from __future__ import annotations

import os
import socket
import subprocess
import time
from urllib.error import URLError
from urllib.request import urlopen

import pytest

from quantum_learning.config import project_root

try:
    from playwright.sync_api import TimeoutError as PlaywrightTimeoutError
    from playwright.sync_api import sync_playwright
except ImportError:  # pragma: no cover - test environment specific
    sync_playwright = None
    PlaywrightTimeoutError = RuntimeError


def _find_free_port() -> int:
    with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as sock:
        try:
            sock.bind(("127.0.0.1", 0))
        except PermissionError:
            pytest.skip("Browser UX tests need localhost ports, which this sandbox blocks.")
        return int(sock.getsockname()[1])


def _wait_for_server(url: str, process: subprocess.Popen[str], timeout_seconds: int = 90) -> None:
    deadline = time.time() + timeout_seconds
    while time.time() < deadline:
        if process.poll() is not None:
            stdout = process.stdout.read() if process.stdout is not None else ""
            raise RuntimeError(f"Jupyter server exited early.\n{stdout}")

        try:
            with urlopen(url, timeout=2):
                return
        except URLError:
            time.sleep(1)

    raise TimeoutError(f"Timed out waiting for JupyterLab at {url}")


def _wait_for_notebook(browser_page, notebook_filename: str, heading: str) -> None:
    browser_page.locator(".lm-TabBar-tabLabel", has_text=notebook_filename).last.wait_for(
        timeout=60000
    )
    browser_page.locator(".jp-RenderedHTMLCommon h1", has_text=heading).last.wait_for(
        timeout=60000
    )


def _open_notebook_from_directory(
    browser_page,
    jupyter_lab_server,
    directory: str,
    notebook_filename: str,
    heading: str,
) -> None:
    url = f"{jupyter_lab_server['base_url']}/lab/tree/{directory}?token={jupyter_lab_server['token']}"
    browser_page.goto(url, wait_until="networkidle")
    browser_page.locator(".jp-DirListing-itemText", has_text=notebook_filename).first.wait_for(
        timeout=60000
    )
    browser_page.locator(".jp-DirListing-itemText", has_text=notebook_filename).first.dblclick()
    _wait_for_notebook(browser_page, notebook_filename, heading)


def _run_all_cells(browser_page) -> None:
    browser_page.locator("text=Run").first.click()
    browser_page.locator("text=Run All Cells").first.click()

    try:
        browser_page.get_by_role("button", name="Select").click(timeout=5000)
    except PlaywrightTimeoutError:
        pass


def _find_code_editor(browser_page):
    textareas = browser_page.locator("textarea")
    for index in range(textareas.count()):
        candidate = textareas.nth(index)
        if not candidate.is_visible():
            continue
        try:
            value = candidate.input_value()
        except PlaywrightTimeoutError:  # pragma: no cover - widget race
            continue
        if "QuantumCircuit" in value:
            return candidate
    raise AssertionError("Could not locate an editable circuit code editor.")


def _wait_for_text_in_body(browser_page, expected_text: str, *, timeout_seconds: int = 120) -> None:
    deadline = time.time() + timeout_seconds
    last_body = ""
    while time.time() < deadline:
        last_body = browser_page.locator("body").inner_text()
        if expected_text in last_body:
            return
        time.sleep(1)

    raise AssertionError(
        f"Did not find {expected_text!r} in rendered page text.\nLast body text excerpt:\n"
        f"{last_body[-4000:]}"
    )


@pytest.fixture(scope="module")
def jupyter_lab_server():
    if sync_playwright is None:
        pytest.skip("Playwright is not installed in this environment.")

    root = project_root()
    browser_root = root / ".playwright-browsers"
    if not browser_root.exists():
        pytest.skip("Project-local Playwright browsers are not installed.")

    port = _find_free_port()
    token = "quantum-learning-browser-test"
    runtime_root = root / ".tmp_test_artifacts" / "browser_jupyter"
    config_dir = runtime_root / "config"
    data_dir = runtime_root / "data"
    runtime_dir = runtime_root / "runtime"
    ipython_dir = runtime_root / "ipython"
    mpl_dir = runtime_root / "matplotlib"
    for path in (config_dir, data_dir, runtime_dir, ipython_dir, mpl_dir):
        path.mkdir(parents=True, exist_ok=True)

    env = os.environ.copy()
    env.update(
        {
            "PATH": f"{root / '.venv' / 'bin'}:/usr/bin:/bin:/usr/sbin:/sbin",
            "JUPYTER_CONFIG_DIR": str(config_dir),
            "JUPYTER_DATA_DIR": str(data_dir),
            "JUPYTER_RUNTIME_DIR": str(runtime_dir),
            "IPYTHONDIR": str(ipython_dir),
            "MPLCONFIGDIR": str(mpl_dir),
            "PLAYWRIGHT_BROWSERS_PATH": str(browser_root),
        }
    )

