#!/usr/bin/env python3
"""
GitHub Repository to Claude Skill Converter (Tasks C1.1-C1.12)

Converts GitHub repositories into Claude AI skills by extracting:
- README and documentation
- Code structure and signatures
- GitHub Issues, Changelog, and Releases
- Usage examples from tests

Usage:
    python3 cli/github_scraper.py --repo facebook/react
    python3 cli/github_scraper.py --config configs/react_github.json
    python3 cli/github_scraper.py --repo owner/repo --token $GITHUB_TOKEN
"""

import os
import sys
import json
import re
import argparse
import logging
from pathlib import Path
from typing import Dict, List, Optional, Any
from datetime import datetime

try:
    from github import Github, GithubException, Repository
    from github.GithubException import RateLimitExceededException
except ImportError:
    print("Error: PyGithub not installed. Run: pip install PyGithub")
    sys.exit(1)

# Configure logging
logging.basicConfig(
    level=logging.INFO,
    format='%(asctime)s - %(levelname)s - %(message)s'
)
logger = logging.getLogger(__name__)


class GitHubScraper:
    """
    GitHub Repository Scraper (C1.1-C1.9)

    Extracts repository information for skill generation:
    - Repository structure
    - README files
    - Code comments and docstrings
    - Programming language detection
    - Function/class signatures
    - Test examples
    - GitHub Issues
    - CHANGELOG
    - Releases
    """

    def __init__(self, config: Dict[str, Any]):
        """Initialize GitHub scraper with configuration."""
        self.config = config
        self.repo_name = config['repo']
        self.name = config.get('name', self.repo_name.split('/')[-1])
        self.description = config.get('description', f'Skill for {self.repo_name}')

        # GitHub client setup (C1.1)
        token = self._get_token()
        self.github = Github(token) if token else Github()
        self.repo: Optional[Repository.Repository] = None

        # Options
        self.include_issues = config.get('include_issues', True)
        self.max_issues = config.get('max_issues', 100)
        self.include_changelog = config.get('include_changelog', True)
        self.include_releases = config.get('include_releases', True)
        self.include_code = config.get('include_code', False)  # Surface layer only
        self.file_patterns = config.get('file_patterns', [])

        # Output paths
        self.skill_dir = f"output/{self.name}"
        self.data_file = f"output/{self.name}_github_data.json"

        # Extracted data storage
        self.extracted_data = {
            'repo_info': {},
            'readme': '',
            'file_tree': [],
            'languages': {},
            'signatures': [],
            'test_examples': [],
            'issues': [],
            'changelog': '',
            'releases': []
        }

    def _get_token(self) -> Optional[str]:
        """
        Get GitHub token from env var or config (both options supported).
        Priority: GITHUB_TOKEN env var > config file > None
        """
        # Try environment variable first (recommended)
        token = os.getenv('GITHUB_TOKEN')
        if token:
            logger.info("Using GitHub token from GITHUB_TOKEN environment variable")
            return token

        # Fall back to config file
        token = self.config.get('github_token')
        if token:
            logger.warning("Using GitHub token from config file (less secure)")
            return token

        logger.warning("No GitHub token provided - using unauthenticated access (lower rate limits)")
        return None

    def scrape(self) -> Dict[str, Any]:
        """
        Main scraping entry point.
        Executes all C1 tasks in sequence.
        """
        try:
            logger.info(f"Starting GitHub scrape for: {self.repo_name}")

            # C1.1: Fetch repository
            self._fetch_repository()

            # C1.2: Extract README
            self._extract_readme()

            # C1.3-C1.6: Extract code structure
            self._extract_code_structure()

            # C1.7: Extract Issues
            if self.include_issues:
                self._extract_issues()

            # C1.8: Extract CHANGELOG
            if self.include_changelog:
                self._extract_changelog()

            # C1.9: Extract Releases
            if self.include_releases:
                self._extract_releases()

            # Save extracted data
            self._save_data()

            logger.info(f"✅ Scraping complete! Data saved to: {self.data_file}")
            return self.extracted_data

        except RateLimitExceededException:
            logger.error("GitHub API rate limit exceeded. Please wait or use authentication token.")
            raise
        except GithubException as e:
            logger.error(f"GitHub API error: {e}")
            raise
        except Exception as e:
            logger.error(f"Unexpected error during scraping: {e}")
            raise

    def _fetch_repository(self):
        """C1.1: Fetch repository structure using GitHub API."""
        logger.info(f"Fetching repository: {self.repo_name}")

        try:
            self.repo = self.github.get_repo(self.repo_name)

