feat: Implement initial tuner application with core logic, audio processing, and presentation components.

src/presentation/hