import json


def load_orders(file_path):
    with open(file_path, "r", encoding="utf-8") as f: # получаем список словарей orders
        return json.load(f)


def validate_order(order):
    if not isinstance(order, dict): # проверка что order это словарь (dict)
        return False

    for field in ["id", "customer", "items", "total_price"]:
        if field not in order: # проверка что есть все элементы
            return False

    if not isinstance(order["items"], list):
        return False

    for item in order["items"]:
        if not isinstance(item, dict):
            return False
        for field in ["name", "price", "quantity"]:
            if field not in item:
                return False
        if not isinstance(item["price"], (int, float)):
            return False
        if not isinstance(item["quantity"], int):
            return False

    return True


def filter_orders_by_customer(orders, customer_name):
    for order in orders:
        if order["customer"] == customer_name:
            return order


def calculate_order_total(order):
    total = 0
    for item in order["items"]:
        total += item["price"] * item["quantity"]
    return total


def update_order_totals(orders):
    for order in orders:
        order["total_price"] = calculate_order_total(order)
    return orders


def get_top_expensive_orders(orders, n):
    return sorted(orders, key=lambda x: x["total_price"], reverse=True)[:n]


def group_orders_by_customer(orders):
    grouped = {}
    for order in orders:
        customer = order["customer"]  # сравниваем по именам, или лучще по id
        if customer not in grouped:
            grouped[customer] = []
        grouped[customer].append(order)
        # id = order["id"]
        # if id not in grouped:
        #    grouped[id] = []
        # grouped[id].append(order)
    return grouped


def calculate_customer_spending(orders):
    spending = {}
    for order in orders:
        customer = order["customer"]
        spending[customer] = spending.get(customer, 0) + order["total_price"]
    return spending


def find_most_popular_product(orders):
    product_counts = {}

    for order in orders:
        for item in order["items"]:
            name = item["name"]
            product_counts[name] = product_counts.get(name, 0) + item["quantity"]

    if not product_counts:
        return None

    return max(product_counts, key=product_counts.get)


def generate_report(orders):
    report = []

    report.append(f"Общее количество действительных заказов: {len(orders)}")

    spending = calculate_customer_spending(orders)
    sorted_customers = sorted(spending.items(), key=lambda x: x[1], reverse=True)

    report.append("\nТоп клиентов:")
    for customer, amount in sorted_customers[:5]:
        report.append(f"{customer}: {amount}")

    popular_product = find_most_popular_product(orders)
    report.append(f"\nСамый популярный продукт: {popular_product}")

    return "\n".join(report)


def main():
    file_path = "data/orders.txt"

    try:
        orders = load_orders(file_path)
    except Exception as e:
        print("Ошибка загрузки файла:", e)
        return

    # Валидация
    valid_orders = []
    invalid_count = 0

    for order in orders:
        if validate_order(order):
            valid_orders.append(order)
        else:
            invalid_count += 1

    print(f"Пропущенные недействительные заказы: {invalid_count}")

    # Пересчет сумм
    valid_orders = update_order_totals(valid_orders)

    # Пример фильтрации
    example_customer = "Alice"
    customer_orders = filter_orders_by_customer(valid_orders, example_customer)

    # Аналитика
    grouped = group_orders_by_customer(valid_orders)
    spending = calculate_customer_spending(valid_orders)
    top_orders = get_top_expensive_orders(valid_orders, 3)

    # Отчет
    report = generate_report(valid_orders)
    print("\n=== ОТЧЕТ ===")
    print(report)

    print("\n=== ТОП 3 ДОРОГИХ ЗАКАЗОВ ===")
    for order in top_orders:
        print(order)

    print(f"\n{example_customer} приобрел(а) {len(customer_orders)} заказов")
    print(f"Общее количество клиентов: {len(grouped)}")


if __name__ == "__main__":
    main()