#!/usr/bin/env node
/**
 * GrokBoy Playwright DOM helper (optional).
 *
 * Modes:
 *   JSONL daemon (default when no --cmd): read JSON lines from stdin, write JSON lines to stdout.
 *   One-shot:  node browser_helper.mjs --cmd '<json>'
 *   Self-test: node browser_helper.mjs --self-test   (no Chromium required)
 *
 * Ops: ping, navigate, snapshot, click, type, eval, close, status
 * Prefer CSS selector or role+name. Screenshots are NOT the primary control surface.
 */

import { createInterface } from "node:readline";
import { dirname } from "node:path";
import { fileURLToPath } from "node:url";

const __dirname = dirname(fileURLToPath(import.meta.url));

const INSTALL_HINT =
  "Playwright not available. From the GrokBoy repo run: " +
  "cd tools/playwright && npm install && npx playwright install chromium";

let browser = null;
let context = null;
let page = null;
let lastUrl = null;

function ok(id, extra = {}) {
  return { id: id ?? null, ok: true, ...extra };
}

function fail(id, error, extra = {}) {
  return {
    id: id ?? null,
    ok: false,
    blocked: true,
    error: String(error),
    ...extra,
  };
}

async function loadPlaywright() {
  try {
    return await import("playwright");
  } catch (e) {
    const err = new Error(`${INSTALL_HINT} (import failed: ${e.message})`);
    err.code = "PLAYWRIGHT_MISSING";
    throw err;
  }
}

async function ensurePage() {
  if (page) return page;
  const { chromium } = await loadPlaywright();
  try {
    browser = await chromium.launch({ headless: true });
  } catch (e) {
    const err = new Error(
      `${INSTALL_HINT} (chromium launch failed: ${e.message})`
    );
    err.code = "CHROMIUM_MISSING";
    throw err;
  }
  context = await browser.newContext();
  page = await context.newPage();
  return page;
}

/** Accessibility-ish text snapshot: roles, names, and useful selectors — not pixels. */
async function buildSnapshot(p) {
  const nodes = await p.evaluate(() => {
    const out = [];
    const max = 400;
    const interesting = new Set([
      "a",
      "button",
      "input",
      "textarea",
      "select",
      "option",
      "h1",
      "h2",
      "h3",
      "h4",
      "h5",
      "h6",
      "label",
      "li",
      "summary",
      "nav",
      "main",
      "form",
      "img",
      "table",
      "th",
      "td",
    ]);

    function cssPath(el) {
      if (el.id) return `#${CSS.escape(el.id)}`;
      const parts = [];
      let cur = el;
      while (cur && cur.nodeType === 1 && parts.length < 5) {
        let part = cur.tagName.toLowerCase();
        if (cur.id) {
          parts.unshift(`#${CSS.escape(cur.id)}`);
          break;
        }
        const parent = cur.parentElement;
        if (parent) {
          const siblings = [...parent.children].filter(
            (c) => c.tagName === cur.tagName
          );
          if (siblings.length > 1) {
            const idx = siblings.indexOf(cur) + 1;
            part += `:nth-of-type(${idx})`;
          }
        }
        parts.unshift(part);
        cur = parent;
      }
      return parts.join(" > ");
    }

    const walker = document.createTreeWalker(
      document.body || document.documentElement,
      NodeFilter.SHOW_ELEMENT
    );
    let node = walker.currentNode;
    while (node && out.length < max) {
      const tag = node.tagName ? node.tagName.toLowerCase() : "";
      const role =
        node.getAttribute("role") ||
        (tag === "a"
          ? "link"
          : tag === "button"
            ? "button"
            : tag === "input"
              ? node.getAttribute("type") === "submit"
                ? "button"
                : "textbox"
              : tag === "textarea"
                ? "textbox"
                : tag === "img"
                  ? "img"
                  : tag.startsWith("h") && tag.length === 2
                    ? "heading"
                    : null);
      const name =
        node.getAttribute("aria-label") ||
        node.getAttribute("alt") ||
        node.getAttribute("placeholder") ||
        node.getAttribute("title") ||
        (node.innerText || node.textContent || "").trim().slice(0, 120);
      const href = node.getAttribute && node.getAttribute("href");
      const type = node.getAttribute && node.getAttribute("type");
      const value =
        "value" in node && typeof node.value === "string"
          ? String(node.value).slice(0, 80)
          : null;

