using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using System.Windows;
using LocalizationTool.Services;

namespace LocalizationTool.ViewModels
{
    /// <summary>
    /// 翻译设置窗口 ViewModel。
    /// 语义：BaseUrl / Model / Keys / AppId / Secret 留空 = 内置默认；填了 = 自定义优先；
    /// "恢复默认"清空自定义字段。
    /// </summary>
    public class TranslationSettingsViewModel : ViewModelBase
    {
        private readonly Config.ConfigRoot _cfg;

        private bool _isBaidu;
        private string _baseUrl;
        private string _model;
        private bool _isLlm;
        private string _reference;
        private string _testText = "保存配置";
        private string _testResult = "翻译结果将显示在这里...";
        private LanguageEntry _testLang;
        private bool _isBusy;
        private List<string> _allModels = new List<string>();

        public TranslationSettingsViewModel(Config.ConfigRoot cfg)
        {
            _cfg = cfg ?? new Config.ConfigRoot();

            // 掩码回显
            var firstKey = Config.GetOpenAiKeys(_cfg.Translation).FirstOrDefault() ?? "";
            OpenAiKeyMask = Config.MaskKey(firstKey);
            var (appId, secret) = Config.GetBaiduCredentials(_cfg.Baidu);
            BaiduAppIdMask = Config.MaskKey(appId);
            BaiduSecretMask = Config.MaskKey(secret);

            BaseUrl = Config.ResolveBaseUrl(_cfg.Translation);
            Model = Config.ResolveModel(_cfg.Translation);
            IsBaidu = string.Equals(_cfg.Translation.Provider, "baidu", StringComparison.OrdinalIgnoreCase);
            IsLlm = string.Equals(_cfg.Baidu.ModelType, "llm", StringComparison.OrdinalIgnoreCase);
            Reference = _cfg.Baidu.Reference ?? "";

            // 输入框初始显示掩码（内容 == 掩码 = 未修改，保存时保持原值）
            OpenAiKeyInput = OpenAiKeyMask;
            BaiduAppIdInput = BaiduAppIdMask;
            BaiduSecretInput = BaiduSecretMask;

            TestCommand = new RelayCommand(() => { var _ = TestTranslateAsync(); });
            FetchModelsCommand = new RelayCommand(() => { var _ = FetchModelsAsync(); });
            ResetOpenAICommand = new RelayCommand(ResetOpenAiToDefault);
            ResetBaiduCommand = new RelayCommand(ResetBaiduToDefault);
            SaveCommand = new RelayCommand(Save);
            CancelCommand = new RelayCommand(Cancel);
            SwitchToOpenAiCommand = new RelayCommand(() => IsOpenAi = true);
            SwitchToBaiduCommand = new RelayCommand(() => IsBaidu = true);
        }

        // ---- 引擎选择 ----

        public bool IsOpenAi
        {
            get => !_isBaidu;
            set { if (value) IsBaidu = false; }
        }

        public bool IsBaidu
        {
            get => _isBaidu;
            set { if (Set(ref _isBaidu, value)) { OnPropertyChanged(nameof(IsOpenAi)); UpdateStatus(); } }
        }

        // ---- OpenAI ----

        public string BaseUrl
        {
            get => _baseUrl;
            set => Set(ref _baseUrl, value);
        }

        public string Model
        {
            get => _model;
            set
            {
                if (Set(ref _model, value)) OnPropertyChanged(nameof(FilteredModels));
            }
        }

        /// <summary>模型最大上下文（token）输入；空/非法 = 用内置默认（agnes-2.5-flash 512K）。</summary>
        public string MaxContextTokensText
        {
            get => _cfg.Translation.MaxContextTokens > 0 ? _cfg.Translation.MaxContextTokens.ToString() : "";
            set
            {
                _cfg.Translation.MaxContextTokens =
                    int.TryParse(value?.Trim(), out var n) && n > 0 ? n : 0;
            }
        }

