"""
Tareas Celery para importación CSV de Trailers y Cajas.
Flujo: scan_file (validación) → insert_valid_rows (commit).
Upsert por trailer_number usando TrailerService.
"""
import os
import base64
import csv
import json
import logging
import re
import unicodedata
from typing import Dict, Any, Optional, List

from core.celery_app import celery_app
from core.database import CoreSessionLocal
from core.paths import layout_path

from .template_config import row_from_template

logger = logging.getLogger(__name__)

TRL_IMPORT_FILE_PREFIX = "trl_import_file:"
TRL_IMPORT_META_PREFIX = "trl_import_meta:"
TRL_IMPORT_ERROR_LINES_PREFIX = "trl_import_error_lines:"
TRL_IMPORT_STATUS_PREFIX = "trl_import_status:"
TRL_IMPORT_REDIS_TTL = 3600


def _get_redis():
    import redis
    url = os.getenv("VALKEY_URL", os.getenv("REDIS_URL", "redis://valkey:6379/0"))
    return redis.Redis.from_url(url, decode_responses=False)


def _worker_upload_dir() -> str:
    return layout_path("imports", "temp")


def _ensure_worker_has_file_from_redis(job_id: str) -> Optional[str]:
    r = _get_redis()
    data = r.get(f"{TRL_IMPORT_FILE_PREFIX}{job_id}")
    if not data:
        return None
    try:
        raw = base64.b64decode(data)
    except Exception as e:
        logger.warning(f"Trailers import: failed to decode file from Redis: {e}")
        return None
    upload_dir = _worker_upload_dir()
    os.makedirs(upload_dir, exist_ok=True)
    file_path = os.path.join(upload_dir, f"trl_{job_id}.csv")
    with open(file_path, "wb") as f:
        f.write(raw)
    return file_path


def _ensure_worker_has_meta_from_redis(job_id: str, file_path: str) -> bool:
    r = _get_redis()
    data = r.get(f"{TRL_IMPORT_META_PREFIX}{job_id}")
    if not data:
        return False
    try:
        meta = json.loads(data.decode("utf-8"))
    except Exception as e:
        logger.warning(f"Trailers import: failed to decode meta from Redis: {e}")
        return False
    meta_path = file_path.replace(".csv", ".meta.json")
    with open(meta_path, "w", encoding="utf-8") as f:
        json.dump(meta, f)
    return True


def _delete_import_from_redis(job_id: str) -> None:
    try:
        r = _get_redis()
        r.delete(
            f"{TRL_IMPORT_FILE_PREFIX}{job_id}",
            f"{TRL_IMPORT_META_PREFIX}{job_id}",
            f"{TRL_IMPORT_ERROR_LINES_PREFIX}{job_id}",
            f"{TRL_IMPORT_STATUS_PREFIX}{job_id}",
        )
    except Exception as e:
        logger.warning(f"Trailers import: failed to delete Redis keys: {e}")


def normalize_header(name: Optional[str]) -> str:
    if not name:
        return ""
    name = unicodedata.normalize("NFKD", str(name)).upper()
    name = "".join(ch for ch in name if not unicodedata.combining(ch))
    name = re.sub(r"[^A-Z0-9]+", " ", name)
    return re.sub(r"\s+", " ", name).strip()


# Max lengths from Trailer model (a76.trailer)
_MAX = {
    "trailer_number": 20,
    "ace_trailer_number": 10,
    "trailer_type_key": 2,
    "seal": 15,
    "entity_code": 1,
    "plate_number": 17,
    "state": 30,
    "country": 3,
    "container_key": 3,
}


def _dedupe_headers(headers: List[str]) -> List[str]:
    counts: Dict[str, int] = {}
    unique: List[str] = []
    for header in headers:
        name = str(header or "").strip() or "COL"
        count = counts.get(name, 0) + 1
        counts[name] = count
        if count == 1:
            unique.append(name)
        else:
            unique.append(f"{name} {count}")
    return unique


def _validate_row_trailer(row: Dict[str, Any], line_num: int) -> Optional[Dict[str, Any]]:
    """Valida una fila para Trailer. Retorna error dict o None."""
    trailer_number = (row.get("NUMERO TRAILER") or "").strip()
    if not trailer_number:
        return {"line": line_num, "col": "NUMERO TRAILER", "msg": "Requerido"}
    if len(trailer_number) > _MAX["trailer_number"]:
        return {"line": line_num, "col": "NUMERO TRAILER", "msg": f"Máximo {_MAX['trailer_number']} caracteres"}

