//! Memory store implementation

use sqlx::SqlitePool;
use zclaw_types::{AgentConfig, AgentId, SessionId, Message, Result, ZclawError};

/// Memory store for persisting ZCLAW data
pub struct MemoryStore {
    pool: SqlitePool,
}

impl MemoryStore {
    /// Create a new memory store with the given database path
    pub async fn new(database_url: &str) -> Result<Self> {
        // Ensure parent directory exists for file-based SQLite databases
        Self::ensure_database_dir(database_url)?;

        let pool = SqlitePool::connect(database_url).await
            .map_err(|e| ZclawError::StorageError(e.to_string()))?;
        let store = Self { pool };
        store.run_migrations().await?;
        Ok(store)
    }

    /// Ensure the parent directory for the database file exists
    fn ensure_database_dir(database_url: &str) -> Result<()> {
        // Parse SQLite URL to extract file path
        // Format: sqlite:/path/to/db or sqlite://path/to/db
        if database_url.starts_with("sqlite:") {
            let path_part = database_url.strip_prefix("sqlite:")
                .ok_or_else(|| ZclawError::StorageError(
                    format!("Invalid database URL format: {}", database_url)
                ))?;

            // Skip in-memory databases
            if path_part == ":memory:" {
                return Ok(());
            }

            // Remove query parameters (e.g., ?mode=rwc)
            let path_without_query = path_part.split('?').next()
                .ok_or_else(|| ZclawError::StorageError(
                    format!("Invalid database URL path: {}", path_part)
                ))?;

            // Handle both absolute and relative paths
            let path = std::path::Path::new(path_without_query);

            // Get parent directory
            if let Some(parent) = path.parent() {
                if !parent.exists() {
                    std::fs::create_dir_all(parent)
                        .map_err(|e| ZclawError::StorageError(
                            format!("Failed to create database directory {}: {}", parent.display(), e)
                        ))?;
                }
            }
        }
        Ok(())
    }

    /// Create an in-memory database (for testing)
    pub async fn in_memory() -> Result<Self> {
        Self::new("sqlite::memory:").await
    }

    /// Run database migrations
    async fn run_migrations(&self) -> Result<()> {
        sqlx::query(crate::schema::CREATE_SCHEMA)
            .execute(&self.pool)
            .await
            .map_err(|e| ZclawError::StorageError(e.to_string()))?;
        Ok(())
    }

    // === Agent CRUD ===

    /// Save an agent configuration
    pub async fn save_agent(&self, agent: &AgentConfig) -> Result<()> {
        let config_json = serde_json::to_string(agent)?;
        let id = agent.id.to_string();
        let name = &agent.name;

        sqlx::query(
            r#"
            INSERT INTO agents (id, name, config, created_at, updated_at)
            VALUES (?, ?, ?, datetime('now'), datetime('now'))
            ON CONFLICT(id) DO UPDATE SET
                name = excluded.name,
                config = excluded.config,
                updated_at = datetime('now')
            "#,
        )
        .bind(&id)
        .bind(name)
        .bind(&config_json)
        .execute(&self.pool)
        .await
        .map_err(|e| ZclawError::StorageError(e.to_string()))?;

        Ok(())
    }

    /// Load an agent by ID
    pub async fn load_agent(&self, id: &AgentId) -> Result<Option<AgentConfig>> {
        let id_str = id.to_string();

        let row = sqlx::query_as::<_, (String,)>(
            "SELECT config FROM agents WHERE id = ?"
        )
        .bind(&id_str)
        .fetch_optional(&self.pool)
        .await
        .map_err(|e| ZclawError::StorageError(e.to_string()))?;

        match row {
            Some((config,)) => {
                let agent: AgentConfig = serde_json::from_str(&config)?;
                Ok(Some(agent))
            }
            None => Ok(None),
        }
    }

