Kick off (#1)

* Kick off
* Update LICENSE copyright

src/db.test.ts

@@ -0,0 +1,155 @@
+import { describe, it, expect, vi } from 'vitest';
+import { getMonitorStates, writeCheckResults, updateMonitorStates, recordAlert } from './db.js';
+
+function createMockDatabase() {
+  const mockRun = vi.fn().mockResolvedValue({});
+  const mockAll = vi.fn().mockResolvedValue({ results: [] });
+  const mockBind = vi.fn().mockReturnThis();
+
+  const mockStmt = {
+    bind: mockBind,
+    run: mockRun,
+    all: mockAll,
+  };
+
+  const mockPrepare = vi.fn().mockReturnValue(mockStmt);
+  const mockBatch = vi.fn().mockResolvedValue([]);
+
+  type MockDb = D1Database & {
+    _mockStmt: typeof mockStmt;
+    _mockBind: typeof mockBind;
+    _mockAll: typeof mockAll;
+    _mockRun: typeof mockRun;
+  };
+
+  return {
+    prepare: mockPrepare,
+    batch: mockBatch,
+    _mockStmt: mockStmt,
+    _mockBind: mockBind,
+    _mockAll: mockAll,
+    _mockRun: mockRun,
+  } as unknown as MockDb;
+}
+
+describe('getMonitorStates', () => {
+  it('returns empty array when no states exist', async () => {
+    const db = createMockDatabase();
+    const result = await getMonitorStates(db);
+    expect(result).toEqual([]);
+  });
+
+  it('returns monitor states from database', async () => {
+    const db = createMockDatabase();
+    const mockStates = [
+      {
+        monitor_name: 'test-monitor',
+        current_status: 'up',
+        consecutive_failures: 0,
+        last_status_change: 1_700_000_000,
+        last_checked: 1_700_001_000,
+      },
+    ];
+    db._mockAll.mockResolvedValue({ results: mockStates });
+
+    const result = await getMonitorStates(db);
+    expect(result).toEqual(mockStates);
+    expect(db.prepare).toHaveBeenCalledWith(expect.stringContaining('SELECT'));
+  });
+});
+
+describe('writeCheckResults', () => {
+  it('does nothing when writes array is empty', async () => {
+    const db = createMockDatabase();
+    await writeCheckResults(db, []);
+    expect(db.batch).not.toHaveBeenCalled();
+  });
+
+  it('batches writes to database', async () => {
+    const db = createMockDatabase();
+    const writes = [
+      {
+        monitorName: 'test-monitor',
+        checkedAt: 1_700_000_000,
+        status: 'up',
+        responseTimeMs: 150,
+        errorMessage: '',
+        attempts: 1,
+      },
+      {
+        monitorName: 'test-monitor-2',
+        checkedAt: 1_700_000_000,
+        status: 'down',
+        responseTimeMs: 5000,
+        errorMessage: 'Timeout',
+        attempts: 3,
+      },
+    ];
+
+    await writeCheckResults(db, writes);
+    expect(db.prepare).toHaveBeenCalledWith(expect.stringContaining('INSERT INTO check_results'));
+    expect(db.batch).toHaveBeenCalledTimes(1);
+    expect(db._mockBind).toHaveBeenCalledTimes(2);
+  });
+});
+
+describe('updateMonitorStates', () => {
+  it('does nothing when updates array is empty', async () => {
+    const db = createMockDatabase();
+    await updateMonitorStates(db, []);
+    expect(db.batch).not.toHaveBeenCalled();
+  });
+
+  it('batches state updates to database', async () => {
+    const db = createMockDatabase();
+    const updates = [
+      {
+        monitorName: 'test-monitor',
+        currentStatus: 'down',
+        consecutiveFailures: 3,
+        lastStatusChange: 1_700_000_000,
+        lastChecked: 1_700_001_000,
+      },
+    ];
+
+    await updateMonitorStates(db, updates);
+    expect(db.prepare).toHaveBeenCalledWith(expect.stringContaining('INSERT INTO monitor_state'));
+    expect(db.prepare).toHaveBeenCalledWith(expect.stringContaining('ON CONFLICT'));
+    expect(db.batch).toHaveBeenCalledTimes(1);
+  });
+});
+
+describe('recordAlert', () => {
+  it('inserts alert record', async () => {
+    const db = createMockDatabase();
+    vi.useFakeTimers();
+    vi.setSystemTime(new Date('2024-01-15T12:00:00Z'));
+
+    await recordAlert(db, 'test-monitor', 'down', 'slack', true);
+
+    expect(db.prepare).toHaveBeenCalledWith(expect.stringContaining('INSERT INTO alerts'));
+    expect(db._mockBind).toHaveBeenCalledWith(
+      'test-monitor',
+      'down',
+      expect.any(Number),
+      'slack',
+      1
+    );
+    expect(db._mockRun).toHaveBeenCalled();
+
+    vi.useRealTimers();
+  });
+
+  it('records failure correctly', async () => {
+    const db = createMockDatabase();
+    await recordAlert(db, 'test-monitor', 'recovery', 'discord', false);
+
+    expect(db._mockBind).toHaveBeenCalledWith(
+      'test-monitor',
+      'recovery',
+      expect.any(Number),
+      'discord',
+      0
+    );
+  });
+});