grafeo_engine/database/

mod.rs

//! The main database struct and operations.
//!
//! Start here with [`GrafeoDB`] - it's your handle to everything.
//!
//! Operations are split across focused submodules:
//! - `query` - Query execution (execute, execute_cypher, etc.)
//! - `crud` - Node/edge CRUD operations
//! - `index` - Property, vector, and text index management
//! - `search` - Vector, text, and hybrid search
//! - `embed` - Embedding model management
//! - `persistence` - Save, load, snapshots, iteration
//! - `admin` - Stats, introspection, diagnostics, CDC

mod admin;
mod crud;
#[cfg(feature = "embed")]
mod embed;
mod index;
mod persistence;
mod query;
mod search;

use std::path::Path;
use std::sync::Arc;
use std::sync::atomic::AtomicUsize;

use parking_lot::RwLock;

#[cfg(feature = "wal")]
use grafeo_adapters::storage::wal::{
    DurabilityMode as WalDurabilityMode, LpgWal, WalConfig, WalRecord, WalRecovery,
};
use grafeo_common::memory::buffer::{BufferManager, BufferManagerConfig};
use grafeo_common::utils::error::Result;
use grafeo_core::graph::GraphStoreMut;
use grafeo_core::graph::lpg::LpgStore;
#[cfg(feature = "rdf")]
use grafeo_core::graph::rdf::RdfStore;

use crate::config::Config;
use crate::query::cache::QueryCache;
use crate::session::Session;
use crate::transaction::TransactionManager;

/// Your handle to a Grafeo database.
///
/// Start here. Create one with [`new_in_memory()`](Self::new_in_memory) for
/// quick experiments, or [`open()`](Self::open) for persistent storage.
/// Then grab a [`session()`](Self::session) to start querying.
///
/// # Examples
///
/// ```
/// use grafeo_engine::GrafeoDB;
///
/// // Quick in-memory database
/// let db = GrafeoDB::new_in_memory();
///
/// // Add some data
/// db.create_node(&["Person"]);
///
/// // Query it
/// let session = db.session();
/// let result = session.execute("MATCH (p:Person) RETURN p")?;
/// # Ok::<(), grafeo_common::utils::error::Error>(())
/// ```
pub struct GrafeoDB {
    /// Database configuration.
    pub(super) config: Config,
    /// The underlying graph store.
    pub(super) store: Arc<LpgStore>,
    /// RDF triple store (if RDF feature is enabled).
    #[cfg(feature = "rdf")]
    pub(super) rdf_store: Arc<RdfStore>,
    /// Transaction manager.
    pub(super) tx_manager: Arc<TransactionManager>,
    /// Unified buffer manager.
    pub(super) buffer_manager: Arc<BufferManager>,
    /// Write-ahead log manager (if durability is enabled).
    #[cfg(feature = "wal")]
    pub(super) wal: Option<Arc<LpgWal>>,
    /// Query cache for parsed and optimized plans.
    pub(super) query_cache: Arc<QueryCache>,
    /// Shared commit counter for auto-GC across sessions.
    pub(super) commit_counter: Arc<AtomicUsize>,
    /// Whether the database is open.
    pub(super) is_open: RwLock<bool>,
    /// Change data capture log for tracking mutations.
    #[cfg(feature = "cdc")]
    pub(super) cdc_log: Arc<crate::cdc::CdcLog>,
    /// Registered embedding models for text-to-vector conversion.
    #[cfg(feature = "embed")]
    pub(super) embedding_models:
        RwLock<hashbrown::HashMap<String, Arc<dyn crate::embedding::EmbeddingModel>>>,
    /// External graph store (when using with_store()).
    /// When set, sessions route queries through this store instead of the built-in LpgStore.
    pub(super) external_store: Option<Arc<dyn GraphStoreMut>>,
}

impl GrafeoDB {
    /// Creates an in-memory database - fast to create, gone when dropped.
    ///
    /// Use this for tests, experiments, or when you don't need persistence.
    /// For data that survives restarts, use [`open()`](Self::open) instead.
    ///
    /// # Examples
    ///
    /// ```
    /// use grafeo_engine::GrafeoDB;
    ///
    /// let db = GrafeoDB::new_in_memory();
    /// let session = db.session();
    /// session.execute("INSERT (:Person {name: 'Alice'})")?;
    /// # Ok::<(), grafeo_common::utils::error::Error>(())
    /// ```
    #[must_use]
    pub fn new_in_memory() -> Self {
        Self::with_config(Config::in_memory()).expect("In-memory database creation should not fail")
    }

