import { promises as fs } from "node:fs";
import path from "node:path";
import { expect, type Page } from "@playwright/test";

export interface E2EPersona {
  code: string;
  display_name: string;
  source: string;
  degraded: boolean;
}

export async function useRealApi(_page: Page) {
  // No-op marker for tests that should use the configured Vite /api proxy unless
  // a spec explicitly installs route fixtures for a focused UI or error state.
  // This helper alone is not proof that every test in the file is fixture-free.
}

function sleep(ms: number) {
  return new Promise<void>((resolve) => {
    setTimeout(resolve, ms);
  });
}

let e2eEmailCounter = 0;

function uniqueE2EEmail(prefix: string, domain: string) {
  e2eEmailCounter += 1;
  return `${prefix}.${Date.now()}.${e2eEmailCounter}@${domain}`;
}

export async function withGlobalEngineConfigLock<T>(
  label: string,
  action: () => Promise<T>,
): Promise<T> {
  const dir = path.join(process.cwd(), "node_modules", ".tmp");
  const lockPath = path.join(dir, "engine-config.lock");
  const startedAt = Date.now();

  await fs.mkdir(dir, { recursive: true });

  while (true) {
    try {
      const handle = await fs.open(lockPath, "wx");
      try {
        await handle.writeFile(`${process.pid} ${label} ${new Date().toISOString()}`);
        return await action();
      } finally {
        await handle.close().catch(() => undefined);
        await fs.unlink(lockPath).catch(() => undefined);
      }
    } catch (err) {
      const code =
        typeof err === "object" && err !== null && "code" in err
          ? String((err as { code?: unknown }).code)
          : "";
      if (code !== "EEXIST") throw err;

      const stat = await fs.stat(lockPath).catch(() => null);
      if (stat && Date.now() - stat.mtimeMs > 60_000) {
        await fs.unlink(lockPath).catch(() => undefined);
        continue;
      }
      if (Date.now() - startedAt > 30_000) {
        throw new Error(`Timed out waiting for engine config lock: ${label}`);
      }
      await sleep(100);
    }
  }
}

export async function signInAsLearner(page: Page) {
  const res = await page.request.post("/api/auth/dev-login", {
    data: {
      email: uniqueE2EEmail("learner", "hs.ac.kr"),
      role: "learner",
      display_name: "E2E Learner",
    },
  });
  expect(res.ok(), await res.text()).toBeTruthy();
  await completeOnboarding(page, {
    legal_name: "E2E Learner",
    affiliation: "한신대학교",
    department: "상담심리학과",
    grade_level: "3학년",
    phone: "010-0000-0000",
    contact_address: "경기도 오산시 한신대학교",
  });
}

export async function signInAsTeacher(page: Page) {
  const res = await page.request.post("/api/auth/dev-login", {
    data: {
      email: uniqueE2EEmail("teacher", "hs.ac.kr"),
      role: "teacher",
      display_name: "E2E Teacher",
    },
  });
  expect(res.ok(), await res.text()).toBeTruthy();
  await completeOnboarding(page, {
    legal_name: "E2E Teacher",
    affiliation: "한신대학교",
    department: "상담심리학과",
    grade_level: "교수",
    phone: "010-1111-1111",
    contact_address: "경기도 오산시 한신대학교",
  });
}

export async function signInAsAdmin(page: Page) {
  const res = await page.request.post("/api/auth/dev-login", {
    data: {
      email: "admin@twentyoz.kr",
      role: "admin",
      display_name: "E2E Admin",
    },
  });
  expect(res.ok(), await res.text()).toBeTruthy();
  await completeOnboarding(page, {
    legal_name: "E2E Admin",
    affiliation: "한신대학교",
    department: "운영",
    grade_level: "관리자",
    phone: "010-2222-2222",
    contact_address: "경기도 오산시 한신대학교",
  });
}

