// api/applications.rs — Server functions for applications and their port associations

use leptos::prelude::*;
use serde::{Deserialize, Serialize};

use crate::models::Application;

// Application row enriched with the number of hosts that use at least one of
// its registered ports.  Host count is computed via the join:
//   application_ports → host_ports (matched on port_number) → hosts
#[derive(Clone, Debug, Serialize, Deserialize)]
pub struct ApplicationWithCounts {
    pub id: i64,
    pub name: String,
    /// Distinct hosts that have at least one port matching this application.
    pub host_count: i64,
}

// ─── Queries ──────────────────────────────────────────────────────────────────

/// Returns all applications enriched with their associated host count.
#[server]
pub async fn get_applications_with_counts() -> Result<Vec<ApplicationWithCounts>, ServerFnError> {
    use sqlx::{AnyPool, Row};

    let pool = use_context::<AnyPool>()
        .ok_or_else(|| ServerFnError::new("Database pool not found in context"))?;

    let rows = sqlx::query(
        "SELECT
             a.id,
             a.name,
             COUNT(DISTINCT hp.host_id) AS host_count
         FROM applications a
         LEFT JOIN application_ports ap ON ap.application_id = a.id
         LEFT JOIN host_ports hp        ON hp.port_number    = ap.port_number
         GROUP BY a.id, a.name
         ORDER BY a.name",
    )
    .fetch_all(&pool)
    .await
    .map_err(|e| ServerFnError::new(e.to_string()))?;

    Ok(rows
        .into_iter()
        .map(|row| ApplicationWithCounts {
            id:         row.get("id"),
            name:       row.get("name"),
            host_count: row.get("host_count"),
        })
        .collect())
}

/// Returns all applications ordered by name.
#[server]
pub async fn get_applications() -> Result<Vec<Application>, ServerFnError> {
    use sqlx::AnyPool;
    use crate::server::repository::applications as repo;

    let pool = use_context::<AnyPool>()
        .ok_or_else(|| ServerFnError::new("Database pool not found in context"))?;

    repo::list_applications(&pool)
        .await
        .map_err(|e| ServerFnError::new(e.to_string()))
}

/// Returns the port numbers associated with an application.
#[server]
pub async fn get_ports_for_application(
    application_id: i64,
) -> Result<Vec<u16>, ServerFnError> {
    use sqlx::AnyPool;
    use crate::server::repository::applications as repo;

    let pool = use_context::<AnyPool>()
        .ok_or_else(|| ServerFnError::new("Database pool not found in context"))?;

    repo::list_ports_for_application(&pool, application_id)
        .await
        .map_err(|e| ServerFnError::new(e.to_string()))
}

// ─── Mutations ────────────────────────────────────────────────────────────────

/// Creates a new application and returns the created record.
#[server]
pub async fn create_application(name: String) -> Result<Application, ServerFnError> {
    use sqlx::AnyPool;
    use crate::server::repository::applications as repo;

    let pool = use_context::<AnyPool>()
        .ok_or_else(|| ServerFnError::new("Database pool not found in context"))?;

    repo::create_application(&pool, &name)
        .await
        .map_err(|e| ServerFnError::new(e.to_string()))
}

/// Deletes an application and all its port associations.
///
/// Returns `true` if the application existed and was deleted.
#[server]
pub async fn delete_application(id: i64) -> Result<bool, ServerFnError> {
    use sqlx::AnyPool;
    use crate::server::repository::applications as repo;

    let pool = use_context::<AnyPool>()
        .ok_or_else(|| ServerFnError::new("Database pool not found in context"))?;

    repo::delete_application(&pool, id)
        .await
        .map_err(|e| ServerFnError::new(e.to_string()))
}

/// Associates a port number with an application.
///
/// If the association already exists, this is a no-op.
#[server]
pub async fn add_port_to_application(
    application_id: i64,
    port_number: u16,
) -> Result<(), ServerFnError> {
    use sqlx::AnyPool;
    use crate::server::repository::applications as repo;

    let pool = use_context::<AnyPool>()
        .ok_or_else(|| ServerFnError::new("Database pool not found in context"))?;

    repo::add_port_to_application(&pool, application_id, port_number)
        .await
        .map_err(|e| ServerFnError::new(e.to_string()))
}

/// Removes a port association from an application.
///
/// If the association does not exist, this is a no-op.
#[server]
pub async fn remove_port_from_application(
    application_id: i64,
    port_number: u16,
) -> Result<(), ServerFnError> {
    use sqlx::AnyPool;
    use crate::server::repository::applications as repo;

    let pool = use_context::<AnyPool>()
        .ok_or_else(|| ServerFnError::new("Database pool not found in context"))?;

    repo::remove_port_from_application(&pool, application_id, port_number)
        .await
        .map_err(|e| ServerFnError::new(e.to_string()))
}