import { expect, test, type Page } from '@playwright/test';
import { inflateSync } from 'node:zlib';

type SigninCase = {
  path: '/ko/signin' | '/en/signin';
  theme: 'light' | 'dark';
};

const signinCases: SigninCase[] = [
  { path: '/ko/signin', theme: 'light' },
  { path: '/ko/signin', theme: 'dark' },
  { path: '/en/signin', theme: 'light' },
  { path: '/en/signin', theme: 'dark' },
];

async function mockPublicApis(page: Page): Promise<void> {
  await page.route('**/api/v1/**', async (route) => {
    const requestUrl = new URL(route.request().url());
    if (requestUrl.pathname.endsWith('/api/v1/user/me')) {
      await route.fulfill({
        status: 401,
        contentType: 'application/json',
        body: JSON.stringify({ error: 'unauthorized' }),
      });
      return;
    }

    if (requestUrl.pathname.endsWith('/api/v1/auth/tenant-info')) {
      await route.fulfill({
        status: 200,
        contentType: 'application/json',
        body: JSON.stringify({}),
      });
      return;
    }

    await route.fulfill({
      status: 200,
      contentType: 'application/json',
      body: JSON.stringify({ ok: true }),
    });
  });
}

async function expectFlutterCanvasRendered(
  page: Page,
  timeoutMs = 5_000,
): Promise<void> {
  await expect
    .poll(() => page.screenshot().then(screenshotHasSigninPaint), {
      timeout: timeoutMs,
    })
    .toBe(true);
}

async function expectBootstrapShellVisible(page: Page): Promise<void> {
  const shell = page.locator('#baron-bootstrap-shell');
  await expect(shell).toBeVisible({ timeout: 1_000 });
  await expect(shell).toContainText(/Baron SW Portal/);
}

function screenshotHasSigninPaint(buffer: Buffer): boolean {
  const image = decodePng(buffer);
  let sampled = 0;
  let nonWhite = 0;
  let dark = 0;
  let buttonBlue = 0;

  for (let y = 0; y < image.height; y += 8) {
    for (let x = 0; x < image.width; x += 8) {
      const offset = (y * image.width + x) * 4;
      const red = image.pixels[offset];
      const green = image.pixels[offset + 1];
      const blue = image.pixels[offset + 2];
      const alpha = image.pixels[offset + 3];
      if (alpha < 16) {
        continue;
      }

      sampled += 1;
      if (red < 245 || green < 245 || blue < 245) {
        nonWhite += 1;
      }
      if (red < 60 && green < 80 && blue < 110) {
        dark += 1;
      }
      if (red < 80 && green < 120 && blue > 130) {
        buttonBlue += 1;
      }
    }
  }

  return sampled > 0 && nonWhite / sampled > 0.02 && dark > 12 && buttonBlue > 12;
}

function decodePng(buffer: Buffer): {
  width: number;
  height: number;
  pixels: Uint8Array;
} {
  const signature = buffer.subarray(0, 8).toString('hex');
  if (signature !== '89504e470d0a1a0a') {
    throw new Error('invalid png signature');
  }

  let offset = 8;
  let width = 0;
  let height = 0;
  let colorType = 0;
  const idat: Buffer[] = [];

  while (offset < buffer.length) {
    const length = buffer.readUInt32BE(offset);
    const type = buffer.subarray(offset + 4, offset + 8).toString('ascii');
    const data = buffer.subarray(offset + 8, offset + 8 + length);
    offset += 12 + length;

    if (type === 'IHDR') {
      width = data.readUInt32BE(0);
      height = data.readUInt32BE(4);
      colorType = data[9];
    } else if (type === 'IDAT') {
      idat.push(data);
    } else if (type === 'IEND') {
      break;
    }
  }

  if (!width || !height || ![2, 6].includes(colorType)) {
    throw new Error(`unsupported png format: ${width}x${height}, color=${colorType}`);
  }

  const bytesPerPixel = colorType === 6 ? 4 : 3;
  const stride = width * bytesPerPixel;
  const inflated = inflateSync(Buffer.concat(idat));
  const raw = new Uint8Array(height * stride);
  let sourceOffset = 0;
  let targetOffset = 0;

  for (let y = 0; y < height; y += 1) {
    const filter = inflated[sourceOffset];
    sourceOffset += 1;
    for (let x = 0; x < stride; x += 1) {
      const value = inflated[sourceOffset + x];
      const left = x >= bytesPerPixel ? raw[targetOffset + x - bytesPerPixel] : 0;
      const up = y > 0 ? raw[targetOffset + x - stride] : 0;
      const upLeft =
        y > 0 && x >= bytesPerPixel
          ? raw[targetOffset + x - stride - bytesPerPixel]
          : 0;
      raw[targetOffset + x] = unfilterByte(filter, value, left, up, upLeft);
    }
    sourceOffset += stride;
    targetOffset += stride;
  }