        /// <summary>当前生效的最大上下文（含内置默认值说明）。</summary>
        public string MaxContextHint =>
            $"留空 = 内置默认 {Config.BuiltInMaxContextTokens:N0} token（agnes-2.5-flash 规格）";

        /// <summary>已存 Key 的掩码（输入框内容 == 掩码 = 未修改）。</summary>
        public string OpenAiKeyMask
        {
            get => _openAiKeyMask;
            set => Set(ref _openAiKeyMask, value);
        }
        private string _openAiKeyMask = "";

        /// <summary>输入框当前内容（由 View 在 PasswordBox 变化时更新）。</summary>
        public string OpenAiKeyInput
        {
            get => _openAiKeyInput;
            set => Set(ref _openAiKeyInput, value);
        }
        private string _openAiKeyInput = "";

        // ---- 百度 ----

        public string BaiduAppIdMask
        {
            get => _baiduAppIdMask;
            set => Set(ref _baiduAppIdMask, value);
        }
        private string _baiduAppIdMask = "";

        public string BaiduSecretMask
        {
            get => _baiduSecretMask;
            set => Set(ref _baiduSecretMask, value);
        }
        private string _baiduSecretMask = "";

        public string BaiduAppIdInput
        {
            get => _baiduAppIdInput;
            set => Set(ref _baiduAppIdInput, value);
        }
        private string _baiduAppIdInput = "";

        public string BaiduSecretInput
        {
            get => _baiduSecretInput;
            set => Set(ref _baiduSecretInput, value);
        }
        private string _baiduSecretInput = "";

        public bool IsLlm
        {
            get => _isLlm;
            set
            {
                if (Set(ref _isLlm, value)) OnPropertyChanged(nameof(IsNmt));
            }
        }

        /// <summary>NMT 模式（与 IsLlm 互斥）。</summary>
        public bool IsNmt
        {
            get => !_isLlm;
            set
            {
                var newLlm = !value;
                if (_isLlm == newLlm) return;
                _isLlm = newLlm;
                OnPropertyChanged(nameof(IsLlm));
                OnPropertyChanged(nameof(IsNmt));
            }
        }

        public string Reference
        {
            get => _reference;
            set => Set(ref _reference, value);
        }

        // ---- 测试 ----

        /// <summary>测试目标语言候选（全量语言目录）。</summary>
        public List<LanguageEntry> TestLanguages => LanguageCatalog.All;

        public LanguageEntry TestLang
        {
            get => _testLang;
            set => Set(ref _testLang, value);
        }

        public string TestText
        {
            get => _testText;
            set => Set(ref _testText, value);
        }

        public string TestResult
        {
            get => _testResult;
            set => Set(ref _testResult, value);
        }

        public bool IsBusy
        {
            get => _isBusy;
            set => Set(ref _isBusy, value);
        }

        // ---- 状态 ----

        private string _openAiStatus = "";
        private string _baiduStatus = "";
        public string OpenAiStatus
        {
            get => _openAiStatus;
            private set => Set(ref _openAiStatus, value);
        }
        public string BaiduStatus
        {
            get => _baiduStatus;
            private set => Set(ref _baiduStatus, value);
        }

        /// <summary>请求关闭窗口（true = 保存成功）。</summary>
        public event Action<bool> RequestClose;

        // ---- 命令 ----

        public RelayCommand TestCommand { get; }
        public RelayCommand FetchModelsCommand { get; }
        public RelayCommand ResetOpenAICommand { get; }
        public RelayCommand ResetBaiduCommand { get; }
        public RelayCommand SaveCommand { get; }
        public RelayCommand CancelCommand { get; }
        public RelayCommand SwitchToOpenAiCommand { get; }
        public RelayCommand SwitchToBaiduCommand { get; }

        // ---- 初始化 ----

        public void Initialize(LanguageEntry defaultLang)
        {
            TestLang = defaultLang;
            UpdateStatus();
        }

        public void UpdateStatus()
        {
            OpenAiStatus = Config.IsDefaultOpenAi(_cfg.Translation)
                ? "✅ 当前使用内置默认 AI（留空即内置默认）"
                : "✏️ 当前使用自定义 AI 配置";
            BaiduStatus = Config.IsDefaultBaidu(_cfg.Baidu)
                ? "✅ 当前使用内置默认凭证（留空即内置默认）"
                : "✏️ 当前使用自定义凭证";
        }

