import sys
from pathlib import Path

sys.path.append(str(Path(__file__).parent.parent.parent))

import g4f
import json
import os
import re
import requests
from typing import Union
from github import Github
from github.PullRequest import PullRequest

g4f.debug.logging = True
g4f.debug.version_check = False

GITHUB_TOKEN = os.getenv('GITHUB_TOKEN')
GITHUB_REPOSITORY = os.getenv('GITHUB_REPOSITORY')
G4F_PROVIDER = os.getenv('G4F_PROVIDER')
G4F_MODEL = os.getenv('G4F_MODEL') or g4f.models.gpt_4

def get_github_token():
    token = os.getenv('GITHUB_TOKEN')
    if not token:
        raise ValueError("GITHUB_TOKEN environment variable is not set")
    print(f"Token length: {len(token)}")
    print(f"Token (masked): {'*' * (len(token) - 4) + token[-4:]}")
    if len(token) != 40 or not token.isalnum():
        raise ValueError("GITHUB_TOKEN appears to be invalid (should be 40 alphanumeric characters)")
    return token

def get_pr_details(github: Github) -> PullRequest:
    """
    Retrieves the details of the pull request from GitHub.

    Args:
        github (Github): The Github object to interact with the GitHub API.

    Returns:
        PullRequest: An object representing the pull request.
    """
    pr_number = os.getenv('PR_NUMBER')
    if not pr_number:
        print("PR_NUMBER environment variable is not set.")
        return None

    try:
        print(f"Attempting to get repo: {GITHUB_REPOSITORY}")
        repo = github.get_repo(GITHUB_REPOSITORY)
        print(f"Successfully got repo: {repo.full_name}")
        
        print(f"Attempting to get pull request: {pr_number}")
        pull = repo.get_pull(int(pr_number))
        print(f"Successfully got pull request: #{pull.number}")
        
        return pull
    except Exception as e:
        print(f"Error in get_pr_details: {e}")
        return None

def get_diff(diff_url: str) -> str:
    """
    Fetches the diff of the pull request from a given URL.

    Args:
        diff_url (str): URL to the pull request diff.

    Returns:
        str: The diff of the pull request.
    """
    response = requests.get(diff_url)
    response.raise_for_status()
    return response.text

def read_json(text: str) -> dict:
    """
    Parses JSON code block from a string.

    Args:
        text (str): A string containing a JSON code block.

    Returns:
        dict: A dictionary parsed from the JSON code block.
    """
    match = re.search(r"```(json|)\n(?P<code>[\S\s]+?)\n```", text)
    if match:
        text = match.group("code")
    try:
        return json.loads(text.strip())
    except json.JSONDecodeError:
        print("No valid json:", text)
        return {}

def read_text(text: str) -> str:
    """
    Extracts text from a markdown code block.

    Args:
        text (str): A string containing a markdown code block.

    Returns:
        str: The extracted text.
    """
    match = re.search(r"```(markdown|)\n(?P<text>[\S\s]+?)\n```", text)
    if match:
        return match.group("text")
    return text

def get_ai_response(prompt: str, as_json: bool = True) -> Union[dict, str]:
    """
    Gets a response from g4f API based on the prompt.

    Args:
        prompt (str): The prompt to send to g4f.
        as_json (bool): Whether to parse the response as JSON.

    Returns:
        Union[dict, str]: The parsed response from g4f, either as a dictionary or a string.
    """
    max_retries = 5
    providers = [None, 'Chatgpt4Online', 'OpenaiChat', 'Bing', 'Ai4Chat', 'NexraChatGPT']
    
    for provider in providers:
        for _ in range(max_retries):
            try:
                response = g4f.chat.completions.create(
                    G4F_MODEL,
                    [{'role': 'user', 'content': prompt}],
                    provider,
                    ignore_stream_and_auth=True
                )
                if as_json:
                    parsed_response = read_json(response)
                    if parsed_response and 'reviews' in parsed_response:
                        return parsed_response
                else:
                    parsed_response = read_text(response)
                    if parsed_response.strip():
                        return parsed_response
            except Exception as e:
                print(f"Error with provider {provider}: {e}")
    
    # If all retries and providers fail, return a default response
    if as_json:
        return {"reviews": []}
    else:
        return "AI Code Review: Unable to generate a detailed response. Please review the changes manually."

def analyze_code(pull: PullRequest, diff: str) -> list[dict]:
    """
    Analyzes the code changes in the pull request.

    Args:
        pull (PullRequest): The pull request object.
        diff (str): The diff of the pull request.

    Returns:
        list[dict]: A list of comments generated by the analysis.
    """
    comments = []
    changed_lines = []
    current_file_path = None
    offset_line = 0

    try:
        for line in diff.split('\n'):
            if line.startswith('+++ b/'):
                current_file_path = line[6:]
                changed_lines = []
            elif line.startswith('@@'):
                match = re.search(r'\+([0-9]+?),', line)
                if match:
                    offset_line = int(match.group(1))
            elif current_file_path:
                if (line.startswith('\\') or line.startswith('diff')) and changed_lines:
                    prompt = create_analyze_prompt(changed_lines, pull, current_file_path)
                    response = get_ai_response(prompt)
                    for review in response.get('reviews', []):
                        review['path'] = current_file_path
                        comments.append(review)
                    current_file_path = None
                elif line.startswith('-'):
                    changed_lines.append(line)
                else:
                    changed_lines.append(f"{offset_line}:{line}")
                    offset_line += 1
    except Exception as e:
        print(f"Error in analyze_code: {e}")
    
    if not comments:
        print("No comments generated by analyze_code")
    
    return comments

def create_analyze_prompt(changed_lines: list[str], pull: PullRequest, file_path: str):
    """
    Creates a prompt for the g4f model.

