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

/// <summary>
/// Represents a group of agents moving together through the maze.
/// The first member is always the leader whose GameObject drives movement.
/// Other members follow by parenting / position copy each frame.
///
/// Max size: 9. Joining chance decreases as group grows.
/// Group shows a single enlarged sphere with a member-count label (AgentGroupVisual).
/// </summary>
public class AgentGroup
{
    public const int MAX_SIZE = 9;

    /// <summary>Unique id for this group (for logging / future UI)</summary>
    public int GroupId { get; private set; }

    /// <summary>All members; index 0 is always the leader.</summary>
    public IReadOnlyList<AIAgent> Members => members;

    /// <summary>The agent that physically moves – others follow.</summary>
    public AIAgent Leader => members.Count > 0 ? members[0] : null;

    public int Size => members.Count;
    public bool IsFull => members.Count >= MAX_SIZE;

    // ------------------------------------------------------------------ //
    //  Combined stats (max of each stat across members – group benefits   //
    //  from having specialists, but average is tracked too for display)   //
    // ------------------------------------------------------------------ //
    public int CombinedStrength { get; private set; }
    public int CombinedSpeed { get; private set; }
    public int CombinedMagic { get; private set; }
    public int CombinedDexterity { get; private set; }
    public int CombinedIntelligence { get; private set; }
    public int CombinedConstitution { get; private set; }

    /// <summary>
    /// Combined group current health: sum of all members' current HP.
    /// </summary>
    public int CombinedHealth => members.Count > 0 ? members.Sum(a => a.Stats.CurrentHealth) : 0;

    /// <summary>
    /// Combined group max health: sum of all members' max HP.
    /// </summary>
    public int CombinedMaxHealth => members.Count > 0 ? members.Sum(a => a.Stats.MaxHealth) : 0;

    public int AvgStrength => members.Count > 0 ? (int)members.Average(a => a.Stats.Strength) : 0;
    public int AvgSpeed => members.Count > 0 ? (int)members.Average(a => a.Stats.Speed) : 0;
    public int AvgMagic => members.Count > 0 ? (int)members.Average(a => a.Stats.Magic) : 0;
    public int AvgDexterity => members.Count > 0 ? (int)members.Average(a => a.Stats.Dexterity) : 0;
    public int AvgIntelligence => members.Count > 0 ? (int)members.Average(a => a.Stats.Intelligence) : 0;
    public int AvgConstitution => members.Count > 0 ? (int)members.Average(a => a.Stats.Constitution) : 0;

    private readonly List<AIAgent> members = new();
    private static int nextGroupId = 1;

    public AgentGroup(AIAgent founder)
    {
        GroupId = nextGroupId++;
        AddMember(founder);
    }

    // ------------------------------------------------------------------ //
    //  Membership                                                         //
    // ------------------------------------------------------------------ //

    /// <summary>
    /// Attempt to add a new agent. Returns true if accepted.
    /// Chance of acceptance drops with group size so large groups are
    /// harder to join.
    /// </summary>
    public bool TryAddMember(AIAgent candidate)
    {
        if (IsFull) return false;
        if (members.Contains(candidate)) return false;

        // Base acceptance roll – bigger group = lower chance to accept new member.
        // Size 1 → 100%, size 8 → ~11%
        float acceptanceChance = 1f / members.Count;

        // High INT candidate is better at selling themselves to the group;
        // high INT leader is more selective (slightly lower base chance but
        // we already reward INT via groupUpAffinity in the caller).
        acceptanceChance *= Mathf.Lerp(0.8f, 1.2f, candidate.GroupUpAffinity);

        if (Random.value > acceptanceChance) return false;

        AddMember(candidate);
        return true;
    }

    private void AddMember(AIAgent agent)
    {
        members.Add(agent);
        agent.JoinGroup(this);
        RecalcStats();
        UpdateVisual();
        Debug.Log($"[Group {GroupId}] {agent.AgentName} joined. Size now {members.Count}");
    }

    public void RemoveMember(AIAgent agent)
    {
        if (!members.Contains(agent)) return;
        bool wasLeader = agent == Leader;
        members.Remove(agent);
        agent.LeaveGroup();
        RecalcStats();

        if (members.Count == 0)
        {
            // Group dissolved
            DestroyVisual();
            return;
        }

        if (wasLeader)
        {
            // Promote next member; move visual to new leader
            Debug.Log($"[Group {GroupId}] Leader left, {Leader.AgentName} is the new leader.");
        }

        UpdateVisual();
        Debug.Log($"[Group {GroupId}] {agent.AgentName} left. Size now {members.Count}");
    }

    // ------------------------------------------------------------------ //
    //  Stats                                                              //
    // ------------------------------------------------------------------ //

    private void RecalcStats()
    {
        if (members.Count == 0) return;
        CombinedStrength = members.Max(a => a.Stats.Strength);
        CombinedSpeed = members.Max(a => a.Stats.Speed);
        CombinedMagic = members.Max(a => a.Stats.Magic);
        CombinedDexterity = members.Max(a => a.Stats.Dexterity);
        CombinedIntelligence = members.Max(a => a.Stats.Intelligence);
        CombinedConstitution = members.Max(a => a.Stats.Constitution);
    }

    // ------------------------------------------------------------------ //
    //  Visual                                                             //
    // ------------------------------------------------------------------ //

    private AgentGroupVisual visual;

    private void UpdateVisual()
    {
        if (Leader == null) return;

        if (visual == null)
        {
            visual = Leader.gameObject.AddComponent<AgentGroupVisual>();
            visual.Init(this);
        }
        else
        {
            visual.Refresh();
        }
    }

    private void DestroyVisual()
    {
        if (visual != null)
        {
            Object.Destroy(visual);
            visual = null;
        }
    }
}