using System.Diagnostics.Contracts;
using System.Xml.Serialization;
using UnityEngine;

public class UnitCommander : MonoBehaviour
{
    public GameObject selectionMarkerPrefab;
    public LayerMask layerMask;
    
    //components
    private UnitSelection unitSelection;
    private Camera cam;

    void Awake()
    {
        //get the components
        unitSelection = GetComponent<UnitSelection>();
        cam = Camera.main;
    }
    // Start is called once before the first execution of Update after the MonoBehaviour is created
    void Start()
    {
        
    }

    // Update is called once per frame
    void Update()
    {
        if(Input.GetMouseButtonDown(1) && unitSelection.HasUnitSelected())
        {
            Ray ray = cam.ScreenPointToRay(Input.mousePosition);
            RaycastHit hit;
            Unit[] selectedUnits = unitSelection.GetSelectedUnits();
            if(Physics.Raycast(ray, out hit, 100, layerMask))
            {
                if(hit.collider.CompareTag("Ground"))
                {
                    SelectionMarker marker = CreateSelectionMarker(hit.point, false);
                    UnitsMoveToPosition(hit.point, selectedUnits, marker);
                }
                else if(hit.collider.CompareTag("Resource"))
                {
                    UnitsGatherResource(hit.collider.GetComponent<ResourceSource>(), selectedUnits);
                    CreateSelectionMarker(hit.point, true);
                }
            }
        }
    }
    void UnitsMoveToPosition(Vector3 movePos, Unit[] units, SelectionMarker marker)
    {
        for(int x = 0; x < units.Length; x++)
        {
            // Only the first unit owns the marker so it isn't destroyed multiple times
            units[x].MoveToPosition(movePos, x == 0 ? marker : null);
        }
    }
    //creates a new selection marker at the position we right click
    SelectionMarker CreateSelectionMarker(Vector3 pos, bool large)
    {
        GameObject marker = Instantiate(selectionMarkerPrefab, pos + new Vector3(0, 0.01f, 0), Quaternion.identity);
        if(large)
            marker.transform.localScale = Vector3.one * 3;
        return marker.GetComponent<SelectionMarker>();
    }
    //called when we command units to move somewhere
    void MoveUnitsToPosition(Vector3 movePos, Unit[] units)
    {
        Vector3[] destinations = UnitMover.GetUnitGroupDestination(movePos, units.Length, 2);
        for(int x = 0; x < units.Length; x++)
        {
            units[x].MoveToPosition(destinations[x]);
        }
    }
    //called when we command units to gather a resource
    void UnitsGatherResource(ResourceSource resource, Unit[] units)
    {
        if(units.Length == 1)
        {
            units[0].GatherResource(resource, UnitMover.GetUnitDestinationAroundResource(resource.transform.position));
        }
        else
        {
            Vector3[] destinations = UnitMover.GetUnitGroupDestinationsAroundResource(resource.transform.position, units.Length);
            for(int x = 0; x <units.Length; x++)
            {
                units[x].GatherResource(resource, destinations[x]);
            }
        }
    }
}