"""Zoopla (zoopla.co.uk) scraper — buy and rental properties.

Zoopla is behind Cloudflare Turnstile (managed interactive challenge), which
blocks all HTTP clients (curl_cffi, httpx) and even Playwright with stealth
patches. Only Camoufox (an anti-fingerprinting Firefox fork) passes reliably.

Zoopla uses Next.js App Router with React Server Components (RSC). Search
result data is server-rendered in an RSC stream, not available via
__NEXT_DATA__ or a JSON API. URL-based location slugs return 0 results —
the working flow requires typing into the autocomplete input, selecting a
suggestion, and clicking Search.

Architecture:
  Unlike the other scrapers which use HTTP clients per outcode, Zoopla keeps
  a single Camoufox browser alive for the entire scrape. For each outcode, it:
    1. Clears and types the outcode into the search input
    2. Selects the first autocomplete suggestion
    3. Clicks Search
    4. Extracts listing data from the rendered DOM
    5. Handles pagination via ?pn=N parameter

  The browser session replaces the cookie/client pattern used by other scrapers.
"""

import logging
import re
import time

from constants import DELAY_BETWEEN_PAGES, PROPERTY_TYPE_MAP, ZOOPLA_BASE
from metrics import zoopla_errors_total, zoopla_pages_scraped, zoopla_properties_scraped
from spatial import PostcodeSpatialIndex

log = logging.getLogger("zoopla")


class TurnstileError(Exception):
    """Raised when Cloudflare Turnstile challenge cannot be passed."""


# Maximum search result pages to scrape per outcode (25 listings/page)
MAX_PAGES_PER_OUTCODE = 10

# JavaScript to extract listings from the rendered DOM.
# Finds all detail links, walks up to the card container, and parses
# price, beds, baths, floor area, address, and tenure from the card text.
_EXTRACT_LISTINGS_JS = r"""() => {
    const links = Array.from(document.querySelectorAll(
        'a[href*="/for-sale/details/"], a[href*="/new-homes/details/"], a[href*="/to-rent/details/"]'
    ));

    const seen = new Set();
    const results = [];

    for (const link of links) {
        const href = link.href;
        const match = href.match(/\/details\/(\d+)\//);
        if (!match) continue;

        const id = match[1];
        if (seen.has(id)) continue;
        seen.add(id);

        // Walk up to the listing card container
        let card = link;
        for (let j = 0; j < 10; j++) {
            card = card.parentElement;
            if (!card) break;
            const text = card.innerText || '';
            if (text.includes('\u00a3') && (text.includes('bed') || text.includes('sq ft'))) {
                break;
            }
        }
        if (!card) continue;

        const text = card.innerText || '';
        const lines = text.split('\n').map(l => l.trim()).filter(Boolean);

        const priceMatch = text.match(/\u00a3([\d,]+)/);
        const bedsMatch = text.match(/(\d+)\s*beds?/i);
        const bathsMatch = text.match(/(\d+)\s*baths?/i);
        const recMatch = text.match(/(\d+)\s*reception/i);
        const areaMatch = text.match(/([\d,]+)\s*sq\s*ft/i);

        let address = '';
        for (const line of lines) {
            if (/[A-Z]{1,2}\d[A-Z\d]?\s*\d[A-Z]{2}/i.test(line) ||
                (line.includes(',') && !line.includes('\u00a3') && !/^\d+ beds?/i.test(line))) {
                address = line;
                break;
            }
        }

        let tenure = '';
        if (/freehold/i.test(text)) tenure = 'Freehold';
        else if (/leasehold/i.test(text)) tenure = 'Leasehold';

        results.push({
            id: id,
            url: href.replace(window.location.origin, ''),
            price: priceMatch ? parseInt(priceMatch[1].replace(/,/g, '')) : null,
            beds: bedsMatch ? parseInt(bedsMatch[1]) : null,
            baths: bathsMatch ? parseInt(bathsMatch[1]) : null,
            receptions: recMatch ? parseInt(recMatch[1]) : null,
            floor_area_sqft: areaMatch ? parseInt(areaMatch[1].replace(/,/g, '')) : null,
            address: address,
            tenure: tenure,
        });
    }

    return results;
}"""

