using System.Collections;
using System.Linq;
using NUnit.Framework;
using NightclubArcadia.Cinematics;
using Unity.Cinemachine;
using UnityEngine;
using UnityEngine.SceneManagement;
using UnityEngine.TestTools;
using Yarn.Unity;

namespace NightclubArcadia.PlayMode.Tests
{
    /// <summary>
    /// Proves the scene split actually comes up.
    ///
    /// Splitting Systems out of the level nulled seven serialized references that
    /// Unity cannot carry across a scene boundary — the two NPCs' dialogue runner, UI
    /// and player fields, and the reveal camera's tracking target. Each is supposed to
    /// be resolved at runtime instead. An EditMode test cannot see any of that, because
    /// none of it has run. This can.
    ///
    /// If this suite fails, the game does not start. Treat it that way.
    /// </summary>
    public class BootstrapTests
    {
        const string Bootstrap = "Bootstrap";
        const string Systems = "Systems";
        const string Level = "SC101_ConferenceHall";

        [UnitySetUp]
        public IEnumerator LoadFromBootstrap()
        {
            yield return SceneManager.LoadSceneAsync(Bootstrap, LoadSceneMode.Single);

            // GameBootstrap loads the other two additively over a few frames.
            var deadline = Time.realtimeSinceStartup + 20f;
            while (Time.realtimeSinceStartup < deadline)
            {
                if (SceneManager.GetSceneByName(Systems).isLoaded &&
                    SceneManager.GetSceneByName(Level).isLoaded)
                {
                    break;
                }
                yield return null;
            }

            // let Awake/Start run on everything that just loaded
            for (var i = 0; i < 5; i++)
            {
                yield return null;
            }
        }

        [Test]
        public void Bootstrap_LoadsSystemsAndLevel()
        {
            Assert.IsTrue(SceneManager.GetSceneByName(Systems).isLoaded, "Systems scene did not load");
            Assert.IsTrue(SceneManager.GetSceneByName(Level).isLoaded, "Level scene did not load");
            Assert.AreEqual(Level, SceneManager.GetActiveScene().name,
                "The level should be the active scene, so new objects and lighting land there");
        }

        [Test]
        public void ThePlayerExists_AndIsTagged()
        {
            var player = GameObject.FindGameObjectWithTag("Player");
            Assert.IsNotNull(player, "No object tagged Player — the reveal camera and the NPCs both need it");
        }

        [Test]
        public void TheDialogueRunnerExists()
        {
            Assert.IsNotNull(Object.FindFirstObjectByType<DialogueRunner>(),
                "No DialogueRunner in any loaded scene");
        }

        /// <summary>
        /// Regression: "Can't start dialogue: no Yarn Project has been configured."
        ///
        /// Asserting the runner merely exists is not enough — it auto-starts on Start(),
        /// and a runner with no project throws that at load with nothing else wrong.
        /// The project is a serialized asset reference supplied by a prefab override, so
        /// it breaks silently if the override is ever dropped.
        /// </summary>
        [Test]
        public void TheDialogueRunner_HasItsYarnProject()
        {
            var runners = Object.FindObjectsByType<DialogueRunner>(
                FindObjectsInactive.Include, FindObjectsSortMode.None);

            Assert.AreEqual(1, runners.Length,
                "Expected exactly one DialogueRunner across the loaded scenes, found " +
                string.Join(", ", runners.Select(r => $"'{r.name}' in {r.gameObject.scene.name}")));

            var runner = runners[0];
            Assert.IsNotNull(runner.YarnProject,
                $"'{runner.name}' in scene '{runner.gameObject.scene.name}' has no Yarn Project. " +
                "It auto-starts, so this is the 'no Yarn Project has been configured' error.");
            Assert.IsNotEmpty(runner.YarnProject.NodeNames, "The Yarn Project compiled no nodes");
        }

        [Test]
        public void EveryNpc_ResolvedItsDialogueRunner()
        {
            var npcs = Object.FindObjectsByType<NPCStandIn>(FindObjectsInactive.Include, FindObjectsSortMode.None);
            Assert.IsNotEmpty(npcs, "Expected NPCs in the level scene");

            foreach (var npc in npcs)
            {
                Assert.IsNotNull(npc.dialogueRunner,
                    $"'{npc.name}' did not resolve a DialogueRunner. It lives in the Systems scene, " +
                    "so the serialized reference is gone and SceneServices.Resolve has to find it.");
            }
        }

        [Test]
        public void RevealCameras_BoundToThePlayer()
        {
            var binders = Object.FindObjectsByType<CinemachineFollowsPlayer>(
                FindObjectsInactive.Include, FindObjectsSortMode.None);
            Assert.IsNotEmpty(binders, "Expected at least one runtime-bound camera");

            foreach (var binder in binders)
            {
                Assert.IsNotNull(binder.GetComponent<CinemachineCamera>().Follow,
                    $"'{binder.name}' never bound its Follow target to the player");
            }
        }

    }
}