pgs/Assets/Scripts/AiController.cs

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

public class AiController : MonoBehaviour {

    [SerializeField] Strategy strategy;
    [SerializeField] public BoxCollider2D closeRangeCollider;
    [SerializeField] public BoxCollider2D focusRangeCollider;
    [SerializeField] public BoxCollider2D attackRangeCollider;
    [SerializeField] public BoxCollider2D playerColldier;

    private CharacterController2D playerCharacterController;

    [SerializeField] private AudioSource audioSource;
    [SerializeField] private AudioClip exclaimAudioClip;

    public GameObject exclamation;
    public bool isExclaiming = false;
    public bool canBeStartled = true;

    public bool shouldExclaim = false;
    public float exclaimTime = 1.0f;
    public float exclaimExpiration = 30.0f;
    public float transposeExclamationY = 0.0f;

    public bool isCoolingDownAttack = false;
    public float attackCooldown = 1.5f;

    public Intent intent = Intent.NONE;
    public bool isPlayerInRange = false;
    public bool isPlayerInAttackRange = false;

    public enum Strategy {
        // Actively chases the player, attacking when roughly in range.
        // Should be annoying.
        RUSHDOWN,

        // Minds own business, only facing when in range and attacking
        // from short range.
        // Probably the easiest to handle.
        REACTIVE,

        // Casually tracks the player, fleeing when approached and
        // rushing down some time later.
        // Very difficult to defeat.
        STRATEGIC,

        // Unpredictable.
        CRAZY
    }

    public enum Intent {
        NONE,
        ATTACK,
        CHASE,
        FLEE
    }

    // Start is called before the first frame update
    void Awake() {
        playerColldier = GameObject.FindGameObjectWithTag("Player").GetComponent<BoxCollider2D>();
        playerCharacterController = GameObject.FindGameObjectWithTag("Player").GetComponent<CharacterController2D>();
    }

    private Intent GetStrategicIntent() {
        float posX = transform.position.x;
        float playerPosX = playerCharacterController.transform.position.x;
        float playerVelX = playerCharacterController.m_Rigidbody2D.velocity.x;
        // If the player is facing away from me, I'll chase!
        if ((playerPosX < posX) != (playerCharacterController.m_FacingRight)) {
            return Intent.CHASE;
        } else {
            // If the player's chasing me, I'll face them!
            if ((playerVelX > 0.01 && playerPosX < posX)
                || (playerVelX < -0.01 && playerPosX > posX)) {
                return Intent.CHASE;
            }
            return Intent.FLEE;
        }
    }

    private Intent GetOnFocusIntent() {
        if (isExclaiming) {
            return Intent.NONE;
        }
        switch (strategy) {
            case Strategy.RUSHDOWN:
                // TODO: Refactor IsTouching to use OnTriggerEnter/Exit events
                if (attackRangeCollider.IsTouching(playerColldier) && !isCoolingDownAttack) {
                    return Intent.ATTACK;
                } else {
                    return Intent.CHASE;
                }
            case Strategy.REACTIVE:
                return Intent.NONE;
            case Strategy.STRATEGIC:
                return GetStrategicIntent();
            case Strategy.CRAZY:
                //float choice = Random.Range(0f, 1f);
                //if (choice < 0.25f) return Intent.ATTACK;
                //if (choice < 0.5f) return Intent.CHASE;
                //if (choice < 0.75f) return Intent.FLEE;
                return Intent.NONE;
            default:
                Debug.LogError("Undefined strategy for monster!");
                return Intent.NONE;
        }
    }

    private void OnTriggerEnter2D(Collider2D collision) {
        if (collision.CompareTag("Player")) {
            isPlayerInRange = true;
            intent = GetOnFocusIntent();
            if (shouldExclaim && canBeStartled && !attackRangeCollider.IsTouching(playerColldier)) {
                audioSource.PlayOneShot(exclaimAudioClip);
                GameObject effect = Instantiate(exclamation);
                effect.transform.position = new Vector2(transform.position.x, transform.position.y + transposeExclamationY);
                isExclaiming = true;
                canBeStartled = false;
                Invoke("StopExclaiming", exclaimTime);
                Invoke("CanStartle", exclaimExpiration);
            }
        }
    }

    public void StopExclaiming() {
        isExclaiming = false;
    }

    public void CanStartle() {
        canBeStartled = true;
    }

    private void OnTriggerExit2D(Collider2D collision) {
        if (collision.gameObject.CompareTag("Player") &&
            !focusRangeCollider.IsTouching(playerColldier)) {
            isPlayerInRange = false;
        }
    }

    private void FixedUpdate() {
        if (isPlayerInRange) {
            intent = GetOnFocusIntent();
        }
    }
}