1 files changed, 185 insertions, 0 deletions
diff --git a/tools/tscn-to-bsn/src/cmd/cmd_build_uid_index.rs b/tools/tscn-to-bsn/src/cmd/cmd_build_uid_index.rs
new file mode 100644
index 0000000..e93392b
--- /dev/null
+++ b/tools/tscn-to-bsn/src/cmd/cmd_build_uid_index.rs
@@ -0,0 +1,185 @@
+use std::collections::BTreeMap;
+use std::io;
+use std::path::{Path, PathBuf};
+
+use mingling::macros::routeify;
+use mingling::{
+    Grouped,
+    macros::{buffer, command, pack_err, r_println, renderer},
+};
+
+use crate::{
+    Next,
+    gd_res_structure::{TscnValue, parse},
+    res::gd_proj_dir::ResGodotProjectDirectory,
+};
+
+pack_err!(ErrorGodotProjectNotFound);
+
+/// Build result
+#[derive(Grouped)]
+pub struct ResultCacheBuilt {
+    path: PathBuf,
+    len: usize,
+}
+
+#[command(node = "build-uid-index", routeify)]
+pub fn build_uid_index(proj: &ResGodotProjectDirectory) -> Next {
+    let Some(ref dir) = proj.dir else {
+        return ErrorGodotProjectNotFound::default().into();
+    };
+
+    // 1. Scan uid → res:// paths
+    let map = scan_project(dir)?;
+
+    // 2. Write .godot/tscn2bsn.uid-idx.json
+    let cache_path = dir.join(".godot").join("tscn2bsn.uid-idx.json");
+    if let Some(parent) = cache_path.parent() {
+        std::fs::create_dir_all(parent)?;
+    }
+    let json = serde_json::to_string_pretty(&map)?;
+    std::fs::write(&cache_path, json)?;
+
+    ResultCacheBuilt {
+        path: cache_path,
+        len: map.len(),
+    }
+    .into()
+}
+
+/// Recursively collect all files in the project, skipping `.godot` / `.git`
+fn collect_files(dir: &Path, out: &mut Vec<PathBuf>) -> io::Result<()> {
+    for entry in std::fs::read_dir(dir)? {
+        let entry = entry?;
+        let path = entry.path();
+        if path.is_dir() {
+            let name = entry.file_name().to_string_lossy().into_owned();
+            if name == ".godot" || name == ".git" {
+                continue;
+            }
+            collect_files(&path, out)?;
+        } else if path.is_file() {
+            out.push(path);
+        }
+    }
+    Ok(())
+}
+
+/// Project relative path → `res://` form (Godot's standard in-project path)
+fn to_res_path(project_dir: &Path, file: &Path) -> String {
+    let rel = file.strip_prefix(project_dir).unwrap_or(file);
+    let rel = rel.to_string_lossy().replace('\\', "/");
+    format!("res://{rel}")
+}
+
+/// Scan all uid sources, aggregate the mapping
+fn scan_project(project_dir: &Path) -> io::Result<BTreeMap<String, String>> {
+    let mut files = Vec::new();
+    collect_files(project_dir, &mut files)?;
+
+    let mut map = BTreeMap::new();
+    for file in files {
+        let ext = file
+            .extension()
+            .and_then(|e| e.to_str())
+            .unwrap_or("")
+            .to_lowercase();
+        match ext.as_str() {
+            // scenes/foo.glb.import → resource path res://scenes/foo.glb
+            "import" => {
+                if let Some(uid) = parse_import_uid(&file) {
+                    let res_path = to_res_path(project_dir, &file);
+                    insert_unique(
+                        &mut map,
+                        uid,
+                        res_path.trim_end_matches(".import").to_string(),
+                    );
+                }
+            }
+            "tscn" | "tres" => {
+                if let Some(uid) = parse_scene_uid(&file) {
+                    insert_unique(&mut map, uid, to_res_path(project_dir, &file));
+                }
+            }
+            // foo.gd.uid → resource path res://foo.gd
+            "uid" => {
+                if let Some(uid) = parse_sidecar_uid(&file) {
+                    let res_path = to_res_path(project_dir, &file);
+                    insert_unique(&mut map, uid, res_path.trim_end_matches(".uid").to_string());
+                }
+            }
+            _ => {}
+        }
+    }
+    Ok(map)
+}
+
+fn insert_unique(map: &mut BTreeMap<String, String>, uid: String, res_path: String) {
+    match map.entry(uid.clone()) {
+        std::collections::btree_map::Entry::Vacant(v) => {
+            v.insert(res_path);
+        }
+        std::collections::btree_map::Entry::Occupied(o) => {
+            eprintln!("Warning: duplicate uid {uid}: {} vs {res_path}", o.get());
+        }
+    }
+}
+
+/// `.import` file: `uid="uid://..."` in the `[remap]` section (writer: editor_file_system.cpp L2693)
+fn parse_import_uid(file: &Path) -> Option<String> {
+    let content = std::fs::read_to_string(file).ok()?;
+    let mut in_remap = false;
+    for line in content.lines() {
+        let line = line.trim();
+        if line.starts_with('[') {
+            in_remap = line == "[remap]";
+            continue;
+        }
+        if in_remap && let Some(v) = line.strip_prefix("uid=") {
+            let uid = v.trim().trim_matches('"');
+            if uid.starts_with("uid://") {
+                return Some(uid.to_string());
+            }
+        }
+    }
+    None
+}
+
+/// `.tscn` / `.tres`: reuse the tscn parser, extract the `uid` field from the header tag
+fn parse_scene_uid(file: &Path) -> Option<String> {
+    let content = std::fs::read_to_string(file).ok()?;
+    let doc = parse(&content).ok()?;
+    for (key, value) in &doc.header.fields {
+        if key == "uid"
+            && let TscnValue::Str(s) = value
+        {
+            return Some(s.clone());
+        }
+    }
+    None
+}
+
+/// `.uid` sidecar file: the first line is `uid://...` (writer: editor_file_system.cpp L939)
+fn parse_sidecar_uid(file: &Path) -> Option<String> {
+    let content = std::fs::read_to_string(file).ok()?;
+    let first = content.lines().next()?.trim();
+    if first.starts_with("uid://") {
+        Some(first.to_string())
+    } else {
+        None
+    }
+}
+
+#[renderer(buffer)]
+pub fn render_cache_built(r: ResultCacheBuilt) {
+    r_println!("OK: wrote {} ({} uids)", r.path.display(), r.len);
+}
+
+#[renderer(buffer)]
+pub fn render_error_godot_project_not_found(_: ErrorGodotProjectNotFound) {
+    r_println!("Error: Godot project not found. ");
+    r_println!("");
+    r_println!(
+        "Please specify the project directory with `/P` or run this command in the project directory!"
+    )
+}