"""
Mirror Evotor product catalog → VK Market.

Runs after both refresh_catalog and refresh_vk_catalog complete.
Only processes stores and groups that have sync enabled (via SyncFilter).
Updates VK products only when at least one synced field has changed.
"""
import logging
import os
from datetime import datetime, timezone
from decimal import Decimal

from celery import shared_task

import web.lib.api_logger as api_logger
from web.config import settings
from web.database import SessionLocal
from web.models.connections import (
    CachedGroup, CachedProduct, CachedStore,
    SyncConfig, SyncFilter,
    VkCachedAlbum, VkConnection,
)

logger = logging.getLogger(__name__)

VK_API = "https://api.vk.com/method"

_PHOTO_CACHE: dict[int, str] = {}  # user_id → uploaded photo_id for this run


def _now() -> datetime:
    return datetime.now(timezone.utc).replace(tzinfo=None)


def _calc_price(price: Decimal | None) -> int:
    """Return price in kopecks for VK Market API."""
    if price is None:
        return 0
    return int(float(price) * 100)


def _build_description(name: str, measure: str | None, evo_description: str | None) -> str:
    price_info = (measure or "").strip()
    desc = f"{name} (цена за {price_info}.)\n\n"
    if evo_description:
        desc += evo_description
    return desc


def _name_for_vk(name: str) -> str:
    return name.replace(";", ",")


def _vk_post(method: str, data: dict, token: str, user_id: int | None = None) -> dict:
    data = {**data, "access_token": token, "v": settings.VK_API_VERSION}
    r = api_logger.post(f"{VK_API}/{method}", user_id=user_id, data=data, timeout=30)
    r.raise_for_status()
    return r.json()


def _upload_photo(token: str, group_id: str, user_id: int | None = None) -> str | None:
    """Upload the default product photo and return photo_id, or None on failure."""
    photo_path = settings.VK_DEFAULT_PHOTO_PATH
    if not os.path.exists(photo_path):
        logger.warning("Default photo not found at %s", photo_path)
        return None
    try:
        # Step 1: get upload URL
        resp = _vk_post("market.getProductPhotoUploadServer", {"group_id": group_id}, token, user_id=user_id)
        if "error" in resp:
            logger.warning("getProductPhotoUploadServer error: %s", resp["error"])
            return None
        upload_url = resp["response"]["upload_url"]

        # Step 2: upload file
        with open(photo_path, "rb") as f:
            up = api_logger.post(upload_url, user_id=user_id, files={"file": f}, timeout=30)
            up.raise_for_status()
        upload_obj = up.text

        # Step 3: save
        resp2 = _vk_post("market.saveProductPhoto", {"upload_response": upload_obj}, token, user_id=user_id)
        if "error" in resp2:
            logger.warning("saveProductPhoto error: %s", resp2["error"])
            return None
        return str(resp2["response"]["photo_id"])
    except Exception as e:
        logger.warning("Photo upload failed: %s", e)
        return None


def _get_photo_id(user_id: int, token: str, group_id: str) -> str | None:
    """Upload photo once per sync run per user, cache the result."""
    if user_id not in _PHOTO_CACHE:
        _PHOTO_CACHE[user_id] = _upload_photo(token, group_id, user_id=user_id)
    return _PHOTO_CACHE[user_id]


def _enabled_store_ids(db, user_id: int) -> set[str] | None:
    cfg = db.query(SyncConfig).filter_by(user_id=user_id).first()
    if not cfg:
        return None
    filters = db.query(SyncFilter).filter_by(
        sync_config_id=cfg.id, entity_type="store", filter_mode="include",
    ).all()
    return None if not filters else {f.entity_id for f in filters}


def _enabled_group_ids(db, user_id: int, store_evotor_id: str) -> set[str] | None:
    cfg = db.query(SyncConfig).filter_by(user_id=user_id).first()
    if not cfg:
        return None
    filters = db.query(SyncFilter).filter_by(
        sync_config_id=cfg.id, entity_type="group", filter_mode="include",
        parent_entity_id=store_evotor_id,
    ).all()
    return None if not filters else {f.entity_id for f in filters}


def _ensure_album(db, user_id: int, vk_group_id: str, group_name: str, token: str) -> str | None:
    """Return VK album_id for the given group name, creating it if needed."""
    album = db.query(VkCachedAlbum).filter_by(
        user_id=user_id, vk_group_id=vk_group_id,
    ).filter(VkCachedAlbum.title == group_name).first()

    if album:
        return album.album_id

    # Create album in VK
    resp = _vk_post("market.addAlbum", {
        "owner_id": f"-{vk_group_id}",
        "title": group_name,
    }, token, user_id=user_id)
    if "error" in resp:
        logger.warning("market.addAlbum error for '%s': %s", group_name, resp["error"])
        return None

    album_id = str(resp["response"]["market_album_id"])
    db.add(VkCachedAlbum(
        user_id=user_id,
        vk_group_id=vk_group_id,
        album_id=album_id,
        title=group_name,
        fetched_at=_now(),
    ))
    db.flush()
    logger.info("user=%s created VK album '%s' id=%s", user_id, group_name, album_id)
    return album_id