            # Extract basic repo info
            self.extracted_data['repo_info'] = {
                'name': self.repo.name,
                'full_name': self.repo.full_name,
                'description': self.repo.description,
                'url': self.repo.html_url,
                'homepage': self.repo.homepage,
                'stars': self.repo.stargazers_count,
                'forks': self.repo.forks_count,
                'open_issues': self.repo.open_issues_count,
                'default_branch': self.repo.default_branch,
                'created_at': self.repo.created_at.isoformat() if self.repo.created_at else None,
                'updated_at': self.repo.updated_at.isoformat() if self.repo.updated_at else None,
                'language': self.repo.language,
                'license': self.repo.license.name if self.repo.license else None,
                'topics': self.repo.get_topics()
            }

            logger.info(f"Repository fetched: {self.repo.full_name} ({self.repo.stargazers_count} stars)")

        except GithubException as e:
            if e.status == 404:
                raise ValueError(f"Repository not found: {self.repo_name}")
            raise

    def _extract_readme(self):
        """C1.2: Extract README.md files."""
        logger.info("Extracting README...")

        # Try common README locations
        readme_files = ['README.md', 'README.rst', 'README.txt', 'README',
                       'docs/README.md', '.github/README.md']

        for readme_path in readme_files:
            try:
                content = self.repo.get_contents(readme_path)
                if content:
                    self.extracted_data['readme'] = content.decoded_content.decode('utf-8')
                    logger.info(f"README found: {readme_path}")
                    return
            except GithubException:
                continue

        logger.warning("No README found in repository")

    def _extract_code_structure(self):
        """
        C1.3-C1.6: Extract code structure, languages, signatures, and test examples.
        Surface layer only - no full implementation code.
        """
        logger.info("Extracting code structure...")

        # C1.4: Get language breakdown
        self._extract_languages()

        # Get file tree
        self._extract_file_tree()

        # Extract signatures and test examples
        if self.include_code:
            self._extract_signatures_and_tests()

    def _extract_languages(self):
        """C1.4: Detect programming languages in repository."""
        logger.info("Detecting programming languages...")

        try:
            languages = self.repo.get_languages()
            total_bytes = sum(languages.values())

            self.extracted_data['languages'] = {
                lang: {
                    'bytes': bytes_count,
                    'percentage': round((bytes_count / total_bytes) * 100, 2) if total_bytes > 0 else 0
                }
                for lang, bytes_count in languages.items()
            }

            logger.info(f"Languages detected: {', '.join(languages.keys())}")

        except GithubException as e:
            logger.warning(f"Could not fetch languages: {e}")

    def _extract_file_tree(self):
        """Extract repository file tree structure."""
        logger.info("Building file tree...")

        try:
            contents = self.repo.get_contents("")
            file_tree = []

            while contents:
                file_content = contents.pop(0)

                file_info = {
                    'path': file_content.path,
                    'type': file_content.type,
                    'size': file_content.size if file_content.type == 'file' else None
                }
                file_tree.append(file_info)

                if file_content.type == "dir":
                    contents.extend(self.repo.get_contents(file_content.path))

            self.extracted_data['file_tree'] = file_tree
            logger.info(f"File tree built: {len(file_tree)} items")

        except GithubException as e:
            logger.warning(f"Could not build file tree: {e}")

    def _extract_signatures_and_tests(self):
        """
        C1.3, C1.5, C1.6: Extract signatures, docstrings, and test examples.
        Note: This is a simplified implementation - full extraction would require
        parsing each file, which is implemented in the surface layer approach.
        """
        logger.info("Extracting code signatures and test examples...")