    command = [
        str(root / ".venv" / "bin" / "jupyter"),
        "lab",
        "--no-browser",
        "--ip=127.0.0.1",
        f"--port={port}",
        f"--IdentityProvider.token={token}",
        f"--ServerApp.root_dir={root}",
    ]
    process = subprocess.Popen(
        command,
        cwd=root,
        env=env,
        stdout=subprocess.PIPE,
        stderr=subprocess.STDOUT,
        text=True,
    )
    base_url = f"http://127.0.0.1:{port}"
    _wait_for_server(f"{base_url}/lab?token={token}", process)

    try:
        yield {"base_url": base_url, "token": token, "browser_root": browser_root}
    finally:
        process.terminate()
        try:
            process.wait(timeout=10)
        except subprocess.TimeoutExpired:  # pragma: no cover - cleanup path
            process.kill()


@pytest.fixture()
def browser_page(jupyter_lab_server):
    os.environ["PLAYWRIGHT_BROWSERS_PATH"] = str(jupyter_lab_server["browser_root"])
    with sync_playwright() as playwright:
        browser = playwright.chromium.launch(headless=True)
        page = browser.new_page()
        try:
            yield page
        finally:
            browser.close()


@pytest.mark.browser
def test_start_here_loads_as_the_entrypoint_in_jupyterlab(browser_page, jupyter_lab_server):
    url = (
        f"{jupyter_lab_server['base_url']}/lab/tree/notebooks/START_HERE.ipynb"
        f"?token={jupyter_lab_server['token']}"
    )
    browser_page.goto(url, wait_until="networkidle")
    _wait_for_notebook(browser_page, "START_HERE.ipynb", "Start Here")
    assert browser_page.locator(".jp-Notebook .jp-RenderedHTMLCommon", has_text="only supported starting point").first.is_visible()
    _wait_for_text_in_body(browser_page, "Course Blueprint")


@pytest.mark.browser
def test_foundations_lab_supports_quiz_answering_and_circuit_editing(
    browser_page,
    jupyter_lab_server,
):
    _open_notebook_from_directory(
        browser_page,
        jupyter_lab_server,
        "notebooks/foundations/module_01_principles_and_circuit_literacy",
        "lab.ipynb",
        "Principles and Circuit Literacy Lab",
    )
    _run_all_cells(browser_page)

    browser_page.get_by_label("A. Only one deterministic outcome from the all-zero input").check()
    browser_page.get_by_role("button", name="Check answer").first.click()
    browser_page.locator("text=Correct.").first.wait_for(timeout=120000)

    editor = _find_code_editor(browser_page)
    editor.fill(
        'circuit = QuantumCircuit(1, 1, name="workflow")\n'
        "circuit.x(0)\n"
        "circuit.measure(0, 0)\n"
    )
    browser_page.get_by_role("button", name="Render circuit").first.click()
    browser_page.locator("pre", has_text="{'1': 256}").first.wait_for(timeout=120000)


@pytest.mark.browser
def test_capstone_studio_supports_checklist_feedback_and_rubric_workflows(
    browser_page,
    jupyter_lab_server,
):
    _open_notebook_from_directory(
        browser_page,
        jupyter_lab_server,
        "notebooks/professional/module_04_capstone_design_review",
        "studio.ipynb",
        "Capstone Circuit Design Review Studio",
    )
    _run_all_cells(browser_page)

    browser_page.get_by_role("button", name="Render circuit").first.wait_for(timeout=120000)
    browser_page.locator("text=Capstone Circuit Design Review Evidence Checklist").first.wait_for(
        timeout=120000
    )

    browser_page.get_by_placeholder("State the current claim or judgement.").fill(
        "The middle-root GHZ candidate best satisfies the declared local brief."
    )
    browser_page.get_by_placeholder("Name the exact evidence supporting that claim.").fill(
        "It preserves the ideal target, compiles with lower burden on the line, and retains stronger noisy support."
    )
    browser_page.get_by_placeholder("Name the main remaining risk, assumption, or weakness.").fill(
        "The comparison still depends on a synthetic local noise model."
    )
    browser_page.get_by_placeholder("State the next revision, experiment, or rewrite.").fill(
        "Compare the same candidates under a second line-constrained noise profile."
    )
    browser_page.get_by_role("button", name="Review draft").click()
    browser_page.locator("text=Missing sections: None").first.wait_for(timeout=120000)

    _wait_for_text_in_body(browser_page, "Capstone Circuit Design Review Studio Self-Grading")
    _wait_for_text_in_body(browser_page, "Brief Clarity")
    _wait_for_text_in_body(browser_page, "Total: 0/28")
    _wait_for_text_in_body(browser_page, "Band: revision-needed")