#!/usr/bin/env python3
"""
Pig Query Strategy

This module implements the Pig query strategy for Apache Pig Latin operations.

Company: eXonware.com
Author: Eng. Muhammad AlShehri
Email: connect@exonware.com
Version: 0.0.1.19
Generation Date: January 2, 2025
"""

import re
from typing import Any, Dict, List, Optional, Union
from .base import AStructuredQueryStrategy
from ...errors import XWNodeTypeError, XWNodeValueError
from ...contracts import QueryMode, QueryTrait


class PigStrategy(AStructuredQueryStrategy):
    """
    Pig query strategy for Apache Pig Latin operations.
    
    Supports:
    - Pig Latin language
    - LOAD, STORE, FILTER, FOREACH operations
    - GROUP BY and COGROUP operations
    - JOIN and UNION operations
    - Built-in functions and UDFs
    """
    
    def __init__(self, **options):
        super().__init__(**options)
        self._mode = QueryMode.PIG
        self._traits = QueryTrait.STRUCTURED | QueryTrait.ANALYTICAL | QueryTrait.BATCH
    
    def execute(self, query: str, **kwargs) -> Any:
        """Execute Pig query."""
        if not self.validate_query(query):
            raise XWNodeValueError(f"Invalid Pig query: {query}")
        
        query_type = self._get_query_type(query)
        
        if query_type == "LOAD":
            return self._execute_load(query, **kwargs)
        elif query_type == "STORE":
            return self._execute_store(query, **kwargs)
        elif query_type == "FILTER":
            return self._execute_filter(query, **kwargs)
        elif query_type == "FOREACH":
            return self._execute_foreach(query, **kwargs)
        else:
            raise XWNodeValueError(f"Unsupported query type: {query_type}")
    
    def validate_query(self, query: str) -> bool:
        """Validate Pig query syntax."""
        if not query or not isinstance(query, str):
            return False
        
        # Basic Pig validation
        query = query.strip().upper()
        valid_operations = ["LOAD", "STORE", "FILTER", "FOREACH", "GROUP", "COGROUP", "JOIN", "UNION", "SPLIT", "CROSS", "DISTINCT", "ORDER", "LIMIT", "SAMPLE", "PARALLEL", "REGISTER", "DEFINE", "IMPORT"]
        
        for operation in valid_operations:
            if query.startswith(operation):
                return True
        
        return False
    
    def get_query_plan(self, query: str) -> Dict[str, Any]:
        """Get Pig query execution plan."""
        query_type = self._get_query_type(query)
        
        return {
            "query_type": query_type,
            "operation": query_type,
            "complexity": self._estimate_complexity(query),
            "estimated_cost": self._estimate_cost(query),
            "operations": self._extract_operations(query),
            "optimization_hints": self._get_optimization_hints(query)
        }
    
    def select_query(self, table: str, columns: List[str], where_clause: str = None) -> Any:
        """Execute SELECT query."""
        query = f"data = LOAD '{table}' AS ({', '.join(columns)});"
        if where_clause:
            query += f" filtered = FILTER data BY {where_clause};"
            query += f" result = FOREACH filtered GENERATE {', '.join(columns)};"
        else:
            query += f" result = FOREACH data GENERATE {', '.join(columns)};"
        
        return self.execute(query)
    
    def insert_query(self, table: str, data: Dict[str, Any]) -> Any:
        """Execute INSERT query."""
        # Pig doesn't support INSERT, use LOAD and STORE
        query = f"data = LOAD '{table}'; new_data = LOAD 'new_data' AS ({', '.join(data.keys())}); combined = UNION data, new_data; STORE combined INTO '{table}';"
        return self.execute(query)
    
    def update_query(self, table: str, data: Dict[str, Any], where_clause: str = None) -> Any:
        """Execute UPDATE query."""
        # Pig doesn't support UPDATE, use FILTER and FOREACH
        query = f"data = LOAD '{table}';"
        if where_clause:
            query += f" filtered = FILTER data BY {where_clause};"
            query += f" updated = FOREACH filtered GENERATE {', '.join([f'{k} AS {k}' for k in data.keys()])};"
        else:
            query += f" updated = FOREACH data GENERATE {', '.join([f'{k} AS {k}' for k in data.keys()])};"
        
