One test fails :(

resources/migrations/sql/create_tables_001.sql

@@ -2,7 +2,6 @@ PRAGMA journal_mode= WAL;
 
 CREATE TABLE IF NOT EXISTS ledger_internal
 (
-    -- th
     id            INTEGER PRIMARY KEY AUTOINCREMENT,
     creation_time DATETIME DEFAULT CURRENT_TIMESTAMP,
     cookie_secret TEXT NOT NULL
@@ -38,6 +37,20 @@ CREATE TABLE IF NOT EXISTS securities
     FOREIGN KEY (security_type) REFERENCES security_types (name)
 );
 
+CREATE TABLE IF NOT EXISTS interest_rates
+(
+    id INTEGER PRIMARY KEY AUTOINCREMENT,
+    security_id INTEGER NOT NULL,
+    security_rate_id INTEGER NOT NULL,
+    start_date DATETIME NOT NULL,
+    end_date DATETIME,
+    rate REAL NOT NULL,
+    FOREIGN KEY (security_id) REFERENCES securities(id),
+    CONSTRAINT unique_security_rate_id UNIQUE (security_id, security_rate_id),
+    CHECK (end_date IS NULL OR start_date <= end_date),
+    CHECK ( rate >= 0 )
+);
+
 CREATE TABLE IF NOT EXISTS account_types
 (
     name TEXT PRIMARY KEY
@@ -60,7 +73,9 @@ CREATE TABLE IF NOT EXISTS accounts
     creation_time DATETIME DEFAULT CURRENT_TIMESTAMP,
 
     FOREIGN KEY (security) REFERENCES securities (id),
-    FOREIGN KEY (account_type) REFERENCES account_types (name)
+    FOREIGN KEY (account_type) REFERENCES account_types (name),
+    CHECK (amount >= 0 OR (account_type = 'security_emitter'))
+
 );
 
 CREATE TABLE IF NOT EXISTS accounts_history

src/db/_accounts.rs

@@ -373,6 +373,13 @@ fn update_account_history(tx: &Connection, account_id: &AccountId) -> CustomResu
     Ok(())
 }
 
+/// Super low level functions that needs to be wrapped in something else.
+///
+/// This method does NOT guarantee that all amount added into an account
+/// comes from another account.
+///
+/// This method does NOT guarantee that checking account cannot go in the
+/// negative.
 pub fn add_to_account(
     tx: &Connection,
     account_id: &AccountId,
@@ -411,6 +418,10 @@ pub fn get_number_of_accounts(tx: &Connection,
     tx.query_row(q, params, |row| row.get("count")).map_err(Error::SqlError)
 }
 
+/// Market cap is computer by summing the security emitter accounts.
+/// We use this technique because the sum of the security
+/// emitter accounts MUST equals (more or less very tiny interest
+/// amounts) the sum of the checking accounts.
 pub fn get_security_market_cap(tx: &Connection,
                                sec: &SecurityId) -> CustomResult<i64> {
     let q = "

src/db/_interests.rs

@@ -1 +1,30 @@
 
+const _one_massive_fucking_query : &str = "
+WITH RECURSIVE
+    effective_interest_rates
+        AS (SELECT ROW_NUMBER() OVER ()                                  AS id,
+                   interest_rates.id                                     AS shit_id,
+                   max(13, start_date)                                   AS start_date,
+                   min(coalesce(end_date, 20), 20)                       AS end_date,
+                   min(coalesce(end_date, 20), 20) - max(13, start_date) AS duration,
+                   interest_rate
+            FROM interest_rates
+            WHERE ((start_date >= 13) AND NOT (start_date > 20))
+               OR ((start_date < 13) AND (end_date > 13 OR end_date IS NULL))
+            ORDER BY start_date ASC),
+    compound_value(compound_value_id, value, interest_rate, duration)
+        AS (SELECT 0, 100, 0, 0 -- the 100 is the initial value
+            UNION
+            SELECT compound_value.compound_value_id + 1,
+                   compound_value.value *
+                   pow(1 + effective_interest_rates.interest_rate, effective_interest_rates.duration),
+                   effective_interest_rates.interest_rate,
+                   effective_interest_rates.duration
+            FROM effective_interest_rates
+                     JOIN compound_value ON compound_value.compound_value_id + 1 = effective_interest_rates.id)
+SELECT value
+FROM compound_value
+ORDER BY compound_value_id DESC
+LIMIT 1
+";
+

src/db/_securities.rs

@@ -1,4 +1,4 @@
-use rusqlite::{params, Connection, Result, Row, ToSql, Transaction, OptionalExtension};
+use rusqlite::{params, Connection, OptionalExtension, Result, Row, ToSql, Transaction};
 use serde::Serialize;
 
 use crate::db::_external_id::{Id, SecurityId};
@@ -104,15 +104,93 @@ pub struct NewSecurity {
     pub name: String,
 }
 
