use axum::Router;
use axum::routing::{get, post};
use uuid::Uuid;

use erp_core::error::AppResult;
use erp_core::events::EventBus;
use erp_core::module::ErpModule;

use crate::handler::{
    definition_handler, instance_handler, task_handler,
};

/// Workflow module implementing the `ErpModule` trait.
///
/// Manages workflow definitions, process instances, tasks,
/// and the token-driven execution engine.
pub struct WorkflowModule;

impl WorkflowModule {
    pub fn new() -> Self {
        Self
    }

    /// Build protected (authenticated) routes for the workflow module.
    pub fn protected_routes<S>() -> Router<S>
    where
        crate::workflow_state::WorkflowState: axum::extract::FromRef<S>,
        S: Clone + Send + Sync + 'static,
    {
        Router::new()
            // Definition routes
            .route(
                "/workflow/definitions",
                get(definition_handler::list_definitions)
                    .post(definition_handler::create_definition),
            )
            .route(
                "/workflow/definitions/{id}",
                get(definition_handler::get_definition)
                    .put(definition_handler::update_definition),
            )
            .route(
                "/workflow/definitions/{id}/publish",
                post(definition_handler::publish_definition),
            )
            // Instance routes
            .route(
                "/workflow/instances",
                post(instance_handler::start_instance)
                    .get(instance_handler::list_instances),
            )
            .route(
                "/workflow/instances/{id}",
                get(instance_handler::get_instance),
            )
            .route(
                "/workflow/instances/{id}/suspend",
                post(instance_handler::suspend_instance),
            )
            .route(
                "/workflow/instances/{id}/terminate",
                post(instance_handler::terminate_instance),
            )
            // Task routes
            .route(
                "/workflow/tasks/pending",
                get(task_handler::list_pending_tasks),
            )
            .route(
                "/workflow/tasks/completed",
                get(task_handler::list_completed_tasks),
            )
            .route(
                "/workflow/tasks/{id}/complete",
                post(task_handler::complete_task),
            )
            .route(
                "/workflow/tasks/{id}/delegate",
                post(task_handler::delegate_task),
            )
    }
}

impl Default for WorkflowModule {
    fn default() -> Self {
        Self::new()
    }
}

#[async_trait::async_trait]
impl ErpModule for WorkflowModule {
    fn name(&self) -> &str {
        "workflow"
    }

    fn version(&self) -> &str {
        env!("CARGO_PKG_VERSION")
    }

    fn dependencies(&self) -> Vec<&str> {
        vec!["auth"]
    }

    fn register_routes(&self, router: Router) -> Router {
        router
    }

    fn register_event_handlers(&self, _bus: &EventBus) {}

    async fn on_tenant_created(&self, _tenant_id: Uuid) -> AppResult<()> {
        Ok(())
    }

    async fn on_tenant_deleted(&self, _tenant_id: Uuid) -> AppResult<()> {
        Ok(())
    }

    fn as_any(&self) -> &dyn std::any::Any {
        self
    }
}