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

This module implements the SQL query strategy for structured data queries.

Company: eXonware.com
Author: eXonware Backend Team
Email: connect@exonware.com
Version: 0.0.1.8
Generation Date: January 2, 2025
"""

from typing import Any
from .base import AStructuredQueryStrategy
from exonware.xwnode.errors import XWNodeValueError
from exonware.xwnode.contracts import QueryMode, QueryTrait
from exonware.xwnode.base import XWNodeBase


class SQLStrategy(AStructuredQueryStrategy):
    """
    SQL query strategy for standard SQL operations.
    
    Supports:
    - SELECT, INSERT, UPDATE, DELETE operations
    - JOIN operations
    - Aggregate functions
    - WHERE clauses
    - ORDER BY, GROUP BY, HAVING
    """
    
    def __init__(self, **options):
        super().__init__(**options)
        self._mode = QueryMode.SQL
        self._traits = QueryTrait.STRUCTURED | QueryTrait.ANALYTICAL | QueryTrait.BATCH
    
    def execute(self, query: str, **kwargs) -> Any:
        """Execute SQL query."""
        if not self.validate_query(query):
            raise XWNodeValueError(f"Invalid SQL query: {query}")
        
        query_type = self._get_query_type(query)
        
        if query_type == "SELECT":
            return self._execute_select(query, **kwargs)
        elif query_type == "INSERT":
            return self._execute_insert(query, **kwargs)
        elif query_type == "UPDATE":
            return self._execute_update(query, **kwargs)
        elif query_type == "DELETE":
            return self._execute_delete(query, **kwargs)
        else:
            raise XWNodeValueError(f"Unsupported query type: {query_type}")
    
    def validate_query(self, query: str) -> bool:
        """Validate SQL query syntax."""
        if not query or not isinstance(query, str):
            return False
        
        # Basic SQL validation
        query = query.strip().upper()
        valid_operations = ["SELECT", "INSERT", "UPDATE", "DELETE", "CREATE", "DROP", "ALTER"]
        
        for operation in valid_operations:
            if query.startswith(operation):
                return True
        
        return False
    
    def get_query_plan(self, query: str) -> dict[str, Any]:
        """Get SQL 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),
            "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"SELECT {', '.join(columns)} FROM {table}"
        if where_clause:
            query += f" WHERE {where_clause}"
        
        return self.execute(query)
    
    def insert_query(self, table: str, data: dict[str, Any]) -> Any:
        """Execute INSERT query."""
        columns = list(data.keys())
        values = list(data.values())
        
        query = f"INSERT INTO {table} ({', '.join(columns)}) VALUES ({', '.join(['?' for _ in values])})"
        return self.execute(query, values=values)
    
    def update_query(self, table: str, data: dict[str, Any], where_clause: str = None) -> Any:
        """Execute UPDATE query."""
        set_clause = ', '.join([f"{k} = ?" for k in data.keys()])
        query = f"UPDATE {table} SET {set_clause}"
        
        if where_clause:
            query += f" WHERE {where_clause}"
        
        return self.execute(query, values=list(data.values()))
    
    def delete_query(self, table: str, where_clause: str = None) -> Any:
        """Execute DELETE query."""
        query = f"DELETE FROM {table}"
        if where_clause:
            query += f" WHERE {where_clause}"
        
        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"SELECT * FROM {tables[0]}"
        for i, table in enumerate(tables[1:], 1):
            if i <= len(join_conditions):
                query += f" JOIN {table} ON {join_conditions[i-1]}"
            else:
                query += f" CROSS JOIN {table}"
        
        return self.execute(query)
    
    def aggregate_query(self, table: str, functions: list[str], group_by: list[str] = None) -> Any:
        """Execute aggregate query."""
        query = f"SELECT {', '.join(functions)} FROM {table}"
        if group_by:
            query += f" GROUP BY {', '.join(group_by)}"
        
        return self.execute(query)
    
    def _get_query_type(self, query: str) -> str:
        """Extract query type from SQL query."""
        query = query.strip().upper()
        for operation in ["SELECT", "INSERT", "UPDATE", "DELETE", "CREATE", "DROP", "ALTER"]:
            if query.startswith(operation):
                return operation
        return "UNKNOWN"
    
    def _execute_select(self, query: str, **kwargs) -> Any:
        """Execute SELECT query."""
        # Placeholder implementation
        return {"result": "SELECT executed", "query": query}
    