      if (interesting.has(tag) || node.getAttribute("role") || node.id) {
        const entry = {
          tag,
          role: role || tag,
          name: name || "",
          selector: cssPath(node),
        };
        if (href) entry.href = href;
        if (type) entry.type = type;
        if (value) entry.value = value;
        if (node.id) entry.id = node.id;
        out.push(entry);
      }
      node = walker.nextNode();
    }
    return out;
  });

  const title = await p.title();
  const url = p.url();
  const lines = nodes.map((n, i) => {
    const bits = [`[${i}]`, n.role || n.tag];
    if (n.name) bits.push(`name=${JSON.stringify(n.name)}`);
    if (n.selector) bits.push(`sel=${n.selector}`);
    if (n.href) bits.push(`href=${n.href}`);
    if (n.type) bits.push(`type=${n.type}`);
    if (n.value) bits.push(`value=${JSON.stringify(n.value)}`);
    return bits.join(" ");
  });

  return {
    url,
    title,
    count: nodes.length,
    text: lines.join("\n"),
    nodes,
  };
}

async function resolveLocator(p, args) {
  if (args.selector) {
    return p.locator(String(args.selector)).first();
  }
  if (args.role) {
    const opts = {};
    if (args.name) opts.name = String(args.name);
    return p.getByRole(String(args.role), opts).first();
  }
  if (args.text) {
    return p.getByText(String(args.text), { exact: !!args.exact }).first();
  }
  if (args.label) {
    return p.getByLabel(String(args.label)).first();
  }
  if (args.placeholder) {
    return p.getByPlaceholder(String(args.placeholder)).first();
  }
  throw new Error(
    "click/type requires selector, role(+name), text, label, or placeholder"
  );
}

async function handle(req) {
  const id = req.id ?? null;
  const op = req.op || req.command;
  if (!op) return fail(id, "missing op");

  try {
    switch (op) {
      case "ping":
        return ok(id, {
          pong: true,
          protocol: 1,
          ops: [
            "ping",
            "navigate",
            "snapshot",
            "click",
            "type",
            "eval",
            "close",
            "status",
          ],
        });

      case "status": {
        return ok(id, {
          browser_open: !!browser,
          last_url: lastUrl,
          page_url: page ? page.url() : null,
        });
      }

      case "navigate": {
        const url = req.url;
        if (!url) return fail(id, "navigate: missing url");
        const p = await ensurePage();
        const resp = await p.goto(String(url), {
          waitUntil: "domcontentloaded",
          timeout: req.timeout_ms ?? 30000,
        });
        lastUrl = p.url();
        return ok(id, {
          url: lastUrl,
          title: await p.title(),
          status: resp ? resp.status() : null,
        });
      }

      case "snapshot":
      case "dom": {
        const p = await ensurePage();
        const snap = await buildSnapshot(p);
        lastUrl = snap.url;
        return ok(id, {
          url: snap.url,
          title: snap.title,
          count: snap.count,
          snapshot: snap.text,
          nodes: snap.nodes.slice(0, 200),
        });
      }

      case "click": {
        const p = await ensurePage();
        const loc = await resolveLocator(p, req);
        await loc.click({ timeout: req.timeout_ms ?? 10000 });
        lastUrl = p.url();
        return ok(id, { clicked: true, url: lastUrl });
      }

      case "type": {
        const p = await ensurePage();
        const text = req.text ?? req.value;
        if (text == null) return fail(id, "type: missing text");
        const loc = await resolveLocator(p, req);
        if (req.clear !== false) {
          await loc.fill(String(text), { timeout: req.timeout_ms ?? 10000 });
        } else {
          await loc.type(String(text), { timeout: req.timeout_ms ?? 10000 });
        }
        lastUrl = p.url();
        return ok(id, { typed: true, url: lastUrl });
      }

