from __future__ import annotations

import re
import unicodedata

from sqlalchemy import select
from sqlalchemy.ext.asyncio import AsyncSession

from models.market_place import MarketPlace
from models.ghost_content import Post
from suma_browser.app.utils import utcnow


class MarketError(ValueError):
    """Base error for market service operations."""


def slugify(value: str, max_len: int = 255) -> str:
    if value is None:
        value = ""
    value = unicodedata.normalize("NFKD", value)
    value = value.encode("ascii", "ignore").decode("ascii")
    value = value.lower()
    value = value.replace("/", "-")
    value = re.sub(r"[^a-z0-9]+", "-", value)
    value = re.sub(r"-{2,}", "-", value)
    value = value.strip("-")[:max_len].strip("-")
    return value or "market"


async def create_market(sess: AsyncSession, post_id: int, name: str) -> MarketPlace:
    """
    Create a market for a page. Name must be unique per page.
    If a market with the same (post_id, slug) exists but is soft-deleted,
    it will be revived.
    """
    name = (name or "").strip()
    if not name:
        raise MarketError("Market name must not be empty.")
    slug = slugify(name)

    post = (await sess.execute(select(Post).where(Post.id == post_id))).scalar_one_or_none()
    if not post:
        raise MarketError(f"Post {post_id} does not exist.")
    if not post.is_page:
        raise MarketError("Markets can only be created on pages, not posts.")

    # Look for existing (including soft-deleted)
    existing = (await sess.execute(
        select(MarketPlace).where(MarketPlace.post_id == post_id, MarketPlace.slug == slug)
    )).scalar_one_or_none()

    if existing:
        if existing.deleted_at is not None:
            existing.deleted_at = None
            existing.name = name
            await sess.flush()
            return existing
        raise MarketError(f'Market with slug "{slug}" already exists for this page.')

    market = MarketPlace(post_id=post_id, name=name, slug=slug)
    sess.add(market)
    await sess.flush()
    return market


async def soft_delete(sess: AsyncSession, post_slug: str, market_slug: str) -> bool:
    market = (
        await sess.execute(
            select(MarketPlace)
            .join(Post, MarketPlace.post_id == Post.id)
            .where(
                Post.slug == post_slug,
                MarketPlace.slug == market_slug,
                MarketPlace.deleted_at.is_(None),
            )
        )
    ).scalar_one_or_none()

    if not market:
        return False

    market.deleted_at = utcnow()
    await sess.flush()
    return True