From 1688b2acc286f98fed74eac26ec048005d10fd44 Mon Sep 17 00:00:00 2001
From: Kate Korsaro <kate.korsaro@gmail.com>
Date: Sun, 16 Nov 2025 09:30:22 +0100
Subject: [PATCH] feat: add method max to Outcome

---
 .../examples/roll_d20_with_advantage.rs       |  7 ++++
 01.workspace/oxidice_lib/src/imp/mod.rs       |  1 +
 .../oxidice_lib/src/imp/outcome_max.rs        | 41 +++++++++++++++++++
 01.workspace/oxidice_lib/src/str/failed_to.rs |  1 +
 4 files changed, 50 insertions(+)
 create mode 100644 01.workspace/oxidice_lib/examples/roll_d20_with_advantage.rs
 create mode 100644 01.workspace/oxidice_lib/src/imp/outcome_max.rs

diff --git a/01.workspace/oxidice_lib/examples/roll_d20_with_advantage.rs b/01.workspace/oxidice_lib/examples/roll_d20_with_advantage.rs
new file mode 100644
index 0000000..a519ef5
--- /dev/null
+++ b/01.workspace/oxidice_lib/examples/roll_d20_with_advantage.rs
@@ -0,0 +1,7 @@
+use oxidice_lib::dice::*;
+
+fn main() {
+    let roll_result = Handful::grab(2, 20).roll();
+    let result = roll_result.clone().max().unwrap();
+    println!("{} -> {}", roll_result, result);
+}
diff --git a/01.workspace/oxidice_lib/src/imp/mod.rs b/01.workspace/oxidice_lib/src/imp/mod.rs
index c75e913..99a175a 100644
--- a/01.workspace/oxidice_lib/src/imp/mod.rs
+++ b/01.workspace/oxidice_lib/src/imp/mod.rs
@@ -2,4 +2,5 @@ pub mod die_new;
 pub mod die_roll;
 pub mod handful_grab;
 pub mod handful_roll;
+pub mod outcome_max;
 pub mod outcome_sum;
diff --git a/01.workspace/oxidice_lib/src/imp/outcome_max.rs b/01.workspace/oxidice_lib/src/imp/outcome_max.rs
new file mode 100644
index 0000000..f1b2baa
--- /dev/null
+++ b/01.workspace/oxidice_lib/src/imp/outcome_max.rs
@@ -0,0 +1,41 @@
+use crate::*;
+
+fn max_of(values: Vec<u16>) -> Result<Outcome, FailedTo> {
+    if values.is_empty() {
+        return Err(FailedTo::ProcessInput);
+    }
+    let ret = Ok(Outcome::Scalar(u16::MAX));
+    ret.and_then(|_| {
+        values
+            .iter()
+            .max()
+            .ok_or(FailedTo::FindMin)
+            .map(|min| Outcome::Scalar(*min))
+    })
+}
+
+impl Outcome {
+    pub fn max(self) -> Result<Outcome, FailedTo> {
+        match self {
+            Outcome::Scalar(value) => Ok(Outcome::Scalar(value)),
+            Outcome::List(values) => max_of(values),
+        }
+    }
+}
+
+#[cfg(test)]
+mod unit_tests {
+    use super::*;
+    #[test]
+    fn check_max() {
+        let outcome = Handful::grab(2, 20).roll();
+        let max = outcome.clone().max().unwrap();
+        match outcome {
+            Outcome::List(values) => {
+                let expected_max = values.iter().max().unwrap();
+                assert_eq!(max, Outcome::Scalar(*expected_max));
+            }
+            _ => panic!("outcome is not a list"),
+        }
+    }
+}
diff --git a/01.workspace/oxidice_lib/src/str/failed_to.rs b/01.workspace/oxidice_lib/src/str/failed_to.rs
index a408565..5a10d3c 100644
--- a/01.workspace/oxidice_lib/src/str/failed_to.rs
+++ b/01.workspace/oxidice_lib/src/str/failed_to.rs
@@ -4,6 +4,7 @@
 
 #[derive(Debug, PartialEq, PartialOrd, Eq, Ord, Clone, Copy, Hash)]
 pub enum E {
+    FindMin,
     ProcessInput,
     SumValues,
 }