From 96a449476838cd1fdfcc8c93863a16722eff58d0 Mon Sep 17 00:00:00 2001
From: "Arthur G.P. Schuster" <arthur@apuhapu.at>
Date: Sat, 9 Aug 2025 20:55:57 +0200
Subject: [PATCH] add support for durations and timestamps

---
 index.html |  12 ++++++
 src/lib.rs | 109 ++++++++++++++++++++++++++++++++++++++++++++++++++++-
 2 files changed, 119 insertions(+), 2 deletions(-)

diff --git a/index.html b/index.html
index 49da250..1fec599 100644
--- a/index.html
+++ b/index.html
@@ -199,6 +199,18 @@ name + " is " + string(age) + " years old and " + (active ? "active" : "inactive
           true}}}</code
         >
       </div>
+
+      <div class="example" onclick="loadExample(this)">
+        <h4>Time and Date Operations</h4>
+        <code
+          data-expression="some_date < now - old ? 'old' : 'recent'"
+          data-context='{"some_date": "2023-10-01T12:00:00Z", "now": "2023-10-03T12:00:00Z", "old": "24h"}'
+          >Expression: some_date < now - old ? 'old' : 'recent'</code
+        >
+        <code
+          >Context: {"some_date": "2023-10-01T12:00:00Z", "now":
+          "2023-10-03T12:00:00Z", "old": "24h"}</code
+        >
     </div>
 
     <script type="module">
diff --git a/src/lib.rs b/src/lib.rs
index 1dc3d55..433f18c 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1,4 +1,5 @@
 use cel::{Context, Program, Value};
+use chrono::Duration as ChronoDuration;
 use js_sys;
 use serde::Serialize;
 use std::collections::HashMap;
@@ -20,6 +21,59 @@ macro_rules! console_log {
     ($($t:tt)*) => (log(&format_args!($($t)*).to_string()))
 }
 
+/// Parse an ISO 8601 timestamp string into a CEL Timestamp
+fn parse_timestamp(timestamp_str: &str) -> Result<Value, String> {
+    Ok(Value::Timestamp(
+        timestamp_str
+            .parse()
+            .map_err(|e| format!("Invalid timestamp format: {}", e))?,
+    ))
+}
+
+/// Parse a duration string (e.g., "1h30m", "45s", "2.5h") into a CEL Duration
+fn parse_duration(duration_str: &str) -> Result<Value, String> {
+    // Parse duration strings like "1h30m45s", "2.5h", "300s", etc.
+    let duration_str = duration_str.trim();
+
+    // Simple parser for common duration formats
+    let mut total_seconds = 0.0;
+    let mut current_number = String::new();
+
+    for ch in duration_str.chars() {
+        if ch.is_numeric() || ch == '.' {
+            current_number.push(ch);
+        } else {
+            if !current_number.is_empty() {
+                let value: f64 = current_number
+                    .parse()
+                    .map_err(|_| format!("Invalid number in duration: {}", current_number))?;
+
+                let multiplier = match ch {
+                    's' => 1.0,
+                    'm' => 60.0,
+                    'h' => 3600.0,
+                    'd' => 86400.0,
+                    _ => return Err(format!("Unknown duration unit: {}", ch)),
+                };
+
+                total_seconds += value * multiplier;
+                current_number.clear();
+            }
+        }
+    }
+
+    // Handle case where string ends with a number (assume seconds)
+    if !current_number.is_empty() {
+        let value: f64 = current_number
+            .parse()
+            .map_err(|_| format!("Invalid number in duration: {}", current_number))?;
+        total_seconds += value;
+    }
+
+    let duration = ChronoDuration::seconds(total_seconds as i64);
+    Ok(Value::Duration(duration))
+}
+
 /// Convert a JavaScript value to a CEL Value recursively
 fn js_value_to_cel_value(js_val: &JsValue) -> Result<Value, String> {
     if js_val.is_null() || js_val.is_undefined() {
@@ -34,7 +88,26 @@ fn js_value_to_cel_value(js_val: &JsValue) -> Result<Value, String> {
             Ok(Value::Float(n))
         }
     } else if let Some(s) = js_val.as_string() {
-        Ok(Value::String(s.into()))
+        // Check if this string represents a timestamp or duration
+        if s.contains('T') && (s.contains('Z') || s.contains('+') || s.contains('-')) {
+            // Looks like an ISO 8601 timestamp
+            match parse_timestamp(&s) {
+                Ok(ts) => Ok(ts),
+                Err(_) => Ok(Value::String(s.into())), // Fall back to string if parsing fails
+            }
+        } else if s
+            .chars()
+            .any(|c| c == 'h' || c == 'm' || c == 's' || c == 'd')
+            && s.chars().any(|c| c.is_numeric())
+        {
+            // Looks like a duration string
+            match parse_duration(&s) {
+                Ok(dur) => Ok(dur),
+                Err(_) => Ok(Value::String(s.into())), // Fall back to string if parsing fails
+            }
+        } else {
+            Ok(Value::String(s.into()))
+        }
     } else if js_val.is_array() {
         // Handle arrays
         let array = js_sys::Array::from(js_val);
@@ -70,7 +143,6 @@ fn js_value_to_cel_value(js_val: &JsValue) -> Result<Value, String> {
     }
 }
 
-// Simple wrapper to make Value serializable for JS conversion
 #[derive(Serialize)]
 #[serde(untagged)]
 enum SerializableValue {
@@ -81,6 +153,8 @@ enum SerializableValue {
     String(String),
     List(Vec<SerializableValue>),
     Map(HashMap<String, SerializableValue>),
+    Timestamp(String), // Serialize timestamps as ISO strings
+    Duration(String),  // Serialize durations as strings like "1h30m45s"
     Other(String),
 }
 
@@ -101,6 +175,37 @@ fn cel_value_to_serializable(cel_val: &Value) -> SerializableValue {
                 .map(|(k, v)| (k.to_string(), cel_value_to_serializable(v)))
                 .collect(),
         ),
+        Value::Timestamp(ts) => SerializableValue::Timestamp(ts.to_string()),
+        Value::Duration(dur) => {
+            // Convert duration back to a readable string format
+            let total_seconds = dur.as_seconds_f64();
+            let hours = (total_seconds / 3600.0).floor() as u64;
+            let minutes = ((total_seconds % 3600.0) / 60.0).floor() as u64;
+            let seconds = total_seconds % 60.0;
+
+            if hours > 0 {
+                if seconds.fract() == 0.0 {
+                    SerializableValue::Duration(format!(
+                        "{}h{}m{}s",
+                        hours, minutes, seconds as u64
+                    ))
+                } else {
+                    SerializableValue::Duration(format!("{}h{}m{:.3}s", hours, minutes, seconds))
+                }
+            } else if minutes > 0 {
+                if seconds.fract() == 0.0 {
+                    SerializableValue::Duration(format!("{}m{}s", minutes, seconds as u64))
+                } else {
+                    SerializableValue::Duration(format!("{}m{:.3}s", minutes, seconds))
+                }
+            } else {
+                if seconds.fract() == 0.0 {
+                    SerializableValue::Duration(format!("{}s", seconds as u64))
+                } else {
+                    SerializableValue::Duration(format!("{:.3}s", seconds))
+                }
+            }
+        }
         _ => SerializableValue::Other(format!("{:?}", cel_val)),
     }
 }