[javascript] Implementing market data gathering and caching

nodejs/database/004_markets.sql

@@ -0,0 +1,7 @@
+CREATE TABLE markets (
+       id INTEGER PRIMARY KEY,
+       system TEXT NOT NULL,
+       data JSON NOT NULL
+);
+CREATE INDEX markets_system on markets (system);
+CREATE UNIQUE INDEX markets_symbol on markets(json_extract(data, '$.symbol'));

nodejs/database/db.js

@@ -6,6 +6,7 @@ const allMigrations = [
 	'database/001_systems.sql',
 	'database/002_ships.sql',
 	'database/003_surveys.sql',
+	'database/004_markets.sql',
 ];
 
 const db = new Database(

nodejs/database/markets.js

@@ -0,0 +1,34 @@
+import db from './db.js';
+import * as utils from '../lib/utils.js';
+
+const addMarketStatement = db.prepare(`INSERT INTO markets(system, data) VALUES (?, json(?));`);
+const getMarketAtWaypointStatement = db.prepare(`SELECT data FROM markets WHERE data->>'symbol' = ?;`);
+const getMarketsInSystemStatement = db.prepare(`SELECT data FROM markets WHERE system = ?;`);
+const updateMarketStatement = db.prepare(`UPDATE markets SET data = json(:data) WHERE data->>'symbol' = :symbol;`);
+
+export function getMarketAtWaypoint(symbol) {
+    const data = getMarketAtWaypointStatement.get(symbol);
+    if (data === undefined) {
+	return null;
+    }
+    return JSON.parse(data.data);
+}
+
+export function getMarketsInSystem(symbol) {
+    const data = getMarketsInSystemStatement.get(symbol);
+    if (data === undefined) {
+	return null;
+    }
+    return JSON.parse(data.data);
+}
+
+export function setMarket(data) {
+    if (getMarketAtWaypoint(data.symbol) === null) {
+	const system = utils.systemFromWaypoint(data.symbol);
+	return addMarketStatement.run(system, JSON.stringify(data)).lastInsertRowid;
+    }
+    return updateMarketStatement.run({
+	data: JSON.stringify(data),
+	symbol: data.symbol,
+    }).changes;
+}