From b2333d49782b604ef4ffda8bd11454e0455b05ff Mon Sep 17 00:00:00 2001
From: Mika <kontakt@donau2space.de>
Date: Sun, 19 Apr 2026 02:07:47 +0000
Subject: [PATCH] Add data_visualization/src/data_visualization/cli.py

---
 .../src/data_visualization/cli.py             | 70 +++++++++++++++++++
 1 file changed, 70 insertions(+)
 create mode 100644 data_visualization/src/data_visualization/cli.py

diff --git a/data_visualization/src/data_visualization/cli.py b/data_visualization/src/data_visualization/cli.py
new file mode 100644
index 0000000..40b8d72
--- /dev/null
+++ b/data_visualization/src/data_visualization/cli.py
@@ -0,0 +1,70 @@
+import argparse
+import csv
+import os
+from pathlib import Path
+from typing import List
+import numpy as np
+import matplotlib.pyplot as plt
+
+from data_visualization import core
+
+
+def _validate_frequency_row(row: dict) -> bool:
+    """Validates that a frequency data row contains valid float values."""
+    try:
+        float(row['frequency_hz'])
+        float(row['amplitude_db'])
+        return True
+    except (KeyError, ValueError, TypeError):
+        return False
+
+
+def _read_frequency_data(csv_path: Path) -> List[float]:
+    """Reads and validates frequency data from a CSV file."""
+    frequency_data = []
+    with csv_path.open('r', newline='', encoding='utf-8') as csvfile:
+        reader = csv.DictReader(csvfile)
+        required_fields = {'frequency_hz', 'amplitude_db'}
+        if not required_fields.issubset(reader.fieldnames or []):
+            raise ValueError(f"CSV file must contain fields: {required_fields}")
+
+        for row in reader:
+            if _validate_frequency_row(row):
+                frequency_data.append((float(row['frequency_hz']), float(row['amplitude_db'])))
+            else:
+                raise ValueError(f"Invalid row in CSV: {row}")
+
+    assert len(frequency_data) > 0, "No valid frequency data found."
+    return frequency_data
+
+
+def main() -> None:
+    """CLI entry point for generating spectrum visualization from frequency CSV data."""
+    parser = argparse.ArgumentParser(description="Visualize frequency spectrum from urban acoustic reflection data.")
+    parser.add_argument("--input", required=True, help="Path to the CSV file containing frequency data.")
+    parser.add_argument("--output", required=False, default="output/spectrum_plot.png", help="Path to save the spectrum PNG plot.")
+
+    args = parser.parse_args()
+
+    input_path = Path(args.input).resolve()
+    output_path = Path(args.output).resolve()
+
+    if not input_path.exists() or not input_path.is_file():
+        raise FileNotFoundError(f"Input file not found: {input_path}")
+
+    frequency_data = _read_frequency_data(input_path)
+
+    # Extract just amplitude list for plotting function if it expects list[float]
+    amplitudes = [amp for _, amp in frequency_data]
+    fig = core.plot_spectrum(amplitudes)
+
+    output_dir = output_path.parent
+    os.makedirs(output_dir, exist_ok=True)
+    fig.savefig(output_path, dpi=300, bbox_inches='tight')
+    plt.close(fig)
+
+    print(f"Spectrum plot saved to: {output_path}")
+
+
+if __name__ == "__main__":
+    main()
\ No newline at end of file