split to separate fee file

src/model/user/fee.rs

@@ -0,0 +1,55 @@
+#[derive(Debug, Serialize)]
+pub struct Fee {
+    pub sum_in_cents: i32,
+    pub parts: Vec<(String, i32)>,
+    pub name: String,
+    pub user_ids: String,
+    pub paid: bool,
+    pub users: Vec<User>,
+}
+
+impl Default for Fee {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
+impl Fee {
+    pub fn new() -> Self {
+        Self {
+            sum_in_cents: 0,
+            name: "".into(),
+            parts: Vec::new(),
+            user_ids: "".into(),
+            users: Vec::new(),
+            paid: false,
+        }
+    }
+
+    pub fn add(&mut self, desc: String, price_in_cents: i32) {
+        self.sum_in_cents += price_in_cents;
+
+        self.parts.push((desc, price_in_cents));
+    }
+
+    pub fn add_person(&mut self, user: &User) {
+        if !self.name.is_empty() {
+            self.name.push_str(" + ");
+            self.user_ids.push('&');
+        }
+        self.name.push_str(&user.name);
+
+        self.user_ids.push_str(&format!("user_ids[]={}", user.id));
+        self.users.push(user.clone());
+    }
+
+    pub fn paid(&mut self) {
+        self.paid = true;
+    }
+
+    pub fn merge(&mut self, fee: Fee) {
+        for (desc, price_in_cents) in fee.parts {
+            self.add(desc, price_in_cents);
+        }
+    }
+}