    for col, max_len in [
        ("CLAVE ACE", _MAX["ace_trailer_number"]),
        ("TIPO TRAILER", _MAX["trailer_type_key"]),
        ("PRECINTO", _MAX["seal"]),
        ("CODIGO ENTIDAD", _MAX["entity_code"]),
        ("PLACAS", _MAX["plate_number"]),
        ("ESTADO", _MAX["state"]),
        ("PAIS", _MAX["country"]),
        ("CLAVE CONTENEDOR", _MAX["container_key"]),
    ]:
        val = (row.get(col) or "").strip()
        if val and len(val) > max_len:
            return {"line": line_num, "col": col, "msg": f"Máximo {max_len} caracteres"}

    return None


def _str_or_none(val: Any, max_len: Optional[int] = None) -> Optional[str]:
    if val is None:
        return None
    s = str(val).strip()
    if not s:
        return None
    if max_len and len(s) > max_len:
        return s[:max_len]
    return s


def _row_to_trailer_dto(row: Dict[str, Any], tenant_id: int, company_id: int) -> Dict[str, Any]:
    """Build dict for TrailerCreateDTO / TrailerUpdateDTO from normalized row."""
    trailer_number = _str_or_none(row.get("NUMERO TRAILER"), _MAX["trailer_number"])
    if not trailer_number:
        return {}
    return {
        "trailer_number": trailer_number,
        "ace_trailer_number": _str_or_none(row.get("CLAVE ACE"), _MAX["ace_trailer_number"]),
        "trailer_type_key": _str_or_none(row.get("TIPO TRAILER"), _MAX["trailer_type_key"]),
        "seal": _str_or_none(row.get("PRECINTO"), _MAX["seal"]),
        "entity_code": _str_or_none(row.get("CODIGO ENTIDAD"), _MAX["entity_code"]),
        "plate_number": _str_or_none(row.get("PLACAS"), _MAX["plate_number"]),
        "state": _str_or_none(row.get("ESTADO"), _MAX["state"]),
        "country": _str_or_none(row.get("PAIS"), _MAX["country"]),
        "container_key": _str_or_none(row.get("CLAVE CONTENEDOR"), _MAX["container_key"]),
    }


def _do_scan(job_id: str, progress_callback: Optional[Any] = None) -> Dict[str, Any]:
    file_path = _ensure_worker_has_file_from_redis(job_id)
    if not file_path:
        return {"status": "failed", "error": "Archivo no encontrado (expirado o no subido). Sube de nuevo."}
    _ensure_worker_has_meta_from_redis(job_id, file_path)

    error_dir = layout_path("imports", "errors")
    os.makedirs(error_dir, exist_ok=True)
    error_path = os.path.join(error_dir, f"trl_{job_id}.jsonl")

    total_rows = 0
    try:
        with open(file_path, "r", encoding="utf-8-sig") as f:
            total_rows = sum(1 for _ in f) - 1
    except Exception as e:
        return {"status": "failed", "error": str(e)}

    meta_path = file_path.replace(".csv", ".meta.json")
    meta = {}
    if os.path.exists(meta_path):
        try:
            with open(meta_path, "r", encoding="utf-8") as f:
                meta = json.load(f) or {}
        except Exception as e:
            logger.warning(f"Trailers import: failed to read meta: {e}")

    tenant_id = meta.get("tenant_id")
    company_id = meta.get("company_id")
    if not tenant_id or not company_id:
        return {"status": "failed", "error": "Falta contexto (tenant/company)"}

    error_count = 0
    processed_rows = 0
    errors_detail: List[Dict[str, Any]] = []

    try:
        with open(file_path, "r", encoding="utf-8-sig") as f_in, open(
            error_path, "w", encoding="utf-8"
        ) as f_err:
            sample = f_in.read(2048)
            f_in.seek(0)
            try:
                dialect = csv.Sniffer().sniff(sample, delimiters=",;\t")
            except Exception:
                dialect = "excel"
            reader = csv.reader(f_in, dialect=dialect)
            try:
                headers = next(reader)
            except StopIteration:
                headers = []
            headers = _dedupe_headers(headers)
            dict_reader = csv.DictReader(f_in, fieldnames=headers, dialect=dialect)

            for i, row in enumerate(dict_reader, start=1):
                if progress_callback and i % 500 == 0:
                    progress_callback(i, total_rows, error_count)

                row_norm = row_from_template(row, normalize_header)
                err = _validate_row_trailer(row_norm, i)
                if err:
                    error_count += 1
                    f_err.write(json.dumps(err) + "\n")
                    if len(errors_detail) < 500:
                        errors_detail.append(
                            {"line": err["line"], "col": err.get("col", ""), "msg": err.get("msg", "")}
                        )
                processed_rows += 1

    except Exception as e:
        logger.error(f"Trailers import scan failed: {e}")
        return {"status": "failed", "error": str(e)}

