using System;
using System.Collections.Generic;
using System.IO;

namespace TeamAAS
{
    /// <summary>
    /// 统一路径/文件名入口。全应用的文件/目录一律经由此类拼取，
    /// 需要整体迁移数据目录（或更换宿主）时，只需改 <see cref="Root"/> 一处，内核逻辑不变。
    /// </summary>
    public static class PathHelper
    {
        /// <summary>统一数据根目录（唯一对外可改参数）。默认=程序基目录。</summary>
        public static string Root { get; set; } = AppDomain.CurrentDomain.BaseDirectory;

        // 子目录名（固定）
        private const string ConfigFolder = "Config";
        private const string ProductsFolder = "Products";
        private const string RecipeFolder = "Recipe";
        private const string RuntimeFolder = "Runtime";
        private const string LocalizationFolder = "Localization";
        private const string PluginsFolder = "Plugins";

        // 共享配置/数据文件名（固定）
        private const string SystemConfigName = "SystemConfiguration.json";
        private const string GlobalEventName = "GlobalEventConfig.json";
        private const string FeedersName = "Feeders.json";
        private const string FeederRecipesName = "Feeder_recipes.json";
        private const string DatabaseName = "Database.db";

        private static string Ensure(string dir)
        {
            if (!string.IsNullOrEmpty(dir) && !Directory.Exists(dir)) Directory.CreateDirectory(dir);
            return dir;
        }

        /// <summary>Config 目录（自动创建）。</summary>
        public static string ConfigDirectory => Ensure(Path.Combine(Root, ConfigFolder));
        /// <summary>Products 目录（自动创建）。</summary>
        public static string ProductsDir => Ensure(Path.Combine(Root, ProductsFolder));
        /// <summary>Recipe（配方/全局变量）目录（自动创建）。</summary>
        public static string RecipeDir => Ensure(Path.Combine(Root, RecipeFolder));
        /// <summary>Runtime 目录（依赖/插件/语言包，只读不创建）。</summary>
        public static string RuntimeDir => Path.Combine(Root, RuntimeFolder);
        /// <summary>插件目录 Runtime\Plugins。</summary>
        public static string PluginsDir => Path.Combine(RuntimeDir, PluginsFolder);
        /// <summary>语言包目录 Runtime\Localization。</summary>
        public static string LocalizationDir => Path.Combine(RuntimeDir, LocalizationFolder);

        /// <summary>解析语言包目录：优先 Runtime\Localization，回退 Root\Localization。</summary>
        public static string ResolveLocalizationDir()
        {
            if (Directory.Exists(LocalizationDir)) return LocalizationDir;
            var alt = Path.Combine(Root, LocalizationFolder);
            return Directory.Exists(alt) ? alt : LocalizationDir;
        }

        // 共享配置/数据文件绝对路径
        /// <summary>Config\SystemConfiguration.json。</summary>
        public static string SystemConfigurationFile => Path.Combine(ConfigDirectory, SystemConfigName);
        /// <summary>Config\GlobalEventConfig.json。</summary>
        public static string GlobalEventConfigFile => Path.Combine(ConfigDirectory, GlobalEventName);
        /// <summary>Config\feeders.json。</summary>
        public static string FeedersConfigFile => Path.Combine(ConfigDirectory, FeedersName);
        /// <summary>Config\feeder_recipes.json。</summary>
        public static string FeederRecipesFile => Path.Combine(ConfigDirectory, FeederRecipesName);
        /// <summary>根目录下的 database.db。</summary>
        public static string DatabaseFile => Path.Combine(Root, DatabaseName);

        /// <summary>Config\global_vars.json（机器级全局固定变量，不随产品变）。</summary>
        public static string GlobalFixedVarsFile => Path.Combine(ConfigDirectory, "global_vars.json");

        /// <summary>
        /// 将名称中的非法文件名字符替换为 '_'。
        /// </summary>
        public static string SanitizeFileName(string name)
        {
            if (string.IsNullOrEmpty(name)) return name;
            foreach (char c in Path.GetInvalidFileNameChars())
                name = name.Replace(c, '_');
            return name;
        }

        /// <summary>
        /// 生成不重复的名称（如 流程1、流程2...）。候选集由 existPredicate 判定。
        /// </summary>
        public static string GenerateUniqueName(string baseName, Func<string, bool> existsPredicate)
        {
            if (existsPredicate == null) throw new ArgumentNullException(nameof(existsPredicate));

            string candidate = baseName;
            int suffix = 1;
            while (existsPredicate(candidate))
                candidate = baseName + suffix++;
            return candidate;
        }

        /// <summary>
        /// 生成不重复的名称（基于已有名称集合）。
        /// </summary>
        public static string GenerateUniqueName(string baseName, ICollection<string> existingNames)
        {
            if (existingNames == null) throw new ArgumentNullException(nameof(existingNames));
            return GenerateUniqueName(baseName, n => existingNames.Contains(n));
        }
    }
}