# JavaScript to dismiss the Usercentrics cookie consent overlay (shadow DOM).
_DISMISS_COOKIES_JS = """() => {
    const aside = document.querySelector('#usercentrics-cmp-ui');
    if (aside && aside.shadowRoot) {
        const btns = aside.shadowRoot.querySelectorAll('button');
        for (const btn of btns) {
            if (btn.innerText.includes('Accept')) { btn.click(); return true; }
        }
    }
    if (aside) { aside.remove(); return true; }
    return false;
}"""


# ---------------------------------------------------------------------------
# Browser lifecycle
# ---------------------------------------------------------------------------


def launch_browser():
    """Launch Camoufox, navigate to Zoopla homepage, pass Cloudflare Turnstile,
    and dismiss cookie consent. Returns (browser, page) tuple.

    Raises TurnstileError if Cloudflare cannot be passed within 60 seconds.
    Caller must close browser when done."""
    from camoufox.pkgman import camoufox_path

    # Verify camoufox is pre-installed — never download at runtime
    camoufox_path(download_if_missing=False)

    from camoufox.sync_api import Camoufox

    log.info("Launching Camoufox browser for Zoopla...")
    browser = Camoufox(headless=True).__enter__()
    page = browser.new_page()

    log.info("Navigating to Zoopla homepage...")
    page.goto(f"{ZOOPLA_BASE}/", wait_until="domcontentloaded", timeout=60000)

    # Wait for Cloudflare Turnstile to resolve.
    # Try clicking the Turnstile checkbox if present (helps in some cases).
    for i in range(20):
        if "Just a moment" not in page.title():
            break
        # Attempt to click the Turnstile checkbox in the challenge iframe
        for frame in page.frames:
            if "challenges.cloudflare.com" in frame.url:
                try:
                    iframe_el = page.query_selector('iframe[src*="challenges.cloudflare"]')
                    if iframe_el:
                        box = iframe_el.bounding_box()
                        if box:
                            page.mouse.click(box["x"] + 30, box["y"] + box["height"] / 2)
                except Exception:
                    pass
                break
        time.sleep(3)
    else:
        page.close()
        browser.close()
        raise TurnstileError("Cloudflare Turnstile did not resolve after 60s")

    log.info("Cloudflare passed — title: %s", page.title())
    time.sleep(2)

    # Dismiss cookie consent
    page.evaluate(_DISMISS_COOKIES_JS)
    time.sleep(1)

    return browser, page


def _ensure_not_challenged(page) -> None:
    """Check if current page is a Cloudflare challenge and wait/raise."""
    if "Just a moment" not in page.title():
        return

    log.warning("Cloudflare challenge detected mid-session, waiting...")
    for i in range(20):
        time.sleep(3)
        if "Just a moment" not in page.title():
            log.info("Cloudflare challenge resolved")
            return

    raise TurnstileError("Cloudflare re-challenge did not resolve")


# ---------------------------------------------------------------------------
# Search navigation
# ---------------------------------------------------------------------------


def _navigate_search(page, outcode: str, channel: str) -> bool:
    """Navigate to search results for an outcode via the homepage search flow.

    Returns True if results were found, False if no results or navigation failed.
    Raises TurnstileError if Cloudflare blocks us."""
    # Navigate to homepage to reset search state
    page.goto(f"{ZOOPLA_BASE}/", wait_until="domcontentloaded", timeout=30000)
    time.sleep(2)
    _ensure_not_challenged(page)

    # Dismiss cookie consent (may reappear after navigation)
    page.evaluate(_DISMISS_COOKIES_JS)
    time.sleep(1)

    # Select Buy/Rent tab
    if channel == "RENT":
        rent_tab = page.query_selector(
            'button:has-text("Rent"), [role="tab"]:has-text("Rent")'
        )
        if rent_tab:
            rent_tab.click()
            time.sleep(0.5)

    # Find and fill search input
    search_input = page.query_selector(
        'input[name="autosuggest-input"]'
    ) or page.query_selector('input[type="text"]')
    if not search_input:
        log.warning("Could not find search input on homepage")
        return False

    search_input.click()
    time.sleep(0.3)
    search_input.fill("")
    search_input.type(outcode, delay=60)
    time.sleep(2)

