gigabrain / src / cypher / executor.rs

use crate::cypher::planner::{QueryPlan, ScanPlan, CreatePlan, ProjectPlan};
use crate::cypher::ast::{CypherQuery, MatchClause, CreateClause, ReturnClause, Expression, PatternElement};
use crate::core::{Graph, PropertyValue};
use crate::index::{IndexQuery, IndexType};
use crate::{Result, GigabrainError, NodeId, RelationshipId};
use std::sync::Arc;
use std::collections::HashMap;
use tracing::{debug, info};

pub struct QueryExecutor {
    graph: Arc<Graph>,
}

impl QueryExecutor {
    pub fn new(graph: Arc<Graph>) -> Self {
        Self { graph }
    }
    
    pub async fn execute_query(&self, query: &CypherQuery) -> Result<QueryResult> {
        match query {
            CypherQuery::Match(match_clause) => self.execute_match(match_clause).await,
            CypherQuery::Create(create_clause) => self.execute_create_query(create_clause).await,
            CypherQuery::Return(return_clause) => self.execute_return(return_clause).await,
            CypherQuery::Compound(queries) => {
                let mut context = ExecutionContext::new();
                for query in queries {
                    let _result = self.execute_query_with_context(query, &mut context).await?;
                    // Store intermediate results in context for compound queries
                }
                Ok(context.into_result())
            },
            _ => Err(GigabrainError::Query("Query type not supported yet".to_string())),
        }
    }
    
    fn execute_query_with_context<'a>(&'a self, query: &'a CypherQuery, context: &'a mut ExecutionContext) -> std::pin::Pin<Box<dyn std::future::Future<Output = Result<QueryResult>> + 'a>> {
        Box::pin(async move {
            match query {
                CypherQuery::Match(match_clause) => {
                    let result = self.execute_match_with_context(match_clause, context).await?;
                    context.merge_result(result);
                    Ok(QueryResult::empty())
                },
                CypherQuery::Return(return_clause) => {
                    self.execute_return_with_context(return_clause, context).await
                },
                _ => self.execute_query(query).await,
            }
        })
    }
    
    async fn execute_match(&self, match_clause: &MatchClause) -> Result<QueryResult> {
        let mut context = ExecutionContext::new();
        self.execute_match_with_context(match_clause, &mut context).await?;
        
        // Return all matched nodes directly
        let all_nodes = self.graph.get_all_nodes();
        let columns = vec!["n".to_string()];
        let mut rows = Vec::new();
        
        for node_id in all_nodes {
            rows.push(Row { 
                values: vec![Value::Node(node_id)]
            });
        }
        
        Ok(QueryResult { rows, columns })
    }
    
    async fn execute_match_with_context(&self, match_clause: &MatchClause, context: &mut ExecutionContext) -> Result<QueryResult> {
        // Simple pattern matching for demonstration
        // In reality, this would use a sophisticated query planner
        
        let pattern = &match_clause.pattern;
        
        // Process pattern elements sequentially
        let mut i = 0;
        while i < pattern.elements.len() {
            match &pattern.elements[i] {
                PatternElement::Node(node_pattern) => {
                    if let Some(variable) = &node_pattern.variable {
                        // Get nodes matching the pattern
                        let matching_nodes = self.find_matching_nodes(node_pattern).await?;
                        context.bind_variable(variable.clone(), VariableBinding::Nodes(matching_nodes));
                    }
                    i += 1;
                },
                PatternElement::Relationship(rel_pattern) => {
                    // Handle relationship patterns
                    if let Some(variable) = &rel_pattern.variable {
                        // For now, get all relationships
                        // TODO: Implement proper relationship matching based on type and direction
                        let all_relationships = self.get_all_relationships().await?;
                        context.bind_variable(variable.clone(), VariableBinding::Relationships(all_relationships));
                    }
                    i += 1;
                },
                _ => {
                    i += 1;
                }
            }
        }
        
        // Apply WHERE clause filtering if present
        if let Some(where_expr) = &match_clause.where_clause {
            self.apply_where_filter(context, where_expr).await?;
        }
        
        Ok(QueryResult::empty())
    }
    
    async fn apply_where_filter(&self, context: &mut ExecutionContext, where_expr: &Expression) -> Result<()> {
        // Create a new context to store filtered results
        let mut filtered_context = ExecutionContext::new();
        