        return self.execute(query)
    
    def delete_query(self, table: str, where_clause: str = None) -> Any:
        """Execute DELETE query."""
        # Pig doesn't support DELETE, use FILTER
        query = f"data = LOAD '{table}';"
        if where_clause:
            query += f" filtered = FILTER data BY NOT ({where_clause});"
        else:
            query += f" filtered = FILTER data BY false;"
        
        return self.execute(query)
    
    def join_query(self, tables: List[str], join_conditions: List[str]) -> Any:
        """Execute JOIN query."""
        if len(tables) < 2:
            raise XWNodeValueError("JOIN requires at least 2 tables")
        
        query = f"table1 = LOAD '{tables[0]}'; table2 = LOAD '{tables[1]}';"
        query += f" joined = JOIN table1 BY {join_conditions[0]}, table2 BY {join_conditions[0]};"
        
        return self.execute(query)
    
    def aggregate_query(self, table: str, functions: List[str], group_by: List[str] = None) -> Any:
        """Execute aggregate query."""
        query = f"data = LOAD '{table}';"
        if group_by:
            query += f" grouped = GROUP data BY ({', '.join(group_by)});"
            query += f" aggregated = FOREACH grouped GENERATE group, {', '.join(functions)};"
        else:
            query += f" aggregated = FOREACH data GENERATE {', '.join(functions)};"
        
        return self.execute(query)
    
    def _get_query_type(self, query: str) -> str:
        """Extract query type from Pig query."""
        query = query.strip().upper()
        for operation in ["LOAD", "STORE", "FILTER", "FOREACH", "GROUP", "COGROUP", "JOIN", "UNION", "SPLIT", "CROSS", "DISTINCT", "ORDER", "LIMIT", "SAMPLE", "PARALLEL", "REGISTER", "DEFINE", "IMPORT"]:
            if query.startswith(operation):
                return operation
        return "UNKNOWN"
    
    def _execute_load(self, query: str, **kwargs) -> Any:
        """Execute LOAD query."""
        return {"result": "Pig LOAD executed", "query": query}
    
    def _execute_store(self, query: str, **kwargs) -> Any:
        """Execute STORE query."""
        return {"result": "Pig STORE executed", "query": query}
    
    def _execute_filter(self, query: str, **kwargs) -> Any:
        """Execute FILTER query."""
        return {"result": "Pig FILTER executed", "query": query}
    
    def _execute_foreach(self, query: str, **kwargs) -> Any:
        """Execute FOREACH query."""
        return {"result": "Pig FOREACH executed", "query": query}
    
    def _estimate_complexity(self, query: str) -> str:
        """Estimate query complexity."""
        operations = self._extract_operations(query)
        
        if len(operations) > 8:
            return "HIGH"
        elif len(operations) > 4:
            return "MEDIUM"
        else:
            return "LOW"
    
    def _estimate_cost(self, query: str) -> int:
        """Estimate query cost."""
        complexity = self._estimate_complexity(query)
        if complexity == "HIGH":
            return 250  # Higher cost due to MapReduce
        elif complexity == "MEDIUM":
            return 125
        else:
            return 60
    
    def _extract_operations(self, query: str) -> List[str]:
        """Extract Pig operations from query."""
        operations = []
        
        pig_operations = ["LOAD", "STORE", "FILTER", "FOREACH", "GROUP", "COGROUP", "JOIN", "UNION", "SPLIT", "CROSS", "DISTINCT", "ORDER", "LIMIT", "SAMPLE", "PARALLEL", "REGISTER", "DEFINE", "IMPORT"]
        
        for operation in pig_operations:
            if operation in query.upper():
                operations.append(operation)
        
        return operations
    
    def _get_optimization_hints(self, query: str) -> List[str]:
        """Get query optimization hints."""
        hints = []
        
        if "GROUP" in query.upper():
            hints.append("Consider using COGROUP for multiple group operations")
        
        if "JOIN" in query.upper():
            hints.append("Consider using replicated joins for small datasets")
        
        if "FOREACH" in query.upper():
            hints.append("Consider using nested FOREACH for complex transformations")
        
        return hints
