"""
Dead Code Eliminator Agent

Identifies and removes dead code, unused imports, unreachable code,
and unused variables.
"""

from typing import Any, Dict, List
from agents.base import BaseAgent


class DeadCodeEliminatorAgent(BaseAgent):
    """
    Finds and removes dead code.

    Detects:
    - Unused functions
    - Unused variables
    - Unused imports
    - Unreachable code
    - Unused exports
    - Dead branches
    """

    def __init__(self):
        super().__init__(
            name='dead-code-eliminator',
            description='Find and remove dead code',
            category='engineering',
            version='1.0.0',
            tags=['dead-code', 'optimization', 'cleanup', 'refactoring']
        )

    async def execute(self, params: Dict[str, Any]) -> Dict[str, Any]:
        """
        Find and eliminate dead code.

        Args:
            params: {
                'target_path': str,
                'language': 'python|javascript|typescript|go|rust',
                'detection_types': List[str],  # Types of dead code to find
                'options': {
                    'remove_automatically': bool,
                    'exclude_patterns': List[str],
                    'min_confidence': float,
                    'dry_run': bool
                }
            }

        Returns:
            {
                'status': 'success|failed',
                'dead_code_found': List[Dict],
                'files_modified': List[str],
                'lines_removed': int,
                'size_reduction': int
            }
        """
        target_path = params.get('target_path')
        language = params.get('language', 'python')
        detection_types = params.get('detection_types', ['all'])
        options = params.get('options', {})

        self.logger.info(
            f"Analyzing {target_path} for dead code"
        )

        # Mock dead code detection
        dead_code_items = [
            {
                'type': 'unused_function',
                'file': 'src/utils/helpers.py',
                'line': 45,
                'name': 'calculate_old_total',
                'reason': 'Function never called in codebase',
                'confidence': 0.98,
                'lines': 12,
                'removable': True
            },
            {
                'type': 'unused_import',
                'file': 'src/services/user_service.py',
                'line': 3,
                'name': 'datetime',
                'reason': 'Import not used anywhere in file',
                'confidence': 1.0,
                'lines': 1,
                'removable': True
            },
            {
                'type': 'unused_variable',
                'file': 'src/api/routes.py',
                'line': 67,
                'name': 'temp_data',
                'reason': 'Variable assigned but never read',
                'confidence': 0.95,
                'lines': 1,
                'removable': True
            },
            {
                'type': 'unreachable_code',
                'file': 'src/models/user.py',
                'line': 89,
                'name': 'return statement after return',
                'reason': 'Code after unconditional return',
                'confidence': 1.0,
                'lines': 5,
                'removable': True
            },
            {
                'type': 'unused_class',
                'file': 'src/legacy/old_processor.py',
                'line': 12,
                'name': 'OldDataProcessor',
                'reason': 'Class never instantiated',
                'confidence': 0.92,
                'lines': 45,
                'removable': True
            },
            {
                'type': 'dead_branch',
                'file': 'src/utils/validator.py',
                'line': 34,
                'name': 'if False:',
                'reason': 'Branch condition always False',
                'confidence': 1.0,
                'lines': 8,
                'removable': True
            },
            {
                'type': 'unused_export',
                'file': 'src/components/Button.tsx',
                'line': 123,
                'name': 'OldButton',
                'reason': 'Export never imported anywhere',
                'confidence': 0.89,
                'lines': 34,
                'removable': True
            }
        ]

        files_modified = []
        lines_removed = 0

        if options.get('remove_automatically') and not options.get('dry_run'):
            removable_items = [
                item for item in dead_code_items
                if item['removable'] and item['confidence'] >= options.get('min_confidence', 0.9)
            ]
            files_modified = list(set(item['file'] for item in removable_items))
            lines_removed = sum(item['lines'] for item in removable_items)

        type_counts = {}
        for item in dead_code_items:
            item_type = item['type']
            type_counts[item_type] = type_counts.get(item_type, 0) + 1

        total_lines = sum(item['lines'] for item in dead_code_items)

        return {
            'status': 'success',
            'target_path': target_path,
            'language': language,
            'dead_code_found': dead_code_items,
            'total_items': len(dead_code_items),
            'type_counts': type_counts,
            'files_analyzed': 23,
            'files_with_dead_code': len(set(item['file'] for item in dead_code_items)),
            'files_modified': files_modified if not options.get('dry_run') else [],
            'lines_removed': lines_removed if not options.get('dry_run') else 0,
            'potential_lines_removable': total_lines,
            'size_reduction_kb': round((total_lines * 50) / 1024, 2),  # Estimate
            'confidence_distribution': {
                'high': sum(1 for i in dead_code_items if i['confidence'] >= 0.9),
                'medium': sum(1 for i in dead_code_items if 0.7 <= i['confidence'] < 0.9),
                'low': sum(1 for i in dead_code_items if i['confidence'] < 0.7)
            },
            'dry_run': options.get('dry_run', False),
            'auto_removed': options.get('remove_automatically', False),
            'impact_analysis': {
                'maintainability_improvement': 'high',
                'codebase_size_reduction': f'{round((total_lines / 5000) * 100, 1)}%',
                'build_time_improvement': 'minimal',
                'runtime_improvement': 'minimal'
            },
            'recommendations': [
                'Review high-confidence items for removal',
                'Keep commented-out code in version control, not in source',
                'Set up regular dead code scanning',
                'Use IDE features to detect unused code',
                'Consider tree-shaking for frontend code',
                'Add linter rules to prevent dead code'
            ],
            'warnings': [
                'Some exports may be used by external modules',
                'Check for dynamic imports before removing',
                'Review reflection/metaprogramming usage',
                'Verify test coverage before removing code'
            ],
            'next_steps': [
                'Review detected dead code',
                'Remove high-confidence items',
                'Test after removal',
                'Add to CI/CD pipeline',
                'Document removal decisions',
                'Monitor for regressions'
            ]
        }

    def validate_params(self, params: Dict[str, Any]) -> bool:
        """Validate dead code elimination parameters."""
        if 'target_path' not in params:
            self.logger.error("Missing required field: target_path")
            return False

        return True
