//! Batch embedding operations.

use crate::types::Result;
use crate::embeddings::provider::EmbeddingProvider;
use uuid::Uuid;
use std::sync::Arc;
use std::collections::HashMap;
use tokio::sync::RwLock;

/// Batch embedder for efficient bulk operations.
///
/// # Async Embedding Generation
///
/// Supports background embedding generation to avoid blocking inserts:
/// - Entity inserted immediately with UUID
/// - Embedding generation submitted to background worker
/// - Embedding added to entity when complete
/// - Pending embeddings tracked in cache
pub struct BatchEmbedder {
    provider: Box<dyn EmbeddingProvider>,
    batch_size: usize,

    /// Pending embeddings cache (entity_id -> embedding)
    pending: Arc<RwLock<HashMap<Uuid, Vec<f32>>>>,
}

impl BatchEmbedder {
    /// Create new batch embedder.
    ///
    /// # Arguments
    ///
    /// * `provider` - Embedding provider
    /// * `batch_size` - Batch size for API calls
    ///
    /// # Returns
    ///
    /// New `BatchEmbedder`
    pub fn new(provider: Box<dyn EmbeddingProvider>, batch_size: usize) -> Self {
        todo!("Implement BatchEmbedder::new")
    }

    /// Embed batch of texts efficiently.
    ///
    /// # Arguments
    ///
    /// * `texts` - Input texts
    ///
    /// # Returns
    ///
    /// Embedding vectors
    ///
    /// # Errors
    ///
    /// Returns `DatabaseError::EmbeddingError` if embedding fails
    pub async fn embed_batch(&self, texts: &[String]) -> Result<Vec<Vec<f32>>> {
        todo!("Implement BatchEmbedder::embed_batch")
    }

    /// Generate embeddings asynchronously.
    ///
    /// # Arguments
    ///
    /// * `entity_ids` - Entity UUIDs
    /// * `texts` - Input texts to embed
    /// * `worker` - Background worker
    ///
    /// # Returns
    ///
    /// Immediately (non-blocking)
    ///
    /// # Errors
    ///
    /// Returns error if worker submission fails
    ///
    /// # Behavior
    ///
    /// 1. Submit embedding task to worker
    /// 2. Return immediately
    /// 3. Worker generates embeddings
    /// 4. Callback updates entities with embeddings
    ///
    /// # Usage
    ///
    /// Used for non-blocking inserts:
    /// ```rust,ignore
    /// // Insert entity immediately (no embedding yet)
    /// let id = db.insert("articles", data)?;
    ///
    /// // Generate embedding in background
    /// embedder.embed_async(vec![id], vec![content], &worker).await?;
    /// ```
    pub async fn embed_async(
        &self,
        entity_ids: Vec<Uuid>,
        texts: Vec<String>,
        worker: &crate::storage::BackgroundWorker,
    ) -> Result<()> {
        todo!("Implement BatchEmbedder::embed_async")
    }

    /// Get pending embedding for entity.
    ///
    /// # Arguments
    ///
    /// * `entity_id` - Entity UUID
    ///
    /// # Returns
    ///
    /// Embedding vector if pending, None if not found
    pub async fn get_pending(&self, entity_id: Uuid) -> Option<Vec<f32>> {
        self.pending.read().await.get(&entity_id).cloned()
    }

    /// Remove pending embedding.
    ///
    /// # Arguments
    ///
    /// * `entity_id` - Entity UUID
    ///
    /// # Returns
    ///
    /// Embedding vector if was pending
    pub async fn take_pending(&self, entity_id: Uuid) -> Option<Vec<f32>> {
        self.pending.write().await.remove(&entity_id)
    }

    /// Clear all pending embeddings.
    pub async fn clear_pending(&self) {
        self.pending.write().await.clear();
    }
}
