using System.Collections;
using NUnit.Framework;
using NightclubArcadia.Interaction;
using UnityEngine;
using UnityEngine.SceneManagement;
using UnityEngine.TestTools;
using Yarn.Unity;

namespace NightclubArcadia.PlayMode.Tests
{
    /// <summary>
    /// The level must survive being loaded BEFORE the systems it depends on.
    ///
    /// BootstrapTests only covers the happy order — Bootstrap loads Systems, then the
    /// level, so by the time an interactor needs the dialogue runner it is already there.
    /// The Editor does not guarantee that. Open the level on its own, press Play, and
    /// nothing in it can reach the runner. Resolving in Awake and caching the result
    /// produced exactly that, permanently, for the whole session:
    ///
    ///   [SceneServices] Bartender: could not resolve dialogueRunner
    ///
    /// DialogueInteractor resolves at the point of use and caches only success, so load
    /// order stops mattering. This is the test that holds that.
    /// </summary>
    public class SceneOrderTests
    {
        const string Systems = "Systems";
        const string Level = "SC101_ConferenceHall";

        [UnityTearDown]
        public IEnumerator TearDown()
        {
            yield return SceneManager.LoadSceneAsync("Bootstrap", LoadSceneMode.Single);
        }

        [UnityTest]
        public IEnumerator LevelLoadedBeforeSystems_InteractorsStillResolveTheRunner()
        {
            yield return SceneManager.LoadSceneAsync(Level, LoadSceneMode.Single);
            for (var i = 0; i < 2; i++)
            {
                yield return null;
            }

            var interactors = Object.FindObjectsByType<DialogueInteractor>(
                FindObjectsInactive.Include, FindObjectsSortMode.None);
            Assert.IsNotEmpty(interactors, "Expected interactors in the level scene");

            // Non-vacuity: with only the level loaded there must genuinely be no runner
            // to find. If this ever fails, the dependency stopped being cross-scene and
            // the rest of this test proves nothing.
            Assert.IsNull(Object.FindFirstObjectByType<DialogueRunner>(FindObjectsInactive.Include),
                "A DialogueRunner exists with only the level loaded, so this test is no " +
                "longer exercising cross-scene resolution. Rewrite it before trusting it.");

            yield return SceneManager.LoadSceneAsync(Systems, LoadSceneMode.Additive);
            for (var i = 0; i < 2; i++)
            {
                yield return null;
            }

            foreach (var interactor in interactors)
            {
                Assert.IsNotNull(interactor.ResolvedRunner,
                    $"'{interactor.name}' could not reach the DialogueRunner when the level " +
                    "loaded before Systems. Cross-scene resolution must not depend on load order.");
            }
        }
    }
}