using System;
using System.IO;
using System.Text.Json;

namespace AI
{
    /// <summary>
    /// AI 服务配置
    /// </summary>
    public class AISettings
    {
        /// <summary>
        /// 模型 ID
        /// </summary>
        public string ModelId { get; set; } = string.Empty;

        /// <summary>
        /// API Key
        /// </summary>
        public string ApiKey { get; set; } = string.Empty;

        /// <summary>
        /// API Endpoint（OpenAI 兼容接口地址）
        /// </summary>
        public string Endpoint { get; set; } = string.Empty;

        /// <summary>
        /// 从 DLL 所在目录旁的 ai-settings.json 加载配置。
        /// 若文件不存在，抛出 FileNotFoundException。
        /// </summary>
        public static AISettings Load()
        {
            string baseDir = AppContext.BaseDirectory;
            string configPath = Path.Combine(baseDir, "ai-settings.json");

            if (!File.Exists(configPath))
            {
                throw new FileNotFoundException(
                    $"AI 配置文件未找到，请在以下位置创建 ai-settings.json：{configPath}\n" +
                    "文件格式示例：\n" +
                    "{\n" +
                    "  \"ModelId\": \"deepseek-v3\",\n" +
                    "  \"ApiKey\": \"sk-xxx\",\n" +
                    "  \"Endpoint\": \"https://dashscope.aliyuncs.com/compatible-mode/v1\"\n" +
                    "}",
                    configPath);
            }

            string json = File.ReadAllText(configPath);
            var settings = JsonSerializer.Deserialize<AISettings>(json, new JsonSerializerOptions
            {
                PropertyNameCaseInsensitive = true
            });

            if (settings == null)
            {
                throw new InvalidOperationException("ai-settings.json 解析失败，请检查 JSON 格式。");
            }

            if (string.IsNullOrWhiteSpace(settings.ModelId))
                throw new InvalidOperationException("ai-settings.json 中 ModelId 不能为空。");
            if (string.IsNullOrWhiteSpace(settings.ApiKey))
                throw new InvalidOperationException("ai-settings.json 中 ApiKey 不能为空。");
            if (string.IsNullOrWhiteSpace(settings.Endpoint))
                throw new InvalidOperationException("ai-settings.json 中 Endpoint 不能为空。");

            return settings;
        }
    }
}