import re
import logging
import httpx
import asyncio
from datetime import datetime

logger = logging.getLogger(__name__)

# Romanian diacritics to ASCII mapping (same 14 chars as import_service)
_DIACRITICS = str.maketrans('ĂăÂâÎîȘșȚțŞşŢţ', 'AAAAIISSTTSSTT')


def strip_ro_prefix(cod_fiscal: str) -> str:
    """Normalize CUI: strip whitespace, uppercase, remove 'RO' prefix, fix OCR-like typos."""
    if not cod_fiscal:
        return ""
    cleaned = cod_fiscal.strip().upper()
    cleaned = re.sub(r'^RO\s*', '', cleaned)
    # Fix common character confusions in CUI (O→0, I→1, L→1, B→8)
    cleaned = cleaned.translate(str.maketrans('OIL', '011'))
    return cleaned


def validate_cui(bare_cui: str) -> bool:
    """Validate bare CUI: digits only, length 2-10."""
    if not bare_cui:
        return False
    return bare_cui.isdigit() and 2 <= len(bare_cui) <= 10


# Cheia de testare CUI Romania (9 ponderi, aliniate la dreapta cu cifrele fara cifra de control)
_CUI_KEY = [7, 5, 3, 2, 1, 7, 5, 3, 2]


def validate_cui_checksum(bare_cui: str) -> bool:
    """Validate CUI check digit using the Romanian algorithm.

    Algorithm: pad to 9 digits (without check digit), multiply by key 753217532,
    sum products, (sum * 10) % 11 → if 10 then 0, else result == check digit.
    """
    if not validate_cui(bare_cui):
        return False
    digits = [int(d) for d in bare_cui]
    check_digit = digits[-1]
    body = digits[:-1]
    padded = [0] * (9 - len(body)) + body
    total = sum(d * k for d, k in zip(padded, _CUI_KEY))
    result = (total * 10) % 11
    if result == 10:
        result = 0
    return result == check_digit


def sanitize_cui(raw_cf: str) -> tuple[str, str | None]:
    """Sanitize and validate CUI. Returns (clean_cui, warning_or_none).

    Steps: strip RO prefix, fix OCR typos (O→0), validate checksum.
    If sanitized version passes checksum but original didn't, returns the fixed CUI.
    If neither passes, returns original with warning.
    """
    bare = strip_ro_prefix(raw_cf)
    if not bare:
        return bare, None

    if validate_cui(bare) and validate_cui_checksum(bare):
        return bare, None

    # Sanitized version passes format but not checksum
    if validate_cui(bare):
        return bare, f"CUI {bare} nu trece verificarea cifrei de control"

    # Not even valid format
    return bare, f"CUI {raw_cf!r} contine caractere invalide dupa sanitizare: {bare!r}"


async def check_vat_status_batch(cui_list: list[str], date: str = None, log_fn=None) -> dict[str, dict]:
    """POST to ANAF API to check VAT status for a batch of CUIs.

    Chunks in batches of 500 (ANAF API limit).
    Returns {cui_str: {"scpTVA": bool|None, "denumire_anaf": str, "checked_at": str}, ...}
    """
    if not cui_list:
        return {}

    check_date = date or datetime.now().strftime("%Y-%m-%d")
    results = {}

    for i in range(0, len(cui_list), 500):
        chunk = cui_list[i:i+500]
        body = [{"cui": int(cui), "data": check_date} for cui in chunk if cui.isdigit()]
        if not body:
            continue

        chunk_results = await _call_anaf_api(body, log_fn=log_fn)
        results.update(chunk_results)

    return results


async def _call_anaf_api(body: list[dict], retry: int = 0, log_fn=None) -> dict[str, dict]:
    """Internal: single ANAF API call with retry logic."""
    url = "https://webservicesp.anaf.ro/api/PlatitorTvaRest/v9/tva"
    results = {}

    def _log_error(msg: str):
        logger.error(msg)
        if log_fn:
            log_fn(f"ANAF eroare: {msg}")

