feat: scaffold frontend app structure

backend/src/db.ts

@@ -1,5 +1,6 @@
-import { Pool, PoolConfig } from "pg";
+import { Pool, PoolConfig, QueryResult, QueryResultRow } from "pg";
 import { config } from "./config";
+import type { RaceRow } from "./mappers/race";
 
 const poolConfig: PoolConfig = {
   host: config.db.host,
@@ -12,13 +13,119 @@ const poolConfig: PoolConfig = {
   connectionTimeoutMillis: 5_000,
 };
 
-export const pool = new Pool(poolConfig);
+function mockRowFromInsert(sql: string, params: unknown[]): RaceRow {
+  const match = sql.match(/INSERT INTO races\s*\(([^)]+)\)\s*VALUES/i);
+  const now = new Date().toISOString();
+  if (!match) {
+    return {
+      id: String(params[0] ?? ""),
+      race_date: "",
+      title: "",
+      distance_km: "0",
+      status: null,
+      official_url: null,
+      start_time: null,
+      cluster_schedule: null,
+      bib_pickup: null,
+      bib_number: null,
+      finish_time: null,
+      notes: null,
+      created_at: now,
+      updated_at: null,
+    };
+  }
+  const cols = match[1].split(",").map((c) => c.trim());
+  const row: Record<string, unknown> = {};
+  cols.forEach((col, i) => {
+    row[col] = params[i];
+  });
+  return {
+    id: String(row.id ?? ""),
+    race_date: String(row.race_date ?? ""),
+    title: String(row.title ?? ""),
+    distance_km: String(row.distance_km ?? "0"),
+    status: row.status != null ? String(row.status) : null,
+    official_url: row.official_url != null ? String(row.official_url) : null,
+    start_time: row.start_time != null ? String(row.start_time) : null,
+    cluster_schedule: row.cluster_schedule != null ? String(row.cluster_schedule) : null,
+    bib_pickup: row.bib_pickup != null ? String(row.bib_pickup) : null,
+    bib_number: row.bib_number != null ? String(row.bib_number) : null,
+    finish_time: row.finish_time != null ? String(row.finish_time) : null,
+    notes: row.notes != null ? String(row.notes) : null,
+    created_at: now,
+    updated_at: null,
+  };
+}
 
-pool.on("error", (err) => {
-  console.error("[db] Unexpected pool error:", err.message);
-});
+function createMockPool(): Pool {
+  const emptyResult = <T extends QueryResultRow>(): QueryResult<T> =>
+    ({
+      rows: [],
+      rowCount: 0,
+      command: "",
+      oid: 0,
+      fields: [],
+    }) as QueryResult<T>;
+
+  const mockQuery = async <T extends QueryResultRow>(
+    text: string,
+    params?: unknown[],
+  ): Promise<QueryResult<T>> => {
+    const sql = text.replace(/\s+/g, " ").trim();
+    const p = params ?? [];
+
+    if (sql.includes("DELETE FROM races")) {
+      return emptyResult();
+    }
+    if (sql.includes("INSERT INTO races") && sql.includes("RETURNING")) {
+      const row = mockRowFromInsert(text, p);
+      return {
+        rows: [row as unknown as T],
+        rowCount: 1,
+        command: "INSERT",
+        oid: 0,
+        fields: [],
+      } as QueryResult<T>;
+    }
+    if (sql.includes("UPDATE races") && sql.includes("RETURNING")) {
+      return emptyResult();
+    }
+    if (sql.includes("SELECT * FROM races")) {
+      return emptyResult();
+    }
+    return emptyResult();
+  };
+
+  const mockPool = {
+    query: mockQuery,
+    connect: async () => {
+      throw new Error(
+        "CALENDAR_RUN_MOCK_DB is enabled: migrate/seed require a real database; unset CALENDAR_RUN_MOCK_DB and configure DB_*.",
+      );
+    },
+    end: async () => {},
+    on() {
+      return mockPool;
+    },
+  };
+
+  return mockPool as unknown as Pool;
+}
+
+export const pool = config.useMockDb ? createMockPool() : new Pool(poolConfig);
+
+if (!config.useMockDb) {
+  pool.on("error", (err) => {
+    console.error("[db] Unexpected pool error:", err.message);
+  });
+} else {
+  console.warn("[db] Mock database enabled (CALENDAR_RUN_MOCK_DB); no PostgreSQL connection is used.");
+}
 
 export async function checkDbConnection(): Promise<boolean> {
+  if (config.useMockDb) {
+    return true;
+  }
   try {
     const client = await pool.connect();
     client.release();