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

[DisallowMultipleComponent]
public sealed class MapTargetController : MonoBehaviour
{
    [Header("Target Types")]
    [SerializeField] private TargetConfig[] randomTargetConfigs = Array.Empty<TargetConfig>();
    [SerializeField] private bool showLiveTargetVisuals;

    [Header("Current Wave (Runtime)")]
    [SerializeField, Min(0)] private int currentWave;
    [SerializeField] private List<MapTarget> currentWaveTargets = new();

    private readonly List<MapTarget> pooledTargets = new();
    private readonly Dictionary<int, MapTarget> targetsById = new();
    private readonly HashSet<int> synchronizedTargetIds = new();
    private MapCoordinateSystem coordinateSystem;
    private Transform targetParent;
    private MapPlayer player;

    public IReadOnlyList<MapTarget> Targets => currentWaveTargets;
    public IReadOnlyList<TargetConfig> TargetConfigs => randomTargetConfigs;
    public int CurrentWave => currentWave;

    private void OnValidate()
    {
        currentWave = Mathf.Max(0, currentWave);
    }

    public void Configure(
        MapCoordinateSystem newCoordinateSystem,
        Transform newTargetParent,
        MapPlayer newPlayer)
    {
        coordinateSystem = newCoordinateSystem;
        targetParent = newTargetParent != null ? newTargetParent : transform;
        player = newPlayer;

        pooledTargets.Clear();
        targetsById.Clear();
        currentWaveTargets.Clear();
        foreach (MapTarget existingTarget in targetParent.GetComponentsInChildren<MapTarget>(true))
        {
            existingTarget.SetVisualsVisible(false);
            existingTarget.gameObject.SetActive(false);
            pooledTargets.Add(existingTarget);
        }
    }

    public void ApplyNetworkTargets(
        IReadOnlyList<MapTargetNetworkState> states,
        int wave)
    {
        currentWave = Mathf.Max(0, wave);
        synchronizedTargetIds.Clear();

        for (int index = 0; index < states.Count; index++)
        {
            MapTargetNetworkState state = states[index];
            TargetConfig config = GetConfig(state.ConfigIndex);
            if (config == null || config.TargetPrefab == null)
                continue;

            synchronizedTargetIds.Add(state.TargetId);
            if (!targetsById.TryGetValue(state.TargetId, out MapTarget target) || target == null)
            {
                target = GetPooledTarget(config);
                if (target == null)
                    target = Instantiate(config.TargetPrefab, targetParent);

                targetsById[state.TargetId] = target;
                currentWaveTargets.Add(target);
            }

            target.name = $"Wave {currentWave} - {config.name} - {state.TargetId}";
            target.Configure(config, coordinateSystem, player);
            target.ApplyNetworkState(state);
            target.SetVisualsVisible(showLiveTargetVisuals);
            target.gameObject.SetActive(true);
        }

        for (int index = currentWaveTargets.Count - 1; index >= 0; index--)
        {
            MapTarget target = currentWaveTargets[index];
            if (target != null && synchronizedTargetIds.Contains(target.TargetId))
                continue;

            RetireTarget(target);
            currentWaveTargets.RemoveAt(index);
        }
    }

    public TargetConfig GetConfig(int index) =>
        index >= 0 && index < randomTargetConfigs.Length
            ? randomTargetConfigs[index]
            : null;

    public int GetRandomValidConfigIndex()
    {
        if (randomTargetConfigs == null || randomTargetConfigs.Length == 0)
            return -1;

        int startIndex = UnityEngine.Random.Range(0, randomTargetConfigs.Length);
        for (int offset = 0; offset < randomTargetConfigs.Length; offset++)
        {
            int index = (startIndex + offset) % randomTargetConfigs.Length;
            TargetConfig config = randomTargetConfigs[index];
            if (config != null && config.TargetPrefab != null)
                return index;
        }

        return -1;
    }

    public bool HasValidConfiguration() =>
        coordinateSystem != null && coordinateSystem.HasValidCorners() &&
        GetRandomValidConfigIndex() >= 0;

    public void SetTargetVisualsVisible(bool isVisible)
    {
        showLiveTargetVisuals = isVisible;
        foreach (MapTarget target in currentWaveTargets)
        {
            if (target != null)
                target.SetVisualsVisible(isVisible);
        }
    }

    public MapTarget GetTarget(int index) =>
        index >= 0 && index < currentWaveTargets.Count
            ? currentWaveTargets[index]
            : null;

    public bool StartNextWave()
    {
        MapController mapController = FindFirstObjectByType<MapController>();
        return mapController != null && mapController.StartNextWave();
    }

    private MapTarget GetPooledTarget(TargetConfig config)
    {
        for (int index = pooledTargets.Count - 1; index >= 0; index--)
        {
            MapTarget candidate = pooledTargets[index];
            if (candidate == null)
            {
                pooledTargets.RemoveAt(index);
                continue;
            }

            if (candidate.GetType() != config.TargetPrefab.GetType())
                continue;

            pooledTargets.RemoveAt(index);
            return candidate;
        }

        return null;
    }

    private void RetireTarget(MapTarget target)
    {
        if (target == null)
            return;

        targetsById.Remove(target.TargetId);
        target.SetVisualsVisible(false);
        target.gameObject.SetActive(false);
        if (!pooledTargets.Contains(target))
            pooledTargets.Add(target);
    }
}