        // For each variable binding, evaluate the WHERE clause
        let variable_names: Vec<String> = context.variables.keys().cloned().collect();
        
        if variable_names.is_empty() {
            return Ok(());
        }
        
        // Get all possible combinations of variable bindings
        let combinations = self.generate_binding_combinations(context).await?;
        
        // Filter combinations based on WHERE clause
        let mut filtered_combinations = Vec::new();
        for combination in combinations {
            // Create a temporary context with this specific binding combination
            let mut temp_context = ExecutionContext::new();
            for (var_name, binding) in &combination {
                temp_context.bind_variable(var_name.clone(), binding.clone());
            }
            
            // Evaluate WHERE clause with this binding
            let result = self.evaluate_expression(where_expr, &temp_context, None).await?;
            
            if self.is_truthy(&result) {
                filtered_combinations.push(combination);
            }
        }
        
        // Rebuild the context with filtered results
        self.rebuild_context_from_combinations(context, filtered_combinations);
        
        Ok(())
    }
    
    async fn generate_binding_combinations(&self, context: &ExecutionContext) -> Result<Vec<HashMap<String, VariableBinding>>> {
        let mut combinations = Vec::new();
        let variable_names: Vec<String> = context.variables.keys().cloned().collect();
        
        if variable_names.is_empty() {
            return Ok(combinations);
        }
        
        // Generate all combinations of variable bindings
        // This is a simplified approach - for performance, we'd use join algorithms
        if variable_names.len() == 1 {
            let var_name = &variable_names[0];
            if let Some(binding) = context.variables.get(var_name) {
                match binding {
                    VariableBinding::Nodes(node_ids) => {
                        for &node_id in node_ids {
                            let mut combination = HashMap::new();
                            combination.insert(var_name.clone(), VariableBinding::Nodes(vec![node_id]));
                            combinations.push(combination);
                        }
                    },
                    VariableBinding::Relationships(rel_ids) => {
                        for &rel_id in rel_ids {
                            let mut combination = HashMap::new();
                            combination.insert(var_name.clone(), VariableBinding::Relationships(vec![rel_id]));
                            combinations.push(combination);
                        }
                    }
                }
            }
        } else {
            // For multiple variables, generate cartesian product
            // This is simplified - real implementation would be more efficient
            self.generate_cartesian_product(context, &variable_names, 0, &mut HashMap::new(), &mut combinations);
        }
        
        Ok(combinations)
    }
    
    fn generate_cartesian_product(
        &self,
        context: &ExecutionContext,
        variable_names: &[String],
        index: usize,
        current_combination: &mut HashMap<String, VariableBinding>,
        combinations: &mut Vec<HashMap<String, VariableBinding>>
    ) {
        if index >= variable_names.len() {
            combinations.push(current_combination.clone());
            return;
        }
        
        let var_name = &variable_names[index];
        if let Some(binding) = context.variables.get(var_name) {
            match binding {
                VariableBinding::Nodes(node_ids) => {
                    for &node_id in node_ids {
                        current_combination.insert(var_name.clone(), VariableBinding::Nodes(vec![node_id]));
                        self.generate_cartesian_product(context, variable_names, index + 1, current_combination, combinations);
                    }
                },
                VariableBinding::Relationships(rel_ids) => {
                    for &rel_id in rel_ids {
                        current_combination.insert(var_name.clone(), VariableBinding::Relationships(vec![rel_id]));
                        self.generate_cartesian_product(context, variable_names, index + 1, current_combination, combinations);
                    }
                }
            }
        }
    }
    
    fn rebuild_context_from_combinations(&self, context: &mut ExecutionContext, combinations: Vec<HashMap<String, VariableBinding>>) {
        // Clear current context
        context.variables.clear();
        
        // Group combinations back into variable bindings
        let mut var_to_nodes: HashMap<String, Vec<NodeId>> = HashMap::new();
        let mut var_to_rels: HashMap<String, Vec<RelationshipId>> = HashMap::new();
        
        for combination in combinations {
            for (var_name, binding) in combination {
                match binding {
                    VariableBinding::Nodes(node_ids) => {
                        var_to_nodes.entry(var_name).or_insert_with(Vec::new).extend(node_ids);
                    },
                    VariableBinding::Relationships(rel_ids) => {
                        var_to_rels.entry(var_name).or_insert_with(Vec::new).extend(rel_ids);
                    }
                }
            }
        }
        