        // ---- 恢复默认 ----

        private void ResetOpenAiToDefault()
        {
            Config.ResetOpenAiToDefault(_cfg.Translation);
            BaseUrl = Config.BuiltInBaseUrl;
            Model = Config.BuiltInModel;
            OpenAiKeyMask = Config.MaskKey(Config.GetOpenAiKeys(_cfg.Translation).FirstOrDefault() ?? "");
            OpenAiKeyInput = OpenAiKeyMask;
            UpdateStatus();
        }

        private void ResetBaiduToDefault()
        {
            Config.ResetBaiduToDefault(_cfg.Baidu);
            BaiduAppIdMask = Config.MaskKey(Config.GetBaiduCredentials(_cfg.Baidu).appId);
            BaiduSecretMask = Config.MaskKey(Config.GetBaiduCredentials(_cfg.Baidu).secret);
            BaiduAppIdInput = BaiduAppIdMask;
            BaiduSecretInput = BaiduSecretMask;
            UpdateStatus();
        }

        // ---- 保存 ----

        private void Save()
        {
            if (IsOpenAi)
            {
                _cfg.Translation.Provider = "openai";
                _cfg.Translation.ApiKey = null;

                var url = BaseUrl?.Trim();
                _cfg.Translation.BaseUrl =
                    (string.IsNullOrEmpty(url) || url == Config.BuiltInBaseUrl) ? "" : url;
                var model = Model?.Trim();
                _cfg.Translation.Model =
                    (string.IsNullOrEmpty(model) || model == Config.BuiltInModel) ? "" : model;

                if (OpenAiKeyInput.Length == 0)
                    _cfg.Translation.Keys = new List<string>();
                else if (OpenAiKeyInput != OpenAiKeyMask)
                    _cfg.Translation.Keys = new List<string> { Config.EncryptKey(OpenAiKeyInput) };
            }
            else
            {
                _cfg.Translation.Provider = "baidu";
                _cfg.Baidu.ModelType = IsLlm ? "llm" : "nmt";
                _cfg.Baidu.Reference = Reference?.Trim();

                if (BaiduAppIdInput.Length == 0)
                    _cfg.Baidu.AppId = "";
                else if (BaiduAppIdInput != BaiduAppIdMask)
                    _cfg.Baidu.AppId = Config.EncryptKey(BaiduAppIdInput);

                if (BaiduSecretInput.Length == 0)
                    _cfg.Baidu.Secret = "";
                else if (BaiduSecretInput != BaiduSecretMask)
                    _cfg.Baidu.Secret = Config.EncryptKey(BaiduSecretInput);
            }

            Config.Save(_cfg);
            Translation.Reset();
            RequestClose?.Invoke(true);
        }

        private void Cancel() => RequestClose?.Invoke(false);

        // ---- 测试翻译 ----

        private async Task TestTranslateAsync()
        {
            var text = TestText?.Trim();
            if (string.IsNullOrEmpty(text))
            {
                MessageBox.Show("请输入测试文本", "提示");
                return;
            }

            var langEntry = TestLang;
            var targetLang = langEntry?.Code ?? "en-US";
            var targetDisplay = langEntry?.Display ?? targetLang;

            try
            {
                IsBusy = true;
                TestResult = $"翻译中...（目标：{targetDisplay}）";

