from datetime import datetime

from flask import Blueprint, redirect, render_template, request, url_for
from sqlalchemy import distinct, select
from werkzeug.wrappers.response import Response

from app.db import SessionLocal
from app.models import Drink, Transaction

bp = Blueprint("main", __name__)


@bp.get("/")
def index() -> str:
    return render_template("index.html")


@bp.get("/add")
def create_drink_get() -> str:
    return render_template("add.html")


@bp.post("/add")
def create_drink_post() -> Response | tuple[str, int]:
    name = request.form.get("name")
    stock_raw = request.form.get("stock")
    price_raw = request.form.get("price")
    contact = request.form.get("phone_number")

    if name is None or stock_raw is None or price_raw is None or contact is None:
        return "Missing required fields", 400

    name = name.strip()
    contact = contact.strip()

    try:
        stock = int(stock_raw)
        price = float(price_raw)
    except ValueError:
        return "Invalid numeric input", 400

    if stock <= 0 or price <= 0:
        return "Invalid stock or price", 400

    session = SessionLocal()

    drink = Drink(name=name, stock=stock, price=price, stocked_by=contact)

    session.add(drink)
    session.commit()

    return redirect(url_for("main.list_drinks_get", id=drink.id))


@bp.get("/drink/<id>/manage")
def manage_drink_get(id: int) -> str | tuple[str, int]:  # noqa: A002
    session = SessionLocal()

    drink = session.get(Drink, id)
    if drink is None:
        return "Drink not found", 404

    return render_template("drink_manage.html", drink=drink)


@bp.post("/drink/<id>/restock")
def restock_drink_post(id: int) -> Response | tuple[str, int]:  # noqa: A002
    session = SessionLocal()

    drink = session.get(Drink, id)
    if drink is None:
        return "Drink not found", 404

    amount_raw = request.form.get("amount")

    if amount_raw is None:
        return "Missing fields", 400

    try:
        amount = int(amount_raw)
    except ValueError:
        return "Non numeric amount", 400

    if amount <= 0:
        return "Invalid amount", 400

    drink.stock += amount
    session.commit()

    return redirect(url_for("main.manage_drink_get", id=id))


@bp.post("/drink/<id>/delete")
def delete_drink_post(id: int) -> Response | tuple[str, int]:  # noqa: A002
    session = SessionLocal()

    drink = session.get(Drink, id)
    if drink is None:
        return "Drink not found", 404

    session.delete(drink)
    session.commit()

    return redirect(url_for("main.list_drinks_get"))


@bp.get("/drinks")
def list_drinks_get() -> str:
    session = SessionLocal()

    stmt = select(Drink)
    result = session.execute(stmt)
    drinks = [row[0] for row in result if row[0]]

    return render_template("drink_list.html", drinks=drinks)


@bp.get("/drink/<id>")
def buy_drink_get(id: int) -> str | tuple[str, int]:  # noqa: A002
    session = SessionLocal()

    drink = session.get(Drink, id)
    if drink is None:
        return "Drink not found", 404

    # Find user names
    stmt = select(distinct(Transaction.user_name)).order_by(Transaction.user_name)
    result = session.execute(stmt).all()
    names = [row[0] for row in result if row[0]]

    return render_template("drink_buy.html", drink=drink, names=names)


@bp.post("/drink/<id>/buy")
def buy_drink_post(id: int) -> Response | tuple[str, int]:  # noqa: A002
    session = SessionLocal()

    drink = session.get(Drink, id)
    if drink is None:
        return "Drink not found", 404

    name = request.form.get("name")
    qty_raw = request.form.get("quantity")

    if name is None or qty_raw is None:
        return "Missing fields", 400

    name = name.strip()

    try:
        quantity = int(qty_raw)
    except ValueError:
        return "Invalid quantity", 400

    if quantity <= 0:
        return "Quantity must be positive", 400

    if drink.stock < quantity:
        return "Not enough stock", 400

    # Update stock
    drink.stock -= quantity

    # Create transaction
    transaction = Transaction(drink=drink.id, user_name=name, quantity=quantity, timestamp=datetime.now().astimezone())

    session.add(transaction)
    session.commit()

    return redirect(url_for("main.list_drinks_get", id=id))


@bp.get("/transactions")
def list_transactions_get() -> str:
    session = SessionLocal()

    stmt = select(Transaction).order_by(Transaction.timestamp)
    result = session.execute(stmt).all()
    txs: list[Transaction] = [row[0] for row in result if row[0]]

    stmt = select(Drink)
    result = session.execute(stmt).all()
    drinks: dict[int, Drink] = {row[0].id: row[0] for row in result if row[0]}

    patched = [
        {
            "drink_name": drinks[t.drink].name if t.drink in drinks else "<removed drink>",
            "user_name": t.user_name,
            "quantity": t.quantity,
            "timestamp": t.timestamp,
        }
        for t in txs
    ]

    return render_template("transactions.html", transactions=patched)