"""Public listing of inventory items owners marked as `available`.

Read-only and unauthenticated, like the catalog. Notes are never included: the
listing only reveals the owner's username, quantity and catalog details.
"""
import math

from fastapi import APIRouter, Depends, Query
from sqlalchemy import select
from sqlalchemy.orm import Session as DbSession

from app.db import get_db
from app.inventory import SORT_KEYS, enrich_entry
from app.models import InventoryEntry, User
from app.schemas import AvailablePage

router = APIRouter(prefix="/api/v1/available", tags=["available"])

MAX_PAGE_SIZE = 100


@router.get("", response_model=AvailablePage)
def list_available(
    category: str | None = None,
    search: str | None = None,
    sort: str = Query(default="updated", pattern="^(name|category|quantity|updated)$"),
    page: int = Query(default=1, ge=1),
    page_size: int = Query(default=25, ge=1),
    db: DbSession = Depends(get_db),
):
    page_size = min(page_size, MAX_PAGE_SIZE)
    rows = db.execute(
        select(InventoryEntry, User.username)
        .join(User, User.id == InventoryEntry.user_id)
        .where(InventoryEntry.visibility == "available")
    ).all()

    items = []
    for entry, username in rows:
        enriched = enrich_entry(entry)
        if not enriched["available"]:
            continue
        enriched["username"] = username
        items.append(enriched)

    if category is not None and category.strip():
        wanted = category.strip()
        items = [i for i in items if i["category"] == wanted]
    if search is not None and search.strip():
        needle = search.strip().lower()
        items = [
            i
            for i in items
            if needle in i["name"].lower()
            or needle in i["class_name"].lower()
            or needle in i["username"].lower()
        ]

    items.sort(key=SORT_KEYS[sort])
    total = len(items)
    total_pages = max(1, math.ceil(total / page_size))
    start = (page - 1) * page_size
    return {
        "total": total,
        "page": page,
        "page_size": page_size,
        "total_pages": total_pages,
        "items": items[start : start + page_size],
    }