using Microsoft.Extensions.Localization;
using System.Globalization;
using System.Net.Http;
using System.Text.Json;

namespace Atomx.Admin.Client.Services
{
    public class JsonStringLocalizer : IStringLocalizer
    {
        private readonly string _resourcesPath;
        private readonly Dictionary<string, Dictionary<string, string>> _resourcesCache = new();
        private readonly object _lock = new();
        private readonly HttpClient? _httpClient;

        // resourcesPath 应为相对于站点根的“目录”名称，例如 "Localization"
        // 在 Blazor WebAssembly 场景下，会使用注入的 HttpClient 从 wwwroot/Localization/{culture}.json 获取资源
        public JsonStringLocalizer(string resourcesPath, HttpClient? httpClient = null)
        {
            _resourcesPath = (resourcesPath ?? "localization").Trim('/'); // 规范化
            _httpClient = httpClient;
        }

        public LocalizedString this[string name]
        {
            get
            {
                var value = GetString(name);
                return new LocalizedString(name, value ?? name, resourceNotFound: value == null);
            }
        }

        public LocalizedString this[string name, params object[] arguments]
        {
            get
            {
                var format = GetString(name);
                var value = string.Format(format ?? name, arguments);
                return new LocalizedString(name, value, resourceNotFound: format == null);
            }
        }

        public IEnumerable<LocalizedString> GetAllStrings(bool includeParentCultures)
        {
            var culture = CultureInfo.CurrentUICulture.Name;
            var resources = LoadResources(culture);
            return resources.Select(r => new LocalizedString(r.Key, r.Value, false));
        }

        private string? GetString(string name)
        {
            var culture = CultureInfo.CurrentUICulture.Name;
            var resources = LoadResources(culture);

            // 尝试当前文化
            if (resources.TryGetValue(name, out var value))
                return value;

            // 如果还找不到，尝试英文作为后备
            if (culture != "en-US")
            {
                var enResources = LoadResources("en-US");
                if (enResources.TryGetValue(name, out var enValue))
                    return enValue;
            }

            return null;
        }

        private Dictionary<string, string> LoadResources(string culture)
        {
            lock (_lock)
            {
                if (_resourcesCache.TryGetValue(culture, out var cachedResources))
                    return cachedResources;

                var resources = new Dictionary<string, string>(StringComparer.OrdinalIgnoreCase);
                var fileName = $"{culture}.json";

                // 在浏览器（WASM）环境下，通过 HttpClient 从静态资源目录获取
                if (OperatingSystem.IsBrowser() && _httpClient != null)
                {
                    try
                    {
                        // 构造相对 URL，例如 "Localization/zh-Hans.json"
                        var relativeUrl = $"{_resourcesPath}/{fileName}";
                        var json = _httpClient.GetStringAsync(relativeUrl).ConfigureAwait(false).GetAwaiter().GetResult();
                        var jsonResources = JsonSerializer.Deserialize<Dictionary<string, string>>(json);
                        if (jsonResources != null)
                        {
                            foreach (var item in jsonResources)
                            {
                                resources[item.Key] = item.Value;
                            }
                        }
                    }
                    catch (Exception ex)
                    {
                        Console.WriteLine($"Error loading localization file {fileName} via HttpClient: {ex.Message}");
                    }

                    _resourcesCache[culture] = resources;
                    return resources;
                }

                // 非浏览器（例如 Server 或在 prerender 阶段）尝试从文件系统读取。
                // 尝试几种可能的路径：基路径为 AppContext.BaseDirectory 或当前工作目录，或直接使用传入的路径。
                try
                {
                    var candidates = new[]
                    {
                        Path.Combine(AppContext.BaseDirectory, _resourcesPath, fileName),
                        Path.Combine(Directory.GetCurrentDirectory(), _resourcesPath, fileName),
                        Path.Combine(_resourcesPath, fileName),
                    };

                    var filePath = candidates.FirstOrDefault(File.Exists);

                    if (!string.IsNullOrEmpty(filePath))
                    {
                        var json = File.ReadAllText(filePath);
                        var jsonResources = JsonSerializer.Deserialize<Dictionary<string, string>>(json);
                        if (jsonResources != null)
                        {
                            foreach (var item in jsonResources)
                            {
                                resources[item.Key] = item.Value;
                            }
                        }
                    }
                }
                catch (Exception ex)
                {
                    Console.WriteLine($"Error loading localization file {fileName} from disk: {ex.Message}");
                }

                _resourcesCache[culture] = resources;
                return resources;
            }
        }
    }
}