    /// Opens a database at the given path, creating it if it doesn't exist.
    ///
    /// If you've used this path before, Grafeo recovers your data from the
    /// write-ahead log automatically. First open on a new path creates an
    /// empty database.
    ///
    /// # Errors
    ///
    /// Returns an error if the path isn't writable or recovery fails.
    ///
    /// # Examples
    ///
    /// ```no_run
    /// use grafeo_engine::GrafeoDB;
    ///
    /// let db = GrafeoDB::open("./my_social_network")?;
    /// # Ok::<(), grafeo_common::utils::error::Error>(())
    /// ```
    #[cfg(feature = "wal")]
    pub fn open(path: impl AsRef<Path>) -> Result<Self> {
        Self::with_config(Config::persistent(path.as_ref()))
    }

    /// Creates a database with custom configuration.
    ///
    /// Use this when you need fine-grained control over memory limits,
    /// thread counts, or persistence settings. For most cases,
    /// [`new_in_memory()`](Self::new_in_memory) or [`open()`](Self::open)
    /// are simpler.
    ///
    /// # Errors
    ///
    /// Returns an error if the database can't be created or recovery fails.
    ///
    /// # Examples
    ///
    /// ```
    /// use grafeo_engine::{GrafeoDB, Config};
    ///
    /// // In-memory with a 512MB limit
    /// let config = Config::in_memory()
    ///     .with_memory_limit(512 * 1024 * 1024);
    ///
    /// let db = GrafeoDB::with_config(config)?;
    /// # Ok::<(), grafeo_common::utils::error::Error>(())
    /// ```
    pub fn with_config(config: Config) -> Result<Self> {
        // Validate configuration before proceeding
        config
            .validate()
            .map_err(|e| grafeo_common::utils::error::Error::Internal(e.to_string()))?;

        let store = Arc::new(LpgStore::new());
        #[cfg(feature = "rdf")]
        let rdf_store = Arc::new(RdfStore::new());
        let tx_manager = Arc::new(TransactionManager::new());

        // Create buffer manager with configured limits
        let buffer_config = BufferManagerConfig {
            budget: config.memory_limit.unwrap_or_else(|| {
                (BufferManagerConfig::detect_system_memory() as f64 * 0.75) as usize
            }),
            spill_path: config
                .spill_path
                .clone()
                .or_else(|| config.path.as_ref().map(|p| p.join("spill"))),
            ..BufferManagerConfig::default()
        };
        let buffer_manager = BufferManager::new(buffer_config);

        // Initialize WAL if persistence is enabled
        #[cfg(feature = "wal")]
        let wal = if config.wal_enabled {
            if let Some(ref db_path) = config.path {
                // Create database directory if it doesn't exist
                std::fs::create_dir_all(db_path)?;

                let wal_path = db_path.join("wal");

                // Check if WAL exists and recover if needed
                if wal_path.exists() {
                    let recovery = WalRecovery::new(&wal_path);
                    let records = recovery.recover()?;
                    Self::apply_wal_records(&store, &records)?;
                }

                // Open/create WAL manager with configured durability
                let wal_durability = match config.wal_durability {
                    crate::config::DurabilityMode::Sync => WalDurabilityMode::Sync,
                    crate::config::DurabilityMode::Batch {
                        max_delay_ms,
                        max_records,
                    } => WalDurabilityMode::Batch {
                        max_delay_ms,
                        max_records,
                    },
                    crate::config::DurabilityMode::Adaptive { target_interval_ms } => {
                        WalDurabilityMode::Adaptive { target_interval_ms }
                    }
                    crate::config::DurabilityMode::NoSync => WalDurabilityMode::NoSync,
                };
                let wal_config = WalConfig {
                    durability: wal_durability,
                    ..WalConfig::default()
                };
                let wal_manager = LpgWal::with_config(&wal_path, wal_config)?;
                Some(Arc::new(wal_manager))
            } else {
                None
            }
        } else {
            None
        };

        // Create query cache with default capacity (1000 queries)
        let query_cache = Arc::new(QueryCache::default());

        Ok(Self {
            config,
            store,
            #[cfg(feature = "rdf")]
            rdf_store,
            tx_manager,
            buffer_manager,
            #[cfg(feature = "wal")]
            wal,
            query_cache,
            commit_counter: Arc::new(AtomicUsize::new(0)),
            is_open: RwLock::new(true),
            #[cfg(feature = "cdc")]
            cdc_log: Arc::new(crate::cdc::CdcLog::new()),
            #[cfg(feature = "embed")]
            embedding_models: RwLock::new(hashbrown::HashMap::new()),
            external_store: None,
        })
    }

