use log::debug;
use serde_json::Value;

use super::tools::{KeepTools, ToolError};
use crate::modes::server::common::AppState;

/// Server handler for MCP (Model Context Protocol) requests.
///
/// Routes requests to appropriate tools and handles responses. Clones AppState for tool usage.
///
/// # Fields
///
/// * `state` - The shared application state (DB, config, etc.).
#[derive(Clone)]
pub struct KeepMcpServer {
    state: AppState,
}

/// Creates a new `KeepMcpServer` instance.
///
/// # Arguments
///
/// * `state` - The application state containing DB, config, and services.
///
/// # Returns
///
/// A new `KeepMcpServer` instance.
///
/// # Examples
///
/// ```
/// let server = KeepMcpServer::new(app_state);
/// ```
impl KeepMcpServer {
    pub fn new(state: AppState) -> Self {
        Self { state }
    }

    /// Handles an MCP request by routing to the appropriate tool.
    ///
    /// Supports methods like "save_item", "get_item", "list_items". Logs the request and delegates to KeepTools.
    ///
    /// # Arguments
    ///
    /// * `method` - The MCP method name (string).
    /// * `params` - Optional JSON parameters as serde_json::Value.
    ///
    /// # Returns
    ///
    /// `Ok(String)` with JSON-serialized response on success, or `Err(ToolError)` on failure.
    ///
    /// # Errors
    ///
    /// * ToolError::UnknownTool if method unsupported.
    /// * Propagates tool-specific errors (e.g., invalid args, DB failures).
    ///
    /// # Examples
    ///
    /// ```
    /// let result = server.handle_request("save_item", Some(params)).await?;
    /// ```
    pub async fn handle_request(
        &self,
        method: &str,
        params: Option<Value>,
    ) -> Result<String, ToolError> {
        debug!(
            "MCP: Handling request '{}' with params: {:?}",
            method, params
        );

        let tools = KeepTools::new(self.state.clone());

        match method {
            "save_item" => tools.save_item(params).await,
            "get_item" => tools.get_item(params).await,
            "get_latest_item" => tools.get_latest_item(params).await,
            "list_items" => tools.list_items(params).await,
            "search_items" => tools.search_items(params).await,
            _ => Err(ToolError::UnknownTool(method.to_string())),
        }
    }
}