using System.Runtime.CompilerServices;
using System.Text.Json;

namespace Bff.Tests;

/// <summary>
/// Guards the committed OpenAPI contract (<c>services/bff/openapi.json</c>) against drift: it must
/// equal the document the running BFF serves. S-08's Angular client is generated from this file, so a
/// stale spec is a bug. To regenerate: run the BFF and save <c>/openapi/v1.json</c> over the file.
/// </summary>
public class OpenApiSpecTests
{
    [Fact]
    public async Task Committed_openapi_spec_matches_the_served_document()
    {
        using var factory = new BffFactory();

        var served = await factory.CreateClient().GetStringAsync("/openapi/v1.json");
        var committed = await File.ReadAllTextAsync(SpecPath());

        Assert.Equal(Canonical(committed), Canonical(served));
    }

    // Reformat both sides identically so the comparison is about content, not whitespace.
    private static string Canonical(string json)
    {
        using var doc = JsonDocument.Parse(json);
        return JsonSerializer.Serialize(doc.RootElement, new JsonSerializerOptions { WriteIndented = true });
    }

    // The committed spec sits at services/bff/openapi.json — one level up from this test file.
    private static string SpecPath([CallerFilePath] string thisFile = "")
        => Path.Combine(Path.GetDirectoryName(thisFile)!, "..", "openapi.json");
}