    /// Creates a database backed by a custom [`GraphStoreMut`] implementation.
    ///
    /// The external store handles all data persistence. WAL, CDC, and index
    /// management are the responsibility of the store implementation.
    ///
    /// Query execution (all 6 languages, optimizer, planner) works through the
    /// provided store. Admin operations (schema introspection, persistence,
    /// vector/text indexes) are not available on external stores.
    ///
    /// # Examples
    ///
    /// ```no_run
    /// use std::sync::Arc;
    /// use grafeo_engine::{GrafeoDB, Config};
    /// use grafeo_core::graph::GraphStoreMut;
    ///
    /// fn example(store: Arc<dyn GraphStoreMut>) -> grafeo_common::utils::error::Result<()> {
    ///     let db = GrafeoDB::with_store(store, Config::in_memory())?;
    ///     let result = db.execute("MATCH (n) RETURN count(n)")?;
    ///     Ok(())
    /// }
    /// ```
    ///
    /// [`GraphStoreMut`]: grafeo_core::graph::GraphStoreMut
    pub fn with_store(store: Arc<dyn GraphStoreMut>, config: Config) -> Result<Self> {
        config
            .validate()
            .map_err(|e| grafeo_common::utils::error::Error::Internal(e.to_string()))?;

        let dummy_store = Arc::new(LpgStore::new());
        let tx_manager = Arc::new(TransactionManager::new());

        let buffer_config = BufferManagerConfig {
            budget: config.memory_limit.unwrap_or_else(|| {
                (BufferManagerConfig::detect_system_memory() as f64 * 0.75) as usize
            }),
            spill_path: None,
            ..BufferManagerConfig::default()
        };
        let buffer_manager = BufferManager::new(buffer_config);

        let query_cache = Arc::new(QueryCache::default());

        Ok(Self {
            config,
            store: dummy_store,
            #[cfg(feature = "rdf")]
            rdf_store: Arc::new(RdfStore::new()),
            tx_manager,
            buffer_manager,
            #[cfg(feature = "wal")]
            wal: None,
            query_cache,
            commit_counter: Arc::new(AtomicUsize::new(0)),
            is_open: RwLock::new(true),
            #[cfg(feature = "cdc")]
            cdc_log: Arc::new(crate::cdc::CdcLog::new()),
            #[cfg(feature = "embed")]
            embedding_models: RwLock::new(hashbrown::HashMap::new()),
            external_store: Some(store),
        })
    }

    /// Applies WAL records to restore the database state.
    #[cfg(feature = "wal")]
    fn apply_wal_records(store: &LpgStore, records: &[WalRecord]) -> Result<()> {
        for record in records {
            match record {
                WalRecord::CreateNode { id, labels } => {
                    let label_refs: Vec<&str> = labels.iter().map(|s| s.as_str()).collect();
                    store.create_node_with_id(*id, &label_refs);
                }
                WalRecord::DeleteNode { id } => {
                    store.delete_node(*id);
                }
                WalRecord::CreateEdge {
                    id,
                    src,
                    dst,
                    edge_type,
                } => {
                    store.create_edge_with_id(*id, *src, *dst, edge_type);
                }
                WalRecord::DeleteEdge { id } => {
                    store.delete_edge(*id);
                }
                WalRecord::SetNodeProperty { id, key, value } => {
                    store.set_node_property(*id, key, value.clone());
                }
                WalRecord::SetEdgeProperty { id, key, value } => {
                    store.set_edge_property(*id, key, value.clone());
                }
                WalRecord::AddNodeLabel { id, label } => {
                    store.add_label(*id, label);
                }
                WalRecord::RemoveNodeLabel { id, label } => {
                    store.remove_label(*id, label);
                }
                WalRecord::TxCommit { .. }
                | WalRecord::TxAbort { .. }
                | WalRecord::Checkpoint { .. } => {
                    // Transaction control records don't need replay action
                    // (recovery already filtered to only committed transactions)
                }
            }
        }
        Ok(())
    }

    // =========================================================================
    // Session & Configuration
    // =========================================================================

