using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading;
using System.Threading.Tasks;
using ImageCatalog_2.Models;
using Microsoft.Extensions.Logging;

namespace ImageCatalog_2.Services;

public class AiExtractionService : IAiExtractionService
{
    private readonly ILogger<AiExtractionService> _logger;

    public AiExtractionService(ILogger<AiExtractionService> logger)
    {
        _logger = logger;
    }

    public async Task RunAsync(
        AiExtractionRequest request,
        CancellationToken token,
        Func<AiResultItem, Task> onResult,
        Func<double, Task> onProgress)
    {
        var searchOption = request.Recursive ? SearchOption.AllDirectories : SearchOption.TopDirectoryOnly;

        var imageFiles = Directory.EnumerateFiles(request.SearchRoot, "*.*", searchOption)
            .Where(f => f.EndsWith(".jpg", StringComparison.OrdinalIgnoreCase)
                     || f.EndsWith(".jpeg", StringComparison.OrdinalIgnoreCase)
                     || f.EndsWith(".png", StringComparison.OrdinalIgnoreCase)
                     || f.EndsWith(".bmp", StringComparison.OrdinalIgnoreCase)
                     || f.EndsWith(".gif", StringComparison.OrdinalIgnoreCase))
            .ToList();

        if (imageFiles.Count == 0)
        {
            return;
        }

        var extractedResults = new List<AiResultItem>();

        Type? aiProcessorType = null;
        object? aiProcessor = null;

        try
        {
            var assembly = AppDomain.CurrentDomain.GetAssemblies()
                .FirstOrDefault(a => a.GetName().Name?.Equals("AIFotoONLUS.Core", StringComparison.OrdinalIgnoreCase) == true);
            if (assembly != null)
            {
                aiProcessorType = assembly.GetType("AIFotoONLUS.Core.AiProcessor");
                if (aiProcessorType != null)
                {
                    aiProcessor = Activator.CreateInstance(aiProcessorType);
                }
            }
        }
        catch (Exception ex)
        {
            _logger.LogDebug(ex, "AIFotoONLUS.Core not available or failed to load via reflection");
        }

        var processed = 0;
        var total = imageFiles.Count;

        foreach (var file in imageFiles)
        {
            token.ThrowIfCancellationRequested();

            var extracted = string.Empty;

            if (aiProcessorType is not null && aiProcessor is not null)
            {
                try
                {
                    var method = aiProcessorType.GetMethod("ExtractNumbersFromImage")
                                 ?? aiProcessorType.GetMethod("ExtractTextFromImage");
                    if (method is not null)
                    {
                        var value = method.Invoke(aiProcessor, new object[] { file });
                        if (value != null)
                        {
                            extracted = value.ToString() ?? string.Empty;
                        }
                    }
                }
                catch (Exception ex)
                {
                    _logger.LogWarning(ex, "Error invoking AI processor for {File}", file);
                }
            }

            if (!string.IsNullOrWhiteSpace(extracted))
            {
                var result = new AiResultItem { Path = file, Text = extracted };
                extractedResults.Add(result);
                await onResult(result).ConfigureAwait(false);
            }

            processed++;
            var percent = total > 0 ? (processed * 100.0 / total) : 100.0;
            await onProgress(percent).ConfigureAwait(false);
        }

        if (!string.IsNullOrWhiteSpace(request.CsvOutputPath))
        {
            try
            {
                var dir = Path.GetDirectoryName(request.CsvOutputPath) ?? string.Empty;
                if (!string.IsNullOrWhiteSpace(dir) && !Directory.Exists(dir))
                {
                    Directory.CreateDirectory(dir);
                }

                using var sw = new StreamWriter(request.CsvOutputPath, false, Encoding.UTF8);
                sw.WriteLine("Path,Text");
                foreach (var r in extractedResults)
                {
                    var safeText = (r.Text ?? string.Empty).Replace("\"", "\"\"");
                    sw.WriteLine($"\"{r.Path}\",\"{safeText}\"");
                }
            }
            catch (Exception ex)
            {
                _logger.LogError(ex, "Failed to write CSV to {CsvOutputPath}", request.CsvOutputPath);
            }
        }
    }
}