using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text.Json;
using System.Text.Json.Serialization;
using xAiService.Models.Dtos;
using xCommons.Extensions;

namespace xAiService.Helpers
{
    public static class XPromptHelper
    {
        /// <summary>
        /// Holds Initialized Prompts ...
        /// </summary>
        private static XPromptsDto prompts;

        /// <summary>
        /// Initialize Prompt Helper ...
        /// </summary>
        /// <param name="path"></param>
        /// <exception cref="Exception"></exception>
        /// <exception cref="InvalidDataException"></exception>
        public static void Initialize(string path = "prompts.json")
        {
            //
            // Create full Path and Check File Exists ...
            var fullPath = Path.Combine(AppContext.BaseDirectory, path);
            if (!File.Exists(fullPath))
            {
                throw new Exception($"Prompts Resources not found: {fullPath}");
            }

            //
            // Read File as Json Text ...
            var json = File.ReadAllText(fullPath);
            var options = new JsonSerializerOptions
            {
                AllowTrailingCommas = true,
                PropertyNameCaseInsensitive = true,
                ReadCommentHandling = JsonCommentHandling.Skip,
                Converters =
                {
                    new JsonStringEnumConverter(
                        namingPolicy: null,
                        allowIntegerValues: false
                    )
                }
            };

            //
            // Serialized Root Object ...
            var root = JsonSerializer.Deserialize<XPromptsDto>(json, options);
            if (!root.IsNullOrDefault())
            {
                prompts = new XPromptsDto { Prompts = root.Prompts };
            }
        }

        /// <summary>
        /// Retrieve all Allowed Prompts as Enumerable ...
        /// </summary>
        /// <returns></returns>
        public static IEnumerable<XPromptDto> GetPrompts()
        {
            return prompts!.Prompts.AsEnumerable();
        }

        /// <summary>
        /// Get Specified Prompt ...
        /// </summary>
        /// <param name="name"></param>
        /// <returns></returns>
        /// <exception cref="Exception"></exception>
        public static XPromptDto GetPrompt(string name)
        {
            //
            return GetPrompts()
                .FirstOrDefault(p => p.Name == name);
        }
    }
}