    /// Opens a new session for running queries.
    ///
    /// Sessions are cheap to create - spin up as many as you need. Each
    /// gets its own transaction context, so concurrent sessions won't
    /// block each other on reads.
    ///
    /// # Examples
    ///
    /// ```
    /// use grafeo_engine::GrafeoDB;
    ///
    /// let db = GrafeoDB::new_in_memory();
    /// let session = db.session();
    ///
    /// // Run queries through the session
    /// let result = session.execute("MATCH (n) RETURN count(n)")?;
    /// # Ok::<(), grafeo_common::utils::error::Error>(())
    /// ```
    #[must_use]
    pub fn session(&self) -> Session {
        if let Some(ref ext_store) = self.external_store {
            return Session::with_external_store(
                Arc::clone(ext_store),
                Arc::clone(&self.tx_manager),
                Arc::clone(&self.query_cache),
                self.config.adaptive.clone(),
                self.config.factorized_execution,
                self.config.graph_model,
                self.config.query_timeout,
                Arc::clone(&self.commit_counter),
                self.config.gc_interval,
            );
        }

        #[cfg(feature = "rdf")]
        let mut session = Session::with_rdf_store_and_adaptive(
            Arc::clone(&self.store),
            Arc::clone(&self.rdf_store),
            Arc::clone(&self.tx_manager),
            Arc::clone(&self.query_cache),
            self.config.adaptive.clone(),
            self.config.factorized_execution,
            self.config.graph_model,
            self.config.query_timeout,
            Arc::clone(&self.commit_counter),
            self.config.gc_interval,
        );
        #[cfg(not(feature = "rdf"))]
        let mut session = Session::with_adaptive(
            Arc::clone(&self.store),
            Arc::clone(&self.tx_manager),
            Arc::clone(&self.query_cache),
            self.config.adaptive.clone(),
            self.config.factorized_execution,
            self.config.graph_model,
            self.config.query_timeout,
            Arc::clone(&self.commit_counter),
            self.config.gc_interval,
        );

        #[cfg(feature = "cdc")]
        session.set_cdc_log(Arc::clone(&self.cdc_log));

        // Suppress unused_mut when cdc is disabled
        let _ = &mut session;

        session
    }

    /// Returns the adaptive execution configuration.
    #[must_use]
    pub fn adaptive_config(&self) -> &crate::config::AdaptiveConfig {
        &self.config.adaptive
    }

    /// Returns the configuration.
    #[must_use]
    pub fn config(&self) -> &Config {
        &self.config
    }

    /// Returns the graph data model of this database.
    #[must_use]
    pub fn graph_model(&self) -> crate::config::GraphModel {
        self.config.graph_model
    }

    /// Returns the configured memory limit in bytes, if any.
    #[must_use]
    pub fn memory_limit(&self) -> Option<usize> {
        self.config.memory_limit
    }

    /// Returns the underlying store.
    ///
    /// This provides direct access to the LPG store for algorithm implementations
    /// and admin operations (index management, schema introspection, MVCC internals).
    ///
    /// For code that only needs read/write graph operations, prefer
    /// [`graph_store()`](Self::graph_store) which returns the trait interface.
    #[must_use]
    pub fn store(&self) -> &Arc<LpgStore> {
        &self.store
    }

    /// Returns the graph store as a trait object.
    ///
    /// This provides the [`GraphStoreMut`] interface for code that should work
    /// with any storage backend. Use this when you only need graph read/write
    /// operations and don't need admin methods like index management.
    ///
    /// [`GraphStoreMut`]: grafeo_core::graph::GraphStoreMut
    #[must_use]
    pub fn graph_store(&self) -> Arc<dyn GraphStoreMut> {
        if let Some(ref ext_store) = self.external_store {
            Arc::clone(ext_store)
        } else {
            Arc::clone(&self.store) as Arc<dyn GraphStoreMut>
        }
    }

    /// Garbage collects old MVCC versions that are no longer visible.
    ///
    /// Determines the minimum epoch required by active transactions and prunes
    /// version chains older than that threshold. Also cleans up completed
    /// transaction metadata in the transaction manager.
    pub fn gc(&self) {
        let min_epoch = self.tx_manager.min_active_epoch();
        self.store.gc_versions(min_epoch);
        self.tx_manager.gc();
    }

    /// Returns the buffer manager for memory-aware operations.
    #[must_use]
    pub fn buffer_manager(&self) -> &Arc<BufferManager> {
        &self.buffer_manager
    }

    /// Returns the query cache.
    #[must_use]
    pub fn query_cache(&self) -> &Arc<QueryCache> {
        &self.query_cache
    }

    // =========================================================================
    // Lifecycle
    // =========================================================================

