things3-core 2.1.0

//! L3 Database query result cache with smart invalidation

use crate::models::{Area, Project, Task, ThingsId};
use anyhow::Result;
use chrono::{DateTime, Utc};
use moka::future::Cache;
use parking_lot::RwLock;
use serde::{Deserialize, Serialize};
use std::sync::Arc;
use std::time::Duration;
use tracing::{debug, warn};

/// Query cache configuration
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct QueryCacheConfig {
    /// Maximum number of cached queries
    pub max_queries: u64,
    /// Time to live for cached queries
    pub ttl: Duration,
    /// Time to idle for cached queries
    pub tti: Duration,
    /// Enable query result compression
    pub enable_compression: bool,
    /// Maximum query result size to cache (in bytes)
    pub max_result_size: usize,
}

impl Default for QueryCacheConfig {
    fn default() -> Self {
        Self {
            max_queries: 1000,
            ttl: Duration::from_secs(1800), // 30 minutes
            tti: Duration::from_secs(300),  // 5 minutes
            enable_compression: true,
            max_result_size: 1024 * 1024, // 1MB
        }
    }
}

/// Cached query result
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct CachedQueryResult<T> {
    /// The actual query result
    pub data: T,
    /// When the query was executed
    pub executed_at: DateTime<Utc>,
    /// When the result expires
    pub expires_at: DateTime<Utc>,
    /// Query execution time
    pub execution_time_ms: u64,
    /// Query parameters hash for invalidation
    pub params_hash: String,
    /// Tables/entities this query depends on
    pub dependencies: Vec<QueryDependency>,
    /// Query result size in bytes
    pub result_size: usize,
    /// Whether the result is compressed
    pub compressed: bool,
}

/// Query dependency for smart invalidation
#[derive(Debug, Clone, Serialize, Deserialize, PartialEq, Eq, Hash)]
pub struct QueryDependency {
    /// Table name
    pub table: String,
    /// Specific entity ID (if applicable)
    pub entity_id: Option<ThingsId>,
    /// Operations that would invalidate this query
    pub invalidating_operations: Vec<String>,
}

/// Query cache statistics
#[derive(Debug, Clone, Default, Serialize, Deserialize)]
pub struct QueryCacheStats {
    pub total_queries: u64,
    pub hits: u64,
    pub misses: u64,
    pub hit_rate: f64,
    pub total_size_bytes: u64,
    pub average_execution_time_ms: f64,
    pub compressed_queries: u64,
    pub uncompressed_queries: u64,
}

impl QueryCacheStats {
    pub fn calculate_hit_rate(&mut self) {
        let total = self.hits + self.misses;
        self.hit_rate = if total > 0 {
            #[allow(clippy::cast_precision_loss)]
            {
                self.hits as f64 / total as f64
            }
        } else {
            0.0
        };
    }
}

/// L3 Database query result cache
pub struct QueryCache {
    /// Tasks query cache
    tasks_cache: Cache<String, CachedQueryResult<Vec<Task>>>,
    /// Projects query cache
    projects_cache: Cache<String, CachedQueryResult<Vec<Project>>>,
    /// Areas query cache
    areas_cache: Cache<String, CachedQueryResult<Vec<Area>>>,
    /// Search results query cache
    search_cache: Cache<String, CachedQueryResult<Vec<Task>>>,
    /// Statistics
    stats: Arc<RwLock<QueryCacheStats>>,
    /// Configuration
    config: QueryCacheConfig,
}

impl QueryCache {
    /// Create a new query cache
    #[must_use]
    pub fn new(config: QueryCacheConfig) -> Self {
        let tasks_cache = Cache::builder()
            .max_capacity(config.max_queries)
            .time_to_live(config.ttl)
            .time_to_idle(config.tti)
            .build();

        let projects_cache = Cache::builder()
            .max_capacity(config.max_queries)
            .time_to_live(config.ttl)
            .time_to_idle(config.tti)
            .build();

        let areas_cache = Cache::builder()
            .max_capacity(config.max_queries)
            .time_to_live(config.ttl)
            .time_to_idle(config.tti)
            .build();

        let search_cache = Cache::builder()
            .max_capacity(config.max_queries)
            .time_to_live(config.ttl)
            .time_to_idle(config.tti)
            .build();

