using Microsoft.Extensions.Configuration;
using QuestionsApi.Models;
using QuestionsApi.Services;
using Xunit;

namespace QuestionsApi.Tests;

public sealed class DynamicQuestionTests
{
    [Fact]
    public void Generator_IsDeterministic_AndPreservesCorrectAnswer()
    {
        var blueprint = Blueprint();
        var generator = new DynamicQuestionGenerator();

        var first = generator.Generate(blueprint, "same-seed", "one").Question;
        var second = generator.Generate(blueprint, "same-seed", "two").Question;

        Assert.Equal(first.Stem, second.Stem);
        Assert.Equal(first.Choices.Select(value => value.Text), second.Choices.Select(value => value.Text));
        Assert.Equal("correct", first.CorrectChoiceId);
        Assert.Null(DynamicQuestionGenerator.Validate(blueprint));
    }

    [Fact]
    public void SignedTokens_AreUserBound_AndRejectTampering()
    {
        var configuration = new ConfigurationBuilder()
            .AddInMemoryCollection(new Dictionary<string, string?> { ["DynamicQuestions:SigningKey"] = "unit-test-key" })
            .Build();
        var service = new DynamicQuestionTokenService(configuration);
        var claims = new DynamicGenerationClaims
        {
            UserId = "user-one",
            BlueprintExternalId = "test",
            BlueprintVersion = 1,
            ObjectiveId = "objective",
            Seed = "seed",
            Nonce = "nonce",
            GeneratorVersion = 1,
            ExpiresUtc = DateTime.UtcNow.AddMinutes(5)
        };

        var token = service.SignGeneration(claims);

        Assert.Equal("seed", service.ReadGeneration(token, "user-one").Seed);
        Assert.Throws<ArgumentException>(() => service.ReadGeneration(token, "user-two"));
        Assert.ThrowsAny<Exception>(() => service.ReadGeneration(token + "x", "user-one"));
    }

    private static DynamicQuestionBlueprint Blueprint() => new()
    {
        ExternalId = "test",
        ObjectiveId = "objective",
        StemTemplate = "Patient age {{age}}.",
        LeadIn = "What is correct?",
        Variables = new()
        {
            ["age"] = new DynamicVariableDefinition { Minimum = 20, Maximum = 80, Step = 1 }
        },
        CorrectAnswer = new DynamicAnswerTemplate { Id = "correct", TextTemplate = "Correct" },
        Distractors =
        [
            new() { Id = "a", TextTemplate = "A" },
            new() { Id = "b", TextTemplate = "B" },
            new() { Id = "c", TextTemplate = "C" },
            new() { Id = "d", TextTemplate = "D" }
        ],
        References = [new QuestionReference { Title = "Reference", Url = "https://example.test" }]
    };
}