using System;
using System.Collections.Generic;
using MediaBrowser.Model.Cryptography;

namespace Jellyfin.Plugin.WatchedTogether.Tests;

/// <summary>
/// A crypto provider that accepts exactly the (stored hash, submitted password) pairs it is given.
/// </summary>
/// <remarks>
/// Hand-written rather than mocked: <see cref="ICryptoProvider.Verify"/> takes a
/// <c>ReadOnlySpan&lt;char&gt;</c>, and a ref struct cannot be used as a generic type argument to
/// Moq's <c>It.IsAny&lt;T&gt;</c>.
/// </remarks>
public sealed class StubCryptoProvider : ICryptoProvider
{
    private readonly IReadOnlyList<(string Hash, string Password)> _validPairs;

    public StubCryptoProvider(IReadOnlyList<(string Hash, string Password)> validPairs)
    {
        _validPairs = validPairs;
    }

    /// <summary>
    /// Gets the salt of each credential this provider was asked to verify, in call order. Lets a
    /// test assert which member's password was checked first.
    /// </summary>
    public List<string> VerifiedSalts { get; } = new();

    public string DefaultHashMethod => "PBKDF2-SHA512";

    public bool Verify(PasswordHash hash, ReadOnlySpan<char> password)
    {
        var candidate = password.ToString();

        // Identify the stored credential by its salt rather than by re-formatting the whole hash,
        // which need not round-trip through Parse/ToString byte for byte.
        var salt = Convert.ToHexString(hash.Salt);
        VerifiedSalts.Add(salt);

        foreach (var (validHash, validPassword) in _validPairs)
        {
            var expectedSalt = validHash.Split('$')[3];
            if (string.Equals(salt, expectedSalt, StringComparison.OrdinalIgnoreCase)
                && candidate == validPassword)
            {
                return true;
            }
        }

        return false;
    }

    public PasswordHash CreatePasswordHash(ReadOnlySpan<char> password)
        => throw new NotSupportedException();

    public byte[] GenerateSalt() => throw new NotSupportedException();

    public byte[] GenerateSalt(int length) => throw new NotSupportedException();
}