ledger.rs: Compile change events for account + symbol

2 files changed, 58 insertions, 0 deletions

diff --git a/src/app/store/ledger.rs b/src/app/store/ledger.rs
new file mode 100644
index 0000000..841f7b3
--- /dev/null
+++ b/src/app/store/ledger.rs
@@ -0,0 +1,56 @@
+use bigdecimal::{BigDecimal, Zero};
+use crate::app::store::records::{EquityChangeEvent, EquitySymbol, FiduciaryAccount, ROUNDING_MODE};
+
+/// An estimated ledger is the effective sum of all the equity change events
+/// derived from record for a particular fiduciary account and equity symbol.
+pub struct EstimatedLedger<'a> {
+    pub fiduciary_account: &'a FiduciaryAccount,
+    pub equity_symbol: &'a EquitySymbol,
+    pub equity_change_events: Vec<&'a EquityChangeEvent>,
+    pub account_symbol_quantity: BigDecimal,
+    pub account_symbol_cost_basis_price: BigDecimal,
+    pub account_symbol_cost_basis_total_usd: BigDecimal,
+    pub account_symbol_last_effective_price: BigDecimal,
+    pub account_symbol_last_update_timestamp: chrono::DateTime<chrono::Utc>,
+}
+
+impl EstimatedLedger<'_> {
+
+    /// Takes a list of all change events, a fiduciary account, and an equity
+    /// symbol for which to create a ledger.
+    /// 
+    /// All values are taken by reference, so they need to be maintained elsewhere
+    pub fn compile_change_events<'a>(fiduciary_account: &'a FiduciaryAccount, equity_symbol: &'a EquitySymbol, events: Vec<&'a EquityChangeEvent>) -> EstimatedLedger<'a> {
+        let mut acsym_events = vec![];
+        let mut quantity = BigDecimal::zero();
+        let mut cost_basis_total = BigDecimal::zero();
+        let mut last_event: Option<&EquityChangeEvent> = None;
+
+        for event in events {
+            if event.fiduciary_account_id != fiduciary_account.fiduciary_account_id || event.equity_symbol_id != equity_symbol.equity_symbol_id {
+                continue;
+            }
+
+            if last_event.is_none() || last_event.unwrap().equity_change_timestamp < event.equity_change_timestamp {
+                last_event = Some(event);
+            }
+
+            quantity += event.scored_quantity();
+            cost_basis_total += event.scored_cost_basis();
+
+            acsym_events.push(event);
+        }
+
+        EstimatedLedger {
+            fiduciary_account,
+            equity_symbol,
+            equity_change_events: acsym_events,
+            account_symbol_quantity: quantity.clone(),
+            account_symbol_cost_basis_price: (cost_basis_total.clone() / quantity).with_scale_round(2, ROUNDING_MODE),
+            account_symbol_cost_basis_total_usd: cost_basis_total.with_scale_round(2, ROUNDING_MODE),
+            account_symbol_last_effective_price: last_event.map_or_else(|| BigDecimal::zero().with_scale(2), |ev| ev.estimated_price()),
+            account_symbol_last_update_timestamp: last_event.map_or_else(|| chrono::DateTime::<chrono::Utc>::MIN_UTC, |ev| ev.equity_change_timestamp),
+        }
+    }
+
+}
\ No newline at end of file
diff --git a/src/app/store/mod.rs b/src/app/store/mod.rs
index d038167..da01fba 100644
--- a/src/app/store/mod.rs
+++ b/src/app/store/mod.rs
@@ -1,4 +1,6 @@
 mod sqlite;
+mod records;
+mod ledger;
 
 use sqlite::{SQLiteStore};
 use miette::{Diagnostic, Result};