From 986b0c9edef25ecbcf3652441e472730b552402b Mon Sep 17 00:00:00 2001
From: Mika <kontakt@donau2space.de>
Date: Sun, 14 Jun 2026 02:06:39 +0000
Subject: [PATCH] Add data_analysis/src/data_analysis/core.py

---
 data_analysis/src/data_analysis/core.py | 91 +++++++++++++++++++++++++
 1 file changed, 91 insertions(+)
 create mode 100644 data_analysis/src/data_analysis/core.py

diff --git a/data_analysis/src/data_analysis/core.py b/data_analysis/src/data_analysis/core.py
new file mode 100644
index 0000000..326fa25
--- /dev/null
+++ b/data_analysis/src/data_analysis/core.py
@@ -0,0 +1,91 @@
+from __future__ import annotations
+import json
+import math
+import logging
+from dataclasses import dataclass, asdict
+from typing import List, Union
+import numpy as np
+from scipy.signal import find_peaks
+import librosa
+
+
+# Logging setup for CI readiness
+logger = logging.getLogger(__name__)
+logger.setLevel(logging.INFO)
+if not logger.handlers:
+    handler = logging.StreamHandler()
+    formatter = logging.Formatter('[%(asctime)s] %(levelname)s in %(name)s: %(message)s')
+    handler.setFormatter(formatter)
+    logger.addHandler(handler)
+
+
+class PatternAnalysisError(Exception):
+    """Custom exception for errors during audio pattern analysis."""
+    pass
+
+
+@dataclass
+class PatternReport:
+    """Repräsentiert das Ergebnis einer Mustererkennung in den Audiodaten."""
+    pattern_name: str
+    frequency: float
+    correlation: float
+    comments: str
+
+    def to_json(self) -> str:
+        return json.dumps(asdict(self), ensure_ascii=False, indent=2)
+
+
+# Helper validation
+def _validate_audio_data(audio_data: Union[np.ndarray, list[float]]) -> np.ndarray:
+    if isinstance(audio_data, list):
+        audio_data = np.array(audio_data, dtype=float)
+    if not isinstance(audio_data, np.ndarray):
+        raise TypeError("audio_data must be numpy.ndarray or list[float]")
+    if audio_data.size == 0:
+        raise ValueError("audio_data cannot be empty")
+    if not np.isfinite(audio_data).all():
+        raise ValueError("audio_data contains non-finite values")
+    return audio_data
+
+
+def analyze_patterns(audio_data: Union[np.ndarray, list[float]]) -> List[PatternReport]:
+    """Analysiert Audiodaten, extrahiert Frequenzmuster und berechnet Korrelationen zwischen erkannten Mustern."""
+    logger.info("Starting audio pattern analysis.")
+    try:
+        data = _validate_audio_data(audio_data)
+        sr = 22050  # sampling rate assumption
+
+        # Compute FFT magnitude spectrum
+        fft_mag = np.abs(np.fft.rfft(data))
+        freqs = np.fft.rfftfreq(len(data), 1 / sr)
+
+        # Find peaks in frequency domain
+        peaks, _ = find_peaks(fft_mag, height=np.mean(fft_mag) * 1.5)
+        if len(peaks) == 0:
+            logger.warning("No prominent peaks detected in audio data.")
+
+        pattern_reports: List[PatternReport] = []
+        for i, peak_idx in enumerate(peaks[:10]):  # limit to top 10 patterns
+            freq = freqs[peak_idx]
+
+            # Simulate a simple correlation heuristic: relative intensity
+            correlation = float(min(1.0, fft_mag[peak_idx] / (np.max(fft_mag) + 1e-9)))
+            pattern_name = f"Pattern_{i+1}"
+            comments = f"Detected frequency peak at {freq:.1f} Hz."
+
+            report = PatternReport(
+                pattern_name=pattern_name,
+                frequency=float(freq),
+                correlation=correlation,
+                comments=comments,
+            )
+            pattern_reports.append(report)
+
+        logger.info(f"Analysis completed: {len(pattern_reports)} patterns detected.")
+        assert all(isinstance(r, PatternReport) for r in pattern_reports), "Return integrity check failed."
+        return pattern_reports
+
+    except Exception as exc:
+        logger.error(f"Error during pattern analysis: {exc}")
+        raise PatternAnalysisError(str(exc)) from exc