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

/// <summary>
/// Manages spawning and tracking of AI agents in the maze
/// Supports configurable spawn counts and runtime spawning
/// </summary>
public class AIAgentManager : MonoBehaviour
{
    [Header("Agent Spawning")]
    [SerializeField] private int initialAgentCount = 10;
    [SerializeField] private string agentCharacterType = "Default";
    [SerializeField] private float spawnDelay = 0.1f;

    [Header("Agent Prefab")]
    [SerializeField] private GameObject agentPrefab;

    [Header("Visual Settings")]
    [Tooltip("Show path debug lines for all agents. Disable for large agent counts (>100) for major performance gains.")]
    [SerializeField] private bool showAgentPaths = false;
    [SerializeField] private Color agentPathColor = Color.yellow;
    [SerializeField] private Material agentMaterial;

    [Header("Grouping")]
    [SerializeField] private float groupCheckInterval = 2f;
    [SerializeField] private float groupingRadius = 1.5f;

    private MazeController mazeController;
    private List<AIAgent> activeAgents = new();
    private readonly List<AgentGroup> activeGroups = new();
    private int nextAgentId = 0;
    private bool isInitialized = false;
    private float lastGroupCheck = 0f;

    // ---- Death statistics ----
    private int agentsKilledByMonsters = 0;
    private int monstersKilledByAgents = 0;

    /// <summary>How many agents have been killed by monsters this run.</summary>
    public int AgentsKilledByMonsters => agentsKilledByMonsters;

    /// <summary>How many monsters agents have killed this run.</summary>
    public int MonstersKilledByAgents => monstersKilledByAgents;

    /// <summary>
    /// Called by a dying AIAgent so the manager can update stats and clean up.
    /// </summary>
    public void RegisterAgentDeath(AIAgent agent)
    {
        agentsKilledByMonsters++;
        activeAgents.Remove(agent);
        Debug.Log($"[Manager] Agent {agent.AgentName} killed. Total killed: {agentsKilledByMonsters}");
    }

    /// <summary>Called by an agent after landing a killing blow on a monster.</summary>
    public void RegisterMonsterKill()
    {
        monstersKilledByAgents++;
    }

    void Awake()
    {
        mazeController = GetComponent<MazeController>();
        if (mazeController == null)
        {
            mazeController = FindAnyObjectByType<MazeController>();
        }
    }

    void Update()
    {
        if (!isInitialized) return;
        if (Time.time - lastGroupCheck < groupCheckInterval) return;
        lastGroupCheck = Time.time;
        EvaluateGrouping();
    }

    /// <summary>
    /// Checks all solo/leader agents for nearby agents and tries to form or join groups.
    /// </summary>
    private void EvaluateGrouping()
    {
        var candidates = activeAgents
            .Where(a => a != null && !a.IsGroupFollower && !a.HasReachedGoal)
            .ToList();

        for (int i = 0; i < candidates.Count; i++)
        {
            AIAgent a = candidates[i];
            if (Random.value > a.GroupUpAffinity) continue;

            for (int j = i + 1; j < candidates.Count; j++)
            {
                AIAgent b = candidates[j];
                if (Vector3.Distance(a.transform.position, b.transform.position) > groupingRadius) continue;
                if (Random.value > b.GroupUpAffinity) continue;

                if (a.Group != null && !a.IsGroupFollower && b.Group == null)
                    a.Group.TryAddMember(b);
                else if (b.Group != null && !b.IsGroupFollower && a.Group == null)
                    b.Group.TryAddMember(a);
                else if (a.Group == null && b.Group == null)
                {
                    var newGroup = new AgentGroup(a);
                    newGroup.TryAddMember(b);
                    activeGroups.Add(newGroup);
                }
            }
        }

        activeGroups.RemoveAll(g => g.Size <= 1);
    }

    void OnValidate()
    {
        // Called when inspector values change (both in play mode and edit mode)
        // Update all active agents' path visibility
        if (isInitialized && activeAgents.Count > 0)
        {
            SetPathVisibilityForAllAgents(showAgentPaths);
        }
    }

    void Start()
    {
        if (mazeController == null)
        {
            Debug.LogError("AIAgentManager: MazeController not found!");
            enabled = false;
            return;
        }

        // Create agent prefab if not assigned
        if (agentPrefab == null)
        {
            CreateDefaultAgentPrefab();
        }

        // Spawn initial agents
        StartCoroutine(SpawnAgentsCoroutine(initialAgentCount));
        isInitialized = true;
    }

    /// <summary>
    /// Creates a default agent prefab if one isn't assigned
    /// </summary>
    private void CreateDefaultAgentPrefab()
    {
        GameObject prefab = new GameObject("AIAgent");
        prefab.transform.localScale = new Vector3(0.5f, 0.5f, 0.5f);

        // Use 3D collider instead of 2D for 3D environment
        var collider = prefab.AddComponent<SphereCollider>();
        collider.radius = 1.0f;

        // Add mesh renderer with a simple sphere
        var meshFilter = prefab.AddComponent<MeshFilter>();
        var meshRenderer = prefab.AddComponent<MeshRenderer>();

        // Use Unity's built-in sphere primitive mesh
        meshFilter.mesh = Resources.GetBuiltinResource<Mesh>("Sphere.fbx");

