1 files changed, 38 insertions, 0 deletions
diff --git a/src/payer.rs b/src/payer.rs
new file mode 100644
index 0000000..48cee52
--- /dev/null
+++ b/src/payer.rs
@@ -0,0 +1,38 @@
+use std::collections::HashMap;
+
+use crate::model::user::User;
+
+pub fn exceeding(
+    users: &Vec<User>,
+    user_incomes: &HashMap<i64, i64>,
+    user_payments: &HashMap<i64, i64>,
+) -> Vec<(String, i64)> {
+    let ratios = users.into_iter().map(|u| {
+        let income = *user_incomes.get(&u.id).unwrap_or(&0);
+        if income == 0 {
+            (u.name.clone(), 0, 0.0)
+        } else {
+            let payments = *user_payments.get(&u.id).unwrap_or(&0);
+            let ratio = payments as f64 / income as f64;
+            (u.name.clone(), income, ratio)
+        }
+    });
+    let min_ratio = ratios
+        .clone()
+        .map(|r| r.2)
+        .min_by(|r1, r2| {
+            ((r1 * 100_000_000.0).round() as i64)
+                .cmp(&((r2 * 100_000_000.0).round() as i64))
+        })
+        .unwrap_or(0.0);
+    ratios
+        .filter_map(|r| {
+            let exceeding = ((r.2 - min_ratio) * r.1 as f64).round() as i64;
+            if exceeding == 0 {
+                None
+            } else {
+                Some((r.0, exceeding))
+            }
+        })
+        .collect()
+}