        Self {
            tasks_cache,
            projects_cache,
            areas_cache,
            search_cache,
            stats: Arc::new(RwLock::new(QueryCacheStats::default())),
            config,
        }
    }

    /// Create a new query cache with default configuration
    #[must_use]
    pub fn new_default() -> Self {
        Self::new(QueryCacheConfig::default())
    }

    /// Cache a tasks query result
    ///
    /// # Errors
    ///
    /// This function will return an error if:
    /// - The fetcher function fails
    /// - Cache operations fail
    /// - Serialization/deserialization fails
    pub async fn cache_tasks_query<F, Fut>(
        &self,
        query_key: &str,
        params_hash: &str,
        fetcher: F,
    ) -> Result<Vec<Task>>
    where
        F: FnOnce() -> Fut,
        Fut: std::future::Future<Output = Result<Vec<Task>>>,
    {
        // Check if query is already cached
        if let Some(cached) = self.tasks_cache.get(query_key).await {
            if !cached.is_expired() && cached.params_hash == params_hash {
                self.record_hit();
                debug!("Query cache hit for tasks: {}", query_key);
                return Ok(cached.data);
            }
        }

        // Execute the query
        let start_time = std::time::Instant::now();
        let data = fetcher().await?;
        #[allow(clippy::cast_possible_truncation)]
        let execution_time = start_time.elapsed().as_millis() as u64;

        // Check if result is too large to cache
        let result_size = Self::calculate_result_size(&data);
        if result_size > self.config.max_result_size {
            warn!("Query result too large to cache: {} bytes", result_size);
            self.record_miss();
            return Ok(data);
        }

        // Create dependencies for smart invalidation
        let dependencies = Self::create_task_dependencies(&data);

        // Create cached result
        let cached_result = CachedQueryResult {
            data: data.clone(),
            executed_at: Utc::now(),
            expires_at: Utc::now()
                + chrono::Duration::from_std(self.config.ttl).unwrap_or_default(),
            execution_time_ms: execution_time,
            params_hash: params_hash.to_string(),
            dependencies,
            result_size,
            compressed: self.config.enable_compression,
        };

        // Store in cache
        self.tasks_cache
            .insert(query_key.to_string(), cached_result)
            .await;

        // Update statistics
        self.update_stats(result_size, execution_time, false);

        self.record_miss();
        debug!(
            "Cached tasks query: {} ({}ms, {} bytes)",
            query_key, execution_time, result_size
        );
        Ok(data)
    }

    /// Cache a projects query result
    ///
    /// # Errors
    ///
    /// This function will return an error if:
    /// - The fetcher function fails
    /// - Cache operations fail
    /// - Serialization/deserialization fails
    pub async fn cache_projects_query<F, Fut>(
        &self,
        query_key: &str,
        params_hash: &str,
        fetcher: F,
    ) -> Result<Vec<Project>>
    where
        F: FnOnce() -> Fut,
        Fut: std::future::Future<Output = Result<Vec<Project>>>,
    {
        // Check if query is already cached
        if let Some(cached) = self.projects_cache.get(query_key).await {
            if !cached.is_expired() && cached.params_hash == params_hash {
                self.record_hit();
                debug!("Query cache hit for projects: {}", query_key);
                return Ok(cached.data);
            }
        }

        // Execute the query
        let start_time = std::time::Instant::now();
        let data = fetcher().await?;
        #[allow(clippy::cast_possible_truncation)]
        let execution_time = start_time.elapsed().as_millis() as u64;

        // Check if result is too large to cache
        let result_size = Self::calculate_result_size(&data);
        if result_size > self.config.max_result_size {
            warn!("Query result too large to cache: {} bytes", result_size);
            self.record_miss();
            return Ok(data);
        }

        // Create dependencies for smart invalidation
        let dependencies = Self::create_project_dependencies(&data);

        // Create cached result
        let cached_result = CachedQueryResult {
            data: data.clone(),
            executed_at: Utc::now(),
            expires_at: Utc::now()
                + chrono::Duration::from_std(self.config.ttl).unwrap_or_default(),
            execution_time_ms: execution_time,
            params_hash: params_hash.to_string(),
            dependencies,
            result_size,
            compressed: self.config.enable_compression,
        };