export async function completeOnboarding(
  page: Page,
  profile: {
    legal_name: string;
    affiliation: string;
    department: string;
    grade_level: string;
    phone: string;
    contact_address: string;
    nickname?: string;
    self_introduction?: string;
    avatar_url?: string;
  },
) {
  const onboarding = await page.request.post("/api/users/me/onboarding", {
    data: {
      ...profile,
      nickname: profile.nickname ?? profile.legal_name,
      self_introduction:
        profile.self_introduction ?? "상담 시뮬레이션 훈련을 위한 테스트 사용자입니다.",
      avatar_url: profile.avatar_url ?? "",
      terms_accepted: true,
      privacy_accepted: true,
    },
  });
  expect(onboarding.ok(), await onboarding.text()).toBeTruthy();
}

export async function fetchAvailablePersonas(page: Page): Promise<E2EPersona[]> {
  const res = await page.request.get("/api/personas");
  expect(res.ok(), await res.text()).toBeTruthy();
  const personas = (await res.json()) as E2EPersona[];
  const usable = personas.filter((persona) => persona.source === "database" && !persona.degraded);
  expect(usable.length, `Expected at least one database persona: ${JSON.stringify(personas)}`).toBeGreaterThan(0);
  return usable;
}

export async function fetchAvailablePersona(page: Page, index = 0): Promise<E2EPersona> {
  const personas = await fetchAvailablePersonas(page);
  return personas[index] ?? personas[0];
}

export async function expectNoHorizontalOverflow(page: Page) {
  await expect
    .poll(async () => {
      try {
        return await page.evaluate(() => {
          const doc = document.documentElement;
          return Math.ceil(doc.scrollWidth - doc.clientWidth);
        });
      } catch (err) {
        if (isNavigationRace(err)) return Number.MAX_SAFE_INTEGER;
        throw err;
      }
    })
    .toBeLessThanOrEqual(1);

  const overflow = await page.evaluate(() => {
    const doc = document.documentElement;
    const viewportWidth = doc.clientWidth;
    const delta = Math.ceil(doc.scrollWidth - viewportWidth);
    const offenders = Array.from(document.querySelectorAll<HTMLElement>("body *"))
      .map((el) => {
        const rect = el.getBoundingClientRect();
        const style = window.getComputedStyle(el);
        return {
          tag: el.tagName.toLowerCase(),
          className: String(el.className || ""),
          text: (el.textContent ?? "").replace(/\s+/g, " ").trim().slice(0, 80),
          left: Math.floor(rect.left),
          right: Math.ceil(rect.right),
          width: Math.ceil(rect.width),
          visible:
            style.display !== "none" &&
            style.visibility !== "hidden" &&
            Number(style.opacity) !== 0 &&
            rect.width > 0 &&
            rect.height > 0,
        };
      })
      .filter((item) => item.visible && (item.left < -1 || item.right > viewportWidth + 1))
      .slice(0, 8);

    return { delta, viewportWidth, offenders };
  });

  expect(
    overflow.delta,
    `Horizontal overflow ${overflow.delta}px at ${overflow.viewportWidth}px viewport. Offenders: ${JSON.stringify(
      overflow.offenders,
    )}`,
  ).toBeLessThanOrEqual(1);
}

export async function expectNoDocumentOverflow(page: Page) {
  await expect
    .poll(async () => {
      try {
        return await page.evaluate(() => {
          const doc = document.documentElement;
          return {
            x: Math.ceil(doc.scrollWidth - doc.clientWidth),
            y: Math.ceil(doc.scrollHeight - doc.clientHeight),
          };
        });
      } catch (err) {
        if (isNavigationRace(err)) return { x: Number.MAX_SAFE_INTEGER, y: Number.MAX_SAFE_INTEGER };
        throw err;
      }
    })
    .toEqual({ x: 0, y: 0 });
}

function isNavigationRace(err: unknown) {
  return err instanceof Error && /Execution context was destroyed|most likely because of a navigation/i.test(err.message);
}