        # This would be implemented by parsing specific files
        # For now, we note this as a placeholder for the surface layer
        # Real implementation would parse Python/JS/TS files for signatures

        logger.info("Code extraction: Using surface layer (signatures only, no implementation)")

    def _extract_issues(self):
        """C1.7: Extract GitHub Issues (open/closed, labels, milestones)."""
        logger.info(f"Extracting GitHub Issues (max {self.max_issues})...")

        try:
            # Fetch recent issues (open + closed)
            issues = self.repo.get_issues(state='all', sort='updated', direction='desc')

            issue_list = []
            for issue in issues[:self.max_issues]:
                # Skip pull requests (they appear in issues)
                if issue.pull_request:
                    continue

                issue_data = {
                    'number': issue.number,
                    'title': issue.title,
                    'state': issue.state,
                    'labels': [label.name for label in issue.labels],
                    'milestone': issue.milestone.title if issue.milestone else None,
                    'created_at': issue.created_at.isoformat() if issue.created_at else None,
                    'updated_at': issue.updated_at.isoformat() if issue.updated_at else None,
                    'closed_at': issue.closed_at.isoformat() if issue.closed_at else None,
                    'url': issue.html_url,
                    'body': issue.body[:500] if issue.body else None  # First 500 chars
                }
                issue_list.append(issue_data)

            self.extracted_data['issues'] = issue_list
            logger.info(f"Extracted {len(issue_list)} issues")

        except GithubException as e:
            logger.warning(f"Could not fetch issues: {e}")

    def _extract_changelog(self):
        """C1.8: Extract CHANGELOG.md and release notes."""
        logger.info("Extracting CHANGELOG...")

        # Try common changelog locations
        changelog_files = ['CHANGELOG.md', 'CHANGES.md', 'HISTORY.md',
                          'CHANGELOG.rst', 'CHANGELOG.txt', 'CHANGELOG',
                          'docs/CHANGELOG.md', '.github/CHANGELOG.md']

        for changelog_path in changelog_files:
            try:
                content = self.repo.get_contents(changelog_path)
                if content:
                    self.extracted_data['changelog'] = content.decoded_content.decode('utf-8')
                    logger.info(f"CHANGELOG found: {changelog_path}")
                    return
            except GithubException:
                continue

        logger.warning("No CHANGELOG found in repository")

    def _extract_releases(self):
        """C1.9: Extract GitHub Releases with version history."""
        logger.info("Extracting GitHub Releases...")

        try:
            releases = self.repo.get_releases()

            release_list = []
            for release in releases:
                release_data = {
                    'tag_name': release.tag_name,
                    'name': release.title,
                    'body': release.body,
                    'draft': release.draft,
                    'prerelease': release.prerelease,
                    'created_at': release.created_at.isoformat() if release.created_at else None,
                    'published_at': release.published_at.isoformat() if release.published_at else None,
                    'url': release.html_url,
                    'tarball_url': release.tarball_url,
                    'zipball_url': release.zipball_url
                }
                release_list.append(release_data)

            self.extracted_data['releases'] = release_list
            logger.info(f"Extracted {len(release_list)} releases")

        except GithubException as e:
            logger.warning(f"Could not fetch releases: {e}")

    def _save_data(self):
        """Save extracted data to JSON file."""
        os.makedirs('output', exist_ok=True)

        with open(self.data_file, 'w', encoding='utf-8') as f:
            json.dump(self.extracted_data, f, indent=2, ensure_ascii=False)

        logger.info(f"Data saved to: {self.data_file}")


class GitHubToSkillConverter:
    """
    Convert extracted GitHub data to Claude skill format (C1.10).
    """

    def __init__(self, config: Dict[str, Any]):
        """Initialize converter with configuration."""
        self.config = config
        self.name = config.get('name', config['repo'].split('/')[-1])
        self.description = config.get('description', f'Skill for {config["repo"]}')

        # Paths
        self.data_file = f"output/{self.name}_github_data.json"
        self.skill_dir = f"output/{self.name}"

        # Load extracted data
        self.data = self._load_data()

    def _load_data(self) -> Dict[str, Any]:
        """Load extracted GitHub data from JSON."""
        if not os.path.exists(self.data_file):
            raise FileNotFoundError(f"Data file not found: {self.data_file}")

        with open(self.data_file, 'r', encoding='utf-8') as f:
            return json.load(f)

    def build_skill(self):
        """Build complete skill structure."""
        logger.info(f"Building skill for: {self.name}")

        # Create directories
        os.makedirs(self.skill_dir, exist_ok=True)
        os.makedirs(f"{self.skill_dir}/references", exist_ok=True)
        os.makedirs(f"{self.skill_dir}/scripts", exist_ok=True)
        os.makedirs(f"{self.skill_dir}/assets", exist_ok=True)

