using System.Text.Json;

namespace Tango.Portal.Chat.Web.Services
{
    public sealed class SchemaRegistry
    {
        private readonly IWebHostEnvironment _env;
        private readonly ILogger<SchemaRegistry> _log;
        private readonly AIInstructionService _instructionService;
        private string? _cached;

        public SchemaRegistry(IWebHostEnvironment env, ILogger<SchemaRegistry> log, AIInstructionService instructionService)
        {
            _env = env; 
            _log = log;
            _instructionService = instructionService;
        }

        public string GetSchemaJson()
        {
            if (!string.IsNullOrEmpty(_cached)) return _cached!;
            var path = Path.Combine(_env.ContentRootPath, "Data", "schema.json");
            if (!File.Exists(path))
            {
                _log.LogWarning("Schema file not found at {Path}. Returning empty schema.", path);
                _cached = "{\"tables\":{}}";
                return _cached!;
            }
            _cached = File.ReadAllText(path);
            // Basic sanity check
            JsonDocument.Parse(_cached);
            return _cached!;
        }

        public async Task<string> GetPlannerPromptAsync()
        {
            var path = Path.Combine(_env.ContentRootPath, "Data", "planner_prompt.txt");
            if (!File.Exists(path))
            {
                _log.LogWarning("Planner prompt file not found at {Path}. Returning empty prompt.", path);
                return string.Empty;
            }
            
            var basePrompt = File.ReadAllText(path);
            var aiInstructions = await _instructionService.GetInstructionsTextAsync();
            
            if (!string.IsNullOrWhiteSpace(aiInstructions))
            {
                return $"{basePrompt}\n\nAdditional Instructions:\n{aiInstructions}";
            }
            
            return basePrompt;
        }

        public string GetPlannerPrompt()
        {
            // Keep synchronous version for backward compatibility
            var path = Path.Combine(_env.ContentRootPath, "Data", "planner_prompt.txt");
            if (!File.Exists(path))
            {
                _log.LogWarning("Planner prompt file not found at {Path}. Returning empty prompt.", path);
                return string.Empty;
            }
            return File.ReadAllText(path);
        }

        public string GetPlotySample()
        {
            var path = Path.Combine(_env.ContentRootPath, "Data", "ploty_sample.txt");
            if (!File.Exists(path))
            {
                _log.LogWarning("Ploty sample file not found at {Path}. Returning empty prompt.", path);
                return string.Empty;
            }
            return File.ReadAllText(path);
        }
    }
}