    Args:
        changed_lines (list[str]): The lines of code that have changed.
        pull (PullRequest): The pull request object.
        file_path (str): The path to the file being reviewed.

    Returns:
        str: The generated prompt.
    """
    code = "\n".join(changed_lines)
    example = '{"reviews": [{"line": <line_number>, "body": "<review comment>"}]}'
    return f"""Your task is to review pull requests. Instructions:
- Provide the response in following JSON format: {example}
- Do not give positive comments or compliments.
- Provide comments and suggestions ONLY if there is something to improve, otherwise "reviews" should be an empty array.
- Write the comment in GitHub Markdown format.
- Use the given description only for the overall context and only comment the code.
- IMPORTANT: NEVER suggest adding comments to the code.

Review the following code diff in the file "{file_path}" and take the pull request title and description into account when writing the response.
  
Pull request title: {pull.title}
Pull request description:
---
{pull.body}
---

Each line is prefixed by its number. Code to review:
```
{code}
```
"""

def create_review_prompt(pull: PullRequest, diff: str):
    """
    Creates a prompt to create a review comment.

    Args:
        pull (PullRequest): The pull request object.
        diff (str): The diff of the pull request.

    Returns:
        str: The generated prompt for review.
    """
    description = pull.body if pull.body else "No description provided."
    return f"""Your task is to review a pull request. Instructions:
- Write in name of g4f copilot. Don't use placeholder.
- Write the review in GitHub Markdown format.
- Thank the author for contributing to the project.
- If no issues are found, still provide a brief summary of the changes.

Pull request author: {pull.user.name or "Unknown"}
Pull request title: {pull.title or "Untitled Pull Request"}
Pull request description:
---
{description}
---

Diff:
```diff
{diff}
```

Please provide a comprehensive review of the changes, highlighting any potential issues or improvements, or summarizing the changes if no issues are found.
"""

def main():
    try:
        github_token = get_github_token()
    except ValueError as e:
        print(f"Error: {str(e)}")
        return

    if not GITHUB_REPOSITORY or not os.getenv('PR_NUMBER'):
        print("Error: GITHUB_REPOSITORY or PR_NUMBER environment variables are not set.")
        return

    print(f"GITHUB_REPOSITORY: {GITHUB_REPOSITORY}")
    print(f"PR_NUMBER: {os.getenv('PR_NUMBER')}")
    print("GITHUB_TOKEN is set")

    try:
        github = Github(github_token)
        
        # Test GitHub connection
        print("Testing GitHub connection...")
        try:
            user = github.get_user()
            print(f"Successfully authenticated as: {user.login}")
        except Exception as e:
            print(f"Error authenticating: {str(e)}")
            print(f"Error type: {type(e).__name__}")
            print(f"Error args: {e.args}")
            return
        
        # If connection is successful, proceed with PR details
        pull = get_pr_details(github)
        if not pull:
            print(f"No PR number found or invalid PR number")
            return
        print(f"Successfully fetched PR #{pull.number}")
        if pull.get_reviews().totalCount > 0 or pull.get_issue_comments().totalCount > 0:
            print(f"Has already a review")
            return
        
        diff = get_diff(pull.diff_url)
        review = "AI Code Review: Unable to generate a detailed response."
        comments = []
        
        try:
            review = get_ai_response(create_review_prompt(pull, diff), False)
            comments = analyze_code(pull, diff)
        except Exception as analysis_error:
            print(f"Error during analysis: {analysis_error}")
            review += f" Error during analysis: {str(analysis_error)[:200]}"
        
        print("Comments:", comments)
        
        review_body = review if review and review.strip() else "AI Code Review"
        if not review_body.strip():
            review_body = "AI Code Review: No specific issues found."
        
        try:
            if comments:
                pull.create_review(body=review_body, comments=comments, event='COMMENT')
            else:
                pull.create_review(body=review_body, event='COMMENT')
            print("Review posted successfully")
        except Exception as post_error:
            print(f"Error posting review: {post_error}")
            error_message = f"AI Code Review: An error occurred while posting the review. Error: {str(post_error)[:200]}. Please review the changes manually."
            pull.create_issue_comment(body=error_message)
    
    except Exception as e:
        print(f"Unexpected error in main: {e.__class__.__name__}: {e}")
        try:
            if 'pull' in locals():
                error_message = f"AI Code Review: An error occurred while processing this pull request. Error: {str(e)[:200]}. Please review the changes manually."
                pull.create_issue_comment(body=error_message)
            else:
                print("Unable to post error message: Pull request object not available")
        except Exception as post_error:
            print(f"Failed to post error message to pull request: {post_error}")

if __name__ == "__main__":
    main()