import os
import requests
from requests.auth import HTTPBasicAuth
import logging

logger = logging.getLogger(__name__)

class BitbucketClient:
    def __init__(self):
        self.username = os.getenv("BITBUCKET_USERNAME")
        self.email = os.getenv("BITBUCKET_EMAIL")
        self.app_password = os.getenv("BITBUCKET_APP_PASSWORD")
        self.token = os.getenv("BITBUCKET_TOKEN")
        self.base_url = "https://api.bitbucket.org/2.0"
        
        # Determine the identifier for Basic Auth (Email or Username)
        self.auth_user = self.email or self.username

        if not self.token and (not self.auth_user or not self.app_password):
            logger.warning("Bitbucket credentials (token or email/password) not fully configured.")

    def _get_auth_params(self, is_diff: bool = False):
        """
        Helper to return auth configuration based on available environment variables.
        """
        headers = {}
        if is_diff:
            headers["Accept"] = "text/plain"
        else:
            headers["Accept"] = "application/json"

        # If we have both email and token, and token starts with 'ATA' (Bitbucket App Password/Token),
        # we MUST use Basic Auth (email:token).
        if self.email and self.token and self.token.startswith("ATA"):
            logger.info("Detected Bitbucket App Password/Token. Using Basic Auth with email.")
            return {
                "auth": HTTPBasicAuth(self.email, self.token),
                "headers": headers
            }

        if self.token:
            # Check if token is already a full header string
            if self.token.startswith("Basic ") or self.token.startswith("Bearer "):
                headers["Authorization"] = self.token
            else:
                # Default to Bearer for other tokens (like OAuth)
                headers["Authorization"] = f"Bearer {self.token}"
            
            return {"headers": headers}
        else:
            return {
                "auth": HTTPBasicAuth(self.auth_user, self.app_password),
                "headers": headers
            }

    def get_diff(self, workspace: str, repo_slug: str, pr_id: int) -> str:
        """
        Fetch the diff for a specific pull request.
        """
        url = f"{self.base_url}/repositories/{workspace}/{repo_slug}/pullrequests/{pr_id}/diff"
        
        try:
            auth_params = self._get_auth_params(is_diff=True)
            response = requests.get(url, **auth_params)
            response.raise_for_status()
            return response.text
        except Exception as e:
            logger.error(f"Failed to fetch diff from Bitbucket: {str(e)}")
            raise

    def get_pr_details(self, workspace: str, repo_slug: str, pr_id: int) -> dict:
        """
        Fetch pull request details (like author email).
        """
        url = f"{self.base_url}/repositories/{workspace}/{repo_slug}/pullrequests/{pr_id}"
        
        try:
            auth_params = self._get_auth_params(is_diff=False)
            response = requests.get(url, **auth_params)
            response.raise_for_status()
            return response.json()
        except Exception as e:
            logger.error(f"Failed to fetch PR details from Bitbucket: {str(e)}")
            raise

    @staticmethod
    def parse_url(url: str) -> dict:
        """
        Parse a Bitbucket API URL to extract workspace, repo_slug, and pr_id.
        Example: https://api.bitbucket.org/2.0/repositories/workspace/repo/pullrequests/123/diff
        """
        import re
        pattern = r"repositories/([^/]+)/([^/]+)/pullrequests/(\d+)"
        match = re.search(pattern, url)
        if match:
            return {
                "workspace": match.group(1),
                "repo_slug": match.group(2),
                "pr_id": int(match.group(3))
            }
        raise ValueError("Invalid Bitbucket PR URL format")