    # Select first autocomplete suggestion
    first_option = page.query_selector('[role="option"]')
    if not first_option:
        log.debug("No autocomplete suggestions for outcode %s", outcode)
        return False

    first_option.click()
    time.sleep(0.5)

    # Click search button
    search_btn = page.query_selector('button:has-text("Search")')
    if search_btn:
        search_btn.click()
    else:
        search_input.press("Enter")

    # Wait for results to load
    time.sleep(6)
    _ensure_not_challenged(page)

    return True


def _get_result_count(page) -> int:
    """Extract the total results count from the page body text."""
    try:
        body = page.inner_text("body")
        match = re.search(r"([\d,]+)\s+results?", body)
        if match:
            return int(match.group(1).replace(",", ""))
    except Exception:
        pass
    return 0


# ---------------------------------------------------------------------------
# Extraction and pagination
# ---------------------------------------------------------------------------


def _extract_listings(page) -> list[dict]:
    """Extract listing data from the current search results page DOM."""
    try:
        return page.evaluate(_EXTRACT_LISTINGS_JS)
    except Exception as e:
        log.warning("Failed to extract listings from DOM: %s", e)
        zoopla_errors_total.labels(type="extract_failed").inc()
        return []


def _paginate(page, total_results: int, channel: str) -> list[dict]:
    """Extract listings from all pages of search results.

    Page 1 is already loaded. For subsequent pages, clicks the Next button
    or navigates via URL parameter ?pn=N."""
    all_listings = _extract_listings(page)
    channel_label = "buy" if channel == "BUY" else "rent"
    zoopla_pages_scraped.labels(channel=channel_label).inc()

    if not all_listings or total_results <= len(all_listings):
        return all_listings

    seen_ids = {listing["id"] for listing in all_listings}
    current_url = page.url
    page_num = 2

    while len(all_listings) < total_results and page_num <= MAX_PAGES_PER_OUTCODE:
        time.sleep(DELAY_BETWEEN_PAGES)

        # Try navigating via URL parameter
        if "?" in current_url:
            next_url = re.sub(r"[?&]pn=\d+", "", current_url)
            separator = "&" if "?" in next_url else "?"
            next_url = f"{next_url}{separator}pn={page_num}"
        else:
            next_url = f"{current_url}?pn={page_num}"

        try:
            page.goto(next_url, wait_until="domcontentloaded", timeout=30000)
            time.sleep(4)
            _ensure_not_challenged(page)
        except TurnstileError:
            raise
        except Exception as e:
            log.debug("Pagination navigation failed at page %d: %s", page_num, e)
            break

        page_listings = _extract_listings(page)
        if not page_listings:
            break

        # Deduplicate within this outcode
        new_count = 0
        for listing in page_listings:
            if listing["id"] not in seen_ids:
                seen_ids.add(listing["id"])
                all_listings.append(listing)
                new_count += 1

        zoopla_pages_scraped.labels(channel=channel_label).inc()

        if new_count == 0:
            break  # No new listings on this page

        page_num += 1

    return all_listings


# ---------------------------------------------------------------------------
# Property transformation
# ---------------------------------------------------------------------------


def _extract_postcode(text: str) -> str | None:
    """Extract a full UK postcode from text like 'Dollar Bay Place, Canary Wharf E14 9SS'."""
    match = re.search(r"([A-Z]{1,2}\d[A-Z0-9]?\s*\d[A-Z]{2})", text, re.IGNORECASE)
    if match:
        return match.group(1).upper().strip()
    return None


def _extract_outcode(text: str) -> str | None:
    """Extract a UK outcode from address text like 'Whitechapel Road, London E1'."""
    # Look for outcode at end of string or after last comma
    match = re.search(r"\b([A-Z]{1,2}\d[A-Z0-9]?)\s*$", text.strip(), re.IGNORECASE)
    if match:
        return match.group(1).upper()
    # Try after comma
    parts = text.split(",")
    if len(parts) > 1:
        last = parts[-1].strip()
        match = re.match(r"^([A-Z]{1,2}\d[A-Z0-9]?)$", last, re.IGNORECASE)
        if match:
            return match.group(1).upper()
    return None


