import json
import secrets
from datetime import datetime

from fastapi import APIRouter, Depends, HTTPException, Query
from pydantic import BaseModel
from sqlalchemy import text

from .auth import require_token
from .db import get_db

# Point-of-sale — ring up sales, line/cart discounts, split tender, payment plans (holds),
# trade-in credit. Ported from WowPlatter's sales engine onto RecordGod's own tables.
router = APIRouter(prefix="/sales", tags=["sales"])


class LineIn(BaseModel):
    sku: str
    title: str | None = None
    qty: int = 1
    unit_price: float
    discount: float = 0


class SaleIn(BaseModel):
    items: list[LineIn]
    cart_discount: float = 0
    tax_rate: float = 0
    payment_method: str = "cash"
    split: list[dict] | None = None
    hold: dict | None = None
    trade_in: float = 0
    customer: str | None = None


class PayIn(BaseModel):
    amount: float
    method: str = "cash"


@router.get("/search")
async def search_items(q: str = Query(""), ident=Depends(require_token), db=Depends(get_db)):
    """Find in-stock items to ring up — title/artist/sku/barcode. The counter's search bar."""
    if not q.strip():
        return {"items": []}
    rows = await db.execute(text("""
        SELECT i.sku, coalesce(i.title, dc.title) AS title, dc.artist, dc.thumb,
               i.price::float AS price, i.condition, i.crate_id, c.label_text AS crate
        FROM inventory i
        LEFT JOIN disc_cache dc ON dc.release_id = i.release_id
        LEFT JOIN crate c ON c.id = i.crate_id
        WHERE i.store_id = 1 AND i.in_stock
          AND (i.sku ILIKE :q OR i.identifier = :raw
               OR coalesce(i.title, dc.title) ILIKE :q OR dc.artist ILIKE :q)
        ORDER BY i.updated_at DESC NULLS LAST LIMIT 25
    """), {"q": f"%{q.strip()}%", "raw": q.strip()})
    return {"items": [dict(r) for r in rows.mappings()]}


@router.post("")
async def create_sale(body: SaleIn, ident=Depends(require_token), db=Depends(get_db)):
    if not body.items:
        raise HTTPException(400, "no items")
    gross = sum(li.unit_price * li.qty for li in body.items)
    line_disc = sum(li.discount for li in body.items)
    sub_after = gross - line_disc - body.cart_discount
    tax = round(sub_after * body.tax_rate / 100, 2)
    total = round(sub_after + tax - body.trade_in, 2)

    is_hold = bool(body.hold)
    deposit = float(body.hold.get("deposit", 0)) if is_hold else 0
    amount_paid = deposit if is_hold else total
    status, pay_status = ("held", "hold") if is_hold else ("completed", "paid")
    hold_due = body.hold.get("due_date") if is_hold else None
    sale_number = "S" + datetime.now().strftime("%y%m%d") + "-" + secrets.token_hex(2).upper()

    sale_id = (await db.execute(text("""
        INSERT INTO sales (sale_number, customer_id, subtotal, discount_amount, tax_amount, total,
                           status, payment_method, payment_status, amount_paid, trade_in_credit,
                           hold_expires_at, split_payments, sale_date, created_at)
        VALUES (:sn, NULL, :sub, :disc, :tax, :total, :st, :pm, :ps, :paid, :trade,
                :due, CAST(:split AS jsonb), now(), now())
        RETURNING id
    """), {"sn": sale_number, "sub": gross - line_disc, "disc": line_disc + body.cart_discount,
           "tax": tax, "total": total, "st": status, "pm": body.payment_method, "ps": pay_status,
           "paid": amount_paid, "trade": body.trade_in, "due": hold_due,
           "split": json.dumps(body.split) if body.split else None})).first()[0]

    for li in body.items:
        await db.execute(text("""
            INSERT INTO sale_items (sale_id, sku, item_name, qty, unit_price, line_total,
                                    discount_amount, original_price)
            VALUES (:sid, :sku, :name, :qty, :up, :lt, :disc, :op)
        """), {"sid": sale_id, "sku": li.sku, "name": li.title or li.sku, "qty": li.qty,
               "up": li.unit_price, "lt": li.unit_price * li.qty - li.discount,
               "disc": li.discount, "op": li.unit_price})

    # take the items off the floor (sold, or reserved on a hold) so they can't be double-sold
    await db.execute(text("""
        UPDATE inventory SET in_stock = false, status = :ist,
               sold_date = CASE WHEN :ist = 'sold' THEN now() ELSE NULL END
        WHERE sku = ANY(:skus) AND store_id = 1
    """), {"ist": "held" if is_hold else "sold", "skus": [li.sku for li in body.items]})
    await db.commit()
    return {"ok": True, "sale_id": sale_id, "sale_number": sale_number, "total": total,
            "amount_paid": amount_paid, "balance": round(total - amount_paid, 2), "status": status}


@router.get("")
async def list_sales(status: str = Query(""), ident=Depends(require_token), db=Depends(get_db)):
    where, params = "", {}
    if status == "holds":
        where = "WHERE payment_status = 'hold'"
    elif status:
        where, params = "WHERE status = :st", {"st": status}
    rows = await db.execute(text(f"""
        SELECT id, sale_number, total::float AS total, coalesce(amount_paid,0)::float AS amount_paid,
               (total - coalesce(amount_paid,0))::float AS balance, status, payment_status,
               payment_method, hold_expires_at, sale_date
        FROM sales {where} ORDER BY sale_date DESC NULLS LAST LIMIT 60
    """), params)
    return {"sales": [dict(r) for r in rows.mappings()]}


@router.get("/{sale_id}")
async def sale_detail(sale_id: int, ident=Depends(require_token), db=Depends(get_db)):
    s = (await db.execute(text("SELECT * FROM sales WHERE id=:i"), {"i": sale_id})).mappings().first()
    if not s:
        raise HTTPException(404, "not found")
    items = [dict(r) for r in (await db.execute(text(
        "SELECT sku, item_name, qty, unit_price::float AS unit_price, line_total::float AS line_total, "
        "discount_amount::float AS discount FROM sale_items WHERE sale_id=:i"), {"i": sale_id})).mappings()]
    return {"sale": dict(s), "items": items}


@router.post("/{sale_id}/pay")
async def take_payment(sale_id: int, body: PayIn, ident=Depends(require_token), db=Depends(get_db)):
    """Payment toward a held / payment-plan sale. Fully paid → completes it + sells the items."""
    s = (await db.execute(text("SELECT total::float AS total, coalesce(amount_paid,0)::float AS paid FROM sales WHERE id=:i"),
                          {"i": sale_id})).mappings().first()
    if not s:
        raise HTTPException(404, "not found")
    new_paid = round(s["paid"] + body.amount, 2)
    done = new_paid >= s["total"] - 0.005
    await db.execute(text(
        "UPDATE sales SET amount_paid=:p, payment_status=:ps, status=:st WHERE id=:i"),
        {"p": new_paid, "ps": "paid" if done else "hold",
         "st": "completed" if done else "held", "i": sale_id})
    if done:
        await db.execute(text("""
            UPDATE inventory SET status='sold', sold_date=now()
            WHERE sku IN (SELECT sku FROM sale_items WHERE sale_id=:i) AND store_id = 1
        """), {"i": sale_id})
    await db.commit()
    return {"ok": True, "amount_paid": new_paid, "balance": round(s["total"] - new_paid, 2), "completed": done}