From 15caee2d459c2b1f832ef710017e92ce83b93a3d Mon Sep 17 00:00:00 2001
From: Ridan Vandenbergh <ridanvandenbergh@gmail.com>
Date: Sat, 7 Jun 2025 02:08:20 +0200
Subject: [PATCH] Initial commit

---
 src/icon.rs       |  43 +++++++++++++++++++
 src/search_dir.rs | 103 ++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 146 insertions(+)
 create mode 100644 src/icon.rs
 create mode 100644 src/search_dir.rs

diff --git a/src/icon.rs b/src/icon.rs
new file mode 100644
index 0000000..efec134
--- /dev/null
+++ b/src/icon.rs
@@ -0,0 +1,43 @@
+use std::path::{Path, PathBuf};
+
+#[derive(Debug, Clone)]
+pub struct IconFile {
+    pub path: PathBuf,
+    pub file_type: FileType
+}
+
+impl IconFile {
+    pub fn from_path(path: &Path) -> Option<IconFile> {
+        let file_type = FileType::from_path_ext(path)?;
+
+        Some(IconFile {
+            path: path.to_owned(),
+            file_type,
+        })
+    }
+    
+}
+
+#[derive(Debug, Copy, Clone)]
+pub enum FileType {
+    Png,
+    Xmp,
+    Svg,
+}
+
+impl FileType {
+    pub fn from_path_ext(path: &Path) -> Option<Self> {
+        let ext = path.extension()?;
+        let ext = ext.to_str()?;
+
+        if ext.eq_ignore_ascii_case("png") {
+            Some(FileType::Png)
+        } else if ext.eq_ignore_ascii_case("xmp") {
+            Some(FileType::Xmp)
+        } else if ext.eq_ignore_ascii_case("svg") {
+            Some(FileType::Svg)
+        } else {
+            None
+        }
+    }
+}
\ No newline at end of file
diff --git a/src/search_dir.rs b/src/search_dir.rs
new file mode 100644
index 0000000..ee8d709
--- /dev/null
+++ b/src/search_dir.rs
@@ -0,0 +1,103 @@
+use std::path::{Path, PathBuf};
+use crate::icon::IconFile;
+
+#[derive(Debug, Clone)]
+pub struct SearchDirectories {
+    dirs: Vec<PathBuf>,
+}
+
+impl SearchDirectories {
+    pub fn default() -> Self {
+        <Self as Default>::default()
+    }
+
+    pub fn search_icons_and_theme_indexes(&self) -> (Vec<IconFile>, Vec<PathBuf>) {
+        fn theme_name_from_path(path: &Path) -> Option<&str> {
+            let theme_name = path.components()
+                .nth_back(1); // get the second-to-last component (which should be the theme name)
+
+            Some(theme_name?.as_os_str().to_str()?)
+        }
+
+        // "Each theme is stored as subdirectories of the base directories"
+
+        let (dirs, files) = self.dirs.iter()
+            .flat_map(|base_dir| base_dir.read_dir()) // read the entries in each base dir
+            .flat_map(std::convert::identity) // merge all the iterators
+            .flat_map(std::convert::identity) // remove Err entries
+            .filter_map(|entry| Some((entry.file_type().ok()?, entry))) // get file type for each entry and skip if fail
+            .partition::<Vec<_>, _>(|(ft, _)| ft.is_dir());
+
+        // icons at the top-level in a base_dir don't belong to a theme, but must still be able to be found!
+        let files = files.into_iter()
+            .flat_map(|(_, entry)| IconFile::from_path(&entry.path()))
+            .collect::<Vec<_>>();
+
+        // "In at least one of the theme directories there must be a file called
+        // index.theme that describes the theme. The first index.theme found while
+        // searching the base directories in order is used"
+
+        let mut indexes = dirs.into_iter()
+            .map(|(_, entry)| entry.path().join("index.theme"))
+            .filter(|path| path.exists()) // the index.theme file must exist
+            .collect::<Vec<_>>();
+
+        // only keep the first `index.theme` for each theme
+        indexes.dedup_by_key(|path| theme_name_from_path(&path).map(|s| s.to_string()));
+
+        (files, indexes)
+    }
+}
+
+impl<I, P> From<I> for SearchDirectories
+where
+    I: IntoIterator<Item = P>,
+    P: Into<PathBuf>,
+{
+    fn from(value: I) -> Self {
+        let dirs = value.into_iter().map(Into::into).collect();
+
+        SearchDirectories { dirs }
+    }
+}
+
+impl Default for SearchDirectories {
+    fn default() -> Self {
+        // "By default, apps should look in $HOME/.icons (for backwards compatibility),
+        // in $XDG_DATA_DIRS/icons
+        // and in /usr/share/pixmaps (in that order)."
+
+        let xdg = xdg::BaseDirectories::new();
+
+        let mut directories = vec![];
+
+        if let Some(home) = std::env::home_dir() {
+            directories.push(home.join(".icons"));
+        }
+
+        xdg.data_dirs
+            .into_iter()
+            .map(|data_dir| data_dir.join("icons"))
+            .for_each(|dir| directories.push(dir));
+
+        directories.push("/usr/share/pixmaps".into());
+
+        directories.into()
+    }
+}
+
+#[cfg(test)]
+mod test {
+    use crate::search_dir::SearchDirectories;
+
+    // these tests assume certain applications are installed on the system they are ran on.
+
+    #[test]
+    fn test_find_htop_icon() {
+        let dirs = SearchDirectories::default();
+
+        let (icons, _indexes) = dirs.search_icons_and_theme_indexes();
+
+        assert!(icons.iter().any(|i| i.path.file_name().and_then(|s| s.to_str()) == Some("htop.png")))
+    }
+}