Clean release snapshot

lib/tunings.py

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+"""Tuning data and helpers.
+
+Kept separate from server.py so tests can import it without triggering
+FastAPI / SQLite module-level side effects.
+"""
+
+DEFAULT_REFERENCE_PITCH = 440.0
+
+# Canonical tuning frequencies at 440 Hz reference, keyed by instrument then
+# tuning name. This is the authoritative source; tuner/routes.py previously
+# held a copy — it was removed in favour of this one.
+DEFAULT_TUNINGS: dict[str, dict[str, list[float]]] = {
+    "guitar-6": {
+        "Standard":    [82.41, 110.00, 146.83, 196.00, 246.94, 329.63],
+        "Eb Standard": [77.78, 103.83, 138.59, 185.00, 233.08, 311.13],
+        "Drop D":      [73.42, 110.00, 146.83, 196.00, 246.94, 329.63],
+        "D Standard":  [73.42,  98.00, 130.81, 174.61, 220.00, 293.66],
+        "Drop C":      [65.41,  98.00, 130.81, 174.61, 220.00, 293.66],
+        "Open G":      [73.42,  98.00, 146.83, 196.00, 246.94, 293.66],
+        "Open D":      [73.42, 110.00, 146.83, 185.00, 220.00, 293.66],
+        "DADGAD":      [73.42, 110.00, 146.83, 196.00, 220.00, 293.66],
+        "Open E":      [82.41, 123.47, 164.81, 207.65, 246.94, 329.63],
+    },
+    "guitar-7": {
+        "Standard":    [61.74, 82.41, 110.00, 146.83, 196.00, 246.94, 329.63],
+        "Drop A":      [55.00, 82.41, 110.00, 146.83, 196.00, 246.94, 329.63],
+        "A Standard":  [55.00, 73.42,  98.00, 130.81, 174.61, 220.00, 293.66],
+        "Drop G":      [49.00, 73.42, 110.00, 146.83, 196.00, 246.94, 329.63],
+        "Bb Standard": [58.27, 77.78, 103.83, 138.59, 185.00, 233.08, 311.13],
+    },
+    "guitar-8": {
+        "Standard":    [46.25, 61.74, 82.41, 110.00, 146.83, 196.00, 246.94, 329.63],
+        "Drop E":      [41.20, 61.74, 82.41, 110.00, 146.83, 196.00, 246.94, 329.63],
+        "E Standard":  [41.20, 55.00, 73.42,  98.00, 130.81, 174.61, 220.00, 293.66],
+        "Drop D":      [36.71, 55.00, 73.42,  98.00, 130.81, 174.61, 220.00, 293.66],
+        "Eb Standard": [38.89, 51.91, 69.30,  92.50, 123.47, 164.81, 207.65, 277.18],
+    },
+    "bass-4": {
+        "Standard":    [41.20, 55.00, 73.42,  98.00],
+        "Eb Standard": [38.89, 51.91, 69.30,  92.50],
+        "Drop D":      [36.71, 55.00, 73.42,  98.00],
+        "D Standard":  [36.71, 48.99, 65.41,  87.31],
+        "Drop C":      [32.70, 48.99, 65.41,  87.31],
+    },
+    "bass-5": {
+        "Standard":    [30.87, 41.20, 55.00, 73.42,  98.00],
+        "Eb Standard": [29.14, 38.89, 51.91, 69.30,  92.50],
+        "Drop D":      [30.87, 36.71, 55.00, 73.42,  98.00],
+        "D Standard":  [27.50, 36.71, 48.99, 65.41,  87.31],
+        "Drop C":      [27.50, 32.70, 48.99, 65.41,  87.31],
+    },
+}
+
+
+def apply_reference_pitch(
+    tunings: dict[str, dict[str, list[float]]],
+    reference_pitch: float,
+) -> dict[str, dict[str, list[float]]]:
+    """Return a copy of tunings with all frequencies scaled to reference_pitch."""
+    scale = reference_pitch / DEFAULT_REFERENCE_PITCH
+    return {
+        instrument: {
+            name: [round(f * scale, 4) for f in freqs]
+            for name, freqs in names.items()
+        }
+        for instrument, names in tunings.items()
+    }
+
+
+def tuning_name(offsets: list[int]) -> str:
+    # All three pattern checks below are gated on `len(offsets) == 6`. The
+    # naming conventions here are 6-string-specific — e.g. a 7-string all-zeros
+    # tuning has a low B, not an E, so labeling it "E Standard" would be wrong.
+    # 7+-string community content falls through to the numeric fallback. See #43.
+
+    # Standard tunings (all six strings same offset)
+    standard = {
+        0: "E Standard", -1: "Eb Standard", -2: "D Standard",
+        -3: "C# Standard", -4: "C Standard", -5: "B Standard",
+        -6: "Bb Standard", -7: "A Standard",
+        1: "F Standard", 2: "F# Standard",
+    }
+    if len(offsets) == 6 and all(o == offsets[0] for o in offsets):
+        name = standard.get(offsets[0])
+        if name:
+            return name
+
+    # Drop tunings (low string 2 semitones below the rest)
+    # Named after the low string's note: e.g. offsets[-2,0,0,0,0,0] = Drop D (low E dropped to D)
+    if len(offsets) == 6 and offsets[0] == offsets[1] - 2 and all(o == offsets[1] for o in offsets[1:]):
+        note_names = ["E", "F", "F#", "G", "Ab", "A", "Bb", "B", "C", "C#", "D", "Eb"]
+        low_note = note_names[offsets[0] % 12]
+        return f"Drop {low_note}"
+
+    # Common named tunings
+    named = {
+        (-2, 0, 0, 0, 0, 0): "Drop D",
+        (-4, -2, -2, -2, -2, -2): "Drop C",
+        (-2, -2, 0, 0, 0, 0): "Double Drop D",
+        (0, 0, 0, -1, 0, 0): "Open G",
+        (-2, -2, 0, 0, -2, -2): "Open D",
+        (-2, 0, 0, 0, -2, 0): "DADGAD",
+        (0, 2, 2, 1, 0, 0): "Open E",
+        (-2, 0, 0, 2, 3, 2): "Open D (alt)",
+    }
+    if len(offsets) == 6 and tuple(offsets) in named:
+        return named[tuple(offsets)]
+
+    if not offsets:
+        return "Unknown"
+    return "Custom Tuning"