use crate::function_tool::FunctionCallError;
use crate::session::session::Session;
use crate::session::turn_context::TurnContext;
use crate::tools::context::SharedTurnDiffTracker;
use crate::tools::context::ToolInvocation;
use crate::tools::context::ToolPayload;
use crate::tools::handlers::ToolSearchHandlerCache;
use crate::tools::registry::AnyToolResult;
use crate::tools::registry::ToolArgumentDiffConsumer;
use crate::tools::registry::ToolRegistry;
use crate::tools::spec_plan::build_tool_router;
use codex_mcp::ToolInfo;
use codex_protocol::dynamic_tools::DynamicToolSpec;
use codex_protocol::models::ResponseItem;
use codex_protocol::models::SearchToolCallParams;
use codex_tools::DiscoverableTool;
use codex_tools::ToolCall as ExtensionToolCall;
use codex_tools::ToolExecutor;
use codex_tools::ToolName;
use codex_tools::ToolSpec;
use std::sync::Arc;
use std::sync::atomic::AtomicBool;
use tokio_util::sync::CancellationToken;
use tracing::instrument;

pub use crate::tools::context::ToolCallSource;

#[derive(Clone, Debug)]
pub struct ToolCall {
    pub tool_name: ToolName,
    pub call_id: String,
    pub payload: ToolPayload,
}

pub struct ToolRouter {
    registry: ToolRegistry,
    model_visible_specs: Vec<ToolSpec>,
}

pub(crate) struct ToolRouterParams<'a> {
    pub(crate) mcp_tools: Option<Vec<ToolInfo>>,
    pub(crate) deferred_mcp_tools: Option<Vec<ToolInfo>>,
    pub(crate) discoverable_tools: Option<Vec<DiscoverableTool>>,
    pub(crate) extension_tool_executors: Vec<Arc<dyn ToolExecutor<ExtensionToolCall>>>,
    pub(crate) dynamic_tools: &'a [DynamicToolSpec],
}

impl ToolRouter {
    pub(crate) fn from_turn_context(
        turn_context: &TurnContext,
        params: ToolRouterParams<'_>,
        tool_search_handler_cache: &ToolSearchHandlerCache,
    ) -> Self {
        build_tool_router(turn_context, params, tool_search_handler_cache)
    }

    pub(crate) fn from_parts(registry: ToolRegistry, model_visible_specs: Vec<ToolSpec>) -> Self {
        Self {
            registry,
            model_visible_specs,
        }
    }

    pub fn model_visible_specs(&self) -> Vec<ToolSpec> {
        self.model_visible_specs.clone()
    }

    #[cfg(test)]
    pub(crate) fn registered_tool_names_for_test(&self) -> Vec<ToolName> {
        self.registry.tool_names_for_test()
    }

    #[cfg(test)]
    pub(crate) fn tool_exposure_for_test(
        &self,
        name: &ToolName,
    ) -> Option<crate::tools::registry::ToolExposure> {
        self.registry.tool_exposure(name)
    }

    pub(crate) fn create_diff_consumer(
        &self,
        tool_name: &ToolName,
    ) -> Option<Box<dyn ToolArgumentDiffConsumer>> {
        self.registry.create_diff_consumer(tool_name)
    }

    pub fn tool_supports_parallel(&self, call: &ToolCall) -> bool {
        self.registry
            .supports_parallel_tool_calls(&call.tool_name)
            .unwrap_or(false)
    }

    pub fn tool_waits_for_runtime_cancellation(&self, call: &ToolCall) -> bool {
        self.registry
            .waits_for_runtime_cancellation(&call.tool_name)
            .unwrap_or(false)
    }

