/**
 * Shared helpers for the Freezmo browser suites.
 *
 * The suites run against a locally running production build:
 *   npm run build && systemctl --user restart freezmo
 *   npm run test:e2e
 *
 * The browser is the system Playwright Chromium (CHROME env var wins), so
 * nothing is downloaded and nothing lives outside the repo.
 */
import { chromium } from "playwright-core";
import { spawn } from "node:child_process";
import { existsSync, readdirSync, readFileSync } from "node:fs";
import { createRequire } from "node:module";
import os from "node:os";
import path from "node:path";

export const BASE = process.env.FREEZMO_URL || "http://127.0.0.1:3207";
export const REPO = path.resolve(new URL("..", import.meta.url).pathname);

/* ------------------------------------------------------------------ */
/* Browser                                                             */
/* ------------------------------------------------------------------ */

export function resolveChrome() {
  if (process.env.CHROME && existsSync(process.env.CHROME)) return process.env.CHROME;
  const root = path.join(os.homedir(), ".cache", "ms-playwright");
  const dirs = existsSync(root)
    ? readdirSync(root)
        .filter((entry) => /^chromium-\d+$/.test(entry))
        .sort((a, b) => Number(b.split("-")[1]) - Number(a.split("-")[1]))
    : [];
  for (const dir of dirs) {
    for (const sub of ["chrome-linux64", "chrome-linux"]) {
      const candidate = path.join(root, dir, sub, "chrome");
      if (existsSync(candidate)) return candidate;
    }
  }
  throw new Error(
    "No Chromium found. Set CHROME=/path/to/chrome, or install one with `npx playwright install chromium`.",
  );
}

export const CHROME = resolveChrome();

export async function launchBrowser() {
  return chromium.launch({ executablePath: CHROME, args: ["--no-sandbox"] });
}

/** axe-core source, injected into the page for the contrast audit. */
export function axeSource() {
  const require = createRequire(import.meta.url);
  return readFileSync(require.resolve("axe-core/axe.min.js"), "utf8");
}

/* ------------------------------------------------------------------ */
/* Checks                                                              */
/* ------------------------------------------------------------------ */

export function makeChecker() {
  const results = [];
  const check = (name, ok, extra = "") => {
    results.push({ name, ok: Boolean(ok) });
    console.log(`${ok ? "PASS" : "FAIL"}  ${name}${extra ? ` — ${extra}` : ""}`);
  };
  const finish = () => {
    const failed = results.filter((entry) => !entry.ok);
    console.log(`\n${results.length - failed.length}/${results.length} checks passed`);
    if (failed.length) {
      console.log("FAILURES:\n - " + failed.map((entry) => entry.name).join("\n - "));
      process.exit(1);
    }
  };
  return { check, finish };
}

/* ------------------------------------------------------------------ */
/* Seeding                                                             */
/* ------------------------------------------------------------------ */

/** Seeds localStorage before the page loads. */
export async function seed(
  page,
  {
    locale = "en",
    theme = "dark",
    decks = [],
    folders = [],
    homework = [],
    key = "test-key",
    extra = {},
    onlyIfMissing = false,
  } = {},
) {
  await page.addInitScript(
    ({ locale, theme, decks, folders, homework, key, extra, onlyIfMissing }) => {
      const put = (name, value) => {
        if (onlyIfMissing && localStorage.getItem(name) !== null) return;
        localStorage.setItem(name, value);
      };
      put("freezmo.install.installed", "1");
      put("freezmo.locale.v1", locale);
      put("freezmo.theme", theme);
      if (key) put("freezmo.settings.v1", JSON.stringify({ apiKey: key }));
      put("freezmo.decks.v1", JSON.stringify(decks));
      put("freezmo.folders.v1", JSON.stringify(folders));
      put("freezmo.homework.v1", JSON.stringify(homework));
      for (const [name, value] of Object.entries(extra)) put(name, value);
    },
    { locale, theme, decks, folders, homework, key, extra, onlyIfMissing },
  );
}

export async function makePage(browser, { width = 390, height = 844, deviceScaleFactor = 2, reducedMotion } = {}) {
  const context = await browser.newContext({ viewport: { width, height }, deviceScaleFactor, reducedMotion });
  const page = await context.newPage();
  return { context, page };
}