    /// List all agents
    pub async fn list_agents(&self) -> Result<Vec<AgentConfig>> {
        let rows = sqlx::query_as::<_, (String,)>(
            "SELECT config FROM agents"
        )
        .fetch_all(&self.pool)
        .await
        .map_err(|e| ZclawError::StorageError(e.to_string()))?;

        let agents = rows
            .into_iter()
            .filter_map(|(config,)| serde_json::from_str(&config).ok())
            .collect();
        Ok(agents)
    }

    /// Delete an agent
    pub async fn delete_agent(&self, id: &AgentId) -> Result<()> {
        let id_str = id.to_string();

        sqlx::query("DELETE FROM agents WHERE id = ?")
            .bind(&id_str)
            .execute(&self.pool)
            .await
            .map_err(|e| ZclawError::StorageError(e.to_string()))?;

        Ok(())
    }

    // === Session Management ===

    /// Create a new session for an agent
    pub async fn create_session(&self, agent_id: &AgentId) -> Result<SessionId> {
        let session_id = SessionId::new();
        let session_str = session_id.to_string();
        let agent_str = agent_id.to_string();

        sqlx::query(
            r#"
            INSERT INTO sessions (id, agent_id, created_at, updated_at)
            VALUES (?, ?, datetime('now'), datetime('now'))
            "#,
        )
        .bind(&session_str)
        .bind(&agent_str)
        .execute(&self.pool)
        .await
        .map_err(|e| ZclawError::StorageError(e.to_string()))?;

        Ok(session_id)
    }

    /// Append a message to a session
    pub async fn append_message(&self, session_id: &SessionId, message: &Message) -> Result<()> {
        let session_str = session_id.to_string();
        let message_json = serde_json::to_string(message)?;

        sqlx::query(
            r#"
            INSERT INTO messages (session_id, seq, content, created_at)
            SELECT ?, COALESCE(MAX(seq), 0) + 1, ?, datetime('now')
            FROM messages WHERE session_id = ?
            "#,
        )
        .bind(&session_str)
        .bind(&message_json)
        .bind(&session_str)
        .execute(&self.pool)
        .await
        .map_err(|e| ZclawError::StorageError(e.to_string()))?;

        // Update session updated_at
        sqlx::query("UPDATE sessions SET updated_at = datetime('now') WHERE id = ?")
            .bind(&session_str)
            .execute(&self.pool)
            .await
            .map_err(|e| ZclawError::StorageError(e.to_string()))?;

        Ok(())
    }

    /// Get all messages for a session
    pub async fn get_messages(&self, session_id: &SessionId) -> Result<Vec<Message>> {
        let session_str = session_id.to_string();

        let rows = sqlx::query_as::<_, (String,)>(
            "SELECT content FROM messages WHERE session_id = ? ORDER BY seq"
        )
        .bind(&session_str)
        .fetch_all(&self.pool)
        .await
        .map_err(|e| ZclawError::StorageError(e.to_string()))?;

        let messages = rows
            .into_iter()
            .filter_map(|(content,)| serde_json::from_str(&content).ok())
            .collect();
        Ok(messages)
    }

    // === KV Store ===

    /// Store a key-value pair for an agent
    pub async fn kv_store(&self, agent_id: &AgentId, key: &str, value: &serde_json::Value) -> Result<()> {
        let agent_str = agent_id.to_string();
        let value_json = serde_json::to_string(value)?;

        sqlx::query(
            r#"
            INSERT INTO kv_store (agent_id, key, value, updated_at)
            VALUES (?, ?, ?, datetime('now'))
            ON CONFLICT(agent_id, key) DO UPDATE SET
                value = excluded.value,
                updated_at = datetime('now')
            "#,
        )
        .bind(&agent_str)
        .bind(key)
        .bind(&value_json)
        .execute(&self.pool)
        .await
        .map_err(|e| ZclawError::StorageError(e.to_string()))?;