                var tempConfig = new Config.ConfigRoot
                {
                    Translation = new Config.TranslationConfig
                    {
                        Provider = IsOpenAi ? "openai" : "baidu",
                        BaseUrl = string.IsNullOrWhiteSpace(BaseUrl) ? Config.BuiltInBaseUrl : BaseUrl.Trim(),
                        Model = string.IsNullOrWhiteSpace(Model) ? Config.BuiltInModel : Model.Trim(),
                        Keys = OpenAiKeyInput.Length > 0 && OpenAiKeyInput != OpenAiKeyMask
                            ? new List<string> { Config.EncryptKey(OpenAiKeyInput) }
                            : (_cfg.Translation.Keys ?? new List<string>()),
                    },
                    Baidu = new Config.BaiduConfig
                    {
                        AppId = BaiduAppIdInput.Length > 0 && BaiduAppIdInput != BaiduAppIdMask
                            ? Config.EncryptKey(BaiduAppIdInput) : _cfg.Baidu.AppId,
                        Secret = BaiduSecretInput.Length > 0 && BaiduSecretInput != BaiduSecretMask
                            ? Config.EncryptKey(BaiduSecretInput) : _cfg.Baidu.Secret,
                        ModelType = IsLlm ? "llm" : "nmt",
                        Reference = Reference?.Trim(),
                    }
                };

                Translation.Reset();
                var provider = Translation.Create(tempConfig);
                var result = await provider.TranslateAsync(text, "zh", targetLang);
                TestResult = $"✅ 翻译成功（引擎：{provider.Name}，目标：{targetDisplay}）：\n{result}";
            }
            catch (Exception ex)
            {
                TestResult = $"❌ 翻译失败：\n{ex.Message}";
            }
            finally
            {
                IsBusy = false;
            }
        }

        // ---- 获取模型列表 ----

        private async Task FetchModelsAsync()
        {
            var baseUrl = string.IsNullOrWhiteSpace(BaseUrl)
                ? Config.BuiltInBaseUrl
                : BaseUrl.Trim().TrimEnd('/');
            var key = ResolveOpenAiKey();
            if (string.IsNullOrWhiteSpace(baseUrl) || string.IsNullOrWhiteSpace(key))
            {
                MessageBox.Show("请先填写 Base URL 和 API Key", "提示");
                return;
            }

            try
            {
                IsBusy = true;
                using (var client = new System.Net.Http.HttpClient { Timeout = TimeSpan.FromSeconds(20) })
                {
                    client.DefaultRequestHeaders.Authorization =
                        new System.Net.Http.Headers.AuthenticationHeaderValue("Bearer", key);
                    var resp = await client.GetAsync(baseUrl + "/models");
                    var body = await resp.Content.ReadAsStringAsync();

                    var j = Newtonsoft.Json.Linq.JObject.Parse(body);
                    var arr = j["data"] as Newtonsoft.Json.Linq.JArray;
                    var models = arr?.Select(t => (string)t["id"])
                                     .Where(s => !string.IsNullOrEmpty(s))
                                     .Distinct()
                                     .OrderBy(s => s)
                                     .ToList() ?? new List<string>();

                    if (models.Count == 0)
                    {
                        MessageBox.Show("接口返回为空，未获取到模型", "提示");
                        return;
                    }

                    _allModels = models;
                    Model = models.First();
                    OnPropertyChanged(nameof(FilteredModels));
                }
            }
            catch (Exception ex)
            {
                MessageBox.Show($"获取模型失败：{ex.Message}", "错误");
            }
            finally
            {
                IsBusy = false;
            }
        }

        private string ResolveOpenAiKey()
        {
            var input = OpenAiKeyInput?.Trim() ?? "";
            if (!string.IsNullOrEmpty(input) && input != OpenAiKeyMask) return input;
            return Config.GetOpenAiKeys(_cfg.Translation).FirstOrDefault() ?? "";
        }

        /// <summary>模型下拉候选（按 Model 输入过滤）。</summary>
        public List<string> FilteredModels
        {
            get
            {
                if (_allModels.Count == 0) return null;
                var kw = Model?.Trim() ?? "";
                return string.IsNullOrEmpty(kw)
                    ? _allModels
                    : _allModels.Where(m => m.IndexOf(kw, StringComparison.OrdinalIgnoreCase) >= 0).ToList();
            }
        }

        public void RefreshModelFilter() => OnPropertyChanged(nameof(FilteredModels));
    }
}