// Exercise 2: a value object with records and validation (easy)
//
// Implement Money as a record with:
//   - A constructor that rejects negative amounts and currencies that aren't 3 uppercase letters
//     (throw ArgumentException).
//   - Add(Money other): returns a new Money; throws InvalidOperationException for different currencies.
//   - Allocate(int parts): splits the amount into `parts` Money values in cents that differ by at most 0.01
//     and sum exactly to the original (e.g. 10.00 / 3 → 3.34, 3.33, 3.33). Larger parts first.
//   - Value equality and ToString "<Amount:0.00> <Currency>" (e.g. "10.00 EUR"), formatted with the invariant culture.
//
// Run with: dotnet run (inside a console project).

using System;
using System.Linq;

record Money
{
    public decimal Amount { get; }
    public string Currency { get; }
    public Money(decimal amount, string currency)
    {
        Amount = amount; Currency = currency; // TODO: validate
    }
    public Money Add(Money other) => this; // TODO
    public Money[] Allocate(int parts) => new Money[0]; // TODO
    public override string ToString() => ""; // TODO
}

class Program
{

    static void Main()
    {
        int pass = 0, total = 0;
        void Check(string name, bool ok) { total++; if (ok) pass++; Console.WriteLine($"{(ok ? "PASS" : "FAIL")}: {name}"); }

        bool Throws<T>(Action a) where T : Exception { try { a(); return false; } catch (T) { return true; } }
        Check("rejects negative", Throws<ArgumentException>(() => new Money(-1m, "EUR")));
        Check("rejects bad currency", Throws<ArgumentException>(() => new Money(1m, "eur")) && Throws<ArgumentException>(() => new Money(1m, "EURO")));
        Check("value equality", new Money(5m, "EUR") == new Money(5.00m, "EUR"));
        Check("add", new Money(2.5m, "EUR").Add(new Money(1.25m, "EUR")) == new Money(3.75m, "EUR"));
        Check("currency mismatch", Throws<InvalidOperationException>(() => new Money(1m, "EUR").Add(new Money(1m, "USD"))));
        var parts = new Money(10m, "EUR").Allocate(3);
        Check("allocate " + string.Join(" | ", parts.Select(p => p.ToString())), parts.Select(p => p.Amount).SequenceEqual(new[] { 3.34m, 3.33m, 3.33m }) && parts.Sum(p => p.Amount) == 10m);
        Check("ToString", new Money(10m, "EUR").ToString() == "10.00 EUR");

        Console.WriteLine($"--- {pass}/{total} checks passed ---");
    }
}