first commit

build.rs

@@ -0,0 +1,93 @@
+use serde_json::{json, Value};
+use std::{env, fs, path::PathBuf};
+
+fn required_string<'a>(meta: &'a Value, key: &str, file: &str) -> &'a str {
+    meta.get(key)
+        .and_then(Value::as_str)
+        .filter(|value| !value.trim().is_empty())
+        .unwrap_or_else(|| panic!("{file}: meta.{key} must be a non-empty string"))
+}
+
+fn main() {
+    let manifest_dir = PathBuf::from(env::var("CARGO_MANIFEST_DIR").expect("CARGO_MANIFEST_DIR"));
+    let lang_dir = manifest_dir.join("lang");
+    println!("cargo:rerun-if-changed={}", lang_dir.display());
+
+    let mut files: Vec<PathBuf> = fs::read_dir(&lang_dir)
+        .unwrap_or_else(|error| panic!("cannot read {}: {error}", lang_dir.display()))
+        .filter_map(Result::ok)
+        .map(|entry| entry.path())
+        .filter(|path| path.extension().and_then(|ext| ext.to_str()) == Some("json"))
+        .collect();
+    files.sort();
+
+    if files.is_empty() {
+        panic!("no language files found in {}", lang_dir.display());
+    }
+
+    let mut assets = Vec::new();
+    let mut manifest_languages = Vec::new();
+    let mut has_english = false;
+
+    for path in files {
+        println!("cargo:rerun-if-changed={}", path.display());
+        let filename = path.file_name().and_then(|v| v.to_str()).expect("UTF-8 language filename");
+        let stem = path.file_stem().and_then(|v| v.to_str()).expect("UTF-8 language code");
+        if !stem.chars().all(|ch| ch.is_ascii_alphanumeric() || ch == '-' || ch == '_') {
+            panic!("{filename}: filename may only contain ASCII letters, digits, '-' and '_'");
+        }
+
+        let source = fs::read_to_string(&path)
+            .unwrap_or_else(|error| panic!("cannot read {}: {error}", path.display()));
+        let document: Value = serde_json::from_str(&source)
+            .unwrap_or_else(|error| panic!("{filename}: invalid JSON: {error}"));
+        let meta = document.get("meta").unwrap_or_else(|| panic!("{filename}: missing meta object"));
+        let code = required_string(meta, "code", filename);
+        let name = required_string(meta, "name", filename);
+        let native_name = required_string(meta, "native_name", filename);
+        let locale = required_string(meta, "locale", filename);
+        if code != stem {
+            panic!("{filename}: meta.code '{code}' must match filename '{stem}.json'");
+        }
+        if !document.get("translations").is_some_and(Value::is_object) {
+            panic!("{filename}: translations must be a JSON object");
+        }
+        if code == "en" {
+            has_english = true;
+        }
+
+        manifest_languages.push(json!({
+            "code": code,
+            "name": name,
+            "native_name": native_name,
+            "locale": locale,
+            "path": format!("/lang/{code}.json")
+        }));
+        assets.push((code.to_owned(), path));
+    }
+
+    if !has_english {
+        panic!("lang/en.json is required as the default fallback language");
+    }
+
+    let manifest_json = serde_json::to_string(&json!({
+        "default": "en",
+        "languages": manifest_languages
+    })).expect("serialize language manifest");
+
+    let mut generated = String::new();
+    generated.push_str("// @generated by build.rs - do not edit.\n");
+    generated.push_str(&format!("pub const LANGUAGE_MANIFEST_JSON: &str = {:?};\n", manifest_json));
+    generated.push_str("pub const LANGUAGE_ASSETS: &[(&str, &str)] = &[\n");
+    for (code, path) in assets {
+        generated.push_str(&format!(
+            "    ({:?}, include_str!({:?})),\n",
+            code,
+            path.to_string_lossy()
+        ));
+    }
+    generated.push_str("];\n");
+
+    let out_dir = PathBuf::from(env::var("OUT_DIR").expect("OUT_DIR"));
+    fs::write(out_dir.join("languages.rs"), generated).expect("write generated languages.rs");
+}