def _sync_product(
    db,
    user_id: int,
    product: CachedProduct,
    album_id: str,
    vk_group_id: str,
    token: str,
) -> None:
    name = _name_for_vk(product.name)
    price_kopecks = _calc_price(product.price)
    desc = _build_description(product.name, product.measure_name, None)
    stock = settings.VK_STOCK_AMOUNT if product.allow_to_sell else 0
    owner_id = f"-{vk_group_id}"
    now = _now()

    if product.vk_product_id:
        # Check if update needed
        changed = False
        # Re-read current VK state from cache
        from web.models.connections import VkCachedProduct
        vk_p = db.query(VkCachedProduct).filter_by(
            user_id=user_id, vk_group_id=vk_group_id, vk_product_id=product.vk_product_id,
        ).first()
        album_changed = False
        if vk_p:
            vk_price_kopecks = int(vk_p.price * 100) if vk_p.price is not None else 0
            vk_stock = settings.VK_STOCK_AMOUNT if vk_p.availability == 0 else 0
            vk_name = vk_p.name or ""
            vk_desc = (vk_p.description or "").strip()
            curr_desc = desc.strip()
            album_changed = str(vk_p.album_id) != str(album_id) if album_id else False
            changed = (
                name != vk_name
                or price_kopecks != vk_price_kopecks
                or curr_desc != vk_desc
                or stock != vk_stock
                or album_changed
            )
        else:
            changed = True  # cached VK product gone, push update

        if not changed:
            return

        resp = _vk_post("market.edit", {
            "owner_id": owner_id,
            "item_id": product.vk_product_id,
            "name": name,
            "description": desc.strip(),
            "category_id": settings.VK_CATEGORY_ID,
            "price": price_kopecks,
            "stock_amount": stock,
        }, token, user_id=user_id)
        if "error" in resp:
            logger.warning("market.edit error product=%s: %s", product.evotor_id, resp["error"])
            return

        if album_changed and album_id and vk_p:
            old_album_id = str(vk_p.album_id)
            _vk_post("market.removeFromAlbum", {
                "owner_id": owner_id,
                "item_id": product.vk_product_id,
                "album_ids": old_album_id,
            }, token, user_id=user_id)
            resp_album = _vk_post("market.addToAlbum", {
                "owner_id": owner_id,
                "item_ids": product.vk_product_id,
                "album_ids": album_id,
            }, token, user_id=user_id)
            if "error" in resp_album:
                logger.warning("market.addToAlbum error product=%s: %s", product.evotor_id, resp_album["error"])
            else:
                logger.info("user=%s moved VK product '%s' album %s→%s", user_id, name, old_album_id, album_id)

        product.synced_at = now
        logger.info("user=%s updated VK product '%s' id=%s", user_id, name, product.vk_product_id)

    else:
        # Create — only if allow_to_sell
        if not product.allow_to_sell:
            return

        photo_id = _get_photo_id(user_id, token, vk_group_id)
        if not photo_id:
            logger.warning("user=%s skipping create for '%s': no photo", user_id, name)
            return

        resp = _vk_post("market.add", {
            "owner_id": owner_id,
            "name": name,
            "description": desc,
            "category_id": settings.VK_CATEGORY_ID,
            "price": price_kopecks,
            "main_photo_id": photo_id,
            "stock_amount": stock,
        }, token, user_id=user_id)
        if "error" in resp:
            logger.warning("market.add error product=%s: %s", product.evotor_id, resp["error"])
            return

        vk_item_id = str(resp["response"]["market_item_id"])
        product.vk_product_id = vk_item_id
        product.synced_at = now

        # Add to album
        resp2 = _vk_post("market.addToAlbum", {
            "owner_id": owner_id,
            "item_ids": vk_item_id,
            "album_ids": album_id,
        }, token, user_id=user_id)
        if "error" in resp2:
            logger.warning("market.addToAlbum error product=%s: %s", product.evotor_id, resp2["error"])

        logger.info("user=%s created VK product '%s' id=%s", user_id, name, vk_item_id)


def _sync_product_list(db, user_id, products, album_id, vk_group_id, token, results, owned_ids):
    for product in products:
        was_new = product.vk_product_id is None
        try:
            _sync_product(db, user_id, product, album_id, vk_group_id, token)
            if product.vk_product_id:
                owned_ids.add(product.vk_product_id)
            if product.synced_at:
                if was_new and product.vk_product_id:
                    results["created"] += 1
                elif not was_new:
                    results["updated"] += 1
                else:
                    results["skipped"] += 1
            else:
                results["skipped"] += 1
        except Exception as e:
            logger.error("user=%s sync_product failed '%s': %s", user_id, product.name, e)
            results["errors"] += 1