    error_lines_list = []
    try:
        if os.path.exists(error_path):
            with open(error_path, "r", encoding="utf-8") as f:
                for line in f:
                    try:
                        err = json.loads(line)
                        if "line" in err:
                            error_lines_list.append(err["line"])
                    except Exception:
                        pass
        if error_lines_list:
            r = _get_redis()
            r.set(
                f"{TRL_IMPORT_ERROR_LINES_PREFIX}{job_id}",
                json.dumps(error_lines_list).encode("utf-8"),
                ex=TRL_IMPORT_REDIS_TTL,
            )
    except Exception as e:
        logger.warning(f"Trailers import: failed to store error lines: {e}")

    result = {
        "status": "waiting_confirmation",
        "job_id": job_id,
        "total_rows": processed_rows,
        "error_count": error_count,
        "valid_rows": processed_rows - error_count,
        "errors": errors_detail,
    }
    return result


def run_scan_sync(job_id: str) -> Dict[str, Any]:
    result = _do_scan(job_id, progress_callback=None)
    try:
        r = _get_redis()
        r.set(
            f"{TRL_IMPORT_STATUS_PREFIX}{job_id}",
            json.dumps(result).encode("utf-8"),
            ex=TRL_IMPORT_REDIS_TTL,
        )
    except Exception as e:
        logger.warning(f"Trailers import: failed to store scan status in Redis: {e}")
    return result


@celery_app.task(bind=True)
def scan_file(self, job_id: str, config: str = None):
    logger.info(f"Trailers import: starting scan for job {job_id}")

    def on_progress(current: int, total: int, errors: int) -> None:
        self.update_state(
            state="PROGRESS",
            meta={"current": current, "total": total, "errors": errors},
        )

    result = _do_scan(job_id, progress_callback=on_progress)
    try:
        r = _get_redis()
        r.set(
            f"{TRL_IMPORT_STATUS_PREFIX}{job_id}",
            json.dumps(result).encode("utf-8"),
            ex=TRL_IMPORT_REDIS_TTL,
        )
    except Exception as e:
        logger.warning(f"Trailers import: failed to store scan status in Redis: {e}")
    return result


def _do_commit(job_id: str) -> Dict[str, Any]:
    file_path = _ensure_worker_has_file_from_redis(job_id)
    if not file_path:
        alt_path = os.path.join(_worker_upload_dir(), f"trl_{job_id}.csv")
        if not os.path.exists(alt_path):
            return {
                "status": "failed",
                "error": "Archivo no encontrado (expirado). Sube y confirma de nuevo.",
            }
        file_path = alt_path
    else:
        _ensure_worker_has_meta_from_redis(job_id, file_path)

    error_dir = layout_path("imports", "errors")
    error_path = os.path.join(error_dir, f"trl_{job_id}.jsonl")

    error_lines = set()
    try:
        r = _get_redis()
        raw = r.get(f"{TRL_IMPORT_ERROR_LINES_PREFIX}{job_id}")
        if raw:
            error_lines = set(json.loads(raw.decode("utf-8")))
    except Exception as e:
        logger.debug(f"Trailers import: could not load error lines from Redis: {e}")
    if not error_lines and os.path.exists(error_path):
        with open(error_path, "r", encoding="utf-8") as f:
            for line in f:
                try:
                    err = json.loads(line)
                    error_lines.add(err["line"])
                except Exception:
                    pass

    meta_path = file_path.replace(".csv", ".meta.json")
    tenant_id = None
    company_id = None
    meta = {}
    if os.path.exists(meta_path):
        try:
            with open(meta_path, "r", encoding="utf-8") as f:
                meta = json.load(f) or {}
                tenant_id = meta.get("tenant_id")
                company_id = meta.get("company_id")
        except Exception:
            pass

    if not tenant_id or not company_id:
        return {"status": "failed", "error": "Falta contexto (tenant/company)"}

    from api.v1.modules.a76.transportation.trailers.services import TrailerService
    from api.v1.modules.a76.transportation.trailers.dto import TrailerCreateDTO, TrailerUpdateDTO

    inserted_count = 0
    updated_count = 0
    skipped_invalid = 0
    skipped_duplicate = 0
    skipped_details: List[Dict[str, Any]] = []
    seen_keys_in_file: Dict[str, int] = {}

    try:
        with CoreSessionLocal() as session:
            with open(file_path, "r", encoding="utf-8-sig") as f:
                sample = f.read(2048)
                f.seek(0)
                try:
                    dialect = csv.Sniffer().sniff(sample, delimiters=",;\t")
                except Exception:
                    dialect = "excel"
                reader = csv.reader(f, dialect=dialect)
                try:
                    headers = next(reader)
                except StopIteration:
                    headers = []
                headers = _dedupe_headers(headers)
                dict_reader = csv.DictReader(f, fieldnames=headers, dialect=dialect)

