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_id: int | None = None       # 0 = guest sale; None when unset


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


class CustomerIn(BaseModel):
    first_name: str
    last_name: str | None = ""
    email: str | None = None
    phone: str | None = None
    address: str | None = None


@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()

    cust = body.customer_id if body.customer_id else None   # don't FK-store the synthetic guest (0)
    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, :cust, :sub, :disc, :tax, :total, :st, :pm, :ps, :paid, :trade,
                :due, CAST(:split AS jsonb), now(), now())
        RETURNING id
    """), {"sn": sale_number, "cust": cust, "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}


# ── Customers ────────────────────────────────────────────────────────────────────────────────
@router.get("/customers")
async def list_customers(q: str = Query(""), ident=Depends(require_token), db=Depends(get_db)):
    where, params = "", {}
    if q.strip():
        where = ("WHERE first_name ILIKE :q OR last_name ILIKE :q OR email ILIKE :q "
                 "OR (first_name || ' ' || coalesce(last_name,'')) ILIKE :q")
        params = {"q": f"%{q.strip()}%"}
    rows = await db.execute(text(f"""
        SELECT id, trim(first_name || ' ' || coalesce(last_name,'')) AS name, email, phone, is_guest
        FROM customer {where} ORDER BY is_guest DESC, first_name, last_name LIMIT 300
    """), params)
    return {"customers": [dict(r) for r in rows.mappings()]}


@router.post("/customers")
async def add_customer(body: CustomerIn, ident=Depends(require_token), db=Depends(get_db)):
    if not body.first_name.strip():
        raise HTTPException(400, "first name required")
    row = (await db.execute(text("""
        INSERT INTO customer (first_name, last_name, email, phone, address, is_guest)
        VALUES (:fn, :ln, :em, :ph, :ad, false) RETURNING id
    """), {"fn": body.first_name.strip(), "ln": (body.last_name or "").strip(),
           "em": body.email, "ph": body.phone, "ad": body.address})).first()
    await db.commit()
    return {"ok": True, "id": row[0], "name": f"{body.first_name} {body.last_name or ''}".strip()}


# ── Discounts / promotions ───────────────────────────────────────────────────────────────────
@router.get("/discounts")
async def list_discounts(active_only: bool = Query(True), ident=Depends(require_token), db=Depends(get_db)):
    where = "WHERE is_active" if active_only else ""
    rows = await db.execute(text(f"""
        SELECT id, name, percentage::float AS percentage, discount_type, description, manual_active,
               bubble_text, bubble_color,
               (is_active AND (start_at IS NULL OR start_at <= now())
                          AND (end_at   IS NULL OR end_at   >= now())) AS live
        FROM sales_discount {where} ORDER BY manual_active DESC, percentage DESC
    """))
    return {"discounts": [dict(r) for r in rows.mappings()]}


@router.post("/discounts/{discount_id}/toggle")
async def toggle_discount(discount_id: int, ident=Depends(require_token), db=Depends(get_db)):
    row = (await db.execute(text(
        "UPDATE sales_discount SET manual_active = NOT manual_active WHERE id=:i RETURNING manual_active"
    ), {"i": discount_id})).first()
    if not row:
        raise HTTPException(404, "not found")
    await db.commit()
    return {"ok": True, "manual_active": row[0]}


# ── Settings (currency / tax / default discount) ─────────────────────────────────────────────
@router.get("/settings")
async def get_settings(ident=Depends(require_token), db=Depends(get_db)):
    rows = await db.execute(text("SELECT setting_key, setting_value FROM sales_setting WHERE is_active"))
    s = {r["setting_key"]: r["setting_value"] for r in rows.mappings()}
    return {"currency_symbol": s.get("currency_symbol", "$"),
            "tax_rate": s.get("default_tax_rate", s.get("tax_rate", "0")),
            "discount_rate": s.get("default_discount_rate", "0"),
            "tax_type": s.get("tax_type", "exclusive")}


@router.post("/settings")
async def save_settings(body: dict, ident=Depends(require_token), db=Depends(get_db)):
    m = {"currency_symbol": body.get("currency_symbol"), "default_tax_rate": body.get("tax_rate"),
         "default_discount_rate": body.get("discount_rate"), "tax_type": body.get("tax_type")}
    for k, v in m.items():
        if v is None:
            continue
        await db.execute(text("""
            INSERT INTO sales_setting (setting_key, setting_value, updated_at) VALUES (:k, :v, now())
            ON CONFLICT (setting_key) DO UPDATE SET setting_value = :v, updated_at = now()
        """), {"k": k, "v": str(v)})
    await db.commit()
    return {"ok": True}


# ── Past sales (the migrated history — receipts / lookup / refund) ────────────────────────────
@router.get("/past")
async def past_sales(q: str = Query(""), ident=Depends(require_token), db=Depends(get_db)):
    where, params = "", {}
    if q.strip():
        where = ("WHERE s.sale_number ILIKE :q "
                 "OR trim(c.first_name || ' ' || coalesce(c.last_name,'')) ILIKE :q")
        params = {"q": f"%{q.strip()}%"}
    rows = await db.execute(text(f"""
        SELECT s.id, s.sale_number, s.total::float AS total, s.status, s.payment_method,
               s.payment_status, s.sale_date,
               coalesce(nullif(trim(c.first_name || ' ' || coalesce(c.last_name,'')), ''), 'Guest') AS customer,
               (SELECT count(*) FROM sale_items si WHERE si.sale_id = s.id) AS items
        FROM sales s LEFT JOIN customer c ON c.id = s.customer_id
        {where} ORDER BY s.sale_date DESC NULLS LAST LIMIT 100
    """), params)
    return {"sales": [dict(r) for r in rows.mappings()]}