"""Shared utility для извлечения Cian Redux state из _cianConfig.

Pattern: window._cianConfig['<mfe>'].push({key:..., value:..., priority:..., filter:...})
Used by SERP / detail / newbuilding / valuation scrapers.
"""
import json
import logging
import re
from typing import Any

logger = logging.getLogger(__name__)

# Match both patterns Cian uses:
#   1. window._cianConfig['mfe'].push({key:..., value:..., priority:..., filter:...})
#   2. window._cianConfig['mfe'] = window._cianConfig['mfe'] || [];
#      window._cianConfig['mfe'].push({...})
_RE_CIAN_PUSH = re.compile(
    r"window\._cianConfig\['(?P<mfe>[\w-]+)'\]"
    r"(?:\.push\(\s*|"
    r"\s*=\s*window\._cianConfig\['[\w-]+'\]\s*\|\|\s*\[\];\s*"
    r"window\._cianConfig\['[\w-]+'\]\.push\(\s*)"
    r"\{\s*key:\s*['\"](?P<key>\w+)['\"]\s*,\s*"
    r"value:\s*(?P<value>.+?)\s*,\s*"
    r"priority:",
    re.DOTALL,
)


def extract_state(html: str, mfe: str, key: str = "initialState") -> dict[str, Any] | None:
    """Extract state.value where _cianConfig[<mfe>] entry.key matches.

    Returns parsed JSON dict, or None if not found / parse failed.
    Logs warning at debug level on parse failure for diagnostics.
    """
    for match in _RE_CIAN_PUSH.finditer(html):
        if match.group("mfe") != mfe or match.group("key") != key:
            continue

        value_str = match.group("value").strip()

        # Strategy 1: direct JSON parse (value уже JSON-like)
        try:
            return json.loads(value_str)
        except json.JSONDecodeError:
            pass

        # Strategy 2: JSON.parse("escaped string")
        m_jp = re.match(r'JSON\.parse\(\s*"(.+?)"\s*\)\s*$', value_str, re.DOTALL)
        if m_jp:
            escaped = m_jp.group(1)
            unescaped = (
                escaped
                .replace('\\"', '"')
                .replace('\\\\', '\\')
                .replace('\\n', '\n')
                .replace('\\/', '/')
            )
            try:
                return json.loads(unescaped)
            except json.JSONDecodeError as exc:
                logger.debug(
                    "JSON.parse() unescape failed for mfe=%s key=%s: %s", mfe, key, exc
                )
                continue

        # Strategy 3: raw JS object literal — try demjson3 (optional dep)
        try:
            import demjson3  # type: ignore[import-untyped]

            return demjson3.decode(value_str)
        except ImportError:
            logger.debug(
                "demjson3 not installed; cannot parse raw JS object for mfe=%s key=%s", mfe, key
            )
        except Exception as exc:
            logger.debug("demjson3 parse failed for mfe=%s key=%s: %s", mfe, key, exc)

    return None


def extract_all_states(html: str) -> dict[str, dict[str, Any]]:
    """Returns {mfe_name: {key: parsed_value}} for all push() entries.

    Useful for discovery / debugging during scraper development.
    """
    result: dict[str, dict[str, Any]] = {}
    for match in _RE_CIAN_PUSH.finditer(html):
        mfe = match.group("mfe")
        key = match.group("key")
        parsed = extract_state(html, mfe, key)
        if parsed is not None:
            result.setdefault(mfe, {})[key] = parsed
    return result