complete oop style api up to what Book has to offer

Came accross the lifetime issue again when `Book::running_balance` returns
`Transaction<'a>` where `'a` is of the book. This too does not cross the
`std::cell::Ref<'_, T>` boundry. However, there is a way to get to the underlying
lifetime through an unstable feature 'cell_leak'

see rust-lang/rust#69099

This allows the borrow checker to life-check!

src/accounting.rs

@@ -65,12 +65,7 @@ pub struct Transaction<'a> {
 }
 
 impl<'a> Transaction<'a> {
-    pub fn new(
-        datetime: DateTime<Utc>,
-        from: &'a Account,
-        to: &'a Account,
-        money: Money,
-    ) -> Self {
+    pub fn new(datetime: DateTime<Utc>, from: &'a Account, to: &'a Account, money: Money) -> Self {
         Transaction {
             datetime,
             from,

src/lib.rs

@@ -1,8 +1,10 @@
+#![feature(cell_leak)]
 pub mod accounting;
 pub mod book;
 pub mod monetary;
 
 use accounting::*;
+use std::cell::Ref;
 use std::cell::RefCell;
 use std::rc::Rc;
 
@@ -15,7 +17,9 @@ pub struct BookHandle<'a> {
 
 impl<'a> BookHandle<'a> {
     pub fn new() -> Self {
-        Self { book: Rc::new(RefCell::new(Book::new())) }
+        Self {
+            book: Rc::new(RefCell::new(Book::new())),
+        }
     }
 
     pub fn new_account(&'a self, name: &'a str) -> AccountHandle<'a> {
@@ -27,7 +31,7 @@ impl<'a> BookHandle<'a> {
             .borrow()
             .accounts()
             .into_iter()
-            .map(|account| AccountHandle::new(account,self.book.clone()))
+            .map(|account| AccountHandle::new(account, self.book.clone()))
             .collect()
     }
 }
@@ -39,24 +43,53 @@ pub struct AccountHandle<'a> {
 }
 
 impl<'a> AccountHandle<'a> {
-    fn new(account: Rc<Account>, book: Rc<RefCell<Book<'a>>>) -> Self /* AcconutHandle<'a> */ {
-        AccountHandle { account, book }
+    fn new(account: Rc<Account>, book: Rc<RefCell<Book<'a>>>) -> Self {
+        Self { account, book }
     }
 
-    pub fn transfer(
+    pub fn transfer(&'a self, to: &'a AccountHandle<'a>, money: Money) -> TransactionHandle<'a> {
+        TransactionHandle::new(
+            self.book
+                .borrow_mut()
+                .transfer(&self.account, &to.account, money),
+            self.book.clone(),
+        )
+    }
+
+    pub fn transfer_at(
         &'a self,
+        datetime: DateTime<Utc>,
         to: &'a AccountHandle<'a>,
         money: Money,
     ) -> TransactionHandle<'a> {
         TransactionHandle::new(
-            self.book.borrow_mut().transfer(&self.account, &to.account, money),
+            self.book
+                .borrow_mut()
+                .transfer_at(datetime, &self.account, &to.account, money),
             self.book.clone(),
         )
     }
 
     pub fn balance(&self) -> Money {
         self.book.borrow().balance(&self.account)
     }
+
+    pub fn balance_at(&self, datetime: DateTime<Utc>) -> Money {
+        self.book.borrow().balance_at(datetime, &self.account)
+    }
+
+    pub fn running_balance(&'a self) -> Vec<(TransactionHandle<'a>, Money)> {
+        Ref::leak(self.book.borrow())
+            .running_balance(&self.account)
+            .into_iter()
+            .map(|(transaction, money)| {
+                (
+                    TransactionHandle::new(transaction, self.book.clone()),
+                    money,
+                )
+            })
+            .collect()
+    }
 }
 
 pub struct TransactionHandle<'a> {
@@ -68,4 +101,8 @@ impl<'a> TransactionHandle<'a> {
     fn new(transaction: Rc<Transaction<'a>>, book: Rc<RefCell<Book<'a>>>) -> Self {
         Self { transaction, book }
     }
+
+    pub fn datetime(&self) -> DateTime<Utc> {
+        self.transaction.datetime()
+    }
 }

tests/book_handle.rs

@@ -40,7 +40,7 @@ fn transfer_between_two_accounts() {
     assert_eq!(bank.balance().get(&thb).unwrap(), -40000);
     assert_eq!(wallet.balance().get(&thb).unwrap(), 40000);
 }
-/*
+
 #[test]
 fn balance_at_dates() {
     let mut book = BookHandle::new();
@@ -91,5 +91,3 @@ fn running_balance() {
         vec![2000, 1600, 1300, 1100, 900, 800]
     );
 }
-
-*/