//! Window/tab use cases (ARCHITECTURE §6, §10; L10).
//!
//! [`MoveTabToNewWindow`] detaches a tab into a new OS window. The topology
//! change is the pure [`Workspace::move_tab_to_new_window`] domain operation; the
//! use case only loads/persists the workspace and mints the new window id.

use std::sync::Arc;

use domain::ids::{TabId, WindowId};
use domain::layout::Workspace;
use domain::ports::{IdGenerator, ProjectStore};

use crate::error::AppError;

/// Input for [`MoveTabToNewWindow::execute`].
#[derive(Debug, Clone, PartialEq, Eq)]
pub struct MoveTabToNewWindowInput {
    /// The tab to detach into its own new window.
    pub tab_id: TabId,
}

/// Output of [`MoveTabToNewWindow::execute`].
#[derive(Debug, Clone, PartialEq)]
pub struct MoveTabToNewWindowOutput {
    /// The id minted for the new window.
    pub new_window_id: WindowId,
    /// The resulting workspace (already persisted).
    pub workspace: Workspace,
}

/// Detaches a tab into a freshly-created window and persists the workspace.
pub struct MoveTabToNewWindow {
    store: Arc<dyn ProjectStore>,
    ids: Arc<dyn IdGenerator>,
}

impl MoveTabToNewWindow {
    /// Builds the use case from its ports.
    #[must_use]
    pub fn new(store: Arc<dyn ProjectStore>, ids: Arc<dyn IdGenerator>) -> Self {
        Self { store, ids }
    }

    /// Executes the detach.
    ///
    /// # Errors
    /// - [`AppError::NotFound`] if the tab is not in the workspace,
    /// - [`AppError::Invalid`] if the resulting window is invalid,
    /// - [`AppError::Store`] on persistence failure.
    pub async fn execute(
        &self,
        input: MoveTabToNewWindowInput,
    ) -> Result<MoveTabToNewWindowOutput, AppError> {
        let workspace = self.store.load_workspace().await?;
        let new_window_id = WindowId::from_uuid(self.ids.new_uuid());

        let workspace = workspace
            .move_tab_to_new_window(input.tab_id, new_window_id)
            .map_err(|e| match e {
                domain::layout::LayoutError::TabNotFound(t) => {
                    AppError::NotFound(format!("tab {t}"))
                }
                other => AppError::Invalid(other.to_string()),
            })?;

        self.store.save_workspace(&workspace).await?;

        Ok(MoveTabToNewWindowOutput {
            new_window_id,
            workspace,
        })
    }
}