#!/usr/bin/env python3
#
# Update the Syncthing bundle based on the latest github release
# 1. Loads the latest tag name from github api
# 2. Parses the tag
# 3. Writes the syncthing/Info.plist
# 4. Update the syncthing/Scripts/syncthing-resource.sh
#
###
import os
import sys
import json
import semver
import fileinput
from urllib.request import urlopen
from string import Template

distVersion   = 1 # Syncthing for macOS distribution version
latest_url    = "https://api.github.com/repos/syncthing/syncthing/releases/latest"
infoPlist     = '../../syncthing/Info.plist'
infoPlistTmpl = '../../syncthing/Info.plist.tmpl'
syncthingResourceScript = "../../syncthing/Scripts/syncthing-resource.sh"

###
# Download latest tag from github
###
response = urlopen(latest_url)
body = response.read().decode("utf-8")
data = json.loads(body)

if 'tag_name' not in data:
	raise ValueError("tag_name not present in latest_url")

import urllib.request
import json
import semver

def get_latest_v2_tag_name(repo_owner, repo_name, allow_prerelease: bool = False):
    """
    Fetches the latest v2 (pre)release tag_name from a GitHub repository's releases.

    Args:
        repo_owner (str): The owner of the GitHub repository (e.g., 'syncthing').
        repo_name (str): The name of the GitHub repository (e.g., 'syncthing').

    Returns:
        str or None: The tag_name of the latest v2 prerelease, or None if not found.
    """
    url = f"https://api.github.com/repos/{repo_owner}/{repo_name}/releases"
    try:
        with urllib.request.urlopen(url) as response:
            if response.getcode() == 200:
                data = json.loads(response.read().decode('utf-8'))
            else:
                print(f"Error fetching data: HTTP {response.getcode()}")
                return None
    except urllib.error.URLError as e:
        print(f"Error connecting to GitHub API: {e.reason}")
        return None
    except json.JSONDecodeError:
        print("Error decoding JSON response.")
        return None

    v2_releases = []
    for release in data:
        tag_name = release.get('tag_name')
        prerelease = release.get('prerelease')

        if tag_name:
            try:
                version = semver.Version.parse(tag_name.lstrip('v')) # Remove 'v' prefix if present

                if allow_prerelease and version.major == 2 and version.prerelease:
                    v2_releases.append(version)
                elif version.major == 2 and not version.prerelease:
                    v2_releases.append(version)
            except ValueError:
                # Not a valid semver string, skip
                continue

    if not v2_releases:
        return None

    # Sort the releases to find the latest
    latest_v2_release = max(v2_releases)
    return f"v{latest_v2_release}" # Re-add the 'v' prefix for consistency

###
# Parse the tag version and generate CFBundleShortVersionString and CFBundleVersion
###
owner = "syncthing"
repo = "syncthing"
latest_tag = get_latest_v2_tag_name(owner, repo)

if latest_tag:
	print(f"The latest v2 (pre)release tag_name for {owner}/{repo} is: {latest_tag}")
else:
	print(f"No v2 (pre)release found for {owner}/{repo}.")

# Ugly hack because of https://github.com/python-semver/python-semver/issues/137
tag_name = latest_tag.replace('v', '')
version = semver.VersionInfo.parse(tag_name)

CFBundleShortVersionString = "{}-{:d}".format(
	str(version),
	distVersion)
CFBundleVersion = "{:d}{:03d}{:03d}{:02d}".format(
	version.major,
	version.minor,
	version.patch,
	distVersion)

###
# Update Info.plist from template
###
infoPlistTmplVars = {
	'CFBundleShortVersionString' : CFBundleShortVersionString,
	'CFBundleVersion' : CFBundleVersion
}

f = open(infoPlistTmpl, 'r')
tmpl = Template(f.read())
f.close()
result = tmpl.substitute(infoPlistTmplVars)

f = open(infoPlist, 'w')
f.write(result)
f.close()

###
# Update syncthing/Scripts/syncthing-resource.sh
###
for line in fileinput.input(syncthingResourceScript, inplace=True):
	linePrefix = 'SYNCTHING_VERSION='
	if line.startswith(linePrefix):
		line = '{}"{}"\n'.format(linePrefix, str(version))
	sys.stdout.write(line)

print(f"Found latest tag from github: {tag_name}")
print(f"CFBundleShortVersionString={CFBundleShortVersionString}")
print(f"CFBundleVersion={CFBundleVersion}")