+struct InterestRate {
+    rate: f64,
+    start_date: i64,
+    end_date: Option<i64>,
+}
+
+impl InterestRate {
+    pub fn from_row(row: &Row) -> Result<InterestRate> {
+        Ok(InterestRate {
+            rate: row.get("rate")?,
+            start_date: row.get("start_date")?,
+            end_date: row.get("end_date")?,
+        })
+    }
+}
+
+fn set_initial_interest_rate(tx: &Connection, sec_id: &SecurityId) -> CustomResult<()> {
+    let q = "
+        INSERT INTO interest_rates(
+            security_id,
+            security_rate_id,
+            start_date,
+            end_date,
+            rate
+        )
+        SELECT id, 0, CURRENT_TIMESTAMP, NULL, 1.0
+        FROM securities
+        WHERE id = ?1 AND securities.security_type = ?2
+    ";
+    tx.execute(q, params![sec_id, SecurityType::Currency]).map_err(Error::SqlError)?;
+    Ok(())
+}
+
+fn set_interest_rate(tx: &Connection, sec_id: &SecurityId, rate: f64) -> CustomResult<()> {
+    let q = "
+        INSERT INTO interest_rates(
+            security_id,
+            security_rate_id,
+            start_date,
+            end_date,
+            rate
+        )
+        SELECT ?1 AS security_id,
+               MAX(interest_rates.security_rate_id) + 1 AS security_rate_id,
+               CURRENT_TIMESTAMP AS start_date,
+               NULL AS end_date,
+               ?2 AS rate
+               FROM interest_rates JOIN securities ON interest_rates.security_id = securities.id
+        WHERE interest_rates.security_id = ?1
+              AND securities.security_type = ?3
+    ";
+    tx.execute(q, params![sec_id, rate, SecurityType::Currency])
+        .map_err(Error::SqlError)?;
+    Ok(())
+}
+
+fn get_rates(tx: &Connection, sec_id: &SecurityId) -> CustomResult<Vec<InterestRate>> {
+    let q = "
+    SELECT rate,
+           UNIXEPOCH(start_date) AS start_date,
+           UNIXEPOCH(end_date) AS end_date
+    FROM interest_rates
+    WHERE security_id = ?1
+    ORDER BY security_rate_id ASC";
+    let mut stmt = tx.prepare(q).map_err(Error::SqlError)?;
+    let ret: Vec<InterestRate> = stmt
+        .query_map(params![sec_id], InterestRate::from_row)
+        .map_err(Error::SqlError)?
+        .filter(Result::is_ok)
+        .map(Result::unwrap)
+        .collect();
+    return Ok(ret);
+}
+
 pub fn create_security(tx: &Connection, sec: &NewSecurity) -> CustomResult<Security> {
     let q = "INSERT INTO
                      securities(name, symbol, security_type)
                    VALUES(?1, ?2, ?3)";
     let params = (&sec.name, &sec.symbol, &sec.security_type);
     tx.execute(q, params).map_err(Error::SqlError)?;
-    let new_sec_id:i64  = tx.last_insert_rowid();
+    let new_sec_id = &SecurityId::from_id(tx.last_insert_rowid());
 
-    let ret = get_security_by_id(tx, &SecurityId::from_id(new_sec_id))?;
+    if sec.security_type == SecurityType::Currency {
+        set_initial_interest_rate(tx, new_sec_id)?;
+    }
+
+    let ret = get_security_by_id(tx, new_sec_id)?;
     Ok(ret.unwrap())
 }
 
@@ -126,7 +204,6 @@ pub fn get_security_by_id(tx: &Connection, id: & SecurityId) -> CustomResult<Opt
     tx.query_row(q, params![id], Security::from_row)
         .optional()
         .map_err(Error::SqlError)
-
 }
 
 pub fn list_securities(conn: &Connection) -> CustomResult<Vec<Security>> {
@@ -184,14 +261,39 @@ mod test_securities {
     }
 
     #[test]
-    fn test_create_security() -> CustomResult<()> {
+    fn test_create_security_currency() -> CustomResult<()> {
         let (mut conn, _users) = setup();
         let new_sec = mock_currency_1();
-        let tx = conn.transaction().unwrap();
-        let sec = create_security(&tx, &new_sec)?;
+        let sec = create_security(&conn, &new_sec)?;
         assert_eq!(sec.symbol, new_sec.symbol);
+        assert_eq!(sec.security_type, SecurityType::Currency);
 
-        tx.commit().unwrap();
+        let interest_rate = get_rates(&conn, &sec.id())?;
+        assert_eq!(interest_rate.len(), 1);
+
+        Ok(())
+    }
+
+    #[test]
+    fn test_create_security_bond() -> CustomResult<()> {
+        let (mut conn, _users) = setup();
+        let new_sec = mock_currency_2();
+        let sec = create_security(&conn, &new_sec)?;
+        assert_eq!(sec.symbol, new_sec.symbol);
+        assert_eq!(sec.security_type, SecurityType::Bond);
+        let interest_rate = get_rates(&conn, &sec.id())?;
+        assert_eq!(interest_rate.len(), 0);
+        Ok(())
+    }
+
+    #[test]
+    fn test_set_interest_rate() -> CustomResult<()> {
+        let (mut conn, _users) = setup();
+        let new_sec = mock_currency_1();
+        let sec = &create_security(&conn, &new_sec)?.id();
+        set_interest_rate(&conn, sec, 90.00)?;
+        let interest_rate = get_rates(&conn, sec)?;
+        assert_eq!(interest_rate.len(), 2);
         Ok(())
     }
 

src/services/_transactions.rs

@@ -459,6 +459,7 @@ mod test_caching_cheques {
         let ret = cash_cheque(&mut tx, &cheque, &payee_account);
         match ret {
             Err(Error::InvalidAmount(_)) => Ok(()),
+            Err(x) => Err(Error::Testing(format!("{:?}", x))),
             _ => Err(Error::Testing(
                 "Expected invalid amount error here.".to_string(),
             )),