using System;
using BumpCombat.Enemies;
using UnityEngine;

namespace BumpCombat.Defense
{
    [DisallowMultipleComponent]
    public sealed class DefenseRouteAgent : MonoBehaviour
    {
        private EnemyController enemy;
        private Vector2[] waypoints = Array.Empty<Vector2>();
        private Action<DefenseRouteAgent> arrivalHandler;
        private Transform player;
        private BumpCombat.Player.PlayerHealth playerHealth;
        private float routeSpeed;
        private float playerEngagementRange;
        private float postAttackProgressSeconds;
        private float postAttackProgressRemaining;
        private bool wasAttackSequenceInProgress;
        private bool configured;
        private bool stationaryTowerTestDummy;
        private Vector2 stationaryTowerTestDummyAnchor;
        private int waypointIndex;

        public EnemyController Enemy => enemy;
        public int Lane { get; private set; }
        public int LifetimeId => enemy != null ? enemy.SpawnLifetimeIdentity : -1;
        public DefenseTowerKind ImmuneTowerKind { get; private set; }
        public Vector2 AnchorPosition => waypoints.Length > 0 ? waypoints[0] : transform.position;
        public bool HasArrived { get; private set; }

        public void Configure(
            EnemyController configuredEnemy,
            int lane,
            Vector2[] route,
            float speed,
            float engagementRange,
            float postAttackProgress,
            DefenseTowerKind immuneTowerKind,
            Action<DefenseRouteAgent> onArrived)
        {
            enemy = configuredEnemy;
            Lane = lane;
            waypoints = route ?? Array.Empty<Vector2>();
            routeSpeed = Mathf.Max(0.1f, speed);
            playerEngagementRange = Mathf.Max(0.1f, engagementRange);
            postAttackProgressSeconds = Mathf.Max(0f, postAttackProgress);
            postAttackProgressRemaining = 0f;
            wasAttackSequenceInProgress = false;
            ImmuneTowerKind = immuneTowerKind;
            arrivalHandler = onArrived;
            waypointIndex = 0;
            configured = enemy != null && waypoints.Length > 0;
            HasArrived = false;
            player = FindAnyObjectByType<BumpCombat.Player.PlayerController>()?.transform;
            playerHealth = player != null
                ? player.GetComponent<BumpCombat.Player.PlayerHealth>()
                : null;
            if (configured)
            {
                enemy.TryReposition(waypoints[0]);
            }
        }

        public void ConfigureTowerTestDummy(EnemyController configuredEnemy, DefenseTowerKind immuneTowerKind)
        {
            enemy = configuredEnemy;
            Lane = -1;
            waypoints = Array.Empty<Vector2>();
            routeSpeed = 0f;
            playerEngagementRange = 0f;
            postAttackProgressSeconds = 0f;
            ImmuneTowerKind = immuneTowerKind;
            arrivalHandler = null;
            waypointIndex = 0;
            configured = enemy != null;
            stationaryTowerTestDummy = configured;
            stationaryTowerTestDummyAnchor = configuredEnemy != null
                ? configuredEnemy.transform.position : Vector2.zero;
            HasArrived = false;
            player = FindAnyObjectByType<BumpCombat.Player.PlayerController>()?.transform;
            playerHealth = player != null ? player.GetComponent<BumpCombat.Player.PlayerHealth>() : null;
        }

        public bool TryDriveFixedUpdate(float deltaTime)
        {
            if (stationaryTowerTestDummy)
            {
                if (enemy == null || enemy.IsDead)
                {
                    return true;
                }
                if (enemy.State == EnemyState.Spawn)
                {
                    return false;
                }

                enemy.SetDefenseCombatTarget(null);
                enemy.TryReposition(stationaryTowerTestDummyAnchor);
                return true;
            }

            if (!configured || HasArrived || enemy == null || enemy.IsDead)
            {
                return false;
            }

            if (enemy.State == EnemyState.Spawn)
            {
                return false;
            }

            bool attackSequenceActive = enemy.IsAttackSequenceInProgress;
            if (attackSequenceActive)
            {
                wasAttackSequenceInProgress = true;
                return false;
            }

            if (wasAttackSequenceInProgress)
            {
                wasAttackSequenceInProgress = false;
                postAttackProgressRemaining = postAttackProgressSeconds;
            }

            if (enemy.IsStunned)
            {
                return false;
            }

            DefensePrototypeController defense = DefensePrototypeController.Instance;
            DefenseSummonUnit summonTarget = defense != null
                ? defense.FindNearestSummonTarget(transform.position,
                    Mathf.Max(playerEngagementRange, defense.Tuning.SummonAreaRadius))
                : null;
            enemy.SetDefenseCombatTarget(summonTarget);
            if (summonTarget != null)
            {
                enemy.Alert();
                return false;
            }
            postAttackProgressRemaining = Mathf.Max(
                0f,
                postAttackProgressRemaining - Mathf.Max(0f, deltaTime));
            if (player == null)
            {
                player = FindAnyObjectByType<BumpCombat.Player.PlayerController>()?.transform;
                playerHealth = player != null
                    ? player.GetComponent<BumpCombat.Player.PlayerHealth>()
                    : null;
            }

            if (postAttackProgressRemaining <= 0f
                && player != null
                && playerHealth != null
                && playerHealth.CurrentHealth > 0f
                && (player.position - transform.position).sqrMagnitude
                    <= playerEngagementRange * playerEngagementRange)
            {
                enemy.Alert();
                return false;
            }

            if (waypointIndex >= waypoints.Length)
            {
                CompleteArrival();
                return true;
            }

            Vector2 current = transform.position;
            Vector2 target = waypoints[waypointIndex];
            Vector2 next = Vector2.MoveTowards(
                current,
                target,
                routeSpeed * enemy.MovementSpeedMultiplier * Mathf.Max(0f, deltaTime));
            if (!enemy.TryReposition(next))
            {
                return false;
            }

            Vector2 movementDirection = next - current;
            if (movementDirection.sqrMagnitude > 0.000001f)
            {
                enemy.SetFacingDirection(movementDirection);
            }
            Animator animator = enemy.GetComponent<Animator>();
            animator?.SetBool("IsMoving", (next - current).sqrMagnitude > 0.000001f);
            if ((target - next).sqrMagnitude <= 0.01f)
            {
                waypointIndex++;
                if (waypointIndex >= waypoints.Length)
                {
                    CompleteArrival();
                }
            }

            return true;
        }

        public bool TryTakeTowerDamage(
            DefenseTowerKind sourceKind,
            float requestedDamage,
            float distanceToPlayer,
            float sightRadius,
            float outsideSightEfficiency,
            Vector2 sourcePosition)
        {
            if (!configured
                || HasArrived
                || enemy == null
                || enemy.IsDead
                || DefensePrototypeRules.IsTowerImmune(
                    sourceKind,
                    ImmuneTowerKind))
            {
                return false;
            }

            float efficiency = DefensePrototypeRules.GetTowerEfficiency(
                distanceToPlayer,
                sightRadius,
                1f,
                outsideSightEfficiency);
            Vector2 direction = ((Vector2)transform.position - sourcePosition).normalized;
            return enemy.TryTakeDamage(
                Mathf.Max(0f, requestedDamage) * efficiency,
                direction,
                0f,
                false,
                false,
                EnemyDamageSource.Tower);
        }

        private void CompleteArrival()
        {
            if (HasArrived)
            {
                return;
            }

            HasArrived = true;
            arrivalHandler?.Invoke(this);
        }
    }
}