0.1.4

build.rs

@@ -1,3 +1,93 @@
+use std::env;
+use std::fs;
+use std::path::PathBuf;
+use std::time::Duration;
+
 fn main() {
+    let version = resolve_app_version();
+    println!("cargo:rustc-env=APP_VERSION={version}");
+
     slint_build::compile("ui/app.slint").expect("Slint build failed");
 }
+
+/// Window / package version shown as `Rcalc-{version}`.
+///
+/// On each `release` build the patch in `Cargo.toml` is incremented once
+/// (`0.1.0` → `0.1.1` → …). If Cargo restarts the build script right after we
+/// rewrite `Cargo.toml`, a short mtime guard prevents a double bump.
+fn resolve_app_version() -> String {
+    let manifest_dir = PathBuf::from(env::var("CARGO_MANIFEST_DIR").unwrap());
+    let pkg = env::var("CARGO_PKG_VERSION").unwrap_or_else(|_| "0.0.0".into());
+    let profile = env::var("PROFILE").unwrap_or_default();
+
+    if profile != "release" {
+        return pkg;
+    }
+
+    let cargo_toml = manifest_dir.join("Cargo.toml");
+    let guard_path = manifest_dir.join(".rcalc_last_bump");
+    let already = fs::read_to_string(&guard_path)
+        .map(|s| s.trim().to_string())
+        .unwrap_or_default();
+
+    // Cargo re-invoked us because we just rewrote Cargo.toml — keep version.
+    if already == pkg {
+        if let Ok(meta) = fs::metadata(&cargo_toml) {
+            if let Ok(modified) = meta.modified() {
+                if modified.elapsed().unwrap_or(Duration::MAX) < Duration::from_secs(15) {
+                    return pkg;
+                }
+            }
+        }
+    }
+
+    let Some(next) = bump_patch(&pkg) else {
+        return pkg;
+    };
+
+    if let Err(e) = set_cargo_toml_version(&cargo_toml, &next) {
+        println!("cargo:warning=could not bump Cargo.toml version: {e}");
+        return pkg;
+    }
+    let _ = fs::write(&guard_path, &next);
+    next
+}
+
+fn bump_patch(version: &str) -> Option<String> {
+    let mut parts: Vec<&str> = version.split('.').collect();
+    if parts.is_empty() {
+        return None;
+    }
+    while parts.len() < 3 {
+        parts.push("0");
+    }
+    let patch: u64 = parts[2]
+        .split(['-', '+'])
+        .next()?
+        .parse()
+        .ok()?;
+    Some(format!("{}.{}.{}", parts[0], parts[1], patch + 1))
+}
+
+fn set_cargo_toml_version(path: &PathBuf, version: &str) -> std::io::Result<()> {
+    let raw = fs::read_to_string(path)?;
+    let mut out = String::with_capacity(raw.len() + 8);
+    let mut replaced = false;
+    for line in raw.lines() {
+        if !replaced && line.starts_with("version") && line.contains('=') {
+            out.push_str(&format!("version = \"{version}\""));
+            out.push('\n');
+            replaced = true;
+        } else {
+            out.push_str(line);
+            out.push('\n');
+        }
+    }
+    if !replaced {
+        return Err(std::io::Error::new(
+            std::io::ErrorKind::InvalidData,
+            "version field not found in Cargo.toml",
+        ));
+    }
+    fs::write(path, out)
+}