Add initial llm-bridge project

build.rs

@@ -0,0 +1,44 @@
+//! Build stamp: lets `llm-gateway --version` tell you when the binary was built.
+//!
+//! Without it, a stale release binary looks exactly like a fresh one, which has
+//! already caused a confusing "unknown argument" report.
+
+use std::time::{SystemTime, UNIX_EPOCH};
+
+fn main() {
+    let seconds = SystemTime::now()
+        .duration_since(UNIX_EPOCH)
+        .map(|elapsed| elapsed.as_secs())
+        .unwrap_or(0);
+    println!(
+        "cargo:rustc-env=LLM_GATEWAY_BUILD_TIME={}",
+        format_utc(seconds)
+    );
+}
+
+/// `YYYY-MM-DDTHH:MM:SSZ`, without pulling a date crate into the build script.
+fn format_utc(seconds: u64) -> String {
+    let days = (seconds / 86_400) as i64;
+    let rem = seconds % 86_400;
+
+    // Howard Hinnant's civil-from-days algorithm.
+    let z = days + 719_468;
+    let era = if z >= 0 { z } else { z - 146_096 } / 146_097;
+    let doe = z - era * 146_097;
+    let yoe = (doe - doe / 1460 + doe / 36_524 - doe / 146_096) / 365;
+    let mut year = yoe + era * 400;
+    let doy = doe - (365 * yoe + yoe / 4 - yoe / 100);
+    let mp = (5 * doy + 2) / 153;
+    let day = doy - (153 * mp + 2) / 5 + 1;
+    let month = if mp < 10 { mp + 3 } else { mp - 9 };
+    if month <= 2 {
+        year += 1;
+    }
+
+    format!(
+        "{year:04}-{month:02}-{day:02}T{:02}:{:02}:{:02}Z",
+        rem / 3600,
+        (rem % 3600) / 60,
+        rem % 60
+    )
+}