    /// Closes the database, flushing all pending writes.
    ///
    /// For persistent databases, this ensures everything is safely on disk.
    /// Called automatically when the database is dropped, but you can call
    /// it explicitly if you need to guarantee durability at a specific point.
    ///
    /// # Errors
    ///
    /// Returns an error if the WAL can't be flushed (check disk space/permissions).
    pub fn close(&self) -> Result<()> {
        let mut is_open = self.is_open.write();
        if !*is_open {
            return Ok(());
        }

        // Commit and checkpoint WAL
        #[cfg(feature = "wal")]
        if let Some(ref wal) = self.wal {
            let epoch = self.store.current_epoch();

            // Use the last assigned transaction ID, or create a checkpoint-only tx
            let checkpoint_tx = self.tx_manager.last_assigned_tx_id().unwrap_or_else(|| {
                // No transactions have been started; begin one for checkpoint
                self.tx_manager.begin()
            });

            // Log a TxCommit to mark all pending records as committed
            wal.log(&WalRecord::TxCommit {
                tx_id: checkpoint_tx,
            })?;

            // Then checkpoint
            wal.checkpoint(checkpoint_tx, epoch)?;
            wal.sync()?;
        }

        *is_open = false;
        Ok(())
    }

    /// Returns the typed WAL if available.
    #[cfg(feature = "wal")]
    #[must_use]
    pub fn wal(&self) -> Option<&Arc<LpgWal>> {
        self.wal.as_ref()
    }

    /// Logs a WAL record if WAL is enabled.
    #[cfg(feature = "wal")]
    pub(super) fn log_wal(&self, record: &WalRecord) -> Result<()> {
        if let Some(ref wal) = self.wal {
            wal.log(record)?;
        }
        Ok(())
    }
}

impl Drop for GrafeoDB {
    fn drop(&mut self) {
        if let Err(e) = self.close() {
            tracing::error!("Error closing database: {}", e);
        }
    }
}

impl crate::admin::AdminService for GrafeoDB {
    fn info(&self) -> crate::admin::DatabaseInfo {
        self.info()
    }

    fn detailed_stats(&self) -> crate::admin::DatabaseStats {
        self.detailed_stats()
    }

    fn schema(&self) -> crate::admin::SchemaInfo {
        self.schema()
    }

    fn validate(&self) -> crate::admin::ValidationResult {
        self.validate()
    }

    fn wal_status(&self) -> crate::admin::WalStatus {
        self.wal_status()
    }

    fn wal_checkpoint(&self) -> Result<()> {
        self.wal_checkpoint()
    }
}

// =========================================================================
// Query Result Types
// =========================================================================

/// The result of running a query.
///
/// Contains rows and columns, like a table. Use [`iter()`](Self::iter) to
/// loop through rows, or [`scalar()`](Self::scalar) if you expect a single value.
///
/// # Examples
///
/// ```
/// use grafeo_engine::GrafeoDB;
///
/// let db = GrafeoDB::new_in_memory();
/// db.create_node(&["Person"]);
///
/// let result = db.execute("MATCH (p:Person) RETURN count(p) AS total")?;
///
/// // Check what we got
/// println!("Columns: {:?}", result.columns);
/// println!("Rows: {}", result.row_count());
///
/// // Iterate through results
/// for row in result.iter() {
///     println!("{:?}", row);
/// }
/// # Ok::<(), grafeo_common::utils::error::Error>(())
/// ```
#[derive(Debug)]
pub struct QueryResult {
    /// Column names from the RETURN clause.
    pub columns: Vec<String>,
    /// Column types - useful for distinguishing NodeId/EdgeId from plain integers.
    pub column_types: Vec<grafeo_common::types::LogicalType>,
    /// The actual result rows.
    pub rows: Vec<Vec<grafeo_common::types::Value>>,
    /// Query execution time in milliseconds (if timing was enabled).
    pub execution_time_ms: Option<f64>,
    /// Number of rows scanned during query execution (estimate).
    pub rows_scanned: Option<u64>,
}

impl QueryResult {
    /// Creates a new empty query result.
    #[must_use]
    pub fn new(columns: Vec<String>) -> Self {
        let len = columns.len();
        Self {
            columns,
            column_types: vec![grafeo_common::types::LogicalType::Any; len],
            rows: Vec::new(),
            execution_time_ms: None,
            rows_scanned: None,
        }
    }

    /// Creates a new empty query result with column types.
    #[must_use]
    pub fn with_types(
        columns: Vec<String>,
        column_types: Vec<grafeo_common::types::LogicalType>,
    ) -> Self {
        Self {
            columns,
            column_types,
            rows: Vec::new(),
            execution_time_ms: None,
            rows_scanned: None,
        }
    }

