#!/usr/bin/env python3
import argparse
import base64
import json
import os
import pathlib
import sys
import urllib.error
import urllib.parse
import urllib.request

DEFAULT_REGISTRY_URL = "https://git.thyme-labs.com/api/packages/khodo/generic"
DEFAULT_VERSION = "latest"
PAGE_LIMIT = 50


def read_config(path):
  try:
    data = json.loads(path.read_text(encoding="utf-8"))
  except (OSError, json.JSONDecodeError) as error:
    raise SystemExit(f"failed to read {path}: {error}") from error
  package = data.get("package", {})
  if not isinstance(package, dict):
    raise SystemExit(f"{path}: package must be an object")
  name = package.get("name")
  if not isinstance(name, str) or not name:
    raise SystemExit(f"{path}: package.name must be a non-empty string")
  artifact = package.get("artifact", {})
  if not isinstance(artifact, dict):
    artifact = {}
  registry_url = artifact.get("registry_url")
  if not isinstance(registry_url, str) or not registry_url:
    registry_url = DEFAULT_REGISTRY_URL
  return name, registry_url


def parse_registry_url(registry_url):
  parsed = urllib.parse.urlparse(registry_url.rstrip("/"))
  parts = [urllib.parse.unquote(part) for part in parsed.path.split("/") if part]
  if len(parts) < 4 or parts[-4] != "api" or parts[-3] != "packages" or parts[-1] != "generic":
    raise SystemExit("package artifact registry_url must end with /api/packages/{owner}/generic")
  owner = parts[-2]
  prefix = "/" + "/".join(urllib.parse.quote(part, safe="") for part in parts[:-4]) if parts[:-4] else ""
  return parsed, prefix, owner


def build_url(parsed, path, query=""):
  return urllib.parse.urlunparse((
    parsed.scheme,
    parsed.netloc,
    path,
    "",
    query,
    "",
  ))


def quote_path(*parts):
  return "/".join(urllib.parse.quote(part, safe="") for part in parts)


def version_list_url(parsed, prefix, owner, package_name, page):
  path = f"{prefix}/api/v1/packages/{quote_path(owner, 'generic', package_name)}"
  query = urllib.parse.urlencode({
    "page": page,
    "limit": PAGE_LIMIT,
  })
  return build_url(parsed, path, query)


def version_delete_url(parsed, prefix, owner, package_name, version):
  path = f"{prefix}/api/packages/{quote_path(owner, 'generic', package_name, version)}"
  return build_url(parsed, path)


def file_upload_url(registry_url, package_name, version, path):
  return "/".join((
    registry_url.rstrip("/"),
    urllib.parse.quote(package_name, safe=""),
    urllib.parse.quote(version, safe=""),
    urllib.parse.quote(path.name, safe=""),
  ))


def authorization(user, token):
  encoded = base64.b64encode(f"{user}:{token}".encode("utf-8")).decode("ascii")
  return f"Basic {encoded}"


def request(method, url, auth, data=None, headers=None, missing_ok=False):
  request_headers = {
    "Authorization": auth,
    **(headers or {}),
  }
  request = urllib.request.Request(url, data=data, method=method, headers=request_headers)
  try:
    return urllib.request.urlopen(request)
  except urllib.error.HTTPError as error:
    if missing_ok and error.code == 404:
      return None
    body = error.read().decode("utf-8", errors="replace")
    message = f"{method} {url} failed with HTTP {error.code}"
    if body:
      message += f": {body}"
    raise SystemExit(message) from error
  except urllib.error.URLError as error:
    raise SystemExit(f"{method} {url} failed: {error.reason}") from error


def list_versions(parsed, prefix, owner, package_name, auth):
  versions = []
  page = 1
  while True:
    response = request("GET", version_list_url(parsed, prefix, owner, package_name, page), auth, missing_ok=True)
    if response is None:
      return []
    with response:
      data = json.loads(response.read().decode("utf-8"))
    if not isinstance(data, list):
      raise SystemExit("Gitea package version list response was not an array")
    if not data:
      break
    for item in data:
      if isinstance(item, dict) and isinstance(item.get("version"), str):
        versions.append(item["version"])
    if len(data) < PAGE_LIMIT:
      break
    page += 1
  return sorted(set(versions))


def delete_version(parsed, prefix, owner, package_name, version, auth):
  url = version_delete_url(parsed, prefix, owner, package_name, version)
  response = request("DELETE", url, auth, missing_ok=True)
  if response is None:
    print(f"Package version already absent: {package_name}/{version}")
    return
  with response:
    if response.status != 204:
      raise SystemExit(f"DELETE {url} returned HTTP {response.status}")
  print(f"Deleted package version: {package_name}/{version}")


def discover_artifacts(dist_dir, package_name, version):
  archives = sorted(dist_dir.glob(f"{package_name}-{version}-*.tar.gz"))
  artifacts = []
  for archive in archives:
    artifacts.append(archive)
    checksum = archive.with_name(archive.name + ".sha256")
    if checksum.is_file():
      artifacts.append(checksum)
  if not artifacts:
    raise SystemExit(f"no artifacts found matching {dist_dir}/{package_name}-{version}-*.tar.gz")
  missing = [path for path in artifacts if not path.is_file()]
  if missing:
    raise SystemExit("missing artifact files: " + ", ".join(str(path) for path in missing))
  return artifacts


def upload_file(registry_url, package_name, version, path, auth):
  url = file_upload_url(registry_url, package_name, version, path)
  headers = {
    "Content-Length": str(path.stat().st_size),
    "Content-Type": "application/octet-stream",
  }
  with path.open("rb") as input_file:
    response = request("PUT", url, auth, data=input_file, headers=headers)
    with response:
      if response.status != 201:
        raise SystemExit(f"PUT {url} returned HTTP {response.status}")
  print(f"Uploaded package file: {package_name}/{version}/{path.name}")


def parse_args(argv):
  parser = argparse.ArgumentParser(description="Replace Product Vamp's rolling Gitea generic package.")
  parser.add_argument("--config", type=pathlib.Path, default=pathlib.Path("modulus.json"))
  parser.add_argument("--dist-dir", type=pathlib.Path, default=pathlib.Path("build/packages"))
  parser.add_argument("--version", default=DEFAULT_VERSION)
  parser.add_argument("--user", default=None)
  parser.add_argument("--token", default=None)
  return parser.parse_args(argv)


def main(argv):
  args = parse_args(argv)
  package_name, registry_url = read_config(args.config)
  user = args.user or os_environ("PACKAGE_REGISTRY_USER")
  token = args.token or os_environ("PACKAGE_REGISTRY_TOKEN")
  auth = authorization(user, token)
  parsed, prefix, owner = parse_registry_url(registry_url)
  artifacts = discover_artifacts(args.dist_dir, package_name, args.version)

  existing_versions = list_versions(parsed, prefix, owner, package_name, auth)

  # Gitea rejects duplicate file names within a generic package version, so
  # replacing the rolling release requires deleting the old version first.
  if args.version in existing_versions:
    delete_version(parsed, prefix, owner, package_name, args.version, auth)

  for artifact in artifacts:
    upload_file(registry_url, package_name, args.version, artifact, auth)

  for version in existing_versions:
    if version != args.version:
      delete_version(parsed, prefix, owner, package_name, version, auth)

  return 0


def os_environ(name):
  value = os.environ.get(name)
  if not value:
    raise SystemExit(f"{name} is required")
  return value


if __name__ == "__main__":
  raise SystemExit(main(sys.argv[1:]))