"""
Tareas Celery para importación CSV de Clases de Materiales.
Flujo: scan_file (validación) → insert_valid_rows (commit).
"""
import os
import base64
import csv
import json
import logging
import re
import unicodedata
from typing import Dict, Any, Optional, List, Set

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__)

CLS_IMPORT_FILE_PREFIX = "cls_import_file:"
CLS_IMPORT_META_PREFIX = "cls_import_meta:"
CLS_IMPORT_ERROR_LINES_PREFIX = "cls_import_error_lines:"
CLS_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"{CLS_IMPORT_FILE_PREFIX}{job_id}")
    if not data:
        return None
    try:
        raw = base64.b64decode(data)
    except Exception as e:
        logger.warning(f"Classes 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"cls_{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"{CLS_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"Classes 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"{CLS_IMPORT_FILE_PREFIX}{job_id}",
            f"{CLS_IMPORT_META_PREFIX}{job_id}",
            f"{CLS_IMPORT_ERROR_LINES_PREFIX}{job_id}",
        )
    except Exception as e:
        logger.warning(f"Classes 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()


def _validate_row_class(
    row: Dict[str, Any],
    line_num: int,
    valid_material_keys: Optional[Set[str]] = None,
    valid_uom_codes: Optional[Set[str]] = None,
) -> Optional[Dict[str, Any]]:
    class_code = (row.get("CLASE") or "").strip()
    if not class_code:
        return {"line": line_num, "col": "CLASE", "msg": "Requerido"}
    if len(class_code) > 8:
        return {"line": line_num, "col": "CLASE", "msg": "Máximo 8 caracteres"}

    desc_es = (row.get("DESCRIPCIONE") or "").strip()
    if desc_es and len(desc_es) > 500:
        return {"line": line_num, "col": "DESCRIPCIONE", "msg": "Máximo 500 caracteres"}
    desc_en = (row.get("DESCRIPCIONI") or "").strip()
    if desc_en and len(desc_en) > 500:
        return {"line": line_num, "col": "DESCRIPCIONI", "msg": "Máximo 500 caracteres"}

    material_key = (row.get("CLAVEMAT") or "").strip()
    if material_key:
        if len(material_key) > 10:
            return {"line": line_num, "col": "CLAVEMAT", "msg": "Máximo 10 caracteres"}
        if valid_material_keys is not None and material_key not in valid_material_keys:
            return {"line": line_num, "col": "CLAVEMAT", "msg": "Tipo de material no existe"}

    uom = (row.get("UNIMED") or "").strip()
    if uom:
        if len(uom) > 5:
            return {"line": line_num, "col": "UNIMED", "msg": "Máximo 5 caracteres"}
        if valid_uom_codes is not None and uom not in valid_uom_codes:
            return {"line": line_num, "col": "UNIMED", "msg": "Unidad de medida no existe"}

    fraction = (row.get("FRACCION") or "").strip()
    if fraction and len(fraction) > 20:
        return {"line": line_num, "col": "FRACCION", "msg": "Máximo 20 caracteres"}
    us_fraction = (row.get("FRACCIONAME") or "").strip()
    if us_fraction and len(us_fraction) > 16:
        return {"line": line_num, "col": "FRACCIONAME", "msg": "Máximo 16 caracteres"}
    sub_key = (row.get("CLAVESUB") or "").strip()
    if sub_key and len(sub_key) > 5:
        return {"line": line_num, "col": "CLAVESUB", "msg": "Máximo 5 caracteres"}
    iva_exempt = (row.get("FRACCIONEXENTAIVA") or "").strip()
    if iva_exempt and len(iva_exempt) > 4:
        return {"line": line_num, "col": "FRACCIONEXENTAIVA", "msg": "Máximo 4 caracteres"}