        // Store in cache
        self.projects_cache
            .insert(query_key.to_string(), cached_result)
            .await;

        // Update statistics
        self.update_stats(result_size, execution_time, false);

        self.record_miss();
        debug!(
            "Cached projects query: {} ({}ms, {} bytes)",
            query_key, execution_time, result_size
        );
        Ok(data)
    }

    /// Cache an areas query result
    ///
    /// # Errors
    ///
    /// This function will return an error if:
    /// - The fetcher function fails
    /// - Cache operations fail
    /// - Serialization/deserialization fails
    pub async fn cache_areas_query<F, Fut>(
        &self,
        query_key: &str,
        params_hash: &str,
        fetcher: F,
    ) -> Result<Vec<Area>>
    where
        F: FnOnce() -> Fut,
        Fut: std::future::Future<Output = Result<Vec<Area>>>,
    {
        // Check if query is already cached
        if let Some(cached) = self.areas_cache.get(query_key).await {
            if !cached.is_expired() && cached.params_hash == params_hash {
                self.record_hit();
                debug!("Query cache hit for areas: {}", query_key);
                return Ok(cached.data);
            }
        }

        // Execute the query
        let start_time = std::time::Instant::now();
        let data = fetcher().await?;
        #[allow(clippy::cast_possible_truncation)]
        let execution_time = start_time.elapsed().as_millis() as u64;

        // Check if result is too large to cache
        let result_size = Self::calculate_result_size(&data);
        if result_size > self.config.max_result_size {
            warn!("Query result too large to cache: {} bytes", result_size);
            self.record_miss();
            return Ok(data);
        }

        // Create dependencies for smart invalidation
        let dependencies = Self::create_area_dependencies(&data);

        // Create cached result
        let cached_result = CachedQueryResult {
            data: data.clone(),
            executed_at: Utc::now(),
            expires_at: Utc::now()
                + chrono::Duration::from_std(self.config.ttl).unwrap_or_default(),
            execution_time_ms: execution_time,
            params_hash: params_hash.to_string(),
            dependencies,
            result_size,
            compressed: self.config.enable_compression,
        };

        // Store in cache
        self.areas_cache
            .insert(query_key.to_string(), cached_result)
            .await;

        // Update statistics
        self.update_stats(result_size, execution_time, false);

        self.record_miss();
        debug!(
            "Cached areas query: {} ({}ms, {} bytes)",
            query_key, execution_time, result_size
        );
        Ok(data)
    }

    /// Cache a search query result
    ///
    /// # Errors
    ///
    /// This function will return an error if:
    /// - The fetcher function fails
    /// - Cache operations fail
    /// - Serialization/deserialization fails
    pub async fn cache_search_query<F, Fut>(
        &self,
        query_key: &str,
        params_hash: &str,
        fetcher: F,
    ) -> Result<Vec<Task>>
    where
        F: FnOnce() -> Fut,
        Fut: std::future::Future<Output = Result<Vec<Task>>>,
    {
        // Check if query is already cached
        if let Some(cached) = self.search_cache.get(query_key).await {
            if !cached.is_expired() && cached.params_hash == params_hash {
                self.record_hit();
                debug!("Query cache hit for search: {}", query_key);
                return Ok(cached.data);
            }
        }

        // Execute the query
        let start_time = std::time::Instant::now();
        let data = fetcher().await?;
        #[allow(clippy::cast_possible_truncation)]
        let execution_time = start_time.elapsed().as_millis() as u64;

        // Check if result is too large to cache
        let result_size = Self::calculate_result_size(&data);
        if result_size > self.config.max_result_size {
            warn!("Query result too large to cache: {} bytes", result_size);
            self.record_miss();
            return Ok(data);
        }

        // Create dependencies for smart invalidation
        let dependencies = Self::create_task_dependencies(&data);

        // Create cached result
        let cached_result = CachedQueryResult {
            data: data.clone(),
            executed_at: Utc::now(),
            expires_at: Utc::now()
                + chrono::Duration::from_std(self.config.ttl).unwrap_or_default(),
            execution_time_ms: execution_time,
            params_hash: params_hash.to_string(),
            dependencies,
            result_size,
            compressed: self.config.enable_compression,
        };

