import { test, expect } from '@playwright/test';
import { resolve, dirname } from 'node:path';
import { fileURLToPath } from 'node:url';
import * as fs from 'node:fs';
import * as os from 'node:os';

const __dirname = dirname(fileURLToPath(import.meta.url));
const TEST_IMAGE = resolve(__dirname, 'test-slab.png');

const evidenceDir = resolve(__dirname, '../../test-results/mask-ux-evidence');

function ensureDir(dir: string) {
  if (!fs.existsSync(dir)) fs.mkdirSync(dir, { recursive: true });
}

test.describe('Mask UX timing & overlay', () => {
  test('overlay is translucent — photo visible under green mask', async ({ page }) => {
    await page.goto('/');

    const fileInput = page.locator('#photo-file-input');
    await fileInput.setInputFiles(TEST_IMAGE);

    await expect(page.locator('h2')).toContainText('Mask & Knobs');

    // Wait for the mask canvas to be drawn
    const maskCanvas = page.locator('.mask-canvas');
    await maskCanvas.waitFor({ state: 'visible', timeout: 10000 });

    // Canvas should have actual content (not a blank white canvas)
    const canvasImg = await maskCanvas.screenshot({ type: 'png' });
    expect(canvasImg.length).toBeGreaterThan(0);

    // Screenshot the full mask step area for visual evidence
    ensureDir(evidenceDir);
    await page.locator('.mask-step').screenshot({
      path: resolve(evidenceDir, 'mask-overlay-translucent.png'),
    });
    console.log('Saved mask overlay screenshot to', resolve(evidenceDir, 'mask-overlay-translucent.png'));
  });

  test('sensitivity knob change is fast via programmatic dispatch', async ({ page }) => {
    await page.goto('/');

    const fileInput = page.locator('#photo-file-input');
    await fileInput.setInputFiles(TEST_IMAGE);
    await expect(page.locator('h2')).toContainText('Mask & Knobs');

    const sensitivitySlider = page.locator('input[type="range"]').first();
    await sensitivitySlider.waitFor({ state: 'visible', timeout: 10000 });

    const initialValue = await sensitivitySlider.inputValue();

    const startTime = Date.now();
    // Dispatch input + change events programmatically (range inputs don't support fill/setInputValue)
    await sensitivitySlider.evaluate((el: HTMLInputElement) => {
      el.value = '0.75';
      el.dispatchEvent(new Event('input', { bubbles: true }));
      el.dispatchEvent(new Event('change', { bubbles: true }));
    });
    const elapsed = Date.now() - startTime;

    console.log(`Sensitivity knob change elapsed: ${elapsed}ms`);
    expect(elapsed).toBeLessThan(300);

    const newValue = await sensitivitySlider.inputValue();
    expect(newValue).not.toBe(initialValue);
  });

  test('edge offset knob change is fast via programmatic dispatch', async ({ page }) => {
    await page.goto('/');

    const fileInput = page.locator('#photo-file-input');
    await fileInput.setInputFiles(TEST_IMAGE);
    await expect(page.locator('h2')).toContainText('Mask & Knobs');

    const edgeOffsetSlider = page.locator('input[type="range"]').nth(1);
    await edgeOffsetSlider.waitFor({ state: 'visible', timeout: 10000 });

    const initialVal = await edgeOffsetSlider.inputValue();

    const startTime = Date.now();
    await edgeOffsetSlider.evaluate((el: HTMLInputElement) => {
      el.value = '5';
      el.dispatchEvent(new Event('input', { bubbles: true }));
      el.dispatchEvent(new Event('change', { bubbles: true }));
    });
    const elapsed = Date.now() - startTime;

    console.log(`Edge offset knob change elapsed: ${elapsed}ms`);
    expect(elapsed).toBeLessThan(300);

    const newVal = await edgeOffsetSlider.inputValue();
    expect(newVal).not.toBe(initialVal);
  });

  test('sheet mode switch updates overlay within 1s', async ({ page }) => {
    await page.goto('/');

    const fileInput = page.locator('#photo-file-input');
    await fileInput.setInputFiles(TEST_IMAGE);
    await expect(page.locator('h2')).toContainText('Mask & Knobs');

    const sheetSelect = page.locator('.knob-group select');
    await sheetSelect.waitFor({ state: 'visible', timeout: 10000 });

    const startTime = Date.now();
    await sheetSelect.selectOption({ label: 'Green' });
    const elapsed = Date.now() - startTime;
    console.log(`Sheet switch elapsed: ${elapsed}ms`);
    expect(elapsed).toBeLessThan(1000);
  });
});