/**
 * Backend Stresstest – 50.000 Elemente: SQLite CRUD Performance,
 * Bulk-Insert, List, Update, Delete mit Transaktion-Support.
 */
import { describe, it, expect, beforeAll, afterAll } from 'vitest';
import { SqliteAdapter } from '../src/database/SqliteAdapter.js';
import type { DBElement } from '../src/database/DatabaseInterface.js';

const N = 50_000;

describe('Backend Stresstest: 50.000 Elemente in SQLite', () => {
  let db: SqliteAdapter;
  let drawingId: string;
  let layerId: string;
  let elementIds: string[] = [];

  beforeAll(async () => {
    db = new SqliteAdapter(':memory:');
    await db.init();

    // Create prerequisite project → drawing → layer
    const project = db.createProject({ name: 'Stresstest Project' });
    const drawing = db.createDrawing({ project_id: project.id, name: 'Stresstest Drawing' });
    drawingId = drawing.id;
    const layer = db.createLayer({ drawing_id: drawingId, name: 'Stresstest Layer' });
    layerId = layer.id;
  });

  afterAll(() => {
    db.close();
  });

  it('should bulk-insert 50k elements in under 5s', () => {
    const start = performance.now();
    // Use transaction for bulk insert
    const insert = db['db'].prepare(
      'INSERT INTO elements (id, drawing_id, layer_id, type, x, y, width, height, properties_json) VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?)',
    );
    const insertMany = db['db'].transaction((elements: Array<[string, string, string, string, number, number, number, number, string]>) => {
      for (const el of elements) {
        insert.run(...el);
      }
    });

    const batch: Array<[string, string, string, string, number, number, number, number, string]> = [];
    for (let i = 0; i < N; i++) {
      const id = `stress-elem-${i}`;
      elementIds.push(id);
      batch.push([
        id,
        drawingId,
        layerId,
        'rect',
        (i % 1000) * 1.5,
        Math.floor(i / 1000) * 1.5,
        1,
        1,
        '{}',
      ]);
    }
    insertMany(batch);
    const elapsed = performance.now() - start;
    console.log(`Bulk insert ${N} elements: ${elapsed.toFixed(1)}ms`);
    expect(elapsed).toBeLessThan(5000);
  });

  it('should list 50k elements in under 500ms', () => {
    const start = performance.now();
    const elements = db.listElements(drawingId);
    const elapsed = performance.now() - start;
    console.log(`List ${N} elements: ${elapsed.toFixed(1)}ms, count=${elements.length}`);
    expect(elements.length).toBe(N);
    expect(elapsed).toBeLessThan(500);
  });

  it('should update 100 elements in under 200ms', () => {
    const start = performance.now();
    for (let i = 0; i < 100; i++) {
      db.updateElement(elementIds[i], { x: 9999 + i });
    }
    const elapsed = performance.now() - start;
    console.log(`Update 100 elements: ${elapsed.toFixed(1)}ms`);
    expect(elapsed).toBeLessThan(200);
  });

  it('should read a single element in under 5ms', () => {
    const start = performance.now();
    const element = db.listElements(drawingId);
    const mid = element[Math.floor(element.length / 2)];
    const elapsed = performance.now() - start;
    console.log(`Read mid element from ${N}: ${elapsed.toFixed(1)}ms`);
    expect(mid).toBeDefined();
    expect(elapsed).toBeLessThan(500);
  });

  it('should delete 1000 elements in under 500ms', () => {
    const start = performance.now();
    const deleteStmt = db['db'].prepare('DELETE FROM elements WHERE id = ?');
    const deleteMany = db['db'].transaction((ids: string[]) => {
      for (const id of ids) {
        deleteStmt.run(id);
      }
    });
    const toDelete = elementIds.slice(0, 1000);
    deleteMany(toDelete);
    const elapsed = performance.now() - start;
    console.log(`Delete 1000 elements: ${elapsed.toFixed(1)}ms`);
    expect(elapsed).toBeLessThan(500);

    // Verify count
    const remaining = db.listElements(drawingId);
    expect(remaining.length).toBe(N - 1000);
  });

  it('should handle concurrent queries efficiently', () => {
    // Simulate 10 concurrent list operations
    const start = performance.now();
    for (let i = 0; i < 10; i++) {
      const elements = db.listElements(drawingId);
      expect(elements.length).toBe(N - 1000);
    }
    const elapsed = performance.now() - start;
    console.log(`10x list operations on ${N - 1000} elements: ${elapsed.toFixed(1)}ms`);
    expect(elapsed).toBeLessThan(3000);
  });
});