using Xunit;
using FluentAssertions;
using NSubstitute;
using System.Text.Json;
using FreeCode.Core.Models;

namespace FreeCode.Tests.Unit.Models;

public sealed class ApiRequestTests
{
    [Fact]
    public void ApiRequest_HoldsProvidedSystemPrompt()
    {
        var request = new ApiRequest("system", ParseJson("[]"), ParseJson("[]"), "model");

        request.SystemPrompt.Should().Be("system");
    }

    [Fact]
    public void ApiRequest_HoldsMessagesJson()
    {
        var messages = ParseJson("[{\"role\":\"user\",\"content\":\"hello\"}]");

        var request = new ApiRequest("system", messages, ParseJson("[]"));

        request.Messages.ValueKind.Should().Be(JsonValueKind.Array);
        request.Messages[0].GetProperty("role").GetString().Should().Be("user");
    }

    [Fact]
    public void ApiRequest_HoldsToolsJson()
    {
        var tools = ParseJson("[{\"name\":\"bash\"}]");

        var request = new ApiRequest("system", ParseJson("[]"), tools);

        request.Tools.ValueKind.Should().Be(JsonValueKind.Array);
        request.Tools[0].GetProperty("name").GetString().Should().Be("bash");
    }

    [Fact]
    public void ApiRequest_AllowsNullModel()
    {
        var request = new ApiRequest("system", ParseJson("[]"), ParseJson("[]"));

        request.Model.Should().BeNull();
    }

    [Fact]
    public void ApiRequest_HoldsProvidedModel()
    {
        var request = new ApiRequest("system", ParseJson("[]"), ParseJson("[]"), "claude");

        request.Model.Should().Be("claude");
    }

    [Fact]
    public void ApiRequest_AllowsEmptySystemPrompt()
    {
        var request = new ApiRequest(string.Empty, ParseJson("[]"), ParseJson("[]"));

        request.SystemPrompt.Should().BeEmpty();
    }

    [Fact]
    public void ApiRequest_CanStoreObjectMessagesPayload()
    {
        var messages = ParseJson("{\"items\":[]}");

        var request = new ApiRequest("system", messages, ParseJson("[]"));

        request.Messages.ValueKind.Should().Be(JsonValueKind.Object);
        request.Messages.TryGetProperty("items", out _).Should().BeTrue();
    }

    [Fact]
    public void ApiRequest_DoesNotUseStructuralJsonEqualityAcrossDifferentJsonClones()
    {
        var left = new ApiRequest("system", ParseJson("[]"), ParseJson("[{\"name\":\"bash\"}]"), "model");
        var right = new ApiRequest("system", ParseJson("[]"), ParseJson("[{\"name\":\"bash\"}]"), "model");

        left.Should().NotBe(right);
    }

    [Fact]
    public void ApiRequest_IsNotEqualWhenModelDiffers()
    {
        var left = new ApiRequest("system", ParseJson("[]"), ParseJson("[]"), "model-a");
        var right = new ApiRequest("system", ParseJson("[]"), ParseJson("[]"), "model-b");

        left.Should().NotBe(right);
    }

    [Fact]
    public void ApiRequest_DeconstructsIntoOriginalValues()
    {
        var request = new ApiRequest("system", ParseJson("[]"), ParseJson("[{\"name\":\"bash\"}]"), "model");

        var (systemPrompt, messages, tools, model) = request;

        systemPrompt.Should().Be("system");
        messages.ValueKind.Should().Be(JsonValueKind.Array);
        tools[0].GetProperty("name").GetString().Should().Be("bash");
        model.Should().Be("model");
    }

    private static JsonElement ParseJson(string json)
    {
        using var document = JsonDocument.Parse(json);
        return document.RootElement.Clone();
    }
}