"""Celery task: ingest ТЭП из PDF пояснительных записок ППТ/ПМТ (#1085).

Fetch PDF → parse_ppt_tep → UPSERT в ekb_ppt_tep (ON CONFLICT по doc_ref).
SAVEPOINT per-doc: ошибка одного документа не откатывает всю транзакцию.
Beat НЕ регистрируется — обновление редкое, запуск ручной/через admin.
"""

from __future__ import annotations

import json
import logging

import httpx
from sqlalchemy import text

from app.core.db import SessionLocal
from app.services.scrapers.ekb_ppt_tep_parser import PptTep, parse_ppt_tep
from app.workers.celery_app import celery_app

logger = logging.getLogger(__name__)

# ── Seed-документы ─────────────────────────────────────────────────────────────
# Один образец: ППТ 22823 (2018), пояснительная записка.
# URL — placeholder: VERIFY на екатеринбург.рф/документация/ппт/...
# Реальный URL уточнить у пользователя перед прод-прогоном.
_SEED_DOCS: list[dict] = [
    {
        "doc_ref": "ppt2018_22823",
        "url": "# VERIFY URL: https://xn--80acgfbsl1azdqr.xn--p1ai/документация/ппт/22823",
        "project_type": "ppt",
    },
]

_UPSERT_SQL = text("""
    INSERT INTO ekb_ppt_tep (
        doc_ref, project_type,
        zone_balance, tep, phasing, raw_tables,
        source_pdf, fetched_at
    )
    VALUES (
        :doc_ref, :project_type,
        CAST(:zone_balance AS jsonb),
        CAST(:tep AS jsonb),
        CAST(:phasing AS jsonb),
        CAST(:raw_tables AS jsonb),
        :source_pdf, now()
    )
    ON CONFLICT (doc_ref) DO UPDATE SET
        project_type = EXCLUDED.project_type,
        zone_balance = EXCLUDED.zone_balance,
        tep          = EXCLUDED.tep,
        phasing      = EXCLUDED.phasing,
        raw_tables   = EXCLUDED.raw_tables,
        source_pdf   = EXCLUDED.source_pdf,
        fetched_at   = now()
""")


def _fetch_pdf(url: str) -> bytes:
    """Скачивает PDF по URL; verify=False из-за CA Минцифры (как ekburg_permits, #242)."""
    with httpx.Client(verify=False, timeout=60.0, follow_redirects=True) as client:
        resp = client.get(url, headers={"User-Agent": "GenDesign-SF/1.0 (+https://gendsgn.ru/)"})
        resp.raise_for_status()
    return resp.content


def _tep_to_params(doc_ref: str, project_type: str, source_pdf: str, tep: PptTep) -> dict:
    return {
        "doc_ref": doc_ref,
        "project_type": project_type,
        "zone_balance": json.dumps(tep.zone_balance, ensure_ascii=False),
        "tep": json.dumps(tep.tep, ensure_ascii=False),
        "phasing": json.dumps(tep.phasing, ensure_ascii=False),
        "raw_tables": json.dumps(tep.raw_tables, ensure_ascii=False),
        "source_pdf": source_pdf,
    }


@celery_app.task(name="tasks.ekb_ppt_tep_sync.ingest_ppt_tep")
def ingest_ppt_tep(docs: list[dict] | None = None) -> dict[str, int]:
    """Fetch PDF + parse ТЭП + UPSERT в ekb_ppt_tep.

    Args:
        docs: список [{doc_ref, url, project_type}] или None → используется
              _SEED_DOCS (1 seed-документ образца ppt2018_22823).

    Returns:
        {"docs": N} — число успешно обработанных документов.
    """
    target_docs: list[dict] = docs if docs is not None else _SEED_DOCS
    logger.info("ekb_ppt_tep_sync: start, docs=%d", len(target_docs))

    processed = 0
    failed = 0

    db = SessionLocal()
    try:
        for doc in target_docs:
            doc_ref = doc["doc_ref"]
            url = doc["url"]
            project_type = doc.get("project_type", "ppt")

            # Пропускаем placeholder-URL (seed без реального источника)
            if url.startswith("# VERIFY"):
                logger.warning(
                    "ekb_ppt_tep_sync: doc_ref=%s — URL не задан (placeholder), пропускаем",
                    doc_ref,
                )
                continue

            try:
                logger.info("ekb_ppt_tep_sync: fetch %s (%s)", doc_ref, url)
                pdf_bytes = _fetch_pdf(url)
                tep = parse_ppt_tep(pdf_bytes)

                params = _tep_to_params(doc_ref, project_type, url, tep)

                with db.begin_nested():
                    db.execute(_UPSERT_SQL, params)

                processed += 1
                logger.info(
                    "ekb_ppt_tep_sync: upserted %s — zones=%d tep=%d phasing=%d",
                    doc_ref,
                    len(tep.zone_balance),
                    len(tep.tep),
                    len(tep.phasing),
                )
            except Exception as exc:
                failed += 1
                logger.warning(
                    "ekb_ppt_tep_sync: failed for doc_ref=%s: %s",
                    doc_ref,
                    exc,
                )

        db.commit()
    except Exception:
        db.rollback()
        raise
    finally:
        db.close()

    logger.info("ekb_ppt_tep_sync: done — processed=%d failed=%d", processed, failed)
    return {"docs": processed}