  const pixels = new Uint8Array(width * height * 4);
  for (let i = 0, j = 0; i < raw.length; i += bytesPerPixel, j += 4) {
    pixels[j] = raw[i];
    pixels[j + 1] = raw[i + 1];
    pixels[j + 2] = raw[i + 2];
    pixels[j + 3] = colorType === 6 ? raw[i + 3] : 255;
  }

  return { width, height, pixels };
}

function unfilterByte(
  filter: number,
  value: number,
  left: number,
  up: number,
  upLeft: number,
): number {
  if (filter === 0) {
    return value;
  }
  if (filter === 1) {
    return (value + left) & 0xff;
  }
  if (filter === 2) {
    return (value + up) & 0xff;
  }
  if (filter === 3) {
    return (value + Math.floor((left + up) / 2)) & 0xff;
  }
  if (filter === 4) {
    return (value + paeth(left, up, upLeft)) & 0xff;
  }
  throw new Error(`unsupported png filter: ${filter}`);
}

function paeth(left: number, up: number, upLeft: number): number {
  const estimate = left + up - upLeft;
  const leftDistance = Math.abs(estimate - left);
  const upDistance = Math.abs(estimate - up);
  const upLeftDistance = Math.abs(estimate - upLeft);
  if (leftDistance <= upDistance && leftDistance <= upLeftDistance) {
    return left;
  }
  if (upDistance <= upLeftDistance) {
    return up;
  }
  return upLeft;
}

async function seedAuthTheme(page: Page, theme: SigninCase['theme']): Promise<void> {
  await page.addInitScript((themeValue) => {
    window.localStorage.setItem('userfront_auth_theme', themeValue);
    window.localStorage.setItem('flutter.userfront_auth_theme', themeValue);
  }, theme);
}

test.describe('UserFront signin runtime matrix', () => {
  test.beforeEach(async ({ page }) => {
    await mockPublicApis(page);
  });

  test('first paint exposes bootstrap shell before Flutter renders', async ({
    page,
  }, testInfo) => {
    await page.goto('/ko/signin', { waitUntil: 'domcontentloaded' });
    await expectBootstrapShellVisible(page);
    await page.screenshot({
      path: testInfo.outputPath('mobile-first-paint-ko.png'),
      fullPage: true,
    });
  });

  test('mobile signin paints final UI within 2 seconds with 0.5s captures', async ({
    page,
  }, testInfo) => {
    test.skip(
      !testInfo.project.name.includes('mobile'),
      'mobile loading budget is verified on the mobile project',
    );

    await seedAuthTheme(page, 'light');
    await page.goto('/ko/signin', { waitUntil: 'domcontentloaded' });

    let paintedAtMs: number | null = null;
    let previousElapsedMs = 0;
    for (const elapsedMs of [500, 1000, 1500, 2000]) {
      await page.waitForTimeout(elapsedMs - previousElapsedMs);
      previousElapsedMs = elapsedMs;
      const screenshot = await page.screenshot({
        path: testInfo.outputPath(`mobile-ko-signin-${elapsedMs}ms.png`),
        fullPage: true,
      });
      if (paintedAtMs === null && screenshotHasSigninPaint(screenshot)) {
        paintedAtMs = elapsedMs;
      }
    }

    expect(paintedAtMs).not.toBeNull();
    expect(paintedAtMs ?? Number.POSITIVE_INFINITY).toBeLessThanOrEqual(2_000);
    console.log(`[userfront-e2e] mobile signin painted at ${paintedAtMs}ms`);
  });

  for (const entry of signinCases) {
    test(`${entry.path} renders in ${entry.theme} theme`, async ({ page }) => {
      await seedAuthTheme(page, entry.theme);
      await page.goto(entry.path);
      await expect(page).toHaveURL(new RegExp(`${entry.path}(?:\\?.*)?$`));
      await expectFlutterCanvasRendered(page);
    });
  }

  test('signin uses configured BACKEND_URL for public API requests', async ({
    page,
  }) => {
    const expectedBackendOrigin = process.env.EXPECTED_BACKEND_ORIGIN;
    test.skip(!expectedBackendOrigin, 'set EXPECTED_BACKEND_ORIGIN');

    const requestedApiOrigins = new Set<string>();
    page.on('request', (request) => {
      const requestUrl = new URL(request.url());
      if (requestUrl.pathname.startsWith('/api/v1/')) {
        requestedApiOrigins.add(requestUrl.origin);
      }
    });

    for (const entry of signinCases) {
      await seedAuthTheme(page, entry.theme);
      await page.goto(entry.path);
      await expectFlutterCanvasRendered(page);
      await expect
        .poll(() => [...requestedApiOrigins], { timeout: 30_000 })
        .toContain(expectedBackendOrigin);
      expect(requestedApiOrigins).not.toContain('https://sso.example.test');
    }
  });
});