project-reset/Assets/Scripts/Units/Combat/UnitCombat.cs

using System;
using System.Collections.Generic;
using Reset.Core.Tools;
using Reset.Units;
using Unity.Netcode;
using UnityEngine;
using Random = UnityEngine.Random;

public class UnitCombat : UnitComponent {
    // public List<Collider> draggedUnits = new List<Collider>();
    public Dictionary<Collider, float> draggedColliders = new Dictionary<Collider, float>();
    
    private UnitMovementHandler movement;

    private Vector3 lastPosition;
    private Vector3 positionDelta;

    private float lastSpeed;
    private float speedDelta;
    private float sinAmplitude;
    private float sinOffset;

    private List<Collider> activelyDraggedColliders;
    private List<Collider> expiredColliders;
    
    void Awake(){
        movement = GetComponent<UnitMovementHandler>();

        activelyDraggedColliders = new List<Collider>();
        expiredColliders = new List<Collider>();
    }

    void Start(){
        lastPosition = transform.position;
        sinOffset = Random.value;
        sinAmplitude = 1 + Random.value / 4f;
    }

    // Update is called once per frame
    void Update(){
        // Calculate movement for dragged units
        DragAttackedUnits();

        // Check timers to make sure an object doesn't stay dragged
        CheckUnitTimers();
    }

    // dragTime is set as a maximum. If no time is provided then it defaults to two seconds.
    public void AddDragCollider(Collider newCollider, float dragTime = 2f){
        if (draggedColliders.ContainsKey(newCollider)) {
            draggedColliders[newCollider] = dragTime;
        } else {
            draggedColliders.Add(newCollider, dragTime);
            activelyDraggedColliders.Add(newCollider);
        }
    }

    public void RemoveDragCollider(Collider colliderToRemove){
        draggedColliders.Remove(colliderToRemove);
        activelyDraggedColliders.Remove(colliderToRemove);
    }

    void CheckUnitTimers(){
        // Decrease the timer of the dragged colliders
        foreach (Collider thisCollider in activelyDraggedColliders) {
            draggedColliders[thisCollider] -= 1f * Time.deltaTime;

            // Pend them for removal when ready
            if (draggedColliders[thisCollider] < 0f) {
                expiredColliders.Add(thisCollider);
            }
        }

        // Remove expired colliders
        for (int i = 0; i < expiredColliders.Count; i++) {
            RemoveDragCollider(expiredColliders[i]);
        }

        // Clear list if not empty
        if (expiredColliders.Count > 0f) {
            expiredColliders.Clear();
        }
    }

    void DragAttackedUnits(){
        // Get the original difference in position for speed and direction
        positionDelta = Vector3.Lerp(positionDelta, lastPosition.DirectionTo(transform.position), 5f * Time.deltaTime);
        speedDelta = Vector3.Distance(lastPosition, transform.position) / Time.deltaTime;

        // Add some randomness to the movements based on small offsets
        float sinVal = Mathf.Sin(2f + sinOffset) * sinAmplitude;
        speedDelta += sinVal;
        
        // Set a floor to prevent them from not moving enough
        speedDelta = Mathf.Max(3f, speedDelta);
        
        // Multiply the speed to be lower when further, and faster when close
        float speedDiff = Mathf.Lerp(.2f, 1.4f, speedDelta);
        speedDelta *= speedDiff;
        
        // Debug 
        DebugOverlayDrawer.ChangeValue($"Combat - {name}", "Position Delta", positionDelta);
        DebugOverlayDrawer.ChangeValue($"Combat - {name}", "Speed Delta", speedDelta);
           
        // Update last known position
        lastPosition = transform.position;

        // Apply the speed, direction, and rotation to each unit
        foreach (Collider draggedUnit in activelyDraggedColliders) {
            UnitMovementHandler draggedUnitMovement = draggedUnit.GetComponent<UnitMovementHandler>();
            if (!draggedUnitMovement) {
                Debug.LogError($"No available UnitMovement on {draggedUnit.name}. Aborting drag on this unit.");
                continue;
            }
            
            // Prevent units from entering a runaway situation where they constantly pull each other at high speeds across the map
            speedDelta = Mathf.Min(speedDelta, draggedUnitMovement.data.moveSpeed.Value);

            draggedUnitMovement.SetNewRotation(-transform.position.DirectionTo(draggedUnit.transform.position), 1f, true);
            draggedUnitMovement.SetNewDirection(positionDelta.ToVector2(), 1f, true);
            draggedUnitMovement.SetNewSpeed(speedDelta, 1f, true);
        }
    }
}