        // Store in cache
        self.search_cache
            .insert(query_key.to_string(), cached_result)
            .await;

        // Update statistics
        self.update_stats(result_size, execution_time, false);

        self.record_miss();
        debug!(
            "Cached search query: {} ({}ms, {} bytes)",
            query_key, execution_time, result_size
        );
        Ok(data)
    }

    /// Invalidate queries by entity changes
    pub fn invalidate_by_entity(&self, entity_type: &str, entity_id: Option<&ThingsId>) {
        // Invalidate all caches for now - in a more sophisticated implementation,
        // we would check dependencies and only invalidate relevant queries
        self.tasks_cache.invalidate_all();
        self.projects_cache.invalidate_all();
        self.areas_cache.invalidate_all();
        self.search_cache.invalidate_all();

        debug!(
            "Invalidated all query caches due to entity change: {} {:?}",
            entity_type, entity_id
        );
    }

    /// Invalidate queries by operation
    pub fn invalidate_by_operation(&self, operation: &str) {
        match operation {
            "task_created" | "task_updated" | "task_deleted" | "task_completed" => {
                self.tasks_cache.invalidate_all();
                self.search_cache.invalidate_all();
            }
            "project_created" | "project_updated" | "project_deleted" => {
                self.projects_cache.invalidate_all();
                self.tasks_cache.invalidate_all(); // Tasks depend on projects
            }
            "area_created" | "area_updated" | "area_deleted" => {
                self.areas_cache.invalidate_all();
                self.projects_cache.invalidate_all(); // Projects depend on areas
                self.tasks_cache.invalidate_all(); // Tasks depend on areas
            }
            _ => {
                // For unknown operations, invalidate all caches
                self.invalidate_all();
            }
        }

        debug!("Invalidated query caches due to operation: {}", operation);
    }

    /// Invalidate all query caches
    pub fn invalidate_all(&self) {
        self.tasks_cache.invalidate_all();
        self.projects_cache.invalidate_all();
        self.areas_cache.invalidate_all();
        self.search_cache.invalidate_all();
    }

    /// Get query cache statistics
    #[must_use]
    pub fn get_stats(&self) -> QueryCacheStats {
        let mut stats = self.stats.read().clone();
        stats.calculate_hit_rate();
        stats
    }

    /// Calculate the size of a query result
    fn calculate_result_size<T>(data: &T) -> usize
    where
        T: Serialize,
    {
        // Estimate size by serializing to JSON
        serde_json::to_vec(data).map_or(0, |bytes| bytes.len())
    }

    /// Create dependencies for task data
    fn create_task_dependencies(tasks: &[Task]) -> Vec<QueryDependency> {
        let mut dependencies = Vec::new();

        // Add table dependency
        dependencies.push(QueryDependency {
            table: "TMTask".to_string(),
            entity_id: None,
            invalidating_operations: vec![
                "task_created".to_string(),
                "task_updated".to_string(),
                "task_deleted".to_string(),
                "task_completed".to_string(),
            ],
        });

        // Add specific task dependencies
        for task in tasks {
            dependencies.push(QueryDependency {
                table: "TMTask".to_string(),
                entity_id: Some(task.uuid.clone()),
                invalidating_operations: vec![
                    "task_updated".to_string(),
                    "task_deleted".to_string(),
                    "task_completed".to_string(),
                ],
            });

            // Add project dependency if task belongs to a project
            if let Some(project_uuid) = &task.project_uuid {
                dependencies.push(QueryDependency {
                    table: "TMProject".to_string(),
                    entity_id: Some(project_uuid.clone()),
                    invalidating_operations: vec![
                        "project_updated".to_string(),
                        "project_deleted".to_string(),
                    ],
                });
            }

            // Add area dependency if task belongs to an area
            if let Some(area_uuid) = &task.area_uuid {
                dependencies.push(QueryDependency {
                    table: "TMArea".to_string(),
                    entity_id: Some(area_uuid.clone()),
                    invalidating_operations: vec![
                        "area_updated".to_string(),
                        "area_deleted".to_string(),
                    ],
                });
            }
        }

        dependencies
    }

    /// Create dependencies for project data
    fn create_project_dependencies(projects: &[Project]) -> Vec<QueryDependency> {
        let mut dependencies = Vec::new();