        Ok(())
    }

    /// Recall a value by key
    pub async fn kv_recall(&self, agent_id: &AgentId, key: &str) -> Result<Option<serde_json::Value>> {
        let agent_str = agent_id.to_string();

        let row = sqlx::query_as::<_, (String,)>(
            "SELECT value FROM kv_store WHERE agent_id = ? AND key = ?"
        )
        .bind(&agent_str)
        .bind(key)
        .fetch_optional(&self.pool)
        .await
        .map_err(|e| ZclawError::StorageError(e.to_string()))?;

        match row {
            Some((value,)) => {
                let v: serde_json::Value = serde_json::from_str(&value)?;
                Ok(Some(v))
            }
            None => Ok(None),
        }
    }

    /// List all keys for an agent
    pub async fn kv_list(&self, agent_id: &AgentId) -> Result<Vec<String>> {
        let agent_str = agent_id.to_string();

        let rows = sqlx::query_as::<_, (String,)>(
            "SELECT key FROM kv_store WHERE agent_id = ?"
        )
        .bind(&agent_str)
        .fetch_all(&self.pool)
        .await
        .map_err(|e| ZclawError::StorageError(e.to_string()))?;

        Ok(rows.into_iter().map(|(key,)| key).collect())
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use zclaw_types::{AgentConfig, ModelConfig};

    fn create_test_agent_config(name: &str) -> AgentConfig {
        AgentConfig {
            id: AgentId::new(),
            name: name.to_string(),
            description: None,
            model: ModelConfig::default(),
            system_prompt: None,
            capabilities: vec![],
            tools: vec![],
            max_tokens: None,
            temperature: None,
            enabled: true,
        }
    }

    #[tokio::test]
    async fn test_in_memory_store_creation() {
        let store = MemoryStore::in_memory().await;
        assert!(store.is_ok());
    }

    #[tokio::test]
    async fn test_save_and_load_agent() {
        let store = MemoryStore::in_memory().await.unwrap();
        let config = create_test_agent_config("test-agent");

        store.save_agent(&config).await.unwrap();

        let loaded = store.load_agent(&config.id).await.unwrap();
        assert!(loaded.is_some());
        let loaded = loaded.unwrap();
        assert_eq!(loaded.id, config.id);
        assert_eq!(loaded.name, config.name);
    }

    #[tokio::test]
    async fn test_load_nonexistent_agent() {
        let store = MemoryStore::in_memory().await.unwrap();
        let fake_id = AgentId::new();

        let result = store.load_agent(&fake_id).await.unwrap();
        assert!(result.is_none());
    }

    #[tokio::test]
    async fn test_save_agent_updates_existing() {
        let store = MemoryStore::in_memory().await.unwrap();
        let mut config = create_test_agent_config("original");

        store.save_agent(&config).await.unwrap();

        config.name = "updated".to_string();
        store.save_agent(&config).await.unwrap();

        let loaded = store.load_agent(&config.id).await.unwrap().unwrap();
        assert_eq!(loaded.name, "updated");
    }

    #[tokio::test]
    async fn test_list_agents() {
        let store = MemoryStore::in_memory().await.unwrap();

        let config1 = create_test_agent_config("agent1");
        let config2 = create_test_agent_config("agent2");

        store.save_agent(&config1).await.unwrap();
        store.save_agent(&config2).await.unwrap();

        let agents = store.list_agents().await.unwrap();
        assert_eq!(agents.len(), 2);
    }

    #[tokio::test]
    async fn test_delete_agent() {
        let store = MemoryStore::in_memory().await.unwrap();
        let config = create_test_agent_config("to-delete");

        store.save_agent(&config).await.unwrap();
        store.delete_agent(&config.id).await.unwrap();

        let loaded = store.load_agent(&config.id).await.unwrap();
        assert!(loaded.is_none());
    }

    #[tokio::test]
    async fn test_delete_nonexistent_agent_succeeds() {
        let store = MemoryStore::in_memory().await.unwrap();
        let fake_id = AgentId::new();

        // Deleting nonexistent agent should succeed (idempotent)
        let result = store.delete_agent(&fake_id).await;
        assert!(result.is_ok());
    }

