#!/usr/bin/env python3

import difflib
import os
import re
import sys
from typing import Optional

BASE_DIR = os.path.dirname(os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
sys.path.append(BASE_DIR)
from scripts.lib.setup_path import setup_path

setup_path()


current_path = "/etc/zulip/settings.py"
if len(sys.argv) >= 2:
    current_path = sys.argv[1]

print(f"Reading current configuration from {current_path}...")
with open(current_path) as f:
    current_contents = f.read()

import requests

print("Fetching old versions of setting templates from Github...")
templ = {}
url: Optional[str] = "https://api.github.com/repos/zulip/zulip/tags?per_page=100"

while url is not None:
    resp = requests.get(url)
    if resp.status_code != 200:
        print(resp.content)
        sys.exit(1)

    url = resp.links.get("next", {}).get("url")
    for tag in [t["name"] for t in resp.json()]:
        if not re.match(r"^\d+\.\d+(\.\d+)?$", tag):
            continue

        filename = "zproject/prod_settings_template.py"
        if [int(x) for x in tag.split(".")] < [1, 4]:
            filename = "zproject/local_settings_template.py"

        print(f"  - {tag}")
        resp = requests.get(
            f"https://raw.githubusercontent.com/zulip/zulip/{tag}/{filename}",
        )
        if resp.status_code == 200:
            templ[tag] = resp.content.decode()
        else:
            print("Failure: ")
            print(resp)

print("Computing minimal difference...")
sequence_matchers = {}
for version, contents in templ.items():
    sm = difflib.SequenceMatcher(None, current_contents, contents)
    sequence_matchers[version] = sm

likely = sorted(sequence_matchers.keys(), key=lambda v: sequence_matchers[v].ratio(), reverse=True)
print(f"Most likely version: {likely[0]}")


diff = difflib.unified_diff(
    templ[likely[0]].splitlines(keepends=True),
    current_contents.splitlines(keepends=True),
    fromfile="zulip-server-{version}/zproject/prod_settings_template.py",
    tofile=current_path,
)

print()
print("".join(diff), end="")