using System.Collections;
using System.Linq;
using System.Reflection;
using NUnit.Framework;
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.
    ///
    /// Two checks reach their types by name through reflection rather than referencing
    /// them. NPCStandIn and NightclubArcadia.Cinematics live in Assembly-CSharp, and an
    /// assembly-definition test assembly cannot reference the predefined assemblies —
    /// only the other way round. Giving the runtime code its own asmdefs
    /// (docs/restructure-plan.md Phase 4.1) removes the need for this; until then the
    /// reflection is the accommodation, and it is confined to these two tests.
    /// </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");
        }

        [Test]
        public void EveryNpc_ResolvedItsDialogueRunner()
        {
            var npcs = Object.FindObjectsByType<MonoBehaviour>(FindObjectsInactive.Include, FindObjectsSortMode.None)
                .Where(m => m != null && m.GetType().Name == "NPCStandIn")
                .ToArray();
            Assert.IsNotEmpty(npcs, "Expected NPCs in the level scene");

            foreach (var npc in npcs)
            {
                var field = npc.GetType().GetField("dialogueRunner",
                    BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance);
                Assert.IsNotNull(field, "NPCStandIn no longer has a dialogueRunner field");

                Assert.IsNotNull(field.GetValue(npc) as Object,
                    $"'{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 bound = Object.FindObjectsByType<CinemachineCamera>(FindObjectsInactive.Include, FindObjectsSortMode.None)
                .Where(cam => cam.GetComponents<MonoBehaviour>()
                    .Any(m => m != null && m.GetType().Name == "CinemachineFollowsPlayer"))
                .ToArray();
            Assert.IsNotEmpty(bound, "Expected at least one runtime-bound camera");

            foreach (var cam in bound)
            {
                Assert.IsNotNull(cam.Follow,
                    $"'{cam.name}' never bound its Follow target to the player");
            }
        }

    }
}