    #[tokio::test]
    async fn test_create_session() {
        let store = MemoryStore::in_memory().await.unwrap();
        let config = create_test_agent_config("session-test");

        store.save_agent(&config).await.unwrap();

        let session_id = store.create_session(&config.id).await.unwrap();
        assert!(!session_id.as_uuid().is_nil());
    }

    #[tokio::test]
    async fn test_append_and_get_messages() {
        let store = MemoryStore::in_memory().await.unwrap();
        let config = create_test_agent_config("msg-test");

        store.save_agent(&config).await.unwrap();
        let session_id = store.create_session(&config.id).await.unwrap();

        let msg1 = Message::user("Hello");
        let msg2 = Message::assistant("Hi there!");

        store.append_message(&session_id, &msg1).await.unwrap();
        store.append_message(&session_id, &msg2).await.unwrap();

        let messages = store.get_messages(&session_id).await.unwrap();
        assert_eq!(messages.len(), 2);
    }

    #[tokio::test]
    async fn test_message_ordering() {
        let store = MemoryStore::in_memory().await.unwrap();
        let config = create_test_agent_config("order-test");

        store.save_agent(&config).await.unwrap();
        let session_id = store.create_session(&config.id).await.unwrap();

        for i in 0..10 {
            let msg = Message::user(format!("Message {}", i));
            store.append_message(&session_id, &msg).await.unwrap();
        }

        let messages = store.get_messages(&session_id).await.unwrap();
        assert_eq!(messages.len(), 10);

        // Verify ordering
        for (i, msg) in messages.iter().enumerate() {
            if let Message::User { content } = msg {
                assert_eq!(content, &format!("Message {}", i));
            }
        }
    }

    #[tokio::test]
    async fn test_kv_store_and_recall() {
        let store = MemoryStore::in_memory().await.unwrap();
        let config = create_test_agent_config("kv-test");

        store.save_agent(&config).await.unwrap();

        let value = serde_json::json!({"key": "value", "number": 42});
        store.kv_store(&config.id, "test-key", &value).await.unwrap();

        let recalled = store.kv_recall(&config.id, "test-key").await.unwrap();
        assert!(recalled.is_some());
        assert_eq!(recalled.unwrap(), value);
    }

    #[tokio::test]
    async fn test_kv_recall_nonexistent() {
        let store = MemoryStore::in_memory().await.unwrap();
        let config = create_test_agent_config("kv-missing");

        store.save_agent(&config).await.unwrap();

        let result = store.kv_recall(&config.id, "nonexistent").await.unwrap();
        assert!(result.is_none());
    }

    #[tokio::test]
    async fn test_kv_update_existing() {
        let store = MemoryStore::in_memory().await.unwrap();
        let config = create_test_agent_config("kv-update");

        store.save_agent(&config).await.unwrap();

        let value1 = serde_json::json!({"version": 1});
        let value2 = serde_json::json!({"version": 2});

        store.kv_store(&config.id, "key", &value1).await.unwrap();
        store.kv_store(&config.id, "key", &value2).await.unwrap();

        let recalled = store.kv_recall(&config.id, "key").await.unwrap().unwrap();
        assert_eq!(recalled["version"], 2);
    }

    #[tokio::test]
    async fn test_kv_list() {
        let store = MemoryStore::in_memory().await.unwrap();
        let config = create_test_agent_config("kv-list");

        store.save_agent(&config).await.unwrap();

        store.kv_store(&config.id, "key1", &serde_json::json!(1)).await.unwrap();
        store.kv_store(&config.id, "key2", &serde_json::json!(2)).await.unwrap();
        store.kv_store(&config.id, "key3", &serde_json::json!(3)).await.unwrap();

        let keys = store.kv_list(&config.id).await.unwrap();
        assert_eq!(keys.len(), 3);
        assert!(keys.contains(&"key1".to_string()));
        assert!(keys.contains(&"key2".to_string()));
        assert!(keys.contains(&"key3".to_string()));
    }