/** Writes answers + SRS schedules straight into the IndexedDB store. */
export async function seedLearning(page, { answers = [], srs = [] }) {
  await page.evaluate(
    async ({ answers, srs }) => {
      await new Promise((resolve, reject) => {
        const request = indexedDB.open("freezmo-learning", 1);
        request.onupgradeneeded = () => {
          const db = request.result;
          if (!db.objectStoreNames.contains("answers")) {
            const store = db.createObjectStore("answers", { keyPath: "id" });
            store.createIndex("at", "at");
            store.createIndex("deckId", "deckId");
          }
          if (!db.objectStoreNames.contains("srs")) {
            const store = db.createObjectStore("srs", { keyPath: "key" });
            store.createIndex("dueAt", "dueAt");
          }
        };
        request.onsuccess = () => {
          const db = request.result;
          const tx = db.transaction(["answers", "srs"], "readwrite");
          for (const answer of answers) tx.objectStore("answers").put(answer);
          for (const record of srs) tx.objectStore("srs").put(record);
          tx.oncomplete = () => {
            db.close();
            resolve();
          };
          tx.onerror = () => reject(tx.error);
        };
        request.onerror = () => reject(request.error);
      });
    },
    { answers, srs },
  );
}

export async function readLearning(page) {
  return page.evaluate(
    async () =>
      new Promise((resolve, reject) => {
        const request = indexedDB.open("freezmo-learning", 1);
        request.onsuccess = () => {
          const db = request.result;
          const tx = db.transaction(["answers", "srs"], "readonly");
          const answers = tx.objectStore("answers").getAll();
          const srs = tx.objectStore("srs").getAll();
          tx.oncomplete = () => {
            db.close();
            resolve({ answers: answers.result, srs: srs.result });
          };
          tx.onerror = () => reject(tx.error);
        };
        request.onerror = () => reject(request.error);
      }),
  );
}

/* ------------------------------------------------------------------ */
/* Fixtures                                                            */
/* ------------------------------------------------------------------ */

export const DECK = {
  id: "seed_deck",
  title: "Sky deck",
  subject: "Physics",
  summary: "Light in the atmosphere.",
  language: "English",
  sourceText: "The sky is blue because of Rayleigh scattering. Molecules scatter short wavelengths.",
  difficulty: "easy",
  createdAt: 1,
  updatedAt: 1,
  attempts: 0,
  activities: [
    {
      type: "multiple_choice",
      id: "a1",
      xp: 10,
      topic: "Sky",
      question: "What colour is a clear daytime sky?",
      options: ["Blue", "Green", "Orange", "Pink"],
      correctIndex: 0,
      explanation: "Rayleigh scattering favours blue.",
    },
    {
      type: "multiple_choice",
      id: "a2",
      xp: 10,
      topic: "Sky",
      question: "What makes the sky blue?",
      options: ["Scattering", "Paint", "Reflection", "Wind"],
      correctIndex: 0,
      explanation: "Small molecules scatter short wavelengths.",
    },
  ],
};

export function dueSrs(deckId = "seed_deck", activityId = "a1") {
  const now = Date.now();
  return {
    key: `${deckId}:${activityId}`,
    deckId,
    activityId,
    ease: 2.5,
    reps: 1,
    intervalDays: 1,
    lapses: 0,
    dueAt: now - 60_000,
    lastAt: now - 120_000,
    lastCorrect: true,
  };
}

export function wrongAnswer(deckId = "seed_deck", activityId = "a1") {
  return {
    id: `h-${activityId}`,
    deckId,
    deckTitle: "Sky deck",
    activityId,
    type: "multiple_choice",
    topic: "Sky",
    correct: false,
    at: Date.now() - 60_000,
  };
}

/* ------------------------------------------------------------------ */
/* Extra app instances (stub Ollama, VAPID, ...)                       */
/* ------------------------------------------------------------------ */

/** Fails loudly instead of silently talking to somebody else's server. */
export async function portInUse(port) {
  try {
    const response = await fetch(`http://127.0.0.1:${port}/api/health`);
    return response.status < 500;
  } catch {
    return false;
  }
}

export async function waitForHttp(url, attempts = 60) {
  for (let index = 0; index < attempts; index++) {
    try {
      const response = await fetch(url);
      if (response.status < 500) return true;
    } catch {
      /* not up yet */
    }
    await new Promise((resolve) => setTimeout(resolve, 500));
  }
  return false;
}

/**
 * Starts a second production server on `port` with extra env (a stub Ollama,
 * VAPID keys, ...). Returns a stop() that kills the whole process group so the
 * port is really free for the next suite.
 */
export function spawnApp(port, env = {}) {
  const server = spawn("npx", ["next", "start", "-p", String(port), "-H", "127.0.0.1"], {
    cwd: REPO,
    env: { ...process.env, ...env },
    stdio: "ignore",
    detached: true,
  });
  return {
    server,
    stop() {
      try {
        process.kill(-server.pid, "SIGTERM");
      } catch {
        server.kill("SIGTERM");
      }
    },
  };
}