import { randomUUID } from "node:crypto";
import { chromium, type Browser, type BrowserContext, type Page } from "playwright-core";

type QaWebSession = {
  browser: Browser;
  context: BrowserContext;
  page: Page;
};

type QaWebOpenPageParams = {
  url: string;
  headless?: boolean;
  channel?: "chrome";
  timeoutMs?: number;
  viewport?: { width: number; height: number };
};

type QaWebWaitParams = {
  pageId: string;
  selector?: string;
  text?: string;
  timeoutMs?: number;
};

type QaWebTypeParams = {
  pageId: string;
  selector: string;
  text: string;
  submit?: boolean;
  timeoutMs?: number;
};

type QaWebSnapshotParams = {
  pageId: string;
  timeoutMs?: number;
  maxChars?: number;
};

type QaWebEvaluateParams = {
  pageId: string;
  expression: string;
  timeoutMs?: number;
};

const sessions = new Map<string, QaWebSession>();
const DEFAULT_WEB_TIMEOUT_MS = 20_000;

function resolveTimeoutMs(timeoutMs: number | undefined, fallbackMs = DEFAULT_WEB_TIMEOUT_MS) {
  if (typeof timeoutMs !== "number" || !Number.isFinite(timeoutMs)) {
    return fallbackMs;
  }
  return Math.max(1, Math.floor(timeoutMs));
}

function resolveSession(pageId: string): QaWebSession {
  const session = sessions.get(pageId);
  if (!session) {
    throw new Error(`unknown web session: ${pageId}`);
  }
  return session;
}

export async function qaWebOpenPage(params: QaWebOpenPageParams) {
  const timeoutMs = resolveTimeoutMs(params.timeoutMs);
  const browser = await chromium.launch({
    channel: params.channel ?? "chrome",
    headless: params.headless ?? true,
  });
  const context = await browser.newContext({
    ignoreHTTPSErrors: true,
    viewport: params.viewport ?? { width: 1440, height: 1080 },
  });
  const page = await context.newPage();
  await page.goto(params.url, {
    waitUntil: "domcontentloaded",
    timeout: timeoutMs,
  });
  const pageId = randomUUID();
  sessions.set(pageId, { browser, context, page });
  return {
    pageId,
    url: page.url(),
    title: await page.title().catch(() => ""),
  };
}

export async function qaWebWait(params: QaWebWaitParams) {
  const session = resolveSession(params.pageId);
  const timeoutMs = resolveTimeoutMs(params.timeoutMs);
  if (params.selector) {
    await session.page.waitForSelector(params.selector, { timeout: timeoutMs });
    return { ok: true };
  }
  if (params.text) {
    await session.page.waitForFunction(
      (expected) => document.body?.innerText?.toLowerCase().includes(expected.toLowerCase()),
      params.text,
      { timeout: timeoutMs },
    );
    return { ok: true };
  }
  throw new Error("web wait requires selector or text");
}

export async function qaWebType(params: QaWebTypeParams) {
  const session = resolveSession(params.pageId);
  const timeoutMs = resolveTimeoutMs(params.timeoutMs);
  const locator = session.page.locator(params.selector).first();
  await locator.waitFor({ timeout: timeoutMs });
  await locator.fill(params.text, { timeout: timeoutMs });
  if (params.submit) {
    await locator.press("Enter", { timeout: timeoutMs });
  }
  return { ok: true };
}

export async function qaWebSnapshot(params: QaWebSnapshotParams) {
  const session = resolveSession(params.pageId);
  const timeoutMs = resolveTimeoutMs(params.timeoutMs);
  const body = session.page.locator("body");
  await body.waitFor({ timeout: timeoutMs });
  const text = await body.innerText({ timeout: timeoutMs });
  const maxChars =
    typeof params.maxChars === "number" && Number.isFinite(params.maxChars)
      ? Math.max(1, Math.floor(params.maxChars))
      : undefined;
  return {
    url: session.page.url(),
    title: await session.page.title().catch(() => ""),
    text: maxChars ? text.slice(0, maxChars) : text,
  };
}

export async function qaWebEvaluate<T = unknown>(params: QaWebEvaluateParams): Promise<T> {
  const session = resolveSession(params.pageId);
  const timeoutMs = resolveTimeoutMs(params.timeoutMs);
  return (await Promise.race([
    session.page.evaluate(({ expression }) => (0, eval)(expression) as unknown, {
      expression: params.expression,
    }),
    new Promise<never>((_, reject) =>
      setTimeout(() => reject(new Error(`web evaluate timed out after ${timeoutMs}ms`)), timeoutMs),
    ),
  ])) as T;
}

export async function closeQaWebSessions(pageIds?: Iterable<string>): Promise<void> {
  const active = pageIds
    ? [...pageIds].flatMap((pageId) => {
        const session = sessions.get(pageId);
        sessions.delete(pageId);
        return session ? [session] : [];
      })
    : [...sessions.values()];
  if (!pageIds) {
    sessions.clear();
  }
  for (const session of active) {
    await session.context.close().catch(() => {});
    await session.browser.close().catch(() => {});
  }
}

export async function closeAllQaWebSessions(): Promise<void> {
  await closeQaWebSessions();
}