      case "eval": {
        const p = await ensurePage();
        const expression = req.expression ?? req.js ?? req.code;
        if (!expression) return fail(id, "eval: missing expression");
        // Evaluate as expression body; fail closed on throw.
        const result = await p.evaluate((expr) => {
          // eslint-disable-next-line no-eval
          return eval(expr);
        }, String(expression));
        let serialized;
        try {
          serialized = JSON.parse(JSON.stringify(result));
        } catch {
          serialized = String(result);
        }
        return ok(id, { result: serialized, url: p.url() });
      }

      case "close": {
        if (browser) {
          await browser.close().catch(() => {});
        }
        browser = null;
        context = null;
        page = null;
        return ok(id, { closed: true, last_url: lastUrl });
      }

      default:
        return fail(id, `unknown op: ${op}`);
    }
  } catch (e) {
    const extra = {};
    if (e && e.code) extra.code = e.code;
    return fail(id, e.message || e, extra);
  }
}

function parseArgs(argv) {
  const out = { cmd: null, selfTest: false, daemon: true };
  for (let i = 2; i < argv.length; i++) {
    const a = argv[i];
    if (a === "--self-test") out.selfTest = true;
    else if (a === "--cmd" || a === "-c") {
      out.cmd = argv[++i];
      out.daemon = false;
    } else if (a === "--daemon") out.daemon = true;
    else if (a === "--help" || a === "-h") out.help = true;
  }
  return out;
}

async function runSelfTest() {
  const cases = [];

  // Protocol: ping without playwright
  let r = await handle({ id: "t1", op: "ping" });
  cases.push(["ping", r.ok === true && r.pong === true]);

  // Missing fields fail closed
  r = await handle({ id: "t2", op: "navigate" });
  cases.push(["navigate_missing_url", r.ok === false && r.blocked === true]);

  r = await handle({ id: "t3", op: "type", selector: "#x" });
  // ensurePage may fail if no playwright — either blocked missing text first
  // type checks text before ensurePage... actually type checks text then ensurePage then resolveLocator
  // missing text → fail before playwright
  cases.push(["type_missing_text", r.ok === false]);

  r = await handle({ id: "t4", op: "nope" });
  cases.push(["unknown_op", r.ok === false]);

  r = await handle({ id: "t5", op: "status" });
  cases.push(["status", r.ok === true && r.browser_open === false]);

  const failed = cases.filter(([, okv]) => !okv);
  const summary = {
    ok: failed.length === 0,
    cases: Object.fromEntries(cases),
    failed: failed.map(([n]) => n),
  };
  console.log(JSON.stringify(summary));
  process.exit(failed.length === 0 ? 0 : 1);
}

async function main() {
  const args = parseArgs(process.argv);
  if (args.help) {
    console.log(
      JSON.stringify({
        ok: true,
        usage:
          "browser_helper.mjs [--self-test] | [--cmd JSON] | (JSONL on stdin)",
        install: INSTALL_HINT,
      })
    );
    return;
  }
  if (args.selfTest) {
    await runSelfTest();
    return;
  }
  if (args.cmd) {
    let req;
    try {
      req = JSON.parse(args.cmd);
    } catch (e) {
      console.log(JSON.stringify(fail(null, `invalid --cmd JSON: ${e.message}`)));
      process.exit(1);
      return;
    }
    const res = await handle(req);
    console.log(JSON.stringify(res));
    process.exit(res.ok ? 0 : 1);
    return;
  }

  // JSONL daemon
  const rl = createInterface({ input: process.stdin, crlfDelay: Infinity });
  for await (const line of rl) {
    const trimmed = line.trim();
    if (!trimmed) continue;
    let req;
    try {
      req = JSON.parse(trimmed);
    } catch (e) {
      console.log(
        JSON.stringify(fail(null, `invalid JSON line: ${e.message}`))
      );
      continue;
    }
    const res = await handle(req);
    console.log(JSON.stringify(res));
    if (req.op === "close" || req.command === "close") {
      // keep process alive unless parent closes stdin
    }
  }
  if (browser) {
    await browser.close().catch(() => {});
  }
}

main().catch((e) => {
  console.error(JSON.stringify(fail(null, e.message || e)));
  process.exit(1);
});