        # Generate SKILL.md
        self._generate_skill_md()

        # Generate reference files
        self._generate_references()

        logger.info(f"✅ Skill built successfully: {self.skill_dir}/")

    def _generate_skill_md(self):
        """Generate main SKILL.md file."""
        repo_info = self.data.get('repo_info', {})

        skill_content = f"""# {repo_info.get('name', self.name)}

{self.description}

## Description

{repo_info.get('description', 'GitHub repository skill')}

**Repository:** [{repo_info.get('full_name', 'N/A')}]({repo_info.get('url', '#')})
**Language:** {repo_info.get('language', 'N/A')}
**Stars:** {repo_info.get('stars', 0):,}
**License:** {repo_info.get('license', 'N/A')}

## When to Use This Skill

Use this skill when you need to:
- Understand how to use {self.name}
- Look up API documentation
- Find usage examples
- Check for known issues or recent changes
- Review release history

## Quick Reference

### Repository Info
- **Homepage:** {repo_info.get('homepage', 'N/A')}
- **Topics:** {', '.join(repo_info.get('topics', []))}
- **Open Issues:** {repo_info.get('open_issues', 0)}
- **Last Updated:** {repo_info.get('updated_at', 'N/A')[:10]}

### Languages
{self._format_languages()}

### Recent Releases
{self._format_recent_releases()}

## Available References

- `references/README.md` - Complete README documentation
- `references/CHANGELOG.md` - Version history and changes
- `references/issues.md` - Recent GitHub issues
- `references/releases.md` - Release notes
- `references/file_structure.md` - Repository structure

## Usage

See README.md for complete usage instructions and examples.

---

**Generated by Skill Seeker** | GitHub Repository Scraper
"""

        skill_path = f"{self.skill_dir}/SKILL.md"
        with open(skill_path, 'w', encoding='utf-8') as f:
            f.write(skill_content)

        logger.info(f"Generated: {skill_path}")

    def _format_languages(self) -> str:
        """Format language breakdown."""
        languages = self.data.get('languages', {})
        if not languages:
            return "No language data available"

        lines = []
        for lang, info in sorted(languages.items(), key=lambda x: x[1]['bytes'], reverse=True):
            lines.append(f"- **{lang}:** {info['percentage']:.1f}%")

        return '\n'.join(lines)

    def _format_recent_releases(self) -> str:
        """Format recent releases (top 3)."""
        releases = self.data.get('releases', [])
        if not releases:
            return "No releases available"

        lines = []
        for release in releases[:3]:
            lines.append(f"- **{release['tag_name']}** ({release['published_at'][:10]}): {release['name']}")

        return '\n'.join(lines)

    def _generate_references(self):
        """Generate all reference files."""
        # README
        if self.data.get('readme'):
            readme_path = f"{self.skill_dir}/references/README.md"
            with open(readme_path, 'w', encoding='utf-8') as f:
                f.write(self.data['readme'])
            logger.info(f"Generated: {readme_path}")

        # CHANGELOG
        if self.data.get('changelog'):
            changelog_path = f"{self.skill_dir}/references/CHANGELOG.md"
            with open(changelog_path, 'w', encoding='utf-8') as f:
                f.write(self.data['changelog'])
            logger.info(f"Generated: {changelog_path}")

        # Issues
        if self.data.get('issues'):
            self._generate_issues_reference()

        # Releases
        if self.data.get('releases'):
            self._generate_releases_reference()

        # File structure
        if self.data.get('file_tree'):
            self._generate_file_structure_reference()

    def _generate_issues_reference(self):
        """Generate issues.md reference file."""
        issues = self.data['issues']

        content = f"# GitHub Issues\n\nRecent issues from the repository ({len(issues)} total).\n\n"

        # Group by state
        open_issues = [i for i in issues if i['state'] == 'open']
        closed_issues = [i for i in issues if i['state'] == 'closed']

        content += f"## Open Issues ({len(open_issues)})\n\n"
        for issue in open_issues[:20]:
            labels = ', '.join(issue['labels']) if issue['labels'] else 'No labels'
            content += f"### #{issue['number']}: {issue['title']}\n"
            content += f"**Labels:** {labels} | **Created:** {issue['created_at'][:10]}\n"
            content += f"[View on GitHub]({issue['url']})\n\n"

        content += f"\n## Recently Closed Issues ({len(closed_issues)})\n\n"
        for issue in closed_issues[:10]:
            labels = ', '.join(issue['labels']) if issue['labels'] else 'No labels'
            content += f"### #{issue['number']}: {issue['title']}\n"
            content += f"**Labels:** {labels} | **Closed:** {issue['closed_at'][:10]}\n"
            content += f"[View on GitHub]({issue['url']})\n\n"

        issues_path = f"{self.skill_dir}/references/issues.md"
        with open(issues_path, 'w', encoding='utf-8') as f:
            f.write(content)
        logger.info(f"Generated: {issues_path}")

    def _generate_releases_reference(self):
        """Generate releases.md reference file."""
        releases = self.data['releases']

        content = f"# Releases\n\nVersion history for this repository ({len(releases)} releases).\n\n"

        for release in releases:
            content += f"## {release['tag_name']}: {release['name']}\n"
            content += f"**Published:** {release['published_at'][:10]}\n"
            if release['prerelease']:
                content += f"**Pre-release**\n"
            content += f"\n{release['body']}\n\n"
            content += f"[View on GitHub]({release['url']})\n\n---\n\n"

        releases_path = f"{self.skill_dir}/references/releases.md"
        with open(releases_path, 'w', encoding='utf-8') as f:
            f.write(content)
        logger.info(f"Generated: {releases_path}")

    def _generate_file_structure_reference(self):
        """Generate file_structure.md reference file."""
        file_tree = self.data['file_tree']

        content = f"# Repository File Structure\n\n"
        content += f"Total items: {len(file_tree)}\n\n"
        content += "```\n"

        # Build tree structure
        for item in file_tree:
            indent = "  " * item['path'].count('/')
            icon = "📁" if item['type'] == 'dir' else "📄"
            content += f"{indent}{icon} {os.path.basename(item['path'])}\n"

        content += "```\n"

        structure_path = f"{self.skill_dir}/references/file_structure.md"
        with open(structure_path, 'w', encoding='utf-8') as f:
            f.write(content)
        logger.info(f"Generated: {structure_path}")


def main():
    """C1.10: CLI tool entry point."""
    parser = argparse.ArgumentParser(
        description='GitHub Repository to Claude Skill Converter',
        formatter_class=argparse.RawDescriptionHelpFormatter,
        epilog="""
Examples:
  python3 cli/github_scraper.py --repo facebook/react
  python3 cli/github_scraper.py --config configs/react_github.json
  python3 cli/github_scraper.py --repo owner/repo --token $GITHUB_TOKEN
        """
    )

    parser.add_argument('--repo', help='GitHub repository (owner/repo)')
    parser.add_argument('--config', help='Path to config JSON file')
    parser.add_argument('--token', help='GitHub personal access token')
    parser.add_argument('--name', help='Skill name (default: repo name)')
    parser.add_argument('--description', help='Skill description')
    parser.add_argument('--no-issues', action='store_true', help='Skip GitHub issues')
    parser.add_argument('--no-changelog', action='store_true', help='Skip CHANGELOG')
    parser.add_argument('--no-releases', action='store_true', help='Skip releases')
    parser.add_argument('--max-issues', type=int, default=100, help='Max issues to fetch')
    parser.add_argument('--scrape-only', action='store_true', help='Only scrape, don\'t build skill')

    args = parser.parse_args()

    # Build config from args or file
    if args.config:
        with open(args.config, 'r') as f:
            config = json.load(f)
    elif args.repo:
        config = {
            'repo': args.repo,
            'name': args.name or args.repo.split('/')[-1],
            'description': args.description or f'GitHub repository skill for {args.repo}',
            'github_token': args.token,
            'include_issues': not args.no_issues,
            'include_changelog': not args.no_changelog,
            'include_releases': not args.no_releases,
            'max_issues': args.max_issues
        }
    else:
        parser.error('Either --repo or --config is required')

    try:
        # Phase 1: Scrape GitHub repository
        scraper = GitHubScraper(config)
        scraper.scrape()

        if args.scrape_only:
            logger.info("Scrape complete (--scrape-only mode)")
            return

        # Phase 2: Build skill
        converter = GitHubToSkillConverter(config)
        converter.build_skill()

        logger.info(f"\n✅ Success! Skill created at: output/{config.get('name', config['repo'].split('/')[-1])}/")
        logger.info(f"Next step: python3 cli/package_skill.py output/{config.get('name', config['repo'].split('/')[-1])}/")

    except Exception as e:
        logger.error(f"Error: {e}")
        sys.exit(1)


if __name__ == '__main__':
    main()