        // Add table dependency
        dependencies.push(QueryDependency {
            table: "TMProject".to_string(),
            entity_id: None,
            invalidating_operations: vec![
                "project_created".to_string(),
                "project_updated".to_string(),
                "project_deleted".to_string(),
            ],
        });

        // Add specific project dependencies
        for project in projects {
            dependencies.push(QueryDependency {
                table: "TMProject".to_string(),
                entity_id: Some(project.uuid.clone()),
                invalidating_operations: vec![
                    "project_updated".to_string(),
                    "project_deleted".to_string(),
                ],
            });

            // Add area dependency if project belongs to an area
            if let Some(area_uuid) = &project.area_uuid {
                dependencies.push(QueryDependency {
                    table: "TMArea".to_string(),
                    entity_id: Some(area_uuid.clone()),
                    invalidating_operations: vec![
                        "area_updated".to_string(),
                        "area_deleted".to_string(),
                    ],
                });
            }
        }

        dependencies
    }

    /// Create dependencies for area data
    fn create_area_dependencies(areas: &[Area]) -> Vec<QueryDependency> {
        let mut dependencies = Vec::new();

        // Add table dependency
        dependencies.push(QueryDependency {
            table: "TMArea".to_string(),
            entity_id: None,
            invalidating_operations: vec![
                "area_created".to_string(),
                "area_updated".to_string(),
                "area_deleted".to_string(),
            ],
        });

        // Add specific area dependencies
        for area in areas {
            dependencies.push(QueryDependency {
                table: "TMArea".to_string(),
                entity_id: Some(area.uuid.clone()),
                invalidating_operations: vec![
                    "area_updated".to_string(),
                    "area_deleted".to_string(),
                ],
            });
        }

        dependencies
    }

    /// Record a cache hit
    fn record_hit(&self) {
        let mut stats = self.stats.write();
        stats.hits += 1;
    }

    /// Record a cache miss
    fn record_miss(&self) {
        let mut stats = self.stats.write();
        stats.misses += 1;
    }

    /// Update cache statistics
    #[allow(clippy::cast_precision_loss)]
    fn update_stats(&self, result_size: usize, execution_time_ms: u64, compressed: bool) {
        let mut stats = self.stats.write();
        stats.total_queries += 1;
        stats.total_size_bytes += result_size as u64;

        // Update average execution time
        let total_queries = stats.total_queries as f64;
        let current_avg = stats.average_execution_time_ms;
        stats.average_execution_time_ms =
            (current_avg * (total_queries - 1.0) + execution_time_ms as f64) / total_queries;

        if compressed {
            stats.compressed_queries += 1;
        } else {
            stats.uncompressed_queries += 1;
        }
    }
}

impl<T> CachedQueryResult<T> {
    /// Check if the cached result is expired
    pub fn is_expired(&self) -> bool {
        Utc::now() > self.expires_at
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use crate::models::TaskStatus;
    use crate::test_utils::create_mock_tasks;

    #[tokio::test]
    async fn test_query_cache_basic_operations() {
        let cache = QueryCache::new_default();

        // Test caching a tasks query
        let tasks = create_mock_tasks();
        let query_key = "test_tasks_query";
        let params_hash = "test_params_hash";

        let result = cache
            .cache_tasks_query(query_key, params_hash, || async { Ok(tasks.clone()) })
            .await
            .unwrap();

        assert_eq!(result.len(), tasks.len());

        // Test cache hit
        let cached_result = cache
            .cache_tasks_query(query_key, params_hash, || async {
                panic!("Should not execute fetcher on cache hit");
            })
            .await
            .unwrap();

        assert_eq!(cached_result.len(), tasks.len());

        // Test cache miss with different params
        let different_params = "different_params_hash";
        let _ = cache
            .cache_tasks_query(query_key, different_params, || async {
                Ok(create_mock_tasks())
            })
            .await
            .unwrap();

        let stats = cache.get_stats();
        assert!(stats.hits >= 1);
        assert!(stats.misses >= 1);
    }

    #[tokio::test]
    async fn test_query_cache_invalidation() {
        let cache = QueryCache::new_default();

        // Cache some data
        let tasks = create_mock_tasks();
        cache
            .cache_tasks_query("test_query", "params", || async { Ok(tasks.clone()) })
            .await
            .unwrap();