    def _log_warning(msg: str):
        logger.warning(msg)
        if log_fn:
            log_fn(f"ANAF warn: {msg}")

    try:
        async with httpx.AsyncClient(timeout=10.0) as client:
            response = await client.post(url, json=body)

            if response.status_code == 429:
                if retry < 1:
                    _log_warning("ANAF API rate limited (429), retrying in 10s...")
                    await asyncio.sleep(10)
                    return await _call_anaf_api(body, retry + 1, log_fn)
                _log_error("ANAF API rate limited after retry")
                return {}

            if response.status_code >= 500:
                if retry < 1:
                    _log_warning(f"ANAF API server error ({response.status_code}), retrying in 3s...")
                    await asyncio.sleep(3)
                    return await _call_anaf_api(body, retry + 1, log_fn)
                _log_error(f"ANAF API server error after retry: {response.status_code}")
                return {}

            if 400 <= response.status_code < 500:
                _log_error(f"ANAF API client error {response.status_code} (nu se reincearca)")
                return {}

            response.raise_for_status()
            data = response.json()

            checked_at = datetime.now().isoformat()

            # Parse ANAF response
            found_list = data.get("found", [])
            for item in found_list:
                date_generals = item.get("date_generale", {})
                cui_str = str(date_generals.get("cui", ""))
                results[cui_str] = {
                    "scpTVA": item.get("inregistrare_scop_Tva", {}).get("scpTVA"),
                    "denumire_anaf": date_generals.get("denumire", ""),
                    "checked_at": checked_at,
                }

            # Not found CUIs — ANAF returns plain integers (CUI values), not dicts
            notfound_list = data.get("notFound", [])
            for item in notfound_list:
                if isinstance(item, int):
                    cui_str = str(item)
                else:
                    date_gen = item.get("date_generale", {})
                    cui_str = str(date_gen.get("cui", item.get("cui", "")))
                results[cui_str] = {
                    "scpTVA": None,
                    "denumire_anaf": "",
                    "checked_at": checked_at,
                }

            logger.info(f"ANAF batch: {len(body)} CUIs → {len(found_list)} found, {len(notfound_list)} not found")

    except httpx.TimeoutException:
        if retry < 1:
            _log_warning("ANAF API timeout, retrying in 3s...")
            await asyncio.sleep(3)
            return await _call_anaf_api(body, retry + 1, log_fn)
        _log_error("ANAF API timeout after retry")
    except Exception as e:
        if retry < 1:
            _log_warning(f"ANAF API error: {e}, retrying in 3s...")
            await asyncio.sleep(3)
            return await _call_anaf_api(body, retry + 1, log_fn)
        _log_error(f"ANAF API error after retry: {e}")

    return results


def determine_correct_cod_fiscal(bare_cui: str, is_vat_payer: bool | None) -> str:
    """Determine the correct cod_fiscal format based on ANAF VAT status.
    True → "RO" + bare, False → bare, None → bare (conservative)
    """
    if is_vat_payer is True:
        return "RO" + bare_cui
    return bare_cui


def normalize_company_name(name: str) -> str:
    """Normalize company name for comparison: strip SRL/SA suffixes, diacritics, punctuation."""
    if not name:
        return ""
    result = name.strip().upper()
    # Strip diacritics
    result = result.translate(_DIACRITICS)
    # Remove common suffixes and legal forms
    result = re.sub(r'\b(S\.?R\.?L\.?|S\.?A\.?|S\.?C\.?|S\.?N\.?C\.?|S\.?C\.?S\.?|P\.?F\.?A\.?|INTREPRINDERE\s+INDIVIDUALA)\b', '', result)
    # Strip II only at start of name (avoid matching Roman numeral II in "TEHNICA II SRL")
    result = re.sub(r'^I\.?I\.?\s+', '', result)
    # Remove punctuation and extra spaces
    result = re.sub(r'[^\w\s]', '', result)
    result = re.sub(r'\s+', ' ', result).strip()
    return result