guise-ui 1.5.2

//! Extension filtering shared by [`FileInput`](super::FileInput) and
//! [`Dropzone`](super::Dropzone). Pure logic.

use std::path::{Path, PathBuf};

/// Normalize an accept entry: strip a leading dot, lowercase ("`.PNG`" → "png").
pub(crate) fn normalize_ext(entry: &str) -> String {
  entry.trim().trim_start_matches('.').to_ascii_lowercase()
}

/// Whether `path` passes the accept list. An empty list accepts everything;
/// extensions compare case-insensitively; extension-less paths only pass an
/// empty list.
pub(crate) fn path_accepted(path: &Path, accept: &[String]) -> bool {
  if accept.is_empty() {
    return true;
  }
  path
    .extension()
    .and_then(|e| e.to_str())
    .is_some_and(|ext| {
      let ext = ext.to_ascii_lowercase();
      accept.contains(&ext)
    })
}

/// Keep only the paths passing the accept list.
pub(crate) fn filter_paths(paths: Vec<PathBuf>, accept: &[String]) -> Vec<PathBuf> {
  paths
    .into_iter()
    .filter(|p| path_accepted(p, accept))
    .collect()
}

#[cfg(test)]
mod tests {
  use super::*;

  fn accept(entries: &[&str]) -> Vec<String> {
    entries.iter().map(|e| normalize_ext(e)).collect()
  }

  #[test]
  fn normalizes_entries() {
    assert_eq!(normalize_ext(".PNG"), "png");
    assert_eq!(normalize_ext("jpg"), "jpg");
    assert_eq!(normalize_ext(" .Tar "), "tar");
  }

  #[test]
  fn empty_list_accepts_everything() {
    assert!(path_accepted(Path::new("a.png"), &[]));
    assert!(path_accepted(Path::new("no_extension"), &[]));
  }

  #[test]
  fn filters_by_extension_case_insensitively() {
    let list = accept(&[".png", "JPG"]);
    assert!(path_accepted(Path::new("photo.PNG"), &list));
    assert!(path_accepted(Path::new("photo.jpg"), &list));
    assert!(!path_accepted(Path::new("notes.txt"), &list));
    assert!(!path_accepted(Path::new("archive"), &list));
  }

  #[test]
  fn filter_paths_keeps_matches_in_order() {
    let list = accept(&["rs"]);
    let paths = vec![
      PathBuf::from("a.rs"),
      PathBuf::from("b.txt"),
      PathBuf::from("c.rs"),
    ];
    assert_eq!(
      filter_paths(paths, &list),
      vec![PathBuf::from("a.rs"), PathBuf::from("c.rs")]
    );
  }
}