        // Rebuild context with filtered bindings
        for (var_name, node_ids) in var_to_nodes {
            context.bind_variable(var_name, VariableBinding::Nodes(node_ids));
        }
        
        for (var_name, rel_ids) in var_to_rels {
            context.bind_variable(var_name, VariableBinding::Relationships(rel_ids));
        }
    }
    
    async fn find_matching_nodes(&self, node_pattern: &crate::cypher::ast::NodePattern) -> Result<Vec<NodeId>> {
        debug!("Finding nodes matching pattern: labels={:?}, properties={:?}", 
               node_pattern.labels, node_pattern.properties);
        
        let mut candidate_nodes: Option<Vec<NodeId>> = None;
        
        // Use label indexes if labels are specified
        if !node_pattern.labels.is_empty() {
            debug!("Using label indexes for labels: {:?}", node_pattern.labels);
            let mut label_matches = Vec::new();
            
            for label_name in &node_pattern.labels {
                match self.graph.find_nodes_by_label(label_name) {
                    Ok(nodes) => {
                        if label_matches.is_empty() {
                            label_matches = nodes;
                        } else {
                            // Intersect with previous results (AND logic for multiple labels)
                            label_matches.retain(|node_id| nodes.contains(node_id));
                        }
                    },
                    Err(e) => {
                        debug!("Failed to use label index for '{}': {}", label_name, e);
                        // Fall back to scanning all nodes
                        label_matches = self.graph.get_all_nodes();
                        break;
                    }
                }
            }
            
            candidate_nodes = Some(label_matches);
            info!("Label index returned {} candidate nodes", candidate_nodes.as_ref().unwrap().len());
        }
        
        // Use property indexes if properties are specified
        if let Some(ref properties) = node_pattern.properties {
            debug!("Using property indexes for {} properties", properties.len());
            let mut property_matches: Option<Vec<NodeId>> = None;
            
            for (prop_name, value_expr) in properties {
                // For now, only handle literal values in property patterns
                if let Expression::Literal(prop_value) = value_expr {
                    match self.graph.find_nodes_by_property(prop_name, prop_value) {
                        Ok(nodes) => {
                            if let Some(ref mut existing_matches) = property_matches {
                                // Intersect with previous property matches
                                existing_matches.retain(|node_id| nodes.contains(node_id));
                            } else {
                                property_matches = Some(nodes);
                            }
                        },
                        Err(e) => {
                            debug!("Failed to use property index for '{}': {}", prop_name, e);
                            // Continue with other properties or fall back to scanning
                        }
                    }
                }
            }
            
            if let Some(prop_nodes) = property_matches {
                if let Some(ref mut candidates) = candidate_nodes {
                    // Intersect label matches with property matches
                    candidates.retain(|node_id| prop_nodes.contains(node_id));
                } else {
                    candidate_nodes = Some(prop_nodes);
                }
                info!("Property index intersection returned {} candidate nodes", 
                      candidate_nodes.as_ref().unwrap().len());
            }
        }
        
        // If no indexes were used, scan all nodes
        let result_nodes = candidate_nodes.unwrap_or_else(|| {
            debug!("No indexes available, scanning all nodes");
            self.graph.get_all_nodes()
        });
        
        // TODO: Apply additional filtering for complex property expressions
        // that couldn't be handled by indexes
        
        debug!("Final result: {} nodes matched the pattern", result_nodes.len());
        Ok(result_nodes)
    }
    
    async fn get_all_relationships(&self) -> Result<Vec<RelationshipId>> {
        // Get all relationships in the graph
        // This is a simplified implementation - normally we'd iterate through the graph structure
        let mut all_relationships = Vec::new();
        
        // For each node, get its relationships
        for node_id in self.graph.get_all_nodes() {
            let relationships = self.graph.get_node_relationships(
                node_id, 
                crate::core::relationship::Direction::Both, 
                None
            );
            
            for rel in relationships {
                if !all_relationships.contains(&rel.id) {
                    all_relationships.push(rel.id);
                }
            }
        }
        
