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

/// <summary>
/// 战斗场景的出战生成：开战前按阵型数据在对应格位生成英雄。
/// 优先使用阵型编排场景保存的数据；没有编排数据时按名单使用默认阵型（近战前排 / 远程后排）。
/// </summary>
public class BattleFormationSpawner : MonoBehaviour
{
    [Header("出战英雄名单（没有编排数据时的默认来源）")]
    public HeroRoster roster;

    [Header("生成到哪个父节点（留空则放在场景根）")]
    public Transform heroParent;

    [Header("玩家阵营 ID")]
    public int playerTeamId = 0;

    private void Start()
    {
        SpawnHeroes();
    }

    private void SpawnHeroes()
    {
        // 1. 玩家编排过的阵型
        if (FormationData.HasCustomFormation
            && FormationData.HeroPrefabs != null
            && FormationData.HeroPrefabs.Length > 0)
        {
            for (int i = 0; i < FormationData.HeroPrefabs.Length; i++)
            {
                int cell = i < FormationData.CellIndices.Length ? FormationData.CellIndices[i] : -1;
                if (FormationData.HeroPrefabs[i] == null || !DeployGrid.IsValidIndex(cell))
                {
                    continue;
                }
                Spawn(FormationData.HeroPrefabs[i], cell);
            }
            return;
        }

        // 2. 没有编排数据：默认阵型
        SpawnDefaultFormation();
    }

    private void SpawnDefaultFormation()
    {
        if (roster == null || roster.heroes == null) return;

        int meleeTotal = 0, rangedTotal = 0;
        foreach (HeroEntry entry in roster.heroes)
        {
            if (entry == null) continue;
            if (entry.isMelee) meleeTotal++; else rangedTotal++;
        }

        var used = new HashSet<int>();
        int meleeIndex = 0, rangedIndex = 0;

        foreach (HeroEntry entry in roster.heroes)
        {
            if (entry == null || entry.prefab == null) continue;

            int cell = entry.isMelee
                ? DeployGrid.DefaultCell(true, meleeIndex++, meleeTotal)
                : DeployGrid.DefaultCell(false, rangedIndex++, rangedTotal);

            if (used.Contains(cell))
            {
                cell = NextFreeCell(cell, used);
            }
            if (cell < 0) continue;

            used.Add(cell);
            Spawn(entry.prefab, cell);
        }
    }

    private static int NextFreeCell(int from, HashSet<int> used)
    {
        for (int i = 0; i < DeployGrid.CellCount; i++)
        {
            int candidate = (from + i) % DeployGrid.CellCount;
            if (!used.Contains(candidate)) return candidate;
        }
        return -1;
    }

    private void Spawn(GameObject prefab, int cell)
    {
        CharacterData characterData = FindCharacterDataForPrefab(prefab);
        GameObject unit = Instantiate(prefab, DeployGrid.CellPosition(cell), Quaternion.identity);
        unit.name = "英雄_" + prefab.name;

        if (heroParent != null)
        {
            unit.transform.SetParent(heroParent, true);
        }

        UnitTeam team = unit.GetComponent<UnitTeam>();
        if (team != null)
        {
            team.teamId = playerTeamId;
        }

        UnitBase unitBase = unit.GetComponent<UnitBase>();
        if (unitBase != null)
        {
            unitBase.returnToAnchorWhenIdle = true;
            unitBase.anchorArrivalDistance = 0.35f;
        }

        if (characterData != null && unitBase != null)
        {
            PlayerCharacterData playerData = PlayerDataManager.Instance != null
                ? PlayerDataManager.Instance.GetCharacterData(characterData.characterId)
                : null;
            int level = playerData != null ? playerData.level : 1;
            unitBase.InitializeFromPlayerData(
                characterData.GetMaxHealth(level),
                characterData.GetAttackPower(level),
                characterData.GetMoveSpeed(level));
        }
    }

    private CharacterData FindCharacterDataForPrefab(GameObject prefab)
    {
        if (prefab == null) return null;
        return Resources.LoadAll<CharacterData>("Data")
            .FirstOrDefault(data => data != null && data.unitPrefab == prefab);
    }
}