpenBSD seconds since the Epoch from timestamp file"""
    sec_str = requests.get(timestamp_file_url).text
    return int(sec_str)

if __name__ == "__main__":
    # Arch
    try:
        arch_json = requests.get("https://archlinux.org/mirrors/status/json/").json()
        last_check_str = arch_json["last_check"]
        last_sync_str = [url for url in arch_json["urls"] if url["url"] == \
                         f"{CSC_MIRROR}archlinux/"][0]["last_sync"]
        last_check_dt = datetime.strptime(last_check_str, "%Y-%m-%dT%H:%M:%S.%fZ")
        last_sync_dt = datetime.strptime(last_sync_str, "%Y-%m-%dT%H:%M:%SZ")
        # According to https://archlinux.org/mirrors/status/:
        # Due to the timing of mirror checks, any value under one hour should be viewed as ideal
        OUTPUT = SUCCESS if last_check_dt < last_sync_dt + timedelta(hours = 1) else FAILURE
        print(OUTPUT.format("Arch"))
    except requests.exceptions.RequestException as err:
        print(ERROR.format("Arch", err))

    # Debian
    try:
        official_dt = get_debian_dt("https://ftp-master.debian.org/debian/project/trace/master")
        csc_dt = get_debian_dt(f"{CSC_MIRROR}debian/project/trace/master")
        # Keep the table cell at https://mirror-master.debian.org/status/mirror-status.html
        # green and not yellow
        OUTPUT = SUCCESS if official_dt < csc_dt + timedelta(hours = 7) else FAILURE
        print(OUTPUT.format("Debian"))
    except requests.exceptions.RequestException as err:
        print(ERROR.format("Debian", err))

    # Kernel
    try:
        official_line_count = get_kernel_line_count(
            "https://mirrors.edge.kernel.org/pub/linux/kernel/next/sha256sums.asc")
        csc_line_count = get_kernel_line_count(
            f"{CSC_MIRROR}kernel.org/linux/kernel/next/sha256sums.asc")
        # A new update on a certain day adds 2 new lines
        OUTPUT = SUCCESS if official_line_count <= csc_line_count + 2 else FAILURE
        print(OUTPUT.format("Kernel"))
    except requests.exceptions.RequestException as err:
        print(ERROR.format("Kernel", err))

    # OpenBSD
    try:
        official_sec = get_openbsd_sec("https://ftp.openbsd.org/pub/OpenBSD/timestamp")
        csc_sec = get_openbsd_sec(f"{CSC_MIRROR}OpenBSD/timestamp")
        # Out-of-sync by 1 day maximum
        OUTPUT = SUCCESS if official_sec < csc_sec + 86400 else FAILURE
        print(OUTPUT.format("OpenBSD"))
    except requests.exceptions.RequestException as err:
        print(ERROR.format("OpenBSD", err))