    // === Edge Case Tests ===

    #[tokio::test]
    async fn test_agent_with_empty_name() {
        let store = MemoryStore::in_memory().await.unwrap();
        let config = create_test_agent_config("");

        // Empty name should still work (validation is elsewhere)
        let result = store.save_agent(&config).await;
        assert!(result.is_ok());
    }

    #[tokio::test]
    async fn test_agent_with_special_characters_in_name() {
        let store = MemoryStore::in_memory().await.unwrap();
        let config = create_test_agent_config("agent-with-特殊字符-🎉");

        let result = store.save_agent(&config).await;
        assert!(result.is_ok());

        let loaded = store.load_agent(&config.id).await.unwrap().unwrap();
        assert_eq!(loaded.name, "agent-with-特殊字符-🎉");
    }

    #[tokio::test]
    async fn test_large_message_content() {
        let store = MemoryStore::in_memory().await.unwrap();
        let config = create_test_agent_config("large-msg");

        store.save_agent(&config).await.unwrap();
        let session_id = store.create_session(&config.id).await.unwrap();

        // Create a large message (100KB)
        let large_content = "x".repeat(100_000);
        let msg = Message::user(&large_content);

        let result = store.append_message(&session_id, &msg).await;
        assert!(result.is_ok());

        let messages = store.get_messages(&session_id).await.unwrap();
        assert_eq!(messages.len(), 1);
    }

    #[tokio::test]
    async fn test_message_with_tool_use() {
        let store = MemoryStore::in_memory().await.unwrap();
        let config = create_test_agent_config("tool-msg");

        store.save_agent(&config).await.unwrap();
        let session_id = store.create_session(&config.id).await.unwrap();

        let tool_input = serde_json::json!({"query": "test", "options": {"limit": 10}});
        let msg = Message::tool_use("call-123", zclaw_types::ToolId::new("search"), tool_input.clone());

        store.append_message(&session_id, &msg).await.unwrap();

        let messages = store.get_messages(&session_id).await.unwrap();
        assert_eq!(messages.len(), 1);

        if let Message::ToolUse { id, tool, input } = &messages[0] {
            assert_eq!(id, "call-123");
            assert_eq!(tool.as_str(), "search");
            assert_eq!(*input, tool_input);
        } else {
            panic!("Expected ToolUse message");
        }
    }

    #[tokio::test]
    async fn test_message_with_tool_result() {
        let store = MemoryStore::in_memory().await.unwrap();
        let config = create_test_agent_config("tool-result");

        store.save_agent(&config).await.unwrap();
        let session_id = store.create_session(&config.id).await.unwrap();

        let output = serde_json::json!({"results": ["a", "b", "c"]});
        let msg = Message::tool_result("call-123", zclaw_types::ToolId::new("search"), output.clone(), false);

        store.append_message(&session_id, &msg).await.unwrap();

        let messages = store.get_messages(&session_id).await.unwrap();
        assert_eq!(messages.len(), 1);

        if let Message::ToolResult { tool_call_id, tool, output: o, is_error } = &messages[0] {
            assert_eq!(tool_call_id, "call-123");
            assert_eq!(tool.as_str(), "search");
            assert_eq!(*o, output);
            assert!(!is_error);
        } else {
            panic!("Expected ToolResult message");
        }
    }

    #[tokio::test]
    async fn test_message_with_thinking() {
        let store = MemoryStore::in_memory().await.unwrap();
        let config = create_test_agent_config("thinking");

        store.save_agent(&config).await.unwrap();
        let session_id = store.create_session(&config.id).await.unwrap();

        let msg = Message::assistant_with_thinking("Final answer", "My reasoning...");

        store.append_message(&session_id, &msg).await.unwrap();

        let messages = store.get_messages(&session_id).await.unwrap();
        assert_eq!(messages.len(), 1);

        if let Message::Assistant { content, thinking } = &messages[0] {
            assert_eq!(content, "Final answer");
            assert_eq!(thinking.as_ref().unwrap(), "My reasoning...");
        } else {
            panic!("Expected Assistant message");
        }
    }
}