    def _execute_insert(self, query: str, **kwargs) -> Any:
        """Execute INSERT query."""
        # Placeholder implementation
        return {"result": "INSERT executed", "query": query}
    
    def _execute_update(self, query: str, **kwargs) -> Any:
        """Execute UPDATE query."""
        # Placeholder implementation
        return {"result": "UPDATE executed", "query": query}
    
    def _execute_delete(self, query: str, **kwargs) -> Any:
        """Execute DELETE query."""
        # Placeholder implementation
        return {"result": "DELETE executed", "query": query}
    
    def _estimate_complexity(self, query: str) -> str:
        """Estimate query complexity."""
        query = query.upper()
        if "JOIN" in query:
            return "HIGH"
        elif "GROUP BY" in query or "ORDER BY" in query:
            return "MEDIUM"
        else:
            return "LOW"
    
    def _estimate_cost(self, query: str) -> int:
        """Estimate query cost."""
        complexity = self._estimate_complexity(query)
        if complexity == "HIGH":
            return 100
        elif complexity == "MEDIUM":
            return 50
        else:
            return 10
    
    def _get_optimization_hints(self, query: str) -> list[str]:
        """Get query optimization hints."""
        hints = []
        query = query.upper()
        
        if "SELECT *" in query:
            hints.append("Consider specifying columns instead of using *")
        if "WHERE" not in query and "SELECT" in query:
            hints.append("Consider adding WHERE clause to limit results")
        if "ORDER BY" in query:
            hints.append("Consider adding index on ORDER BY columns")
        
        return hints
    
    def to_actions_tree(self, sql_query: str) -> XWNodeBase:
        """Convert SQL query to XWQuery Script actions tree."""
        from .xwquery import XWQueryScriptStrategy
        
        # Parse SQL into XWQuery Script actions
        XWQueryScriptStrategy()
        
        # Map SQL constructs to XWQuery actions:
        # SELECT -> SELECT action
        # FROM -> FROM action  
        # WHERE -> WHERE action
        # JOIN -> JOIN action (with nested conditions)
        # Subqueries -> nested SELECT actions
        # etc.
        
        # For now, create a basic actions tree
        actions = {
            "root": {
                "type": "PROGRAM",
                "statements": [
                    {
                        "type": "SELECT",
                        "id": "sql_action_1",
                        "content": sql_query,
                        "line_number": 1,
                        "timestamp": "2025-01-02T00:00:00",
                        "children": []
                    }
                ],
                "comments": [],
                "metadata": {
                    "version": "1.0",
                    "created": "2025-01-02T00:00:00",
                    "source_format": "SQL"
                }
            }
        }
        
        return XWNodeBase.from_native(actions)
    
    def from_actions_tree(self, actions_tree: XWNodeBase) -> str:
        """Convert XWQuery Script actions tree to SQL query."""
        from .xwquery import XWQueryScriptStrategy
        
        script_strategy = XWQueryScriptStrategy(actions_tree)
        return script_strategy.to_format("SQL")
    
    def can_handle(self, query_string: str) -> bool:
        """Check if this strategy can handle the given query string."""
        return self.validate_query(query_string)
    
    def get_supported_operations(self) -> list[str]:
        """Get list of supported query operations."""
        return [
            "SELECT", "INSERT", "UPDATE", "DELETE", "CREATE", "DROP", "ALTER",
            "JOIN", "UNION", "GROUP BY", "ORDER BY", "HAVING", "WHERE",
            "WITH", "CASE", "WINDOW", "PARTITION BY", "OVER"
        ]
    
    def estimate_complexity(self, query_string: str) -> dict[str, Any]:
        """Estimate query complexity and resource requirements."""
        complexity = self._estimate_complexity(query_string)
        cost = self._estimate_cost(query_string)
        
        return {
            "complexity_level": complexity,
            "estimated_cost": cost,
            "has_joins": "JOIN" in query_string.upper(),
            "has_subqueries": "SELECT" in query_string.upper().replace("SELECT", "", 1),
            "has_aggregates": any(func in query_string.upper() for func in ["SUM", "COUNT", "AVG", "MIN", "MAX"]),
            "has_window_functions": "OVER" in query_string.upper(),
            "query_length": len(query_string),
            "estimated_memory": "high" if complexity == "HIGH" else "medium" if complexity == "MEDIUM" else "low"
        }