    #[instrument(level = "trace", skip_all, err)]
    pub fn build_tool_call(item: ResponseItem) -> Result<Option<ToolCall>, FunctionCallError> {
        match item {
            ResponseItem::FunctionCall {
                name,
                namespace,
                arguments,
                call_id,
                ..
            } => {
                let tool_name = ToolName::new(namespace, name);
                Ok(Some(ToolCall {
                    tool_name,
                    call_id,
                    payload: ToolPayload::Function { arguments },
                }))
            }
            ResponseItem::ToolSearchCall {
                call_id: Some(call_id),
                execution,
                arguments,
                ..
            } if execution == "client" => {
                let arguments: SearchToolCallParams =
                    serde_json::from_value(arguments).map_err(|err| {
                        FunctionCallError::RespondToModel(format!(
                            "failed to parse tool_search arguments: {err}"
                        ))
                    })?;
                Ok(Some(ToolCall {
                    tool_name: ToolName::plain("tool_search"),
                    call_id,
                    payload: ToolPayload::ToolSearch { arguments },
                }))
            }
            ResponseItem::ToolSearchCall { .. } => Ok(None),
            ResponseItem::CustomToolCall {
                name,
                input,
                call_id,
                ..
            } => Ok(Some(ToolCall {
                tool_name: ToolName::plain(name),
                call_id,
                payload: ToolPayload::Custom { input },
            })),
            _ => Ok(None),
        }
    }

    #[allow(dead_code)]
    #[instrument(level = "trace", skip_all, err)]
    pub async fn dispatch_tool_call_with_code_mode_result(
        &self,
        session: Arc<Session>,
        turn: Arc<TurnContext>,
        cancellation_token: CancellationToken,
        tracker: SharedTurnDiffTracker,
        call: ToolCall,
        source: ToolCallSource,
    ) -> Result<AnyToolResult, FunctionCallError> {
        self.dispatch_tool_call_with_code_mode_result_inner(
            session,
            turn,
            cancellation_token,
            tracker,
            call,
            source,
            /*terminal_outcome_reached*/ None,
        )
        .await
    }

    #[instrument(level = "trace", skip_all, err)]
    #[allow(clippy::too_many_arguments)]
    pub(crate) async fn dispatch_tool_call_with_terminal_outcome(
        &self,
        session: Arc<Session>,
        turn: Arc<TurnContext>,
        cancellation_token: CancellationToken,
        tracker: SharedTurnDiffTracker,
        call: ToolCall,
        source: ToolCallSource,
        terminal_outcome_reached: Arc<AtomicBool>,
    ) -> Result<AnyToolResult, FunctionCallError> {
        self.dispatch_tool_call_with_code_mode_result_inner(
            session,
            turn,
            cancellation_token,
            tracker,
            call,
            source,
            Some(terminal_outcome_reached),
        )
        .await
    }

    #[allow(clippy::too_many_arguments)]
    async fn dispatch_tool_call_with_code_mode_result_inner(
        &self,
        session: Arc<Session>,
        turn: Arc<TurnContext>,
        cancellation_token: CancellationToken,
        tracker: SharedTurnDiffTracker,
        call: ToolCall,
        source: ToolCallSource,
        terminal_outcome_reached: Option<Arc<AtomicBool>>,
    ) -> Result<AnyToolResult, FunctionCallError> {
        let ToolCall {
            tool_name,
            call_id,
            payload,
        } = call;

        let invocation = ToolInvocation {
            session,
            turn,
            cancellation_token,
            tracker,
            call_id,
            tool_name,
            source,
            payload,
        };

        self.registry
            .dispatch_any_with_terminal_outcome(invocation, terminal_outcome_reached)
            .await
    }
}

pub(crate) fn extension_tool_executors(
    session: &Session,
) -> Vec<Arc<dyn ToolExecutor<ExtensionToolCall>>> {
    session
        .services
        .extensions
        .tool_contributors()
        .iter()
        .flat_map(|contributor| {
            contributor.tools(
                &session.services.session_extension_data,
                &session.services.thread_extension_data,
            )
        })
        .collect()
}

#[cfg(test)]
#[path = "router_tests.rs"]
mod tests;