import typing as t
from dataclasses import dataclass
from datetime import datetime
from urllib.parse import urlparse

import requests

from unstructured.ingest.connector.git import (
    GitIngestDoc,
    GitSourceConnector,
    SimpleGitConfig,
)
from unstructured.ingest.error import SourceConnectionError, SourceConnectionNetworkError
from unstructured.ingest.interfaces import SourceMetadata
from unstructured.ingest.logger import logger
from unstructured.utils import requires_dependencies

if t.TYPE_CHECKING:
    from github.Repository import Repository


@dataclass
class SimpleGitHubConfig(SimpleGitConfig):
    def __post_init__(self):
        parsed_gh_url = urlparse(self.url)
        path_fragments = [fragment for fragment in parsed_gh_url.path.split("/") if fragment]

        # If a scheme and netloc are provided, ensure they are correct
        # Additionally, ensure that the path contains two fragments
        if (
            (parsed_gh_url.scheme and parsed_gh_url.scheme != "https")
            or (parsed_gh_url.netloc and parsed_gh_url.netloc != "github.com")
            or len(path_fragments) != 2
        ):
            raise ValueError(
                'Please provide a valid URL, e.g. "https://github.com/Unstructured-IO/unstructured"'
                ' or a repository owner/name pair, e.g. "Unstructured-IO/unstructured".',
            )

        # If there's no issues, store the core repository info
        self.repo_path = parsed_gh_url.path

    @SourceConnectionError.wrap
    @requires_dependencies(["github"], extras="github")
    def get_repo(self) -> "Repository":
        from github import Github

        github = Github(self.access_config.access_token)
        return github.get_repo(self.repo_path)


@dataclass
class GitHubIngestDoc(GitIngestDoc):
    connector_config: SimpleGitHubConfig
    registry_name: str = "github"

    @property
    def date_created(self) -> t.Optional[str]:
        return None

    @requires_dependencies(["github"], extras="github")
    def _fetch_file(self):
        from github.GithubException import UnknownObjectException

        try:
            content_file = self.connector_config.get_repo().get_contents(self.path)
        except UnknownObjectException:
            logger.error(f"File doesn't exists {self.connector_config.url}/{self.path}")
            return None

        return content_file

    @SourceConnectionNetworkError.wrap
    def _fetch_content(self, content_file):
        contents = b""
        if (
            not content_file.content  # type: ignore
            and content_file.encoding == "none"  # type: ignore
            and content_file.size  # type: ignore
        ):
            logger.info("File too large for the GitHub API, using direct download link instead.")
            # NOTE: Maybe add a raise_for_status to catch connection timeout or HTTP Errors?
            response = requests.get(content_file.download_url)  # type: ignore
            if response.status_code != 200:
                logger.info("Direct download link has failed... Skipping this file.")
                return None
            else:
                contents = response.content
        else:
            contents = content_file.decoded_content  # type: ignore
        return contents

    def update_source_metadata(self, **kwargs):
        content_file = kwargs.get("content_file", self._fetch_file())
        if content_file is None:
            self.source_metadata = SourceMetadata(
                exists=False,
            )
            return

        date_modified = datetime.strptime(
            content_file.last_modified,
            "%a, %d %b %Y %H:%M:%S %Z",
        ).isoformat()
        self.source_metadata = SourceMetadata(
            date_modified=date_modified,
            version=content_file.etag,
            source_url=content_file.download_url,
            exists=True,
        )

    def _fetch_and_write(self) -> None:
        content_file = self._fetch_file()
        self.update_source_metadata(content_file=content_file)
        contents = self._fetch_content(content_file)
        if contents is None:
            raise ValueError(
                f"Failed to retrieve file from repo "
                f"{self.connector_config.url}/{self.path}. Check logs",
            )
        with open(self.filename, "wb") as f:
            f.write(contents)


@dataclass
class GitHubSourceConnector(GitSourceConnector):
    connector_config: SimpleGitHubConfig

    @requires_dependencies(["github"], extras="github")
    def check_connection(self):
        from github import Consts
        from github.GithubRetry import GithubRetry
        from github.Requester import Requester

        try:
            requester = Requester(
                auth=self.connector_config.access_config.access_token,
                base_url=Consts.DEFAULT_BASE_URL,
                timeout=Consts.DEFAULT_TIMEOUT,
                user_agent=Consts.DEFAULT_USER_AGENT,
                per_page=Consts.DEFAULT_PER_PAGE,
                verify=True,
                retry=GithubRetry(),
                pool_size=None,
            )
            url_base = (
                "/repositories/" if isinstance(self.connector_config.repo_path, int) else "/repos/"
            )
            url = f"{url_base}{self.connector_config.repo_path}"
            headers, _ = requester.requestJsonAndCheck("HEAD", url)
            logger.debug(f"headers from HEAD request: {headers}")
        except Exception as e:
            logger.error(f"failed to validate connection: {e}", exc_info=True)
            raise SourceConnectionError(f"failed to validate connection: {e}")

    def get_ingest_docs(self):
        repo = self.connector_config.get_repo()
        # Load the Git tree with all files, and then create Ingest docs
        # for all blobs, i.e. all files, ignoring directories
        sha = self.connector_config.branch or repo.default_branch
        git_tree = repo.get_git_tree(sha, recursive=True)
        return [
            GitHubIngestDoc(
                connector_config=self.connector_config,
                processor_config=self.processor_config,
                read_config=self.read_config,
                path=element.path,
            )
            for element in git_tree.tree
            if element.type == "blob"
            and self.is_file_type_supported(element.path)
            and (not self.connector_config.file_glob or self.does_path_match_glob(element.path))
        ]