import errno
import logging
import os
import shutil
import time
import urllib.parse
import xml.etree.ElementTree as ET
from urllib.error import HTTPError

import osc.core

from lib.proxy_sha256 import md5
from lib.request import Request
from lib.user import User


# Add a retry wrapper for some of the HTTP actions.
def retry(func):
    def wrapper(*args, **kwargs):
        retry = 0
        while retry < 5:
            try:
                return func(*args, **kwargs)
            except HTTPError as e:
                if 500 <= e.code <= 599:
                    retry += 1
                    logging.warning(
                        f"HTTPError {e.code} -- Retrying {args[0]} ({retry})"
                    )
                    # TODO: remove when move to async
                    time.sleep(0.5)
                else:
                    raise
            except urllib.error.URLError as e:
                if e.reason.errno in (errno.ENETUNREACH, errno.EADDRNOTAVAIL):
                    retry += 1
                    logging.warning(f"URLError {e} -- Retrying {args[0]} ({retry})")
                    time.sleep(0.5)
                else:
                    logging.warning(f"URLError {e.errno} uncaught")
                    raise
            except OSError as e:
                if e.errno in (
                    errno.ENETUNREACH,
                    errno.EADDRNOTAVAIL,
                ):  # sporadically hits cloud VMs :(
                    retry += 1
                    logging.warning(f"OSError {e} -- Retrying {args[0]} ({retry})")
                    # TODO: remove when move to async
                    time.sleep(0.5)
                else:
                    logging.warning(f"OSError {e.errno} uncaught")
                    raise

    return wrapper


osc.core.http_GET = retry(osc.core.http_GET)


class OBS:
    def __init__(self, url=None):
        if url:
            self.change_url(url)

    def change_url(self, url):
        self.url = url
        osc.conf.get_config(override_apiurl=url)

    def _xml(self, url_path, **params):
        url = osc.core.makeurl(self.url, [url_path], params)
        logging.debug(f"GET {url}")
        return ET.parse(osc.core.http_GET(url)).getroot()

    def _meta(self, project, package, **params):
        try:
            root = self._xml(f"source/{project}/{package}/_meta", **params)
        except HTTPError:
            logging.error(f"Package [{project}/{package} {params}] has no meta")
            return None
        return root

    def _history(self, project, package, **params):
        try:
            root = self._xml(f"source/{project}/{package}/_history", **params)
        except HTTPError:
            logging.error(f"Package [{project}/{package} {params}] has no history")
            return None
        return root

    def _user(self, userid, **params):
        try:
            root = self._xml(f"/person/{userid}", **params)
        except HTTPError:
            logging.error(f"UserID {userid} not found")
            return None
        return root

    def _link(self, project, package, rev):
        try:
            root = self._xml(f"source/{project}/{package}/_link", rev=rev)
        except HTTPError:
            logging.info("Package has no link")
            return None
        except ET.ParseError:
            logging.error(
                f"Package [{project}/{package} rev={rev}] _link can't be parsed"
            )
        return root

    def _request(self, requestid):
        try:
            root = self._xml(f"request/{requestid}")
        except HTTPError:
            logging.warning(f"Cannot fetch request {requestid}")
            return None
        return root

    def exists(self, project, package):
        root = self._meta(project, package)
        if root is None:
            return False
        return root.get("project") == project

    def devel_project(self, project, package):
        root = self._meta(project, package)
        devel = root.find("devel")
        if devel is None:
            return None
        return devel.get("project")

    def request(self, requestid):
        root = self._request(requestid)
        if root is not None:
            return Request().parse(root)

    def user(self, userid):
        root = self._user(userid)
        if root is not None:
            return User().parse(root, userid)

    def files(self, project, package, revision):
        root = self._xml(f"source/{project}/{package}", rev=revision, expand=1)
        return [
            (e.get("name"), int(e.get("size")), e.get("md5"))
            for e in root.findall("entry")
        ]

    def _download(self, project, package, name, revision):
        url = osc.core.makeurl(
            self.url,
            ["source", project, package, urllib.parse.quote(name)],
            {"rev": revision, "expand": 1},
        )
        return osc.core.http_GET(url)

    def download(
        self,
        project: str,
        package: str,
        name: str,
        revision: str,
        dirpath: str,
        cachedir: str,
        file_md5: str,
    ) -> None:

        cached_file = self._path_from_md5(name, cachedir, file_md5)
        if not self.in_cache(name, cachedir, file_md5):
            with (dirpath / name).open("wb") as f:
                f.write(self._download(project, package, name, revision).read())

            # Validate the MD5 of the downloaded file
            if md5(dirpath / name) != file_md5:
                raise Exception(f"Download error in {name}")

            shutil.copy(dirpath / name, cached_file.with_suffix(".new"))
            os.rename(cached_file.with_suffix(".new"), cached_file)
        else:
            shutil.copy(cached_file, dirpath / name)

    def list(self, project, package, srcmd5, linkrev):
        params = {"rev": srcmd5, "expand": "1"}
        if linkrev:
            params["linkrev"] = linkrev

        try:
            root = self._xml(f"source/{project}/{package}", **params)
        except HTTPError as e:
            if e.code == 400:
                logging.error(
                    f"Package [{project}/{package} {params}] can't be expanded: {e}"
                )
                return None
            raise e

        return root

    def _path_from_md5(self, name, cachedir, md5):
        filepath = cachedir / md5[:3]
        filepath.mkdir(parents=True, exist_ok=True)
        return filepath / md5[3:]

    def in_cache(self, name, cachedir, md5):
        return self._path_from_md5(name, cachedir, md5).exists()