using System;
using System.Collections.Generic;
using System.Linq;
using Mapbox.CheapRulerCs;
using Mapbox.Unity.Map;
using UnityEngine;

public class CollectableDuckManager : MonoBehaviour
{
    public List<CollectableDuckData> collectableDucks;

    private readonly HashSet<CollectableDuckData> _collectedDucks = new HashSet<CollectableDuckData>();

    private readonly Dictionary<CollectableDuckData, CollectableDuck> _spawnedDucks = new Dictionary<CollectableDuckData, CollectableDuck>();
    
    public AbstractMap map;
    public Transform player;
    public Transform collectableDuckParent;

    public event EventHandler<CollectableDuckData> DuckClicked; 
    
    /// <summary>
    /// Spawn distance in meters (i.e. how close should the player be to a duck before it spawns on the map
    /// </summary>
    public float spawnDistance = 50;

    public CollectableDuck duckSpawnPrefab;
    
    private static CollectableDuckManager _instance;

    public static CollectableDuckManager Instance
    {
        get { return _instance;  }
        private set { _instance = value; }
    }

    public CollectableDuckManager()
    {
        Instance = this;
    }

    private void Awake()
    {
        CheckCollectableDuckIds();
        _collectedDucks.Clear();
        foreach (var duck in collectableDucks.Where(duck => PlayerPrefs.GetInt("duck." + duck.Id) > 0))
        {
            _collectedDucks.Add(duck);
        }
    }

    private void CheckCollectableDuckIds()
    {
        var duckIds = new HashSet<string>();
        foreach (var duck in collectableDucks)
        {
            if (duckIds.Contains(duck.Id))
            {
                Debug.LogError("Duplicate duck ID: '" + duck.Id + "' for duck '" + duck.name + "'");
            }

            duckIds.Add(duck.Id);
        }
    }

    private void Update()
    {
        var ruler = new CheapRuler(map.CenterLatitudeLongitude.x, CheapRulerUnits.Meters);
        var playerPosition = map.WorldToGeoPosition(player.position).ToArray();
        for (int i = 0; i < collectableDucks.Count; i++)
        {
            var duck = collectableDucks[i];
            var duckCoord = duck.LatitudeLongitude;
            var dist = ruler.Distance(duckCoord.ToArray(), playerPosition);
//            Debug.Log("Distance to " + duck.name + ": " + dist);
            if (dist < spawnDistance && !_collectedDucks.Contains(duck))
            {
                SpawnDuck(duck);
            }
            else
            {
                RemoveDuck(duck);
            }
        }
    }

    private void SpawnDuck(CollectableDuckData duck)
    {
        if (!_spawnedDucks.ContainsKey(duck))
        {
            // Spawn the duck
            var duckSpawn = Instantiate(duckSpawnPrefab, map.GeoToWorldPosition(duck.LatitudeLongitude), 
                Quaternion.identity, collectableDuckParent);
            duckSpawn.CollectableDuckData = duck;
            var duckModel = Instantiate(duck.ModelPrefab, duckSpawn.transform);
            duckModel.transform.localPosition = Vector3.zero;

            _spawnedDucks[duck] = duckSpawn;
        }
        else
        {
            if (!_spawnedDucks[duck].gameObject.activeSelf)
            {
                _spawnedDucks[duck].gameObject.SetActive(true);
            }
        }
    }

    private void RemoveDuck(CollectableDuckData duck)
    {
        if (_spawnedDucks.ContainsKey(duck))
        {
            if (_spawnedDucks[duck].gameObject.activeSelf)
            {
                _spawnedDucks[duck].gameObject.SetActive(false);
            }
        }
    }

    public void OnDuckClicked(CollectableDuckData duck)
    {
        if (DuckClicked != null)
        {
            DuckClicked.Invoke(this, duck);
        }
        
    }

    public void OnDuckCollected(CollectableDuckData duck)
    {
        _collectedDucks.Add(duck);
        PlayerPrefs.SetInt("duck." + duck.Id, 1);

        RemoveDuck(duck);
    }
}