    /// Sets the execution metrics on this result.
    pub fn with_metrics(mut self, execution_time_ms: f64, rows_scanned: u64) -> Self {
        self.execution_time_ms = Some(execution_time_ms);
        self.rows_scanned = Some(rows_scanned);
        self
    }

    /// Returns the execution time in milliseconds, if available.
    #[must_use]
    pub fn execution_time_ms(&self) -> Option<f64> {
        self.execution_time_ms
    }

    /// Returns the number of rows scanned, if available.
    #[must_use]
    pub fn rows_scanned(&self) -> Option<u64> {
        self.rows_scanned
    }

    /// Returns the number of rows.
    #[must_use]
    pub fn row_count(&self) -> usize {
        self.rows.len()
    }

    /// Returns the number of columns.
    #[must_use]
    pub fn column_count(&self) -> usize {
        self.columns.len()
    }

    /// Returns true if the result is empty.
    #[must_use]
    pub fn is_empty(&self) -> bool {
        self.rows.is_empty()
    }

    /// Extracts a single value from the result.
    ///
    /// Use this when your query returns exactly one row with one column,
    /// like `RETURN count(n)` or `RETURN sum(p.amount)`.
    ///
    /// # Errors
    ///
    /// Returns an error if the result has multiple rows or columns.
    pub fn scalar<T: FromValue>(&self) -> Result<T> {
        if self.rows.len() != 1 || self.columns.len() != 1 {
            return Err(grafeo_common::utils::error::Error::InvalidValue(
                "Expected single value".to_string(),
            ));
        }
        T::from_value(&self.rows[0][0])
    }

    /// Returns an iterator over the rows.
    pub fn iter(&self) -> impl Iterator<Item = &Vec<grafeo_common::types::Value>> {
        self.rows.iter()
    }
}

/// Converts a [`grafeo_common::types::Value`] to a concrete Rust type.
///
/// Implemented for common types like `i64`, `f64`, `String`, and `bool`.
/// Used by [`QueryResult::scalar()`] to extract typed values.
pub trait FromValue: Sized {
    /// Attempts the conversion, returning an error on type mismatch.
    fn from_value(value: &grafeo_common::types::Value) -> Result<Self>;
}

impl FromValue for i64 {
    fn from_value(value: &grafeo_common::types::Value) -> Result<Self> {
        value
            .as_int64()
            .ok_or_else(|| grafeo_common::utils::error::Error::TypeMismatch {
                expected: "INT64".to_string(),
                found: value.type_name().to_string(),
            })
    }
}

impl FromValue for f64 {
    fn from_value(value: &grafeo_common::types::Value) -> Result<Self> {
        value
            .as_float64()
            .ok_or_else(|| grafeo_common::utils::error::Error::TypeMismatch {
                expected: "FLOAT64".to_string(),
                found: value.type_name().to_string(),
            })
    }
}

impl FromValue for String {
    fn from_value(value: &grafeo_common::types::Value) -> Result<Self> {
        value.as_str().map(String::from).ok_or_else(|| {
            grafeo_common::utils::error::Error::TypeMismatch {
                expected: "STRING".to_string(),
                found: value.type_name().to_string(),
            }
        })
    }
}

impl FromValue for bool {
    fn from_value(value: &grafeo_common::types::Value) -> Result<Self> {
        value
            .as_bool()
            .ok_or_else(|| grafeo_common::utils::error::Error::TypeMismatch {
                expected: "BOOL".to_string(),
                found: value.type_name().to_string(),
            })
    }
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn test_create_in_memory_database() {
        let db = GrafeoDB::new_in_memory();
        assert_eq!(db.node_count(), 0);
        assert_eq!(db.edge_count(), 0);
    }

    #[test]
    fn test_database_config() {
        let config = Config::in_memory().with_threads(4).with_query_logging();

        let db = GrafeoDB::with_config(config).unwrap();
        assert_eq!(db.config().threads, 4);
        assert!(db.config().query_logging);
    }

    #[test]
    fn test_database_session() {
        let db = GrafeoDB::new_in_memory();
        let _session = db.session();
        // Session should be created successfully
    }

    #[cfg(feature = "wal")]
    #[test]
    fn test_persistent_database_recovery() {
        use grafeo_common::types::Value;
        use tempfile::tempdir;

        let dir = tempdir().unwrap();
        let db_path = dir.path().join("test_db");

