VillageBuilder/Assets/Scripts/JobManager.cs

using UnityEngine;
using System.Collections.Generic;

public class JobManager : MonoBehaviour
{
    public static JobManager Instance;

    private Building targetBuilding;
    private Resource targetResource;
    private NPC targetNPC;
    void Awake()
    {
        Instance = this;
    }
    public Building RequestJob(NPC.Job jobType)
    {
        switch (jobType)
        {
            case NPC.Job.Builder:
                targetBuilding = GetUnfinishedBuildings();
                if(targetBuilding != null)
                {
                    return targetBuilding;
                }
                break;
        }  
        return null; 
    }
    private Building GetUnfinishedBuildings()
    {
        Building[] buildings = GameManager.Instance.CountBuildings();
        List<Building> candidates = new List<Building>();

        foreach (Building building in buildings)
        {
            var state = building.GetBuildingState();
            if (state == Building.BuildingState.Unbuilt)
            {
                if (CanBuildBuilding(building))
                {
                    candidates.Add(building);
                }
            }
            else if (state == Building.BuildingState.Constructing)
            {
                // Allow additional builders to join already-constructing buildings
                candidates.Add(building);
            }
        }

        if (candidates.Count == 0)
            return null;

        int idx = Random.Range(0, candidates.Count);
        return candidates[idx];
    }

    private bool CanBuildBuilding(Building building)
    {
        Resource.ResourceType[] requiredResources = building.GetResourceRequirement();
        int[] requiredCosts = building.GetConstructionCost();

        if (requiredResources == null || requiredCosts == null)
        {
            Debug.LogWarning("Building missing resource or cost arrays");
            return false;
        }

        if (requiredResources.Length != requiredCosts.Length)
        {
            Debug.LogWarning("Building resource and cost arrays don't match in length");
            return false;
        }

        for (int i = 0; i < requiredResources.Length; i++)
        {
            if (GameManager.Instance.GetResource(requiredResources[i]) < requiredCosts[i])
            {
                return false;
            }
        }

        return true;
    }
}