    rev_fisica = row.get("REVFISICA")
    if rev_fisica is not None and rev_fisica != "":
        try:
            v = int(rev_fisica)
            if v < -32768 or v > 32767:
                return {"line": line_num, "col": "REVFISICA", "msg": "Valor fuera de rango"}
        except (ValueError, TypeError):
            return {"line": line_num, "col": "REVFISICA", "msg": "Debe ser número entero"}

    return None


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

    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"cls_{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"Classes 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)"}

    valid_material_keys: Set[str] = set()
    valid_uom_codes: Set[str] = set()
    try:
        with CoreSessionLocal() as session:
            from api.v1.modules.public.reference_data.material_types.models import MaterialType
            from api.v1.modules.a76.general_catalogs.units_of_measure.models import UnitOfMeasure
            for m in session.query(MaterialType.key).all():
                valid_material_keys.add(m[0])
            for u in (
                session.query(UnitOfMeasure.code)
                .filter(
                    UnitOfMeasure.tenant_id == tenant_id,
                    UnitOfMeasure.company_id == company_id,
                )
                .all()
            ):
                valid_uom_codes.add(u[0])
    except Exception as e:
        logger.warning(f"Classes import: could not load FK sets: {e}")

    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.DictReader(f_in, dialect=dialect)

            for i, row in enumerate(reader, start=1):
                if i % 500 == 0:
                    self.update_state(
                        state="PROGRESS",
                        meta={"current": i, "total": total_rows, "errors": error_count},
                    )

                row_norm = row_from_template(row, normalize_header)
                err = _validate_row_class(
                    row_norm, i,
                    valid_material_keys=valid_material_keys,
                    valid_uom_codes=valid_uom_codes,
                )
                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"Classes 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"{CLS_IMPORT_ERROR_LINES_PREFIX}{job_id}",
                json.dumps(error_lines_list).encode("utf-8"),
                ex=CLS_IMPORT_REDIS_TTL,
            )
    except Exception as e:
        logger.warning(f"Classes import: failed to store error lines in Redis: {e}")

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


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 _int_or_none(val: Any) -> Optional[int]:
    if val is None or val == "":
        return None
    try:
        return int(val)
    except (ValueError, TypeError):
        return None


@celery_app.task(bind=True)
def insert_valid_rows(self, job_id: str):
    logger.info(f"Classes import: starting commit for job {job_id}")

    file_path = _ensure_worker_has_file_from_redis(job_id)
    if not file_path:
        alt_path = os.path.join(_worker_upload_dir(), f"cls_{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"cls_{job_id}.jsonl")

    error_lines = set()
    try:
        r = _get_redis()
        raw = r.get(f"{CLS_IMPORT_ERROR_LINES_PREFIX}{job_id}")
        if raw:
            error_lines = set(json.loads(raw.decode("utf-8")))
    except Exception as e:
        logger.debug(f"Classes 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.classes.models import Class

    valid_material_keys: Set[str] = set()
    valid_uom_codes: Set[str] = set()
    try:
        with CoreSessionLocal() as session:
            from api.v1.modules.public.reference_data.material_types.models import MaterialType
            from api.v1.modules.a76.general_catalogs.units_of_measure.models import UnitOfMeasure
            for m in session.query(MaterialType.key).all():
                valid_material_keys.add(m[0])
            for u in (
                session.query(UnitOfMeasure.code)
                .filter(
                    UnitOfMeasure.tenant_id == tenant_id,
                    UnitOfMeasure.company_id == company_id,
                )
                .all()
            ):
                valid_uom_codes.add(u[0])
    except Exception as e:
        logger.warning(f"Classes import: could not load FK sets: {e}")

    inserted_count = 0
    skipped_invalid = 0
    skipped_details: List[Dict[str, Any]] = []
    response = None

    try:
        with CoreSessionLocal() as session:
            existing_by_code: Dict[str, Class] = {}
            for c in (
                session.query(Class)
                .filter(
                    Class.tenant_id == tenant_id,
                    Class.company_id == company_id,
                )
                .all()
            ):
                existing_by_code[c.class_code] = c