def _delete_orphans(db, user_id, vk_group_id, owned_ids, token, results):
    from web.models.connections import VkCachedProduct
    orphans = db.query(VkCachedProduct).filter_by(
        user_id=user_id, vk_group_id=vk_group_id,
    ).filter(VkCachedProduct.vk_product_id.notin_(owned_ids)).all() if owned_ids else \
        db.query(VkCachedProduct).filter_by(user_id=user_id, vk_group_id=vk_group_id).all()

    owner_id = f"-{vk_group_id}"
    for vk_p in orphans:
        try:
            resp = _vk_post("market.delete", {
                "owner_id": owner_id,
                "item_id": vk_p.vk_product_id,
            }, token, user_id=user_id)
            if "error" in resp:
                logger.warning("market.delete error id=%s: %s", vk_p.vk_product_id, resp["error"])
                results["errors"] += 1
            else:
                logger.info("user=%s deleted VK product id=%s '%s'", user_id, vk_p.vk_product_id, vk_p.name)
                db.delete(vk_p)
                results["deleted"] += 1
        except Exception as e:
            logger.error("user=%s delete failed id=%s: %s", user_id, vk_p.vk_product_id, e)
            results["errors"] += 1

    # Also clear vk_product_id on any cached_products that pointed to deleted VK items
    if orphans:
        deleted_vk_ids = {vk_p.vk_product_id for vk_p in orphans}
        stale = db.query(CachedProduct).filter(
            CachedProduct.user_id == user_id,
            CachedProduct.vk_product_id.in_(deleted_vk_ids),
        ).all()
        for p in stale:
            p.vk_product_id = None


def _sync_user(db, user_id: int, token: str, vk_group_id: str) -> dict:
    results = {"created": 0, "updated": 0, "skipped": 0, "deleted": 0, "errors": 0}
    owned_ids: set[str] = set()  # VK product IDs that Evotor owns this run

    enabled_stores = _enabled_store_ids(db, user_id)

    stores = db.query(CachedStore).filter_by(user_id=user_id).all()
    for store in stores:
        if enabled_stores is not None and store.evotor_id not in enabled_stores:
            continue

        enabled_groups = _enabled_group_ids(db, user_id, store.evotor_id)

        groups = db.query(CachedGroup).filter_by(
            user_id=user_id, store_evotor_id=store.evotor_id,
        ).all()

        for group in groups:
            if enabled_groups is not None and group.evotor_id not in enabled_groups:
                continue

            try:
                album_id = _ensure_album(db, user_id, vk_group_id, group.name, token)
            except Exception as e:
                logger.error("user=%s ensure_album failed for '%s': %s", user_id, group.name, e)
                results["errors"] += 1
                continue
            if not album_id:
                results["errors"] += 1
                continue

            products = db.query(CachedProduct).filter_by(
                user_id=user_id, store_evotor_id=store.evotor_id, group_evotor_id=group.evotor_id,
            ).all()
            _sync_product_list(db, user_id, products, album_id, vk_group_id, token, results, owned_ids)

        # Ungrouped products → "Без категории" album
        ungrouped = db.query(CachedProduct).filter_by(
            user_id=user_id, store_evotor_id=store.evotor_id, group_evotor_id=None,
        ).all()
        if ungrouped:
            try:
                fallback_album_id = _ensure_album(db, user_id, vk_group_id, "Без категории", token)
            except Exception as e:
                logger.error("user=%s ensure_album failed for 'Без категории': %s", user_id, e)
                fallback_album_id = None
            if fallback_album_id:
                _sync_product_list(db, user_id, ungrouped, fallback_album_id, vk_group_id, token, results, owned_ids)

    # Delete VK products not owned by any Evotor product
    _delete_orphans(db, user_id, vk_group_id, owned_ids, token, results)

    db.commit()
    return results


@shared_task(
    name="web.tasks.vk_sync.mirror_to_vk",
    queue="sync",
    bind=True,
    max_retries=1,
    default_retry_delay=120,
)
def mirror_to_vk(self) -> dict:
    """Mirror Evotor catalog → VK Market for all users with both connections active."""
    _PHOTO_CACHE.clear()
    db = SessionLocal()
    totals = {"ok": 0, "failed": 0}
    try:
        vk_connections = (
            db.query(VkConnection)
            .filter(
                VkConnection.user_id.isnot(None),
                VkConnection.access_token.isnot(None),
                VkConnection.access_token != "",
                VkConnection.vk_user_id.isnot(None),
                VkConnection.vk_user_id != "",
            )
            .all()
        )
        for conn in vk_connections:
            cfg = db.query(SyncConfig).filter_by(user_id=conn.user_id).first()
            if not cfg or not cfg.is_enabled:
                continue
            try:
                result = _sync_user(db, conn.user_id, conn.access_token, conn.vk_user_id)
                logger.info("user=%s mirror_to_vk: %s", conn.user_id, result)
                totals["ok"] += 1
            except Exception as exc:
                logger.error("mirror_to_vk failed for user=%s: %s", conn.user_id, exc)
                totals["failed"] += 1
    finally:
        db.close()
    logger.info("mirror_to_vk done: %s", totals)
    return totals