        // Create database and add some data
        {
            let db = GrafeoDB::open(&db_path).unwrap();

            let alice = db.create_node(&["Person"]);
            db.set_node_property(alice, "name", Value::from("Alice"));

            let bob = db.create_node(&["Person"]);
            db.set_node_property(bob, "name", Value::from("Bob"));

            let _edge = db.create_edge(alice, bob, "KNOWS");

            // Explicitly close to flush WAL
            db.close().unwrap();
        }

        // Reopen and verify data was recovered
        {
            let db = GrafeoDB::open(&db_path).unwrap();

            assert_eq!(db.node_count(), 2);
            assert_eq!(db.edge_count(), 1);

            // Verify nodes exist
            let node0 = db.get_node(grafeo_common::types::NodeId::new(0));
            assert!(node0.is_some());

            let node1 = db.get_node(grafeo_common::types::NodeId::new(1));
            assert!(node1.is_some());
        }
    }

    #[cfg(feature = "wal")]
    #[test]
    fn test_wal_logging() {
        use tempfile::tempdir;

        let dir = tempdir().unwrap();
        let db_path = dir.path().join("wal_test_db");

        let db = GrafeoDB::open(&db_path).unwrap();

        // Create some data
        let node = db.create_node(&["Test"]);
        db.delete_node(node);

        // WAL should have records
        if let Some(wal) = db.wal() {
            assert!(wal.record_count() > 0);
        }

        db.close().unwrap();
    }

    #[cfg(feature = "wal")]
    #[test]
    fn test_wal_recovery_multiple_sessions() {
        // Tests that WAL recovery works correctly across multiple open/close cycles
        use grafeo_common::types::Value;
        use tempfile::tempdir;

        let dir = tempdir().unwrap();
        let db_path = dir.path().join("multi_session_db");

        // Session 1: Create initial data
        {
            let db = GrafeoDB::open(&db_path).unwrap();
            let alice = db.create_node(&["Person"]);
            db.set_node_property(alice, "name", Value::from("Alice"));
            db.close().unwrap();
        }

        // Session 2: Add more data
        {
            let db = GrafeoDB::open(&db_path).unwrap();
            assert_eq!(db.node_count(), 1); // Previous data recovered
            let bob = db.create_node(&["Person"]);
            db.set_node_property(bob, "name", Value::from("Bob"));
            db.close().unwrap();
        }

        // Session 3: Verify all data
        {
            let db = GrafeoDB::open(&db_path).unwrap();
            assert_eq!(db.node_count(), 2);

            // Verify properties were recovered correctly
            let node0 = db.get_node(grafeo_common::types::NodeId::new(0)).unwrap();
            assert!(node0.labels.iter().any(|l| l.as_str() == "Person"));

            let node1 = db.get_node(grafeo_common::types::NodeId::new(1)).unwrap();
            assert!(node1.labels.iter().any(|l| l.as_str() == "Person"));
        }
    }

    #[cfg(feature = "wal")]
    #[test]
    fn test_database_consistency_after_mutations() {
        // Tests that database remains consistent after a series of create/delete operations
        use grafeo_common::types::Value;
        use tempfile::tempdir;

        let dir = tempdir().unwrap();
        let db_path = dir.path().join("consistency_db");

        {
            let db = GrafeoDB::open(&db_path).unwrap();

            // Create nodes
            let a = db.create_node(&["Node"]);
            let b = db.create_node(&["Node"]);
            let c = db.create_node(&["Node"]);

            // Create edges
            let e1 = db.create_edge(a, b, "LINKS");
            let _e2 = db.create_edge(b, c, "LINKS");

            // Delete middle node and its edge
            db.delete_edge(e1);
            db.delete_node(b);

            // Set properties on remaining nodes
            db.set_node_property(a, "value", Value::Int64(1));
            db.set_node_property(c, "value", Value::Int64(3));

            db.close().unwrap();
        }

        // Reopen and verify consistency
        {
            let db = GrafeoDB::open(&db_path).unwrap();

            // Should have 2 nodes (a and c), b was deleted
            // Note: node_count includes deleted nodes in some implementations
            // What matters is that the non-deleted nodes are accessible
            let node_a = db.get_node(grafeo_common::types::NodeId::new(0));
            assert!(node_a.is_some());

            let node_c = db.get_node(grafeo_common::types::NodeId::new(2));
            assert!(node_c.is_some());

            // Middle node should be deleted
            let node_b = db.get_node(grafeo_common::types::NodeId::new(1));
            assert!(node_b.is_none());
        }
    }