        Ok(all_relationships)
    }
    
    async fn execute_create_query(&self, create_clause: &CreateClause) -> Result<QueryResult> {
        // Create new nodes/relationships based on pattern
        let mut created_nodes = Vec::new();
        let mut created_relationships = Vec::new();
        let mut node_variables = HashMap::new();
        
        // First pass: create all nodes
        for element in &create_clause.pattern.elements {
            if let PatternElement::Node(node_pattern) = element {
                // Create a new node
                let node_id = self.graph.create_node();
                
                // Add labels and properties using update_node
                self.graph.update_node(node_id, |node| {
                    // Add labels if specified
                    if !node_pattern.labels.is_empty() {
                        let schema = self.graph.schema();
                        for label_name in &node_pattern.labels {
                            let label_id = {
                                let mut schema_guard = schema.write();
                                schema_guard.get_or_create_label(label_name)
                            };
                            node.add_label(label_id);
                        }
                    }
                    
                    // Add properties if specified
                    if let Some(ref properties) = node_pattern.properties {
                        let schema = self.graph.schema();
                        for (key, value_expr) in properties {
                            let property_key_id = {
                                let mut schema_guard = schema.write();
                                schema_guard.get_or_create_property_key(key)
                            };
                            
                            // Convert expression to property value (simplified)
                            let property_value = match value_expr {
                                Expression::Literal(literal) => literal.clone(),
                                _ => PropertyValue::String("unknown".to_string()),
                            };
                            
                            node.properties.insert(property_key_id, property_value);
                        }
                    }
                })?;
                
                created_nodes.push(node_id);
                
                // Add to indexes after creating the node
                if let Some(node) = self.graph.get_node(node_id) {
                    let labels: Vec<_> = node.labels.iter().cloned().collect();
                    let properties = node.properties.clone();
                    
                    // Ensure indexes exist for any new labels
                    for &label_id in &labels {
                        let index_type = IndexType::Label(label_id);
                        if let Err(e) = self.graph.index_manager().create_index(index_type, None, false) {
                            debug!("Label index may already exist or failed to create: {}", e);
                        }
                    }
                    
                    // Ensure indexes exist for any new properties
                    for &property_key_id in properties.keys() {
                        let index_type = IndexType::Property(property_key_id);
                        if let Err(e) = self.graph.index_manager().create_index(index_type, None, false) {
                            debug!("Property index may already exist or failed to create: {}", e);
                        }
                    }
                    
                    // Add node to indexes
                    if let Err(e) = self.graph.index_manager().add_node(node_id, &labels, &properties) {
                        debug!("Failed to add created node to indexes: {}", e);
                    } else {
                        debug!("Added newly created node {} to indexes", node_id.0);
                    }
                }
                
                // Store node variable mapping for relationships
                if let Some(var_name) = &node_pattern.variable {
                    node_variables.insert(var_name.clone(), node_id);
                }
            }
        }
        
        // Second pass: create relationships between nodes
        let mut i = 0;
        while i < create_clause.pattern.elements.len() {
            if i + 2 < create_clause.pattern.elements.len() {
                if let (PatternElement::Node(start_node), PatternElement::Relationship(rel_pattern), PatternElement::Node(end_node)) = 
                    (&create_clause.pattern.elements[i], &create_clause.pattern.elements[i + 1], &create_clause.pattern.elements[i + 2]) {
                    
                    // Get start and end node IDs
                    let start_id = if let Some(var_name) = &start_node.variable {
                        node_variables.get(var_name).copied()
                    } else {
                        created_nodes.first().copied()
                    };
                    
                    let end_id = if let Some(var_name) = &end_node.variable {
                        node_variables.get(var_name).copied()
                    } else {
                        created_nodes.last().copied()
                    };
                    
                    if let (Some(start_id), Some(end_id)) = (start_id, end_id) {
                        // Create the relationship
                        let rel_type_id = if let Some(rel_type_name) = rel_pattern.types.first() {
                            let schema = self.graph.schema();
                            let mut schema_guard = schema.write();
                            schema_guard.get_or_create_relationship_type(rel_type_name)
                        } else {
                            0 // Default relationship type
                        };
                        
                        let rel_id = self.graph.create_relationship(start_id, end_id, rel_type_id)?;
                        created_relationships.push(rel_id);
                        
