using System.Security.Cryptography;
using Microsoft.Extensions.Options;
using Microsoft.IdentityModel.JsonWebTokens;
using Microsoft.IdentityModel.Tokens;
using Musify.StreamingGateway.Authentication;
using Musify.StreamingGateway.Configuration;
using Xunit;

namespace Musify.StreamingGateway.Tests.Authentication
{
    public sealed class TicketValidatorTests : IDisposable
    {
        private const string Issuer = "musify-webapi";
        private const string Audience = "media-gateway";

        private readonly string publicKeyPath = Path.GetTempFileName();
        private readonly RSA rsa = RSA.Create(2048);
        private readonly JsonWebTokenHandler tokenHandler = new();

        public TicketValidatorTests() => File.WriteAllText(publicKeyPath, rsa.ExportSubjectPublicKeyInfoPem());

        public void Dispose()
        {
            rsa.Dispose();
            File.Delete(publicKeyPath);
        }

        private TicketValidator CreateValidator() => new(Options.Create(new StreamTicketValidationOptions
        {
            PublicKeyPath = publicKeyPath,
            Audience = Audience,
            Issuer = Issuer
        }));

        private string IssueToken(string prefix = "Tracks/ProcessedAudios/abc/", string issuer = Issuer, string audience = Audience,
            DateTime? expires = null, DateTime? notBefore = null, long? maxBytes = null)
        {
            var claims = new Dictionary<string, object> { ["prefix"] = prefix };
            if (maxBytes != null)
                claims["maxBytes"] = maxBytes.Value.ToString();

            var descriptor = new SecurityTokenDescriptor
            {
                Issuer = issuer,
                Audience = audience,
                NotBefore = notBefore ?? DateTime.UtcNow.AddMinutes(-1),
                Expires = expires ?? DateTime.UtcNow.AddMinutes(5),
                Claims = claims,
                SigningCredentials = new SigningCredentials(new RsaSecurityKey(rsa), SecurityAlgorithms.RsaSha256),
            };
            return tokenHandler.CreateToken(descriptor);
        }

        [Fact]
        public async Task ValidateTicketAsync_ValidToken_ReturnsThePrefixClaim()
        {
            var token = IssueToken(prefix: "Tracks/ProcessedAudios/xyz/");

            var result = await CreateValidator().ValidateTicketAsync(token);

            Assert.True(result.IsValid);
            Assert.Equal("Tracks/ProcessedAudios/xyz/", result.Prefix);
            Assert.Null(result.MaxBytes);
        }

        [Fact]
        public async Task ValidateTicketAsync_TokenWithMaxBytesClaim_ReturnsIt()
        {
            var token = IssueToken(maxBytes: 480_000);

            var result = await CreateValidator().ValidateTicketAsync(token);

            Assert.True(result.IsValid);
            Assert.Equal(480_000, result.MaxBytes);
        }

        [Theory]
        [InlineData(null)]
        [InlineData("")]
        [InlineData("   ")]
        public async Task ValidateTicketAsync_BlankToken_ReturnsInvalid(string? token)
        {
            var result = await CreateValidator().ValidateTicketAsync(token);

            Assert.False(result.IsValid);
            Assert.Equal(string.Empty, result.Prefix);
        }

        [Fact]
        public async Task ValidateTicketAsync_MalformedToken_ReturnsInvalid()
        {
            var result = await CreateValidator().ValidateTicketAsync("not-a-real-jwt");

            Assert.False(result.IsValid);
        }

        [Fact]
        public async Task ValidateTicketAsync_ExpiredToken_ReturnsInvalid()
        {
            var token = IssueToken(expires: DateTime.UtcNow.AddMinutes(-40), notBefore: DateTime.UtcNow.AddMinutes(-50));

            var result = await CreateValidator().ValidateTicketAsync(token);

            Assert.False(result.IsValid);
        }

        [Fact]
        public async Task ValidateTicketAsync_WrongIssuer_ReturnsInvalid()
        {
            var token = IssueToken(issuer: "someone-else");

            var result = await CreateValidator().ValidateTicketAsync(token);

            Assert.False(result.IsValid);
        }

        [Fact]
        public async Task ValidateTicketAsync_WrongAudience_ReturnsInvalid()
        {
            var token = IssueToken(audience: "someone-else");

            var result = await CreateValidator().ValidateTicketAsync(token);

            Assert.False(result.IsValid);
        }

        [Fact]
        public async Task ValidateTicketAsync_SignedWithADifferentKey_ReturnsInvalid()
        {
            using var otherKey = RSA.Create(2048);
            var descriptor = new SecurityTokenDescriptor
            {
                Issuer = Issuer,
                Audience = Audience,
                NotBefore = DateTime.UtcNow.AddMinutes(-1),
                Expires = DateTime.UtcNow.AddMinutes(5),
                Claims = new Dictionary<string, object> { ["prefix"] = "Tracks/ProcessedAudios/abc/" },
                SigningCredentials = new SigningCredentials(new RsaSecurityKey(otherKey), SecurityAlgorithms.RsaSha256),
            };
            var token = tokenHandler.CreateToken(descriptor);

            var result = await CreateValidator().ValidateTicketAsync(token);

            Assert.False(result.IsValid);
        }

        [Fact]
        public async Task ValidateTicketAsync_MissingPrefixClaim_ReturnsInvalid()
        {
            var descriptor = new SecurityTokenDescriptor
            {
                Issuer = Issuer,
                Audience = Audience,
                NotBefore = DateTime.UtcNow.AddMinutes(-1),
                Expires = DateTime.UtcNow.AddMinutes(5),
                SigningCredentials = new SigningCredentials(new RsaSecurityKey(rsa), SecurityAlgorithms.RsaSha256),
            };
            var token = tokenHandler.CreateToken(descriptor);

            var result = await CreateValidator().ValidateTicketAsync(token);

            Assert.False(result.IsValid);
        }
    }
}