        // Invalidate by operation
        cache.invalidate_by_operation("task_updated");

        // Should be a cache miss now
        let _ = cache
            .cache_tasks_query("test_query", "params", || async { Ok(create_mock_tasks()) })
            .await
            .unwrap();

        let stats = cache.get_stats();
        assert!(stats.misses >= 2);
    }

    #[tokio::test]
    async fn test_query_cache_dependencies() {
        let _cache = QueryCache::new_default();

        let tasks = create_mock_tasks();
        let dependencies = QueryCache::create_task_dependencies(&tasks);

        assert!(!dependencies.is_empty());
        assert!(dependencies.iter().any(|dep| dep.table == "TMTask"));
    }

    #[tokio::test]
    async fn test_query_cache_projects_query() {
        let cache = QueryCache::new_default();

        let projects = vec![Project {
            uuid: ThingsId::new_v4(),
            title: "Project 1".to_string(),
            area_uuid: Some(ThingsId::new_v4()),
            created: Utc::now(),
            modified: Utc::now(),
            status: TaskStatus::Incomplete,
            notes: Some("Notes".to_string()),
            deadline: None,
            start_date: None,
            tags: vec![],
            tasks: vec![],
        }];

        let query_key = "test_projects_query";
        let params_hash = "test_params";

        // Test cache miss
        let result = cache
            .cache_projects_query(query_key, params_hash, || async { Ok(projects.clone()) })
            .await
            .unwrap();

        assert_eq!(result.len(), projects.len());

        // Test cache hit
        let cached_result = cache
            .cache_projects_query(query_key, params_hash, || async {
                panic!("Should not execute fetcher on cache hit");
            })
            .await
            .unwrap();

        assert_eq!(cached_result.len(), projects.len());
    }

    #[tokio::test]
    async fn test_query_cache_config_default() {
        let config = QueryCacheConfig::default();
        assert_eq!(config.max_queries, 1000);
        assert_eq!(config.ttl, Duration::from_secs(1800));
        assert_eq!(config.tti, Duration::from_secs(300));
        assert!(config.enable_compression);
        assert_eq!(config.max_result_size, 1024 * 1024);
    }

    #[tokio::test]
    async fn test_cached_query_result_creation() {
        let tasks = create_mock_tasks();
        let now = Utc::now();
        let expires_at = now + chrono::Duration::seconds(1800);

        let dependency = QueryDependency {
            table: "TMTask".to_string(),
            entity_id: None,
            invalidating_operations: vec![
                "INSERT".to_string(),
                "UPDATE".to_string(),
                "DELETE".to_string(),
            ],
        };

        let result = CachedQueryResult {
            data: tasks.clone(),
            executed_at: now,
            expires_at,
            execution_time_ms: 100,
            params_hash: "test_hash".to_string(),
            result_size: 1024,
            dependencies: vec![dependency.clone()],
            compressed: false,
        };

        assert_eq!(result.data.len(), tasks.len());
        assert_eq!(result.execution_time_ms, 100);
        assert_eq!(result.result_size, 1024);
        assert_eq!(result.params_hash, "test_hash");
        assert_eq!(result.dependencies, vec![dependency]);
        assert!(!result.compressed);
    }

    #[tokio::test]
    async fn test_query_cache_areas_query() {
        let cache = QueryCache::new_default();

        let areas = vec![Area {
            uuid: ThingsId::new_v4(),
            title: "Area 1".to_string(),
            created: Utc::now(),
            modified: Utc::now(),
            notes: Some("Notes".to_string()),
            tags: vec![],
            projects: vec![],
        }];

        let query_key = "test_areas_query";
        let params_hash = "test_params";

        // Test cache miss
        let result = cache
            .cache_areas_query(query_key, params_hash, || async { Ok(areas.clone()) })
            .await
            .unwrap();

        assert_eq!(result.len(), areas.len());

