//! TRACES: FR-CAT-1 | FR-CAT-4 | FR-NC-3 | NFR-P9
//! Opening a remote library: scan → catalog → grid.
//!
//! This is the wire between three pieces that already worked separately —
//! `dr_sync::scan` walks the tree, `dr_catalog` indexes it, and
//! `dr_decode::preview` turns bytes into pixels. Until now the "Open library"
//! button logged its intent and stopped.
//!
//! # Threading
//!
//! Slint's event loop is single-threaded and must never block (NFR-P9), so
//! every network and decode operation runs on a worker thread and results
//! return through an mpsc channel drained by a Slint timer. That is the same
//! shape the login flow uses; it is repeated rather than shared because the
//! message types differ and a generic version would obscure both.
//!
//! # Why thumbnails are fetched, not derived from the scan
//!
//! A scan yields paths and sizes, nothing visual. Each thumbnail costs its own
//! range request, so they are fetched **only for cells the grid actually
//! wants** — never for the whole library up front. On the reference library
//! that is the difference between a few MB and ~370 GB (ARCH §6.7).
//!
//! Split into one module per area (docs/dev/code-health.md CH-1): filtering,
//! sidecar writes, on-disk paths, scanning, XMP, thumbnail fetch and
//! generation, the background sweeps, and reading the grid's cells and spans.
//! `mod.rs` re-exports every module's public items so nothing outside
//! `library` needs to change.

mod cells;
mod filters;
mod paths;
mod scan;
mod sidecar;
mod spans;
mod sweep;
mod thumbnails_fetch;
mod thumbnails_gen;
mod xmp;

pub use cells::*;
pub use filters::*;
pub use paths::*;
pub use scan::*;
pub use sidecar::*;
pub use spans::*;
pub use sweep::*;
pub use thumbnails_fetch::*;
pub use thumbnails_gen::*;
pub use xmp::*;

/// What narrows the grid, when something does.
///
/// A collection is a set of originals the photographer files; an album is the
/// photographs whose exports went into one folder. The grid reads either the
/// same way — see `spans::scope_clause`, the one place the difference is
/// spelled — and the whole library is `None`.
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub enum Scope {
    Collection(dr_types::CollectionId),
    Album(dr_catalog::AlbumId),
}

#[cfg(test)]
pub(crate) mod test_support {
    //! Fixtures shared with the modules that build on this one's catalog
    //! layout -- `repairs`, whose work lists are read over the same `images`
    //! and `remote` rows a scan writes.
    use dr_catalog::Catalog;
    use dr_sync::{RemoteEntry, RemoteId, RemotePath};

    use super::scan::persist;

    pub fn entry(path: &str, file_id: u64, size: u64) -> RemoteEntry {
        RemoteEntry {
            id: RemoteId::Stable(file_id),
            path: RemotePath::new(path),
            kind: dr_sync::EntryKind::File,
            validator: dr_sync::Validator::new("v"),
            size,
            modified: None,
            has_preview: false,
            materialised: true,
        }
    }

    /// A catalog with `n` images, ready to file into collections.
    pub fn with_images(n: usize) -> Catalog {
        let catalog = Catalog::in_memory().unwrap();
        let images: Vec<RemoteEntry> = (0..n)
            .map(|i| entry(&format!("PhotosRaw/img{i:03}.CR2"), i as u64, 1000))
            .collect();
        let result = dr_sync::ScanResult {
            images,
            directories: vec![(RemotePath::new("PhotosRaw"), dr_sync::Validator::new("e"))],
            progress: Default::default(),
            sidecars: Vec::new(),
        };
        persist(&catalog, "PhotosRaw", &result).unwrap();
        catalog
    }

    /// A catalog with `n` scanned images, none trashed.
    ///
    /// Shared with `spans`, whose collection-membership tests build on the
    /// same "n images, no folders beyond the root" catalog `cells`'s trash
    /// tests do.
    pub fn scanned(n: u64) -> Catalog {
        let catalog = Catalog::in_memory().unwrap();
        let images = (1..=n)
            .map(|i| entry(&format!("PhotosRaw/IMG_{i:04}.CR2"), 1000 + i, 30_000_000))
            .collect();
        persist(
            &catalog,
            "PhotosRaw",
            &dr_sync::ScanResult {
                images,
                directories: vec![(RemotePath::new("PhotosRaw"), dr_sync::Validator::new("e1"))],
                progress: Default::default(),
                sidecars: Vec::new(),
            },
        )
        .unwrap();
        catalog
    }

    pub fn image_ids(catalog: &Catalog) -> Vec<dr_types::ImageId> {
        let mut stmt = catalog
            .connection()
            .prepare("SELECT id FROM images ORDER BY source_ref")
            .unwrap();
        stmt.query_map([], |r| Ok(dr_types::ImageId(r.get::<_, i64>(0)? as u64)))
            .unwrap()
            .map(Result::unwrap)
            .collect()
    }
}