"""Shared API helpers: DB dependency, serialization, filename sanitization."""
from __future__ import annotations

import json
import re
from datetime import date, datetime

from fastapi import Depends, HTTPException
from sqlalchemy.orm import Session as OrmSession

from ..db.database import get_db
from ..db import models


def db_dep() -> OrmSession:  # thin alias so routes read cleanly
    yield from get_db()


def get_session_or_404(session_id: int, db: OrmSession) -> models.Session:
    s = db.get(models.Session, session_id)
    if s is None:
        raise HTTPException(status_code=404, detail=f"Session {session_id} not found")
    return s


_SAFE = re.compile(r"[^A-Za-z0-9 ._,()\-]+")


def sanitize_filename(name: str) -> str:
    name = name.replace("\\", "/").split("/")[-1]   # strip any path
    name = _SAFE.sub("_", name).strip() or "upload.xlsx"
    return name[:200]


def to_dict(obj, fields: list[str]) -> dict:
    out = {}
    for f in fields:
        v = getattr(obj, f, None)
        if isinstance(v, (date, datetime)):
            v = v.isoformat()
        out[f] = v
    return out


def session_dict(s: models.Session) -> dict:
    d = to_dict(s, [
        "id", "name", "reporting_month", "month_end_date", "reporting_currency",
        "clearing_lag_days", "rounding_tolerance", "allowance_for_returns",
        "manual_adjustment", "manual_adjustment_note", "status", "progress_stage",
        "progress_pct", "progress_rows_done", "progress_rows_total", "eta_seconds",
        "opening_mode", "opening_source_session_id",
        "error", "created_at", "updated_at",
    ])
    return d


def file_dict(f: models.SessionFile) -> dict:
    d = to_dict(f, [
        "id", "filename", "size_bytes", "sha256", "data_sheet", "imported_rows",
        "min_date", "max_date", "currency", "marketplace", "status", "message",
    ])
    try:
        d["worksheets"] = json.loads(f.worksheets) if f.worksheets else []
    except Exception:
        d["worksheets"] = []
    return d