                        // Add relationship properties if specified
                        if let Some(ref properties) = rel_pattern.properties {
                            // TODO: Implement relationship property setting
                            // This would require extending the graph API to update relationship properties
                        }
                    }
                    
                    i += 3; // Skip the relationship pattern and end node
                } else {
                    i += 1;
                }
            } else {
                i += 1;
            }
        }
        
        // Return result indicating what was created
        let mut columns = Vec::new();
        let mut values = Vec::new();
        
        if !created_nodes.is_empty() {
            columns.push("nodes_created".to_string());
            values.push(Value::Integer(created_nodes.len() as i64));
        }
        
        if !created_relationships.is_empty() {
            columns.push("relationships_created".to_string());
            values.push(Value::Integer(created_relationships.len() as i64));
        }
        
        let rows = if !values.is_empty() {
            vec![Row { values }]
        } else {
            vec![Row { values: vec![Value::Integer(0)] }]
        };
        
        Ok(QueryResult { rows, columns })
    }
    
    async fn execute_return(&self, return_clause: &ReturnClause) -> Result<QueryResult> {
        let mut context = ExecutionContext::new();
        self.execute_return_with_context(return_clause, &mut context).await
    }
    
    async fn execute_return_with_context(&self, return_clause: &ReturnClause, context: &ExecutionContext) -> Result<QueryResult> {
        let mut columns = Vec::new();
        let mut rows = Vec::new();
        
        // Extract column names
        for item in &return_clause.items {
            let column_name = if let Some(alias) = &item.alias {
                alias.clone()
            } else {
                self.expression_to_string(&item.expression)
            };
            columns.push(column_name);
        }
        
        // Generate result rows based on variable bindings
        if let Some(first_binding) = context.variables.values().next() {
            match first_binding {
                VariableBinding::Nodes(node_ids) => {
                    for node_id in node_ids {
                        let mut values = Vec::new();
                        for item in &return_clause.items {
                            values.push(self.evaluate_expression(&item.expression, context, Some(*node_id)).await?);
                        }
                        rows.push(Row { values });
                    }
                },
                _ => {}
            }
        }
        
        Ok(QueryResult { rows, columns })
    }
    
    fn evaluate_expression<'a>(&'a self, expr: &'a Expression, context: &'a ExecutionContext, current_node: Option<NodeId>) -> std::pin::Pin<Box<dyn std::future::Future<Output = Result<Value>> + 'a>> {
        Box::pin(async move {
            match expr {
                Expression::Variable(var_name) => {
                    if let Some(binding) = context.variables.get(var_name) {
                        match binding {
                            VariableBinding::Nodes(nodes) => {
                                if let Some(node_id) = current_node {
                                    Ok(Value::Node(node_id))
                                } else if let Some(&first_node) = nodes.first() {
                                    Ok(Value::Node(first_node))
                                } else {
                                    Ok(Value::Null)
                                }
                            },
                            VariableBinding::Relationships(rels) => {
                                if let Some(&first_rel) = rels.first() {
                                    Ok(Value::Relationship(first_rel))
                                } else {
                                    Ok(Value::Null)
                                }
                            }
                        }
                    } else {
                        Ok(Value::Null)
                    }
                },
                Expression::Property(prop_expr) => {
                    let base_value = self.evaluate_expression(&prop_expr.expression, context, current_node).await?;
                    self.get_property_value(base_value, &prop_expr.property).await
                },
                Expression::Literal(literal) => {
                    Ok(self.property_value_to_executor_value(literal))
                },
                Expression::Equal(left, right) => {
                    let left_val = self.evaluate_expression(left, context, current_node).await?;
                    let right_val = self.evaluate_expression(right, context, current_node).await?;
                    Ok(Value::Boolean(self.values_equal(&left_val, &right_val)))
                },
                Expression::NotEqual(left, right) => {
                    let left_val = self.evaluate_expression(left, context, current_node).await?;
                    let right_val = self.evaluate_expression(right, context, current_node).await?;
                    Ok(Value::Boolean(!self.values_equal(&left_val, &right_val)))
                },
                Expression::And(left, right) => {
                    let left_val = self.evaluate_expression(left, context, current_node).await?;
                    let right_val = self.evaluate_expression(right, context, current_node).await?;
                    Ok(Value::Boolean(self.is_truthy(&left_val) && self.is_truthy(&right_val)))
                },
                Expression::Or(left, right) => {
                    let left_val = self.evaluate_expression(left, context, current_node).await?;
                    let right_val = self.evaluate_expression(right, context, current_node).await?;
                    Ok(Value::Boolean(self.is_truthy(&left_val) || self.is_truthy(&right_val)))
                },
                Expression::Not(expr) => {
                    let val = self.evaluate_expression(expr, context, current_node).await?;
                    Ok(Value::Boolean(!self.is_truthy(&val)))
                },
                Expression::LessThan(left, right) => {
                    let left_val = self.evaluate_expression(left, context, current_node).await?;
                    let right_val = self.evaluate_expression(right, context, current_node).await?;
                    Ok(Value::Boolean(self.compare_values(&left_val, &right_val) < 0))
                },
                Expression::LessThanOrEqual(left, right) => {
                    let left_val = self.evaluate_expression(left, context, current_node).await?;
                    let right_val = self.evaluate_expression(right, context, current_node).await?;
                    Ok(Value::Boolean(self.compare_values(&left_val, &right_val) <= 0))
                },
                Expression::GreaterThan(left, right) => {
                    let left_val = self.evaluate_expression(left, context, current_node).await?;
                    let right_val = self.evaluate_expression(right, context, current_node).await?;
                    Ok(Value::Boolean(self.compare_values(&left_val, &right_val) > 0))
                },
                Expression::GreaterThanOrEqual(left, right) => {
                    let left_val = self.evaluate_expression(left, context, current_node).await?;
                    let right_val = self.evaluate_expression(right, context, current_node).await?;
                    Ok(Value::Boolean(self.compare_values(&left_val, &right_val) >= 0))
                },
                _ => Ok(Value::Null), // TODO: Implement remaining expression types
            }
        })
    }
    
