using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;
using System.Text.RegularExpressions;
using UnityEditor;
using UnityEngine;
using UnityEngine.UIElements;
using BaseGames.Dialogue;
using BaseGames.Quest;
using BaseGames.EventChain;

namespace BaseGames.Editor.Modules
{
    /// <summary>
    /// DataHub ID 生成模块 —— 扫描 QuestSO / NpcSO / DialogueSequenceSO / EventChainSO 资产，
    /// 自动生成 <c>Assets/_Game/Scripts/Core/GameIds.Generated.cs</c>，
    /// 提供编译期 ID 常量，消除代码中的魔法字符串。
    /// </summary>
    public class IdCodegenModule : IDataModule, IDataModuleOrdered
    {
        private const string OutputPath = "Assets/_Game/Scripts/Core/GameIds.Generated.cs";

        public string ModuleId    => "idcodegen";
        public string DisplayName => "ID 生成";
        public string IconName    => "d_cs Script Icon";
        public int    DisplayOrder => 140;

        private Label  _statusLabel;
        private string _lastResult;

        // ── IDataModule ───────────────────────────────────────────────────────

        public void Initialize() { }

        public void BuildListPane(VisualElement container, Action<UnityEngine.Object> onSelected)
        {
            var desc = new Label(
                "扫描项目中的 QuestSO / NpcSO / DialogueSequenceSO / EventChainSO 资产，\n" +
                $"生成 {OutputPath} 常量文件。\n\n" +
                "生成后在代码中通过 GameIdsGenerated.Quest.XXX 等访问。");
            desc.style.whiteSpace    = WhiteSpace.Normal;
            desc.style.marginBottom  = 12;
            desc.style.paddingLeft   = 8;
            desc.style.paddingRight  = 8;
            desc.style.fontSize      = 11;
            container.Add(desc);

            var btn = new Button(RunCodegen) { text = "⚡ 生成 GameIds.Generated.cs" };
            btn.style.marginLeft  = 8;
            btn.style.marginRight = 8;
            btn.style.height      = 28;
            container.Add(btn);

            _statusLabel = new Label(_lastResult ?? "");
            _statusLabel.style.whiteSpace   = WhiteSpace.Normal;
            _statusLabel.style.marginTop    = 10;
            _statusLabel.style.marginLeft   = 8;
            _statusLabel.style.marginRight  = 8;
            _statusLabel.style.fontSize     = 11;
            container.Add(_statusLabel);
        }

        public void BuildDetailPane(VisualElement container, UnityEngine.Object selected)
        {
            // 无需详情面板
        }

        public void OnActivated() { }

        // ── 代码生成 ──────────────────────────────────────────────────────────

        private void RunCodegen()
        {
            try
            {
                var quests    = AssetOperations.FindAll<QuestSO>()
                    .Where(q  => !string.IsNullOrEmpty(q.questId))
                    .Select(q => q.questId)
                    .Distinct(StringComparer.Ordinal)
                    .OrderBy(s => s, StringComparer.Ordinal)
                    .ToList();

                var npcs = AssetOperations.FindAll<NpcSO>()
                    .Where(n  => !string.IsNullOrEmpty(n.npcId))
                    .Select(n => n.npcId)
                    .Distinct(StringComparer.Ordinal)
                    .OrderBy(s => s, StringComparer.Ordinal)
                    .ToList();

                var dialogues = AssetOperations.FindAll<DialogueSequenceSO>()
                    .Where(d  => !string.IsNullOrEmpty(d.sequenceId))
                    .Select(d => d.sequenceId)
                    .Distinct(StringComparer.Ordinal)
                    .OrderBy(s => s, StringComparer.Ordinal)
                    .ToList();

                var chains = AssetOperations.FindAll<EventChainSO>()
                    .Where(c  => !string.IsNullOrEmpty(c.chainId))
                    .Select(c => c.chainId)
                    .Distinct(StringComparer.Ordinal)
                    .OrderBy(s => s, StringComparer.Ordinal)
                    .ToList();

                string code = BuildSourceCode(quests, npcs, dialogues, chains);

                string fullPath = Path.GetFullPath(OutputPath);
                string dir      = Path.GetDirectoryName(fullPath);
                if (!Directory.Exists(dir))
                    Directory.CreateDirectory(dir);

