From 921a9ff1bd17c991739a8d3b5b25e65235b49bf5 Mon Sep 17 00:00:00 2001
From: Federico Igne <git@federicoigne.com>
Date: Wed, 3 Nov 2021 18:45:47 +0000
Subject: [rust] Bowling

---
 rust/bowling/src/lib.rs | 45 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 45 insertions(+)
 create mode 100644 rust/bowling/src/lib.rs

(limited to 'rust/bowling/src/lib.rs')

diff --git a/rust/bowling/src/lib.rs b/rust/bowling/src/lib.rs
new file mode 100644
index 0000000..bd517a5
--- /dev/null
+++ b/rust/bowling/src/lib.rs
@@ -0,0 +1,45 @@
+#[derive(Debug, PartialEq)]
+pub enum Error {
+    NotEnoughPinsLeft,
+    GameComplete,
+}
+
+#[derive(Debug, Default)]
+pub struct BowlingGame {
+    throws: Vec<u16>,
+    prev: u16
+}
+
+impl BowlingGame {
+    pub fn new() -> Self {
+        Default::default()
+    }
+
+    pub fn roll(&mut self, pins: u16) -> Result<(), Error> {
+        if pins + self.prev > 10 {
+            Err(Error::NotEnoughPinsLeft)
+        } else if self.score().is_some() {
+            Err(Error::GameComplete)
+        } else {
+            self.throws.push(pins);
+            self.prev = if self.prev + pins == 10 { 0 } else { pins };
+            Ok(())
+        }
+    }
+
+    pub fn score(&self) -> Option<u16> {
+        let mut score = 0;
+        let mut stage = 0;
+        for _ in 1..=10 {
+            let first = self.throws.get(stage)?;
+            let second = self.throws.get(stage+1)?;
+            score += first + second;
+            if first + second >= 10 {
+                let third = self.throws.get(stage+2)?;
+                score += third;
+            }
+            stage += if *first == 10 { 1 } else { 2 };
+        }
+        Some(score)
+    }
+}
-- 
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