    async fn get_property_value(&self, base_value: Value, property_name: &str) -> Result<Value> {
        match base_value {
            Value::Node(node_id) => {
                if let Some(node) = self.graph.get_node(node_id) {
                    // Get property value from node
                    let schema = self.graph.schema();
                    let schema_guard = schema.read();
                    for (prop_key, _) in &schema_guard.property_keys {
                        if prop_key == property_name {
                            let prop_key_id = schema_guard.property_keys[prop_key];
                            if let Some(prop_value) = node.properties.get(&prop_key_id) {
                                return Ok(self.property_value_to_executor_value(prop_value));
                            }
                        }
                    }
                }
                Ok(Value::Null)
            },
            Value::Relationship(_rel_id) => {
                // TODO: Implement relationship property access
                Ok(Value::Null)
            },
            _ => Ok(Value::Null),
        }
    }
    
    fn property_value_to_executor_value(&self, prop_val: &PropertyValue) -> Value {
        match prop_val {
            PropertyValue::String(s) => Value::String(s.clone()),
            PropertyValue::Integer(i) => Value::Integer(*i),
            PropertyValue::Float(f) => Value::Float(*f),
            PropertyValue::Boolean(b) => Value::Boolean(*b),
            PropertyValue::List(list) => {
                let converted_list: Vec<Value> = list.iter()
                    .map(|item| self.property_value_to_executor_value(item))
                    .collect();
                Value::List(converted_list)
            },
            PropertyValue::Null => Value::Null,
            PropertyValue::Map(_) => Value::Null, // TODO: Implement map support
        }
    }
    
    fn values_equal(&self, left: &Value, right: &Value) -> bool {
        match (left, right) {
            (Value::String(a), Value::String(b)) => a == b,
            (Value::Integer(a), Value::Integer(b)) => a == b,
            (Value::Float(a), Value::Float(b)) => (a - b).abs() < f64::EPSILON,
            (Value::Boolean(a), Value::Boolean(b)) => a == b,
            (Value::Node(a), Value::Node(b)) => a == b,
            (Value::Relationship(a), Value::Relationship(b)) => a == b,
            (Value::Null, Value::Null) => true,
            // Type coercion for numbers
            (Value::Integer(a), Value::Float(b)) => (*a as f64 - b).abs() < f64::EPSILON,
            (Value::Float(a), Value::Integer(b)) => (a - *b as f64).abs() < f64::EPSILON,
            _ => false,
        }
    }
    