                for i, row in enumerate(dict_reader, start=1):
                    if i in error_lines:
                        continue

                    row_norm = row_from_template(row, normalize_header)
                    err = _validate_row_trailer(row_norm, i)
                    if err:
                        skipped_invalid += 1
                        skipped_details.append(
                            {
                                "line": i,
                                "trailer_number": (row_norm.get("NUMERO TRAILER") or "").strip()[:20] or "-",
                                "invoice": (row_norm.get("NUMERO TRAILER") or "").strip()[:20] or "-",
                                "reason": f"{err.get('col', '')}: {err.get('msg', '')}",
                            }
                        )
                        continue

                    data = _row_to_trailer_dto(row_norm, tenant_id, company_id)
                    if not data or not data.get("trailer_number"):
                        skipped_invalid += 1
                        continue

                    tn = data["trailer_number"]
                    if tn in seen_keys_in_file:
                        skipped_duplicate += 1
                        skipped_details.append(
                            {
                                "line": i,
                                "trailer_number": tn,
                                "invoice": tn,
                                "reason": "Clave duplicada en el archivo (se usa la primera)",
                            }
                        )
                        continue
                    seen_keys_in_file[tn] = i

                    existing = TrailerService.get_by_id(session, tn, tenant_id, company_id)
                    try:
                        if existing:
                            update_data = TrailerUpdateDTO(**{k: v for k, v in data.items() if k != "trailer_number"})
                            TrailerService.update(session, tn, tenant_id, update_data, company_id)
                            updated_count += 1
                        else:
                            create_data = TrailerCreateDTO(**data)
                            TrailerService.create(session, create_data, tenant_id, company_id)
                            inserted_count += 1
                    except Exception as db_err:
                        session.rollback()
                        skipped_invalid += 1
                        skipped_details.append(
                            {"line": i, "trailer_number": tn, "invoice": tn, "reason": str(db_err)}
                        )
                        continue

            try:
                session.commit()
            except Exception as db_err:
                session.rollback()
                logger.error(f"Trailers import DB error: {db_err}")
                return {"status": "failed", "error": str(db_err)}

    except Exception as e:
        logger.error(f"Trailers import task failed: {e}")
        import traceback
        logger.error(traceback.format_exc())
        return {"status": "failed", "error": str(e)}

    try:
        if file_path and os.path.exists(file_path):
            os.remove(file_path)
        if os.path.exists(error_path):
            os.remove(error_path)
        if os.path.exists(meta_path):
            os.remove(meta_path)
        _delete_import_from_redis(job_id)
    except Exception as cleanup_err:
        logger.warning(f"Trailers import cleanup failed: {cleanup_err}")

    total_ok = inserted_count + updated_count
    if total_ok == 0 and (skipped_invalid + skipped_duplicate) > 0:
        return {
            "status": "warning",
            "inserted": inserted_count,
            "updated": updated_count,
            "skipped_invalid": skipped_invalid,
            "skipped_duplicate": skipped_duplicate,
            "skipped_missing_fk": 0,
            "skipped_details": skipped_details,
            "message": f"No se insertaron registros. {skipped_invalid + skipped_duplicate} rechazados.",
        }
    if total_ok == 0:
        return {
            "status": "failed",
            "error": "No hay registros válidos en el archivo CSV",
            "inserted": 0,
            "updated": 0,
            "skipped_invalid": skipped_invalid,
            "skipped_duplicate": skipped_duplicate,
            "skipped_missing_fk": 0,
            "skipped_details": skipped_details,
        }
    return {
        "status": "finished",
        "inserted": inserted_count,
        "updated": updated_count,
        "skipped_invalid": skipped_invalid,
        "skipped_duplicate": skipped_duplicate,
        "skipped_missing_fk": 0,
        "skipped_details": skipped_details,
    }


def run_commit_sync(job_id: str) -> Dict[str, Any]:
    result = _do_commit(job_id)
    try:
        r = _get_redis()
        r.set(
            f"{TRL_IMPORT_STATUS_PREFIX}{job_id}",
            json.dumps(result).encode("utf-8"),
            ex=TRL_IMPORT_REDIS_TTL,
        )
    except Exception as e:
        logger.warning(f"Trailers import: failed to store commit status in Redis: {e}")
    return result


@celery_app.task(bind=True)
def insert_valid_rows(self, job_id: str):
    logger.info(f"Trailers import: starting commit for job {job_id}")
    result = _do_commit(job_id)
    try:
        r = _get_redis()
        r.set(
            f"{TRL_IMPORT_STATUS_PREFIX}{job_id}",
            json.dumps(result).encode("utf-8"),
            ex=TRL_IMPORT_REDIS_TTL,
        )
    except Exception as e:
        logger.warning(f"Trailers import: failed to store commit status in Redis: {e}")
    return result