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.hash 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):
        self.url = None
        self.change_url(url)

    def change_url(self, url):
        if 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, key, **params):
        try:
            root = self._xml(f"source/{key}/_meta", **params)
        except HTTPError:
            logging.error(f"Project/Package [{key} {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(f"{project}/{package}")
        if root is None:
            return False
        return root.get("project") == project

    def devel_project(self, project, package):
        root = self._meta(f"{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, 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:
                logging.debug(f"Download {project}/{package}/{name}")
                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)
            logging.debug(f"Use cached {project}/{package}/{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()