        // Create a cyan material using URP shader (Universal Render Pipeline)
        var mat = new Material(Shader.Find("Universal Render Pipeline/Lit"));
        if (mat.shader == null)
        {
            // Fallback to simpler URP shader if Lit is not available
            mat = new Material(Shader.Find("Universal Render Pipeline/Simple Lit"));
        }
        if (mat.shader == null)
        {
            // Last resort - use Standard shader
            mat = new Material(Shader.Find("Standard"));
        }
        mat.color = Color.cyan;
        meshRenderer.material = mat;

        prefab.AddComponent<AIAgent>();
        agentPrefab = prefab;
    }

    /// <summary>
    /// Spawns agents with delay
    /// </summary>
    private System.Collections.IEnumerator SpawnAgentsCoroutine(int count)
    {
        for (int i = 0; i < count; i++)
        {
            SpawnAgent();
            yield return new WaitForSeconds(spawnDelay);
        }
    }

    /// <summary>
    /// Spawns a single AI agent
    /// </summary>
    public AIAgent SpawnAgent()
    {
        if (agentPrefab == null)
        {
            Debug.LogError("AIAgentManager: Agent prefab not set!");
            return null;
        }

        GameObject agentGO = Instantiate(agentPrefab);
        agentGO.name = $"AIAgent_{agentCharacterType}_{nextAgentId}";

        var agent = agentGO.GetComponent<AIAgent>();
        agent.SetShowPath(showAgentPaths);
        if (agent == null)
        {
            agent = agentGO.AddComponent<AIAgent>();
        }

        // Set agent properties via reflection or public properties
        var idField = typeof(AIAgent).GetField("agentId",
            System.Reflection.BindingFlags.NonPublic | System.Reflection.BindingFlags.Instance);
        var typeField = typeof(AIAgent).GetField("agentCharacterType",
            System.Reflection.BindingFlags.NonPublic | System.Reflection.BindingFlags.Instance);

        if (idField != null) idField.SetValue(agent, nextAgentId);
        if (typeField != null) typeField.SetValue(agent, agentCharacterType);

        activeAgents.Add(agent);
        nextAgentId++;

        // Suppress per-agent spawn log for large counts (1000 Debug.Log calls is significant overhead)
        // Debug.Log($"Spawned agent {nextAgentId - 1} ({agentCharacterType}). Total agents: {activeAgents.Count}");
        return agent;
    }

    /// <summary>
    /// Spawns multiple agents at once
    /// </summary>
    public void SpawnAgents(int count)
    {
        StartCoroutine(SpawnAgentsCoroutine(count));
    }

    /// <summary>
    /// Removes and destroys an agent
    /// </summary>
    public void RemoveAgent(AIAgent agent)
    {
        if (activeAgents.Remove(agent))
        {
            Destroy(agent.gameObject);
            Debug.Log($"Removed agent {agent.AgentId}. Remaining: {activeAgents.Count}");
        }
    }

    /// <summary>
    /// Gets agents of a specific character type
    /// </summary>
    public List<AIAgent> GetAgentsByType(string characterType)
    {
        var agents = new List<AIAgent>();
        foreach (var agent in activeAgents)
        {
            if (agent.CharacterType == characterType)
            {
                agents.Add(agent);
            }
        }
        return agents;
    }

    /// <summary>
    /// Gets the count of active agents
    /// </summary>
    public int GetAgentCount()
    {
        return activeAgents.Count;
    }

    /// <summary>
    /// Gets agent count by character type
    /// </summary>
    public int GetAgentCountByType(string characterType)
    {
        return GetAgentsByType(characterType).Count;
    }

    /// <summary>
    /// Clears all agents and resets
    /// </summary>
    public void ClearAllAgents()
    {
        foreach (var agent in activeAgents)
        {
            Destroy(agent.gameObject);
        }
        activeAgents.Clear();
        nextAgentId = 0;
        AIRoomMemoryManager.ClearAllMemories();
    }

    /// <summary>
    /// Resets agents for a new maze
    /// </summary>
    public void ResetForNewMaze()
    {
        ClearAllAgents();
        if (isInitialized)
        {
            StartCoroutine(SpawnAgentsCoroutine(initialAgentCount));
        }
    }

    /// <summary>
    /// Gets UI info about agents
    /// </summary>
    public string GetAgentStats()
    {
        int total = activeAgents.Count;
        string stats = $"Total Agents: {total}\n";

        var typeGroups = new Dictionary<string, int>();
        foreach (var agent in activeAgents)
        {
            if (!typeGroups.ContainsKey(agent.CharacterType))
            {
                typeGroups[agent.CharacterType] = 0;
            }
            typeGroups[agent.CharacterType]++;
        }

        foreach (var kvp in typeGroups)
        {
            var memory = AIRoomMemoryManager.GetMemory(kvp.Key);
            stats += $"{kvp.Key}: {kvp.Value} agents, {memory.VisitedCount} rooms explored\n";
        }

        return stats;
    }

    /// <summary>
    /// Gets the initial agent count setting
    /// </summary>
    public int InitialAgentCount => initialAgentCount;

    /// <summary>
    /// Sets the initial agent count (affects next reset)
    /// </summary>
    public void SetInitialAgentCount(int count)
    {
        initialAgentCount = count;
    }

    /// <summary>
    /// Gets the count of active agents
    /// </summary>
    public int GetActiveAgentCount()
    {
        return activeAgents.Count;
    }

    /// <summary>
    /// Gets the list of active agents
    /// </summary>
    public List<AIAgent> GetActiveAgents()
    {
        return activeAgents;
    }

    public IReadOnlyList<AgentGroup> GetActiveGroups() => activeGroups;

    /// <summary>
    /// Updates path visibility for all active agents
    /// </summary>
    public void SetPathVisibilityForAllAgents(bool show)
    {
        showAgentPaths = show;
        foreach (var agent in activeAgents)
        {
            if (agent != null)
            {
                agent.SetShowPath(show);
            }
        }
        Debug.Log($"Path visibility set to: {show} for {activeAgents.Count} agents");
    }
}