//! FiberLB Controller - Manages LoadBalancer service VIP allocation
//!
//! This controller watches for Services with type=LoadBalancer and provisions
//! external VIPs by creating LoadBalancer resources in FiberLB.

use crate::storage::Storage;
use anyhow::Result;
use fiberlb_api::load_balancer_service_client::LoadBalancerServiceClient;
use fiberlb_api::{CreateLoadBalancerRequest, DeleteLoadBalancerRequest};
use k8shost_types::{LoadBalancerIngress, LoadBalancerStatus, ServiceStatus};
use std::sync::Arc;
use std::time::Duration;
use tokio::time::sleep;
use tracing::{debug, info, warn};

/// FiberLB controller for managing LoadBalancer service VIPs
pub struct FiberLbController {
    storage: Arc<Storage>,
    fiberlb_addr: String,
    interval: Duration,
}

impl FiberLbController {
    /// Create a new FiberLB controller
    pub fn new(storage: Arc<Storage>, fiberlb_addr: String) -> Self {
        Self {
            storage,
            fiberlb_addr,
            interval: Duration::from_secs(10), // Check every 10 seconds
        }
    }

    /// Start the controller loop
    pub async fn run(self: Arc<Self>) {
        info!(
            "FiberLB controller started (FiberLB at {}, {}s interval)",
            self.fiberlb_addr,
            self.interval.as_secs()
        );

        loop {
            if let Err(e) = self.reconcile_loadbalancers().await {
                warn!("FiberLB controller cycle failed: {}", e);
            }

            sleep(self.interval).await;
        }
    }

    /// Reconcile LoadBalancer services across all tenants
    async fn reconcile_loadbalancers(&self) -> Result<()> {
        // For MVP, iterate through known tenants
        // In production, would get active tenants from IAM or FlareDB
        let tenants = vec![("default-org".to_string(), "default-project".to_string())];

        for (org_id, project_id) in tenants {
            if let Err(e) = self.reconcile_tenant_loadbalancers(&org_id, &project_id).await {
                warn!(
                    "Failed to reconcile LoadBalancers for tenant {}/{}: {}",
                    org_id, project_id, e
                );
            }
        }

        Ok(())
    }

    /// Reconcile LoadBalancer services for a specific tenant
    async fn reconcile_tenant_loadbalancers(&self, org_id: &str, project_id: &str) -> Result<()> {
        // Get all services for this tenant
        let services = self
            .storage
            .list_services(org_id, project_id, None)
            .await?;

        // Filter for LoadBalancer services that need provisioning
        let lb_services: Vec<_> = services
            .into_iter()
            .filter(|svc| {
                // Service is a LoadBalancer if:
                // 1. type is "LoadBalancer"
                // 2. status is None OR status.load_balancer is None (not yet provisioned)
                svc.spec.r#type.as_deref() == Some("LoadBalancer")
                    && (svc.status.is_none()
                        || svc.status.as_ref().and_then(|s| s.load_balancer.as_ref()).is_none())
            })
            .collect();

        if lb_services.is_empty() {
            debug!("No LoadBalancer services to provision for tenant {}/{}", org_id, project_id);
            return Ok(());
        }

        info!(
            "Found {} LoadBalancer service(s) to provision for tenant {}/{}",
            lb_services.len(),
            org_id,
            project_id
        );

        // Connect to FiberLB
        let mut fiberlb_client =
            match LoadBalancerServiceClient::connect(self.fiberlb_addr.clone()).await {
                Ok(client) => client,
                Err(e) => {
                    warn!("Failed to connect to FiberLB at {}: {}", self.fiberlb_addr, e);
                    return Ok(());
                }
            };

        // Provision each LoadBalancer service
        for mut service in lb_services {
            let namespace = service.metadata.namespace.as_deref().unwrap_or("default");
            let name = &service.metadata.name;

            info!("Provisioning LoadBalancer for service {}/{}", namespace, name);

            // Create LoadBalancer in FiberLB
            let lb_name = format!("{}.{}", name, namespace);
            let create_req = CreateLoadBalancerRequest {
                name: lb_name.clone(),
                org_id: org_id.to_string(),
                project_id: project_id.to_string(),
                description: format!("k8s service {}/{}", namespace, name),
            };

            match fiberlb_client.create_load_balancer(create_req).await {
                Ok(response) => {
                    let lb = response.into_inner().loadbalancer;
                    if let Some(lb) = lb {
                        // vip_address is String in proto (defaults to empty if not set)
                        let vip = if lb.vip_address.is_empty() {
                            warn!("FiberLB returned LoadBalancer without VIP");
                            "0.0.0.0".to_string()
                        } else {
                            lb.vip_address
                        };

                        info!(
                            "FiberLB allocated VIP {} for service {}/{}",
                            vip, namespace, name
                        );

                        // Update service status with VIP
                        service.status = Some(ServiceStatus {
                            load_balancer: Some(LoadBalancerStatus {
                                ingress: vec![LoadBalancerIngress {
                                    ip: Some(vip),
                                    hostname: None,
                                }],
                            }),
                        });

                        // Increment resource version
                        let current_version = service
                            .metadata
                            .resource_version
                            .as_ref()
                            .and_then(|v| v.parse::<u64>().ok())
                            .unwrap_or(0);
                        service.metadata.resource_version = Some((current_version + 1).to_string());

                        // Store LoadBalancer ID in annotations for cleanup on deletion
                        service
                            .metadata
                            .annotations
                            .insert("fiberlb.plasmacloud.io/lb-id".to_string(), lb.id);

                        // Save updated service
                        if let Err(e) = self.storage.put_service(&service).await {
                            warn!(
                                "Failed to update service {}/{} with VIP: {}",
                                namespace, name, e
                            );
                        } else {
                            info!(
                                "Successfully provisioned VIP {} for service {}/{}",
                                service
                                    .status
                                    .as_ref()
                                    .and_then(|s| s.load_balancer.as_ref())
                                    .and_then(|lb| lb.ingress.first())
                                    .and_then(|i| i.ip.as_ref())
                                    .unwrap_or(&"<none>".to_string()),
                                namespace,
                                name
                            );
                        }
                    } else {
                        warn!("FiberLB returned empty LoadBalancer response");
                    }
                }
                Err(e) => {
                    warn!(
                        "Failed to create LoadBalancer in FiberLB for service {}/{}: {}",
                        namespace, name, e
                    );
                }
            }
        }

        Ok(())
    }

    /// Cleanup LoadBalancer when Service is deleted
    ///
    /// This should be called when a Service with type=LoadBalancer is deleted.
    /// For MVP, this is not automatically triggered - would need a deletion watch.
    #[allow(dead_code)]
    async fn cleanup_loadbalancer(&self, lb_id: &str) -> Result<()> {
        let mut fiberlb_client = LoadBalancerServiceClient::connect(self.fiberlb_addr.clone())
            .await?;

        let delete_req = DeleteLoadBalancerRequest {
            id: lb_id.to_string(),
        };

        fiberlb_client
            .delete_load_balancer(delete_req)
            .await?;

        info!("Deleted LoadBalancer {} from FiberLB", lb_id);
        Ok(())
    }
}