            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.DictReader(f, dialect=dialect)

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

                    row_norm = row_from_template(row, normalize_header)
                    err = _validate_row_class(
                        row_norm, i,
                        valid_material_keys=valid_material_keys,
                        valid_uom_codes=valid_uom_codes,
                    )
                    if err:
                        skipped_invalid += 1
                        skipped_details.append(
                            {"line": i, "reason": f"{err.get('col', '')}: {err.get('msg', '')}"}
                        )
                        continue

                    class_code = _str_or_none(row_norm.get("CLASE"), 8)
                    if not class_code:
                        skipped_invalid += 1
                        continue

                    existing = existing_by_code.get(class_code)
                    desc_es = _str_or_none(row_norm.get("DESCRIPCIONE"), 500)
                    desc_en = _str_or_none(row_norm.get("DESCRIPCIONI"), 500)
                    material_key = _str_or_none(row_norm.get("CLAVEMAT"), 10)
                    if material_key and material_key not in valid_material_keys:
                        material_key = None
                    unit_of_measure = _str_or_none(row_norm.get("UNIMED"), 5)
                    if unit_of_measure and unit_of_measure not in valid_uom_codes:
                        unit_of_measure = None
                    fraction = _str_or_none(row_norm.get("FRACCION"), 20)
                    us_fraction = _str_or_none(row_norm.get("FRACCIONAME"), 16)
                    sub_key = _str_or_none(row_norm.get("CLAVESUB"), 5)
                    physical_review = _int_or_none(row_norm.get("REVFISICA"))
                    iva_exempt_fraction = _str_or_none(row_norm.get("FRACCIONEXENTAIVA"), 4)

                    if existing:
                        existing.description_es = desc_es
                        existing.description_en = desc_en
                        existing.material_key = material_key
                        existing.unit_of_measure = unit_of_measure
                        existing.fraction = fraction
                        existing.us_fraction = us_fraction
                        existing.sub_key = sub_key
                        existing.physical_review = physical_review
                        existing.iva_exempt_fraction = iva_exempt_fraction
                        session.add(existing)
                        inserted_count += 1
                    else:
                        new_class = Class(
                            tenant_id=tenant_id,
                            company_id=company_id,
                            class_code=class_code,
                            description_es=desc_es,
                            description_en=desc_en,
                            material_key=material_key,
                            unit_of_measure=unit_of_measure,
                            fraction=fraction,
                            us_fraction=us_fraction,
                            sub_key=sub_key,
                            physical_review=physical_review,
                            iva_exempt_fraction=iva_exempt_fraction,
                        )
                        session.add(new_class)
                        existing_by_code[class_code] = new_class
                        inserted_count += 1

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

            total_skipped = skipped_invalid
            if inserted_count == 0 and total_skipped > 0:
                response = {
                    "status": "warning",
                    "inserted": 0,
                    "skipped_invalid": skipped_invalid,
                    "skipped_missing_fk": 0,
                    "skipped_details": skipped_details,
                    "message": f"No se insertaron registros. {total_skipped} rechazados.",
                }
            elif inserted_count == 0:
                response = {
                    "status": "failed",
                    "error": "No hay registros válidos en el archivo CSV",
                    "inserted": 0,
                    "skipped_invalid": skipped_invalid,
                    "skipped_missing_fk": 0,
                    "skipped_details": skipped_details,
                }
            else:
                response = {
                    "status": "finished",
                    "inserted": inserted_count,
                    "skipped_invalid": skipped_invalid,
                    "skipped_missing_fk": 0,
                    "skipped_details": skipped_details,
                }

    except Exception as e:
        logger.error(f"Classes 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"Classes import cleanup failed: {cleanup_err}")

    if response is None:
        response = {
            "status": "failed",
            "error": "Error inesperado",
            "inserted": 0,
            "skipped_invalid": skipped_invalid,
            "skipped_missing_fk": 0,
            "skipped_details": skipped_details,
        }
    return response