using System;
using System.IO;
using System.Linq;
using Whisper.net;
using System.Threading;
using xAiModels.Models;
using System.Threading.Tasks;
using xAiApi.Interfaces.Extractors;
using DocumentFormat.OpenXml.EMMA;

namespace xAiApi.Providers.Extractors
{
    /// <summary>
    /// Extracts text content from Audio files ...
    /// </summary>    
    public class XAudioFileContentExtractor : IXAudioFileContentExtractor
    {
        /// <summary>
        /// Supported MIME Types ...
        /// </summary>
        private static readonly string[] SupportedMimeTypes =
        [
            "audio/mpeg",
            "audio/mp3",
            "audio/wav",
            "audio/wave",
            "audio/ogg",
            "audio/m4a",
            "audio/mp4",
            "audio/webm"
        ];

        private readonly string language;
        private readonly string whisperModelPath;

        public XAudioFileContentExtractor() : this(
                language: "fa",
                whisperModelPath: "Models/ggml-base.bin"
        )
        { }

        public XAudioFileContentExtractor(
            string whisperModelPath = "Models/ggml-base.bin",
            string language = "fa"
        )
        {
            //
            this.language = language;
            this.whisperModelPath = whisperModelPath;
        }

        /// <summary>
        /// Check if this extractor supports the specified MIME type ...
        /// </summary>
        public bool CanExtract(string mimeType)
        {
            //
            return SupportedMimeTypes.Contains(
                mimeType?.ToLowerInvariant() ?? string.Empty
            );
        }

        /// <summary>
        /// Extract text content from file stream ...
        /// </summary>
        public async Task<string> ExtractAsync(
            Stream fileStream,
            string mimeType,
            CancellationToken cancellationToken = default
        )
        {
            //
            var result = await ExtractRichAsync(
                fileStream,
                "audio",
                mimeType,
                cancellationToken
            );

            //
            return result.AudioTranscript;
        }

        /// <summary>
        /// Extract content from stream as Rich Result ...
        /// </summary>
        /// <param name="fileStream"></param>
        /// <param name="fileName"></param>
        /// <param name="mimeType"></param>
        /// <param name="cancellationToken"></param>
        /// <returns></returns>
        public async Task<XFileExtractionResult> ExtractRichAsync(
            Stream fileStream,
            string fileName,
            string mimeType,
            CancellationToken cancellationToken = default
        )
        {
            //
            var result = new XFileExtractionResult
            {
                FileName = fileName,
                MimeType = mimeType
            };

            //
            try
            {
                //
                using var memoryStream = new MemoryStream();
                await fileStream.CopyToAsync(memoryStream, cancellationToken);
                memoryStream.Position = 0;

                //
                using var wavStream = await ConvertToWavAsync(
                    memoryStream,
                    cancellationToken
                );

                //
                using var factory = WhisperFactory.FromPath(whisperModelPath);
                using var processor = factory.CreateBuilder()
                    .WithLanguage(language)
                    .Build();

                //
                var segments = new System.Text.StringBuilder();
                await foreach (var segment in processor.ProcessAsync(wavStream, cancellationToken))
                {
                    segments.Append(segment.Text);
                }

                //
                result.AudioTranscript = segments.ToString().Trim();
                result.Text = result.AudioTranscript;
            }
            catch (Exception ex)
            {
                result.ErrorMessage = $"Audio extraction failed: {ex.Message}";
            }

            //
            return result;
        }

        /// <summary>
        /// Audio Format Converting ...
        /// </summary>
        private async Task<Stream> ConvertToWavAsync(
            Stream inputStream,
            CancellationToken cancellationToken
        )
        {
            //
            // TODO: Complete this ...
            return await Task.FromResult(inputStream);
        }
    }
}