From 6aa6e5e85dd0d5aa7e7ee875b479481bfe8cdafd Mon Sep 17 00:00:00 2001
From: Mika <kontakt@donau2space.de>
Date: Mon, 23 Mar 2026 11:13:27 +0000
Subject: [PATCH] Add bandwidth_analysis/src/bandwidth_analysis/core.py

---
 .../src/bandwidth_analysis/core.py            | 66 +++++++++++++++++++
 1 file changed, 66 insertions(+)
 create mode 100644 bandwidth_analysis/src/bandwidth_analysis/core.py

diff --git a/bandwidth_analysis/src/bandwidth_analysis/core.py b/bandwidth_analysis/src/bandwidth_analysis/core.py
new file mode 100644
index 0000000..200d318
--- /dev/null
+++ b/bandwidth_analysis/src/bandwidth_analysis/core.py
@@ -0,0 +1,66 @@
+from __future__ import annotations
+import pandas as pd
+from typing import Any, Dict, List, Union, NamedTuple
+
+
+def _validate_input(data: Union[Dict[str, Any], pd.DataFrame], name: str) -> pd.DataFrame:
+    if data is None:
+        raise ValueError(f"{name} darf nicht None sein.")
+    if isinstance(data, dict):
+        df = pd.DataFrame(data)
+    elif isinstance(data, pd.DataFrame):
+        df = data.copy()
+    else:
+        raise TypeError(f"{name} muss ein dict oder pandas.DataFrame sein, nicht {type(data).__name__}.")
+    required_columns = {"segment", "bandwidth", "retry_tail"}
+    if not required_columns.issubset(df.columns):
+        raise ValueError(f"{name} fehlt eine oder mehrere der erforderlichen Spalten: {required_columns}.")
+    return df
+
+
+class AnalysisResult(NamedTuple):
+    bandwidth_change: float
+    retry_tail_change: float
+    hotspot_segments: List[str]
+
+
+def analyze_bandwidth(
+    baseline_data: Union[Dict[str, Any], pd.DataFrame],
+    test_data: Union[Dict[str, Any], pd.DataFrame]
+) -> AnalysisResult:
+    """Vergleicht Baseline- und Testdaten, um Bandbreitenänderung, Tail-Verhalten und Hotspots zu ermitteln."""
+    baseline_df = _validate_input(baseline_data, "baseline_data")
+    test_df = _validate_input(test_data, "test_data")
+
+    baseline_mean_bw = baseline_df["bandwidth"].mean()
+    test_mean_bw = test_df["bandwidth"].mean()
+    baseline_mean_rt = baseline_df["retry_tail"].mean()
+    test_mean_rt = test_df["retry_tail"].mean()
+
+    if baseline_mean_bw == 0:
+        raise ValueError("Baseline Bandwidth darf nicht 0 sein.")
+    if baseline_mean_rt == 0:
+        raise ValueError("Baseline Retry-Tail darf nicht 0 sein.")
+
+    bandwidth_change = (test_mean_bw - baseline_mean_bw) / baseline_mean_bw
+    retry_tail_change = (test_mean_rt - baseline_mean_rt) / baseline_mean_rt
+
+    merged = pd.merge(
+        baseline_df.set_index("segment"),
+        test_df.set_index("segment"),
+        on="segment",
+        how="inner",
+        suffixes=("_base", "_test")
+    )
+
+    merged["bw_rel_change"] = (merged["bandwidth_test"] - merged["bandwidth_base"]) / merged["bandwidth_base"].replace(0, pd.NA)
+    merged["rt_rel_change"] = (merged["retry_tail_test"] - merged["retry_tail_base"]) / merged["retry_tail_base"].replace(0, pd.NA)
+
+    hotspot_mask = (merged["bw_rel_change"].abs() > 0.1) | (merged["rt_rel_change"].abs() > 0.1)
+    hotspot_segments = merged.index[hotspot_mask].tolist()
+
+    return AnalysisResult(
+        bandwidth_change=float(bandwidth_change),
+        retry_tail_change=float(retry_tail_change),
+        hotspot_segments=hotspot_segments,
+    )