use std::collections::HashSet;

use uuid::Uuid;

use crate::application::dtos::favorites_dto::{
    BatchFavoritesResult, FavoriteItemDto, FavoriteResourceRow, FavoritesCursor,
};
use crate::common::errors::Result;
use crate::domain::services::authorization::ResourceKind;

/// Defines operations for managing user favorites
pub trait FavoritesUseCase: Send + Sync {
    /// Get all favorites for a user
    async fn get_favorites(&self, user_id: Uuid) -> Result<Vec<FavoriteItemDto>>;

    /// Add an item to user's favorites
    async fn add_to_favorites(&self, user_id: Uuid, item_id: &str, item_type: &str) -> Result<()>;

    /// Remove an item from user's favorites
    async fn remove_from_favorites(
        &self,
        user_id: Uuid,
        item_id: &str,
        item_type: &str,
    ) -> Result<bool>;

    /// Check if an item is in user's favorites
    async fn is_favorite(&self, user_id: Uuid, item_id: &str, item_type: &str) -> Result<bool>;

    /// Add multiple items to favorites in a single transaction.
    /// Returns enriched favourites list so the client can replace its cache.
    async fn batch_add_to_favorites(
        &self,
        user_id: Uuid,
        items: &[(String, String)],
    ) -> Result<BatchFavoritesResult>;

    /// Check which of the given item IDs are favorites for this user.
    /// Returns the set of item_ids that are favorites.
    async fn batch_check_favorites(
        &self,
        user_id: Uuid,
        item_ids: &[(&str, &str)], // (item_id, item_type) pairs
    ) -> Result<HashSet<String>>;
}

// ─────────────────────────────────────────────────────
// Outbound port — persistence abstraction
// ─────────────────────────────────────────────────────

/// Secondary (outbound) port for favorites persistence.
///
/// Application services depend on this trait instead of
/// accessing `PgPool` directly. The concrete implementation
/// lives in `infrastructure::repositories::pg`.
pub trait FavoritesRepositoryPort: Send + Sync + 'static {
    /// Gets all favorites for a user.
    async fn get_favorites(&self, user_id: Uuid) -> Result<Vec<FavoriteItemDto>>;

    /// Adds an item to favorites. Returns `Ok(())` if it already existed (idempotent).
    async fn add_favorite(&self, user_id: Uuid, item_id: &str, item_type: &str) -> Result<()>;

    /// Removes an item from favorites. Returns `true` if it existed.
    async fn remove_favorite(&self, user_id: Uuid, item_id: &str, item_type: &str) -> Result<bool>;

    /// Checks if an item is in favorites.
    async fn is_favorite(&self, user_id: Uuid, item_id: &str, item_type: &str) -> Result<bool>;

    /// Insert multiple items in a single transaction.
    /// Returns the number of rows actually inserted (ignoring duplicates).
    async fn add_favorites_batch(&self, user_id: Uuid, items: &[(String, String)]) -> Result<u64>;

    /// Check which of the given item IDs are favorites for this user.
    /// Returns the set of item_ids that are favorites.
    async fn batch_check_favorites(
        &self,
        user_id: Uuid,
        item_ids: &[(&str, &str)], // (item_id, item_type) pairs
    ) -> Result<HashSet<String>>;

    /// Cursor-paginated list of a user's favorited resources.
    /// Items that no longer exist (deleted/trashed) are silently excluded.
    /// `kinds = None` → both files and folders.
    async fn list_resources_paged(
        &self,
        user_id: Uuid,
        limit: usize,
        cursor: Option<&FavoritesCursor>,
        order_by: &str,
        kinds: Option<&[ResourceKind]>,
        reverse: bool,
    ) -> Result<Vec<FavoriteResourceRow>>;
}
