// <copyright file="HlcTimestampJsonConverterTests.cs" company="StellaOps">
// Copyright (c) StellaOps. Licensed under AGPL-3.0-or-later.
// </copyright>

using System.Text.Json;
using FluentAssertions;

namespace StellaOps.HybridLogicalClock.Tests;

/// <summary>
/// Unit tests for <see cref="HlcTimestampJsonConverter"/>.
/// </summary>
[Trait("Category", "Unit")]
public sealed class HlcTimestampJsonConverterTests
{
    private readonly JsonSerializerOptions _options = new()
    {
        Converters = { new HlcTimestampJsonConverter() }
    };

    [Fact]
    public void Serialize_ProducesSortableString()
    {
        // Arrange
        var timestamp = new HlcTimestamp
        {
            PhysicalTime = 1704067200000,
            NodeId = "node1",
            LogicalCounter = 42
        };

        // Act
        var json = JsonSerializer.Serialize(timestamp, _options);

        // Assert
        json.Should().Be("\"1704067200000-node1-000042\"");
    }

    [Fact]
    public void Deserialize_ParsesSortableString()
    {
        // Arrange
        var json = "\"1704067200000-node1-000042\"";

        // Act
        var result = JsonSerializer.Deserialize<HlcTimestamp>(json, _options);

        // Assert
        result.PhysicalTime.Should().Be(1704067200000);
        result.NodeId.Should().Be("node1");
        result.LogicalCounter.Should().Be(42);
    }

    [Fact]
    public void RoundTrip_PreservesValues()
    {
        // Arrange
        var original = new HlcTimestamp
        {
            PhysicalTime = 1704067200000,
            NodeId = "scheduler-east-1",
            LogicalCounter = 999
        };

        // Act
        var json = JsonSerializer.Serialize(original, _options);
        var deserialized = JsonSerializer.Deserialize<HlcTimestamp>(json, _options);

        // Assert
        deserialized.Should().Be(original);
    }

    [Fact]
    public void Deserialize_Null_ReturnsZero()
    {
        // Arrange
        var json = "null";

        // Act
        var result = JsonSerializer.Deserialize<HlcTimestamp>(json, _options);

        // Assert
        result.Should().Be(default(HlcTimestamp));
    }

    [Fact]
    public void Deserialize_InvalidFormat_ThrowsJsonException()
    {
        // Arrange
        var json = "\"invalid\"";

        // Act
        var act = () => JsonSerializer.Deserialize<HlcTimestamp>(json, _options);

        // Assert
        act.Should().Throw<JsonException>();
    }

    [Fact]
    public void Deserialize_WrongTokenType_ThrowsJsonException()
    {
        // Arrange
        var json = "12345"; // number, not string

        // Act
        var act = () => JsonSerializer.Deserialize<HlcTimestamp>(json, _options);

        // Assert
        act.Should().Throw<JsonException>();
    }

    [Fact]
    public void SerializeInObject_WorksCorrectly()
    {
        // Arrange
        var obj = new TestWrapper
        {
            Timestamp = new HlcTimestamp
            {
                PhysicalTime = 1704067200000,
                NodeId = "node1",
                LogicalCounter = 1
            },
            Name = "Test"
        };

        // Act
        var json = JsonSerializer.Serialize(obj, _options);
        var deserialized = JsonSerializer.Deserialize<TestWrapper>(json, _options);

        // Assert
        deserialized.Should().NotBeNull();
        deserialized!.Timestamp.Should().Be(obj.Timestamp);
        deserialized.Name.Should().Be(obj.Name);
    }

    private sealed class TestWrapper
    {
        public HlcTimestamp Timestamp { get; set; }
        public string? Name { get; set; }
    }
}