import { TestRunnerPlugin } from '@web/test-runner-core';
import type { ChromeLauncher } from '@web/test-runner-chrome';
import type { PlaywrightLauncher } from '@web/test-runner-playwright';

export interface Viewport {
  width: number;
  height: number;

  // puppeteer only
  deviceScaleFactor?: number;
  isLandscape?: boolean;
}

function isObject(payload: unknown): payload is Record<string, unknown> {
  return payload != null && typeof payload === 'object';
}

function isViewportObject(payload: unknown): payload is { width: number; height: number } {
  if (!isObject(payload)) throw new Error('You must provide a viewport object');
  if (payload.height == null) throw new Error('You must provide a viewport width');
  if (payload.width == null) throw new Error('You must provide a viewport width');
  if (typeof payload.height !== 'number') throw new Error('Viewport height must be a number');
  if (typeof payload.height !== 'number') throw new Error('Viewport width must be a number');
  if (payload.isMobile != null)
    throw new Error('isMobile cannot be used because it triggers a page reload');
  if (payload.hasTouch != null)
    throw new Error('hasTouch cannot be used because it triggers a page reload');
  return true;
}

export function setViewportPlugin(): TestRunnerPlugin {
  return {
    name: 'set-viewport-command',

    async executeCommand({ command, payload, session }) {
      if (command === 'set-viewport') {
        if (!isViewportObject(payload)) {
          throw new Error('You must provide a viewport object');
        }

        if (session.browser.type === 'puppeteer') {
          const page = (session.browser as ChromeLauncher).getPage(session.id);
          await page.setViewport(payload);
          return true;
        }

        if (session.browser.type === 'playwright') {
          const page = (session.browser as PlaywrightLauncher).getPage(session.id);
          await page.setViewportSize(payload);
          return true;
        }

        throw new Error(
          `Setting viewport is not supported for browser type ${session.browser.type}.`,
        );
      }
    },
  };
}