        // Test cache hit
        let cached_result = cache
            .cache_areas_query(query_key, params_hash, || async {
                panic!("Should not execute fetcher on cache hit");
            })
            .await
            .unwrap();

        assert_eq!(cached_result.len(), areas.len());
    }

    #[tokio::test]
    async fn test_query_cache_expiration() {
        let config = QueryCacheConfig {
            max_queries: 100,
            ttl: Duration::from_millis(10), // Very short TTL for testing
            tti: Duration::from_millis(5),
            enable_compression: false,
            max_result_size: 1024,
        };
        let cache = QueryCache::new(config);

        let tasks = create_mock_tasks();
        let query_key = "test_expiration";
        let params_hash = "test_params";

        // Cache a query
        let _result = cache
            .cache_tasks_query(query_key, params_hash, || async { Ok(tasks.clone()) })
            .await
            .unwrap();

        // Wait for expiration
        tokio::time::sleep(Duration::from_millis(20)).await;

        // Should execute fetcher again due to expiration
        let mut fetcher_called = false;
        let _expired_result = cache
            .cache_tasks_query(query_key, params_hash, || async {
                fetcher_called = true;
                Ok(tasks.clone())
            })
            .await
            .unwrap();

        assert!(fetcher_called);
    }

    #[tokio::test]
    async fn test_query_cache_size_limit() {
        let config = QueryCacheConfig {
            max_queries: 2, // Very small limit for testing
            ttl: Duration::from_secs(300),
            tti: Duration::from_secs(60),
            enable_compression: false,
            max_result_size: 1024,
        };
        let cache = QueryCache::new(config);

        let tasks = create_mock_tasks();

        // Cache multiple queries
        let _result1 = cache
            .cache_tasks_query("key1", "params1", || async { Ok(tasks.clone()) })
            .await
            .unwrap();

        let _result2 = cache
            .cache_tasks_query("key2", "params2", || async { Ok(tasks.clone()) })
            .await
            .unwrap();

        // This should evict one of the previous entries
        let _result3 = cache
            .cache_tasks_query("key3", "params3", || async { Ok(tasks.clone()) })
            .await
            .unwrap();

        // Verify cache size is respected - the cache may have evicted entries
        // so we just check that it doesn't exceed the max capacity significantly
        let stats = cache.get_stats();
        // The cache should not have significantly more than the configured max
        assert!(stats.total_queries <= 10); // Allow some flexibility for the cache implementation
    }

    #[tokio::test]
    async fn test_query_cache_concurrent_access() {
        let cache = Arc::new(QueryCache::new_default());
        let tasks = create_mock_tasks();

        // Spawn multiple tasks to access cache concurrently
        let mut handles = vec![];

        for i in 0..10 {
            let cache_clone = cache.clone();
            let tasks_clone = tasks.clone();
            let handle = tokio::spawn(async move {
                let key = format!("concurrent_key_{i}");
                let params = format!("params_{i}");
                let result = cache_clone
                    .cache_tasks_query(&key, &params, || async { Ok(tasks_clone.clone()) })
                    .await
                    .unwrap();
                assert!(!result.is_empty());
            });
            handles.push(handle);
        }

        // Wait for all tasks to complete
        for handle in handles {
            handle.await.unwrap();
        }
    }

    #[tokio::test]
    async fn test_query_cache_error_handling() {
        let cache = QueryCache::new_default();

        let query_key = "error_test";
        let params_hash = "test_params";

        // Test error handling
        let result = cache
            .cache_tasks_query(query_key, params_hash, || async {
                Err(anyhow::anyhow!("Test error"))
            })
            .await;

        assert!(result.is_err());
    }

    #[tokio::test]
    async fn test_query_cache_compression() {
        let config = QueryCacheConfig {
            max_queries: 100,
            ttl: Duration::from_secs(300),
            tti: Duration::from_secs(60),
            enable_compression: true,
            max_result_size: 1024 * 1024,
        };
        let cache = QueryCache::new(config);

        let tasks = create_mock_tasks();
        let query_key = "compression_test";
        let params_hash = "test_params";

        // Cache with compression enabled
        let result = cache
            .cache_tasks_query(query_key, params_hash, || async { Ok(tasks.clone()) })
            .await
            .unwrap();

        assert_eq!(result.len(), tasks.len());

        // Verify cache hit works with compression
        let cached_result = cache
            .cache_tasks_query(query_key, params_hash, || async {
                panic!("Should not execute fetcher on cache hit");
            })
            .await
            .unwrap();

        assert_eq!(cached_result.len(), tasks.len());
    }
}