def _map_property_type(raw_type: str | None) -> str:
    """Map Zoopla property type text to canonical type."""
    if not raw_type:
        return "Other"
    canonical = PROPERTY_TYPE_MAP.get(raw_type)
    if canonical:
        return canonical
    lower = raw_type.lower()
    if "flat" in lower or "apartment" in lower or "maisonette" in lower or "studio" in lower:
        return "Flats/Maisonettes"
    if "detached" in lower and "semi" not in lower:
        return "Detached"
    if "semi" in lower:
        return "Semi-Detached"
    if "terrace" in lower or "mews" in lower:
        return "Terraced"
    if "house" in lower:
        return "Detached"
    return "Other"


def transform_property(
    raw: dict,
    channel: str,
    pc_index: PostcodeSpatialIndex,
    pc_coords: dict[str, tuple[float, float]],
) -> dict | None:
    """Transform a raw Zoopla listing dict into the standard output schema.

    Zoopla search cards do not include coordinates, so we resolve lat/lng
    from postcodes extracted from the address text."""
    price = raw.get("price")
    if not price:
        return None

    address = raw.get("address", "")

    # Resolve postcode and coordinates from address
    postcode = _extract_postcode(address)
    lat = lng = None

    if postcode:
        coords = pc_coords.get(postcode)
        if coords:
            lat, lng = coords

    if lat is None:
        # Try outcode-level fallback
        outcode = _extract_outcode(address)
        if outcode:
            prefix = outcode + " "
            for pcd, coords in pc_coords.items():
                if pcd.startswith(prefix):
                    postcode = pcd
                    lat, lng = coords
                    break

    if lat is None or lng is None or not postcode:
        return None

    # Validate coordinates are in England
    if not (49 <= lat <= 56 and -7 <= lng <= 2):
        return None

    bedrooms = raw.get("beds") or 0
    bathrooms = raw.get("baths") or 0
    receptions = raw.get("receptions") or 0

    # Floor area: convert sq ft to sq m
    floor_area_sqm = None
    sqft = raw.get("floor_area_sqft")
    if sqft:
        floor_area_sqm = round(sqft * 0.092903, 1)

    listing_id = raw.get("id", "")
    listing_url = raw.get("url", "")
    if listing_url and not listing_url.startswith("http"):
        listing_url = ZOOPLA_BASE + listing_url

    return {
        "id": f"zp_{listing_id}",
        "Bedrooms": bedrooms,
        "Bathrooms": bathrooms,
        "Number of bedrooms & living rooms": bedrooms + receptions,
        "lon": lng,
        "lat": lat,
        "Postcode": postcode,
        "Address per Property Register": address,
        "Leasehold/Freehold": raw.get("tenure") or None,
        "Property type": "Other",  # Not reliably extractable from Zoopla search cards
        "Property sub-type": "",
        "price": int(price),
        "price_frequency": "" if channel == "BUY" else "monthly",
        "Price qualifier": "",
        "Total floor area (sqm)": floor_area_sqm,
        "Listing URL": listing_url,
        "Listing features": [],
        "first_visible_date": "",
    }


# ---------------------------------------------------------------------------
# Top-level search function (called by scraper.py)
# ---------------------------------------------------------------------------


def search_outcode(
    page,
    outcode: str,
    channel: str,
    pc_index: PostcodeSpatialIndex,
    pc_coords: dict[str, tuple[float, float]],
) -> list[dict]:
    """Search Zoopla for properties in one outcode.

    Takes a live Camoufox Page (from launch_browser). Navigates through the
    search flow, extracts listings from rendered DOM, and transforms to the
    standard output schema.

    Raises TurnstileError if Cloudflare blocks us mid-session.
    """
    if not _navigate_search(page, outcode, channel):
        return []

    total_results = _get_result_count(page)
    if total_results == 0:
        return []

    raw_listings = _paginate(page, total_results, channel)
    if not raw_listings:
        return []

    channel_label = "buy" if channel == "BUY" else "rent"
    properties = []
    for raw in raw_listings:
        transformed = transform_property(raw, channel, pc_index, pc_coords)
        if transformed:
            properties.append(transformed)
            zoopla_properties_scraped.labels(channel=channel_label).inc()

    return properties