Backend Services Split into separate projects for reference from other front ends

DeepDrftContent.Services/Processors/AudioProcessor.cs

@@ -0,0 +1,161 @@
+using DeepDrftContent.Services.FileDatabase.Models;
+
+namespace DeepDrftContent.Services.Processors;
+
+/// <summary>
+/// Service for processing audio files and extracting metadata
+/// </summary>
+public class AudioProcessor
+{
+    /// <summary>
+    /// Processes a WAV file and creates an AudioBinary object
+    /// </summary>
+    /// <param name="filePath">Path to the WAV file</param>
+    /// <returns>AudioBinary object with metadata</returns>
+    public async Task<AudioBinary?> ProcessWavFileAsync(string filePath)
+    {
+        if (!File.Exists(filePath))
+        {
+            throw new FileNotFoundException($"WAV file not found: {filePath}");
+        }
+
+        if (!Path.GetExtension(filePath).Equals(".wav", StringComparison.OrdinalIgnoreCase))
+        {
+            throw new ArgumentException("File must be a WAV file", nameof(filePath));
+        }
+
+        try
+        {
+            var buffer = await File.ReadAllBytesAsync(filePath);
+            var wavInfo = ExtractWavMetadata(buffer);
+            
+            var parameters = new AudioBinaryParams(
+                Buffer: buffer,
+                Size: buffer.Length,
+                Extension: ".wav",
+                Duration: wavInfo.Duration,
+                Bitrate: wavInfo.Bitrate
+            );
+
+            return new AudioBinary(parameters);
+        }
+        catch (Exception ex)
+        {
+            throw new InvalidOperationException($"Failed to process WAV file: {ex.Message}", ex);
+        }
+    }
+
+    /// <summary>
+    /// Extracts metadata from WAV file buffer
+    /// </summary>
+    private WavMetadata ExtractWavMetadata(byte[] buffer)
+    {
+        try
+        {
+            // WAV file format parsing
+            // RIFF header starts at byte 0
+            if (buffer.Length < 44)
+            {
+                throw new InvalidDataException("WAV file too short to contain valid header");
+            }
+
+            // Check RIFF signature
+            var riffSignature = System.Text.Encoding.ASCII.GetString(buffer, 0, 4);
+            if (riffSignature != "RIFF")
+            {
+                throw new InvalidDataException("Invalid WAV file: Missing RIFF signature");
+            }
+
+            // Check WAVE format
+            var waveSignature = System.Text.Encoding.ASCII.GetString(buffer, 8, 4);
+            if (waveSignature != "WAVE")
+            {
+                throw new InvalidDataException("Invalid WAV file: Missing WAVE signature");
+            }
+
+            // Find fmt chunk
+            var fmtChunkPos = FindChunk(buffer, "fmt ");
+            if (fmtChunkPos == -1)
+            {
+                throw new InvalidDataException("Invalid WAV file: Missing fmt chunk");
+            }
+
+            // Parse fmt chunk
+            var fmtChunkSize = BitConverter.ToUInt32(buffer, fmtChunkPos + 4);
+            var sampleRate = BitConverter.ToUInt32(buffer, fmtChunkPos + 12);
+            var byteRate = BitConverter.ToUInt32(buffer, fmtChunkPos + 16);
+            var channels = BitConverter.ToUInt16(buffer, fmtChunkPos + 10);
+            var bitsPerSample = BitConverter.ToUInt16(buffer, fmtChunkPos + 22);
+
+            // Find data chunk
+            var dataChunkPos = FindChunk(buffer, "data");
+            if (dataChunkPos == -1)
+            {
+                throw new InvalidDataException("Invalid WAV file: Missing data chunk");
+            }
+
+            var dataSize = BitConverter.ToUInt32(buffer, dataChunkPos + 4);
+
+            // Calculate duration
+            var duration = (double)dataSize / byteRate;
+            
+            // Calculate bitrate (bits per second / 1000 for kbps)
+            var bitrate = (int)((sampleRate * channels * bitsPerSample) / 1000);
+
+            return new WavMetadata
+            {
+                Duration = duration,
+                Bitrate = bitrate,
+                SampleRate = (int)sampleRate,
+                Channels = channels,
+                BitsPerSample = bitsPerSample
+            };
+        }
+        catch (Exception ex)
+        {
+            // Fallback to basic metadata if parsing fails
+            Console.WriteLine($"Warning: Could not parse WAV metadata: {ex.Message}");
+            return new WavMetadata
+            {
+                Duration = 180.0, // Default 3 minutes
+                Bitrate = 1411,   // Default CD quality bitrate for WAV
+                SampleRate = 44100,
+                Channels = 2,
+                BitsPerSample = 16
+            };
+        }
+    }
+
+    /// <summary>
+    /// Finds a chunk in the WAV file buffer
+    /// </summary>
+    private int FindChunk(byte[] buffer, string chunkId)
+    {
+        var chunkBytes = System.Text.Encoding.ASCII.GetBytes(chunkId);
+        
+        for (int i = 12; i < buffer.Length - 8; i += 4)
+        {
+            if (buffer[i] == chunkBytes[0] && 
+                buffer[i + 1] == chunkBytes[1] && 
+                buffer[i + 2] == chunkBytes[2] && 
+                buffer[i + 3] == chunkBytes[3])
+            {
+                return i;
+            }
+        }
+        
+        return -1;
+    }
+
+    /// <summary>
+    /// WAV file metadata
+    /// </summary>
+    private class WavMetadata
+    {
+        public double Duration { get; set; }
+        public int Bitrate { get; set; }
+        public int SampleRate { get; set; }
+        public int Channels { get; set; }
+        public int BitsPerSample { get; set; }
+    }
+}