#!/usr/bin/env python3
# Creates or updates the Gitea release for a tag and attaches files to it. Its
# notes are that version's section of CHANGELOG.md. Run again for the same tag,
# it updates the notes and replaces files of the same name.
#
#   gitea-release.py <tag> <file>...
#
# Needs GITEA_URL (https://gitea.example.com), GITEA_REPO (owner/name) and
# GITEA_TOKEN. Used by .gitea/workflows/release.yaml.

import json
import os
import sys
import urllib.error
import urllib.parse
import urllib.request
import uuid


def api(method, path, body=None, content_type="application/json"):
    url = f"{os.environ['GITEA_URL'].rstrip('/')}/api/v1/repos/{os.environ['GITEA_REPO']}{path}"
    if isinstance(body, dict):
        body = json.dumps(body).encode()
    headers = {"Authorization": f"token {os.environ['GITEA_TOKEN']}", "Accept": "application/json"}
    if body is not None:
        headers["Content-Type"] = content_type
    request = urllib.request.Request(url, data=body, method=method, headers=headers)
    try:
        with urllib.request.urlopen(request, timeout=300) as response:
            data = response.read()
            return json.loads(data) if data else None
    except urllib.error.HTTPError as e:
        if e.code == 404 and method == "GET":
            return None
        sys.exit(f"{method} {url}: HTTP {e.code}: {e.read().decode(errors='replace')}")


def changelog_section(version):
    """The lines under '## <version>' in CHANGELOG.md, up to the next '## '."""
    lines, found = [], False
    with open("CHANGELOG.md") as f:
        for line in f:
            if line.startswith("## "):
                if found:
                    break
                found = line[3:].split()[0] == version
                continue
            if found:
                lines.append(line)
    if not found:
        sys.exit(f"CHANGELOG.md has no '## {version}' section")
    return "".join(lines).strip() + "\n"


def upload(release_id, path):
    name = os.path.basename(path)
    boundary = uuid.uuid4().hex
    with open(path, "rb") as f:
        content = f.read()
    body = (f"--{boundary}\r\nContent-Disposition: form-data; name=\"attachment\"; filename=\"{name}\"\r\n"
            f"Content-Type: application/octet-stream\r\n\r\n").encode() + content + f"\r\n--{boundary}--\r\n".encode()
    api("POST", f"/releases/{release_id}/assets?name={urllib.parse.quote(name)}", body,
        f"multipart/form-data; boundary={boundary}")
    print(f"attached {name}")


def main(tag, files):
    notes = changelog_section(tag[1:] if tag.startswith("v") else tag)
    release = api("GET", f"/releases/tags/{urllib.parse.quote(tag)}")
    if release is None:
        release = api("POST", "/releases", {"tag_name": tag, "name": tag, "body": notes})
        print(f"created release {tag}")
    else:
        release = api("PATCH", f"/releases/{release['id']}", {"body": notes})
        print(f"updated release {tag}")
    names = {os.path.basename(p) for p in files}
    for asset in release.get("assets") or []:
        if asset["name"] in names:
            api("DELETE", f"/releases/{release['id']}/assets/{asset['id']}")
    for path in files:
        upload(release["id"], path)
    print(release.get("html_url", ""))


if __name__ == "__main__":
    if len(sys.argv) < 3:
        sys.exit("usage: gitea-release.py <tag> <file>...")
    for var in ("GITEA_URL", "GITEA_REPO", "GITEA_TOKEN"):
        if not os.environ.get(var):
            sys.exit(f"{var} is not set")
    main(sys.argv[1], sys.argv[2:])