    fn is_truthy(&self, value: &Value) -> bool {
        match value {
            Value::Boolean(b) => *b,
            Value::Null => false,
            Value::Integer(i) => *i != 0,
            Value::Float(f) => *f != 0.0,
            Value::String(s) => !s.is_empty(),
            Value::List(list) => !list.is_empty(),
            Value::Node(_) => true,
            Value::Relationship(_) => true,
        }
    }
    
    fn compare_values(&self, left: &Value, right: &Value) -> i32 {
        match (left, right) {
            (Value::Integer(a), Value::Integer(b)) => a.cmp(b) as i32,
            (Value::Float(a), Value::Float(b)) => a.partial_cmp(b).unwrap_or(std::cmp::Ordering::Equal) as i32,
            (Value::Integer(a), Value::Float(b)) => (*a as f64).partial_cmp(b).unwrap_or(std::cmp::Ordering::Equal) as i32,
            (Value::Float(a), Value::Integer(b)) => a.partial_cmp(&(*b as f64)).unwrap_or(std::cmp::Ordering::Equal) as i32,
            (Value::String(a), Value::String(b)) => a.cmp(b) as i32,
            _ => 0, // Incomparable types are considered equal
        }
    }
    
    fn expression_to_string(&self, expr: &Expression) -> String {
        match expr {
            Expression::Variable(name) => name.clone(),
            _ => "expr".to_string(),
        }
    }
    
    pub async fn execute(&self, plan: QueryPlan) -> Result<QueryResult> {
        match plan {
            QueryPlan::Scan(scan_plan) => self.execute_scan(scan_plan).await,
            QueryPlan::Create(create_plan) => self.execute_create(create_plan).await,
            QueryPlan::Project(project_plan) => self.execute_project(project_plan).await,
            _ => Err(GigabrainError::Query("Execution not implemented for this plan type".to_string())),
        }
    }
    
    async fn execute_scan(&self, _scan_plan: ScanPlan) -> Result<QueryResult> {
        Ok(QueryResult::empty())
    }
    
    async fn execute_create(&self, _create_plan: CreatePlan) -> Result<QueryResult> {
        Ok(QueryResult::empty())
    }
    
    async fn execute_project(&self, _project_plan: ProjectPlan) -> Result<QueryResult> {
        Ok(QueryResult::empty())
    }
}

#[derive(Debug)]
pub struct ExecutionContext {
    variables: HashMap<String, VariableBinding>,
}

impl ExecutionContext {
    fn new() -> Self {
        Self {
            variables: HashMap::new(),
        }
    }
    
    fn bind_variable(&mut self, name: String, binding: VariableBinding) {
        self.variables.insert(name, binding);
    }
    
    fn merge_result(&mut self, _result: QueryResult) {
        // Merge results from previous query steps
    }
    
    fn into_result(self) -> QueryResult {
        // If we have variable bindings, create a result from them
        if let Some((var_name, binding)) = self.variables.iter().next() {
            match binding {
                VariableBinding::Nodes(node_ids) => {
                    let columns = vec![var_name.clone()];
                    let mut rows = Vec::new();
                    for node_id in node_ids {
                        rows.push(Row { 
                            values: vec![Value::Node(*node_id)]
                        });
                    }
                    QueryResult { rows, columns }
                },
                VariableBinding::Relationships(rel_ids) => {
                    let columns = vec![var_name.clone()];
                    let mut rows = Vec::new();
                    for rel_id in rel_ids {
                        rows.push(Row { 
                            values: vec![Value::Relationship(*rel_id)]
                        });
                    }
                    QueryResult { rows, columns }
                },
            }
        } else {
            QueryResult::empty()
        }
    }
}

#[derive(Debug, Clone)]
enum VariableBinding {
    Nodes(Vec<NodeId>),
    Relationships(Vec<RelationshipId>),
}

#[derive(Debug)]
pub struct QueryResult {
    pub rows: Vec<Row>,
    pub columns: Vec<String>,
}

impl QueryResult {
    fn empty() -> Self {
        Self {
            rows: Vec::new(),
            columns: Vec::new(),
        }
    }
}

#[derive(Debug)]
pub struct Row {
    pub values: Vec<Value>,
}

#[derive(Debug)]
pub enum Value {
    Null,
    Node(crate::NodeId),
    Relationship(crate::RelationshipId),
    Integer(i64),
    Float(f64),
    String(String),
    Boolean(bool),
    List(Vec<Value>),
}