using System;
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.Assertions;

[RequireComponent(typeof(ProjectileSpawner))]
public class ProjectileTower : Tower
{
    [SerializeField, Range(0.01f, 20f)] private float attackSecondsDelay = 1f;
    [SerializeField] private ProjectilePattern[] projectileSequence;
    [SerializeField] private Barrel barrel;
    [SerializeField] private LineRenderer trajectory;
    [SerializeField] private int trajectoryBounces = 2;
    private const float k_trajectory_maxdist = 100f;

    private ProjectileSpawner projectileSpawner;

    public Vector3 AimDirection => transform.TransformVector(transform.InverseTransformVector(horizontalArc.ToKnobVector) + transform.InverseTransformVector(verticalArc.ToKnobVector));

    protected override void Awake()
    {
        base.Awake();

        projectileSpawner = GetComponent<ProjectileSpawner>();
        Assert.IsNotNull(projectileSpawner);

        horizontalArc.Value.AddListener(UpdateBarrelRotation);
        verticalArc.Value.AddListener(UpdateBarrelRotation);

        horizontalArc.Value.AddListener(UpdateTrajectory);
        verticalArc.Value.AddListener(UpdateTrajectory);

        UpdateBarrelRotation();
        UpdateTrajectory();
        StartCoroutine(AttackLoop());
    }

    private void UpdateTrajectory(float unused) => UpdateTrajectory();

    private void UpdateTrajectory()
    {
        if (trajectory == null) return;

        Vector3 origin = barrel.Tip.position;
        Vector3 dir = barrel.transform.forward;
        List<Vector3> pointsInTrajectory = new();
        pointsInTrajectory.Add(origin);
        for (int i = 0; i < trajectoryBounces; i++)
        {
            Debug.DrawRay(origin, dir.normalized * k_trajectory_maxdist, Color.red, 5f);
            RaycastHit hit;
            if (!Physics.Raycast(origin, dir, out hit, k_trajectory_maxdist))
                break;

            pointsInTrajectory.Add(hit.point);
            dir = Vector3.Reflect(dir, hit.normal);
            origin = hit.point;
        }

        trajectory.positionCount = pointsInTrajectory.Count;
        trajectory.SetPositions(pointsInTrajectory.ToArray());
    }

    protected override void OnDestroy()
    {
        horizontalArc.Value.RemoveListener(UpdateBarrelRotation);
        verticalArc.Value.RemoveListener(UpdateBarrelRotation);
    }

    private IEnumerator AttackLoop()
    {
        do {
            yield return new WaitForSeconds(attackSecondsDelay);
            UpdateBarrelRotation();
            Debug.DrawRay(transform.position, horizontalArc.ToKnobVector, Color.red, attackSecondsDelay);
            Debug.DrawRay(transform.position, verticalArc.ToKnobVector, Color.green, attackSecondsDelay);
            Debug.DrawRay(transform.position, AimDirection, Color.yellow, attackSecondsDelay);
            projectileSpawner.RunBulletSequence(transform.position, transform.up, AimDirection, projectileSequence);
        } while (true);
    }

    private void UpdateBarrelRotation(float unused) => UpdateBarrelRotation();

    // Rotate barrel to match rotation
    private void UpdateBarrelRotation()
    {
        barrel.transform.localRotation = Quaternion.Euler(verticalArc.Value, horizontalArc.Value, 0f);
    }
}