    #[cfg(feature = "wal")]
    #[test]
    fn test_close_is_idempotent() {
        // Calling close() multiple times should not cause errors
        use tempfile::tempdir;

        let dir = tempdir().unwrap();
        let db_path = dir.path().join("close_test_db");

        let db = GrafeoDB::open(&db_path).unwrap();
        db.create_node(&["Test"]);

        // First close should succeed
        assert!(db.close().is_ok());

        // Second close should also succeed (idempotent)
        assert!(db.close().is_ok());
    }

    #[test]
    fn test_query_result_has_metrics() {
        // Verifies that query results include execution metrics
        let db = GrafeoDB::new_in_memory();
        db.create_node(&["Person"]);
        db.create_node(&["Person"]);

        #[cfg(feature = "gql")]
        {
            let result = db.execute("MATCH (n:Person) RETURN n").unwrap();

            // Metrics should be populated
            assert!(result.execution_time_ms.is_some());
            assert!(result.rows_scanned.is_some());
            assert!(result.execution_time_ms.unwrap() >= 0.0);
            assert_eq!(result.rows_scanned.unwrap(), 2);
        }
    }

    #[test]
    fn test_empty_query_result_metrics() {
        // Verifies metrics are correct for queries returning no results
        let db = GrafeoDB::new_in_memory();
        db.create_node(&["Person"]);

        #[cfg(feature = "gql")]
        {
            // Query that matches nothing
            let result = db.execute("MATCH (n:NonExistent) RETURN n").unwrap();

            assert!(result.execution_time_ms.is_some());
            assert!(result.rows_scanned.is_some());
            assert_eq!(result.rows_scanned.unwrap(), 0);
        }
    }

    #[cfg(feature = "cdc")]
    mod cdc_integration {
        use super::*;

        #[test]
        fn test_node_lifecycle_history() {
            let db = GrafeoDB::new_in_memory();

            // Create
            let id = db.create_node(&["Person"]);
            // Update
            db.set_node_property(id, "name", "Alice".into());
            db.set_node_property(id, "name", "Bob".into());
            // Delete
            db.delete_node(id);

            let history = db.history(id).unwrap();
            assert_eq!(history.len(), 4); // create + 2 updates + delete
            assert_eq!(history[0].kind, crate::cdc::ChangeKind::Create);
            assert_eq!(history[1].kind, crate::cdc::ChangeKind::Update);
            assert!(history[1].before.is_none()); // first set_node_property has no prior value
            assert_eq!(history[2].kind, crate::cdc::ChangeKind::Update);
            assert!(history[2].before.is_some()); // second update has prior "Alice"
            assert_eq!(history[3].kind, crate::cdc::ChangeKind::Delete);
        }

        #[test]
        fn test_edge_lifecycle_history() {
            let db = GrafeoDB::new_in_memory();

            let alice = db.create_node(&["Person"]);
            let bob = db.create_node(&["Person"]);
            let edge = db.create_edge(alice, bob, "KNOWS");
            db.set_edge_property(edge, "since", 2024i64.into());
            db.delete_edge(edge);

            let history = db.history(edge).unwrap();
            assert_eq!(history.len(), 3); // create + update + delete
            assert_eq!(history[0].kind, crate::cdc::ChangeKind::Create);
            assert_eq!(history[1].kind, crate::cdc::ChangeKind::Update);
            assert_eq!(history[2].kind, crate::cdc::ChangeKind::Delete);
        }

        #[test]
        fn test_create_node_with_props_cdc() {
            let db = GrafeoDB::new_in_memory();

            let id = db.create_node_with_props(
                &["Person"],
                vec![
                    ("name", grafeo_common::types::Value::from("Alice")),
                    ("age", grafeo_common::types::Value::from(30i64)),
                ],
            );

            let history = db.history(id).unwrap();
            assert_eq!(history.len(), 1);
            assert_eq!(history[0].kind, crate::cdc::ChangeKind::Create);
            // Props should be captured
            let after = history[0].after.as_ref().unwrap();
            assert_eq!(after.len(), 2);
        }

        #[test]
        fn test_changes_between() {
            let db = GrafeoDB::new_in_memory();

            let id1 = db.create_node(&["A"]);
            let _id2 = db.create_node(&["B"]);
            db.set_node_property(id1, "x", 1i64.into());

            // All events should be at the same epoch (in-memory, epoch doesn't advance without tx)
            let changes = db
                .changes_between(
                    grafeo_common::types::EpochId(0),
                    grafeo_common::types::EpochId(u64::MAX),
                )
                .unwrap();
            assert_eq!(changes.len(), 3); // 2 creates + 1 update
        }
    }
}