                File.WriteAllText(fullPath, code, new UTF8Encoding(encoderShouldEmitUTF8Identifier: false));
                AssetDatabase.ImportAsset(OutputPath, ImportAssetOptions.ForceUpdate);

                int total = quests.Count + npcs.Count + dialogues.Count + chains.Count;
                _lastResult = $"✅ 生成完成（{total} 个常量：Quest×{quests.Count} Npc×{npcs.Count} " +
                              $"Dialogue×{dialogues.Count} Chain×{chains.Count}）";
            }
            catch (Exception e)
            {
                _lastResult = $"❌ 生成失败：{e.Message}";
                Debug.LogException(e);
            }

            if (_statusLabel != null)
                _statusLabel.text = _lastResult;
        }

        private static string BuildSourceCode(List<string> quests, List<string> npcs,
                                              List<string> dialogues, List<string> chains)
        {
            var sb = new StringBuilder();
            sb.AppendLine("// <auto-generated>");
            sb.AppendLine("// 此文件由 DataHub > ID生成 模块自动生成，请勿手动编辑。");
            sb.AppendLine("// 手动维护的 ID 常量请放在 GameIds.cs 中。");
            sb.AppendLine("// </auto-generated>");
            sb.AppendLine();
            sb.AppendLine("namespace BaseGames.Core");
            sb.AppendLine("{");
            sb.AppendLine("    /// <summary>自动生成的游戏资产 ID 常量。每次执行 DataHub > ID生成 后刷新。</summary>");
            sb.AppendLine("    public static class GameIdsGenerated");
            sb.AppendLine("    {");

            AppendSection(sb, "Quest",    "QuestSO.questId",           quests,    "Quest_");
            AppendSection(sb, "Npc",      "NpcSO.npcId",               npcs,      "NPC_");
            AppendSection(sb, "Dialogue", "DialogueSequenceSO.sequenceId", dialogues, "DLG_");
            AppendSection(sb, "Chain",    "EventChainSO.chainId",       chains,    "Chain_");

            sb.AppendLine("    }");
            sb.AppendLine("}");
            return sb.ToString();
        }

        private static void AppendSection(StringBuilder sb, string className, string docSource,
                                          List<string> ids, string stripPrefix)
        {
            sb.AppendLine($"        /// <summary>来自 {docSource} 的 ID 常量。</summary>");
            sb.AppendLine($"        public static class {className}");
            sb.AppendLine("        {");

            if (ids.Count == 0)
                sb.AppendLine("            // 项目中暂无此类资产");
            else
                foreach (string id in ids)
                    sb.AppendLine($"            public const string {ToFieldName(id, stripPrefix)} = \"{id}\";");

            sb.AppendLine("        }");
            sb.AppendLine();
        }

        /// <summary>
        /// 将原始 ID 字符串转为合法的 C# 标识符。
        /// 剥离常见前缀（如 "Quest_"），然后将剩余部分中的非字母数字字符替换为下划线，
        /// 确保不以数字开头。
        /// </summary>
        private static string ToFieldName(string rawId, string stripPrefix)
        {
            string name = rawId;
            if (!string.IsNullOrEmpty(stripPrefix) &&
                name.StartsWith(stripPrefix, StringComparison.OrdinalIgnoreCase))
                name = name.Substring(stripPrefix.Length);

            // 将非字母数字字符替换为下划线
            name = Regex.Replace(name, @"[^A-Za-z0-9_]", "_");

            // 不能以数字开头
            if (name.Length > 0 && char.IsDigit(name[0]))
                name = "_" + name;

            if (string.IsNullOrEmpty(name))
                name = "_";

            return name;
        }
    }
}