"""
Auto-optimizer for FSS-Mini-RAG.
Automatically tunes settings based on usage patterns.
"""

from pathlib import Path
import json
from typing import Dict, Any, List
from collections import Counter
import logging

logger = logging.getLogger(__name__)

class AutoOptimizer:
    """Automatically optimizes RAG settings based on project patterns."""
    
    def __init__(self, project_path: Path):
        self.project_path = project_path
        self.rag_dir = project_path / '.mini-rag'
        self.config_path = self.rag_dir / 'config.json'
        self.manifest_path = self.rag_dir / 'manifest.json'
    
    def analyze_and_optimize(self) -> Dict[str, Any]:
        """Analyze current patterns and auto-optimize settings."""
        
        if not self.manifest_path.exists():
            return {"error": "No index found - run indexing first"}
        
        # Load current data
        with open(self.manifest_path) as f:
            manifest = json.load(f)
        
        # Analyze patterns
        analysis = self._analyze_patterns(manifest)
        
        # Generate optimizations
        optimizations = self._generate_optimizations(analysis)
        
        # Apply optimizations if beneficial
        if optimizations['confidence'] > 0.7:
            self._apply_optimizations(optimizations)
            return {
                "status": "optimized",
                "changes": optimizations['changes'],
                "expected_improvement": optimizations['expected_improvement']
            }
        else:
            return {
                "status": "no_changes_needed",
                "analysis": analysis,
                "confidence": optimizations['confidence']
            }
    
    def _analyze_patterns(self, manifest: Dict[str, Any]) -> Dict[str, Any]:
        """Analyze current indexing patterns."""
        files = manifest.get('files', {})
        
        # Language distribution
        languages = Counter()
        sizes = []
        chunk_ratios = []
        
        for filepath, info in files.items():
            lang = info.get('language', 'unknown')
            languages[lang] += 1
            
            size = info.get('size', 0)
            chunks = info.get('chunks', 1)
            
            sizes.append(size)
            chunk_ratios.append(chunks / max(1, size / 1000))  # chunks per KB
        
        avg_chunk_ratio = sum(chunk_ratios) / len(chunk_ratios) if chunk_ratios else 1
        avg_size = sum(sizes) / len(sizes) if sizes else 1000
        
        return {
            'languages': dict(languages.most_common()),
            'total_files': len(files),
            'total_chunks': sum(info.get('chunks', 1) for info in files.values()),
            'avg_chunk_ratio': avg_chunk_ratio,
            'avg_file_size': avg_size,
            'large_files': sum(1 for s in sizes if s > 10000),
            'small_files': sum(1 for s in sizes if s < 500)
        }
    
    def _generate_optimizations(self, analysis: Dict[str, Any]) -> Dict[str, Any]:
        """Generate optimization recommendations."""
        changes = []
        confidence = 0.5
        expected_improvement = 0
        
        # Optimize chunking based on dominant language
        languages = analysis['languages']
        if languages:
            dominant_lang, count = list(languages.items())[0]
            lang_pct = count / analysis['total_files']
            
            if lang_pct > 0.3:  # Dominant language >30%
                if dominant_lang == 'python' and analysis['avg_chunk_ratio'] < 1.5:
                    changes.append("Increase Python chunk size to 3000 for better function context")
                    confidence += 0.2
                    expected_improvement += 15
                
                elif dominant_lang == 'markdown' and analysis['avg_chunk_ratio'] < 1.2:
                    changes.append("Use header-based chunking for Markdown files")
                    confidence += 0.15
                    expected_improvement += 10
        
        # Optimize for large files
        if analysis['large_files'] > 5:
            changes.append("Reduce streaming threshold to 5KB for better large file handling")
            confidence += 0.1
            expected_improvement += 8
        
        # Optimize chunk ratio
        if analysis['avg_chunk_ratio'] < 1.0:
            changes.append("Reduce chunk size for more granular search results")
            confidence += 0.15
            expected_improvement += 12
        elif analysis['avg_chunk_ratio'] > 3.0:
            changes.append("Increase chunk size to reduce overhead")
            confidence += 0.1
            expected_improvement += 5
        
        # Skip tiny files optimization
        small_file_pct = analysis['small_files'] / analysis['total_files']
        if small_file_pct > 0.3:
            changes.append("Skip files smaller than 300 bytes to improve focus")
            confidence += 0.1
            expected_improvement += 3
        
        return {
            'changes': changes,
            'confidence': min(confidence, 1.0),
            'expected_improvement': expected_improvement
        }
    
    def _apply_optimizations(self, optimizations: Dict[str, Any]):
        """Apply the recommended optimizations."""
        
        # Load existing config or create default
        if self.config_path.exists():
            with open(self.config_path) as f:
                config = json.load(f)
        else:
            config = self._get_default_config()
        
        changes = optimizations['changes']
        
        # Apply changes based on recommendations
        for change in changes:
            if "Python chunk size to 3000" in change:
                config.setdefault('chunking', {})['max_size'] = 3000
                
            elif "header-based chunking" in change:
                config.setdefault('chunking', {})['strategy'] = 'header'
                
            elif "streaming threshold to 5KB" in change:
                config.setdefault('streaming', {})['threshold_bytes'] = 5120
                
            elif "Reduce chunk size" in change:
                current_size = config.get('chunking', {}).get('max_size', 2000)
                config.setdefault('chunking', {})['max_size'] = max(1500, current_size - 500)
                
            elif "Increase chunk size" in change:
                current_size = config.get('chunking', {}).get('max_size', 2000)
                config.setdefault('chunking', {})['max_size'] = min(4000, current_size + 500)
                
            elif "Skip files smaller" in change:
                config.setdefault('files', {})['min_file_size'] = 300
        
        # Save optimized config
        config['_auto_optimized'] = True
        config['_optimization_timestamp'] = json.dumps(None, default=str)
        
        with open(self.config_path, 'w') as f:
            json.dump(config, f, indent=2)
        
        logger.info(f"Applied {len(changes)} optimizations to {self.config_path}")
    
    def _get_default_config(self) -> Dict[str, Any]:
        """Get default configuration."""
        return {
            "chunking": {
                "max_size": 2000,
                "min_size": 150,
                "strategy": "semantic"
            },
            "streaming": {
                "enabled": True,
                "threshold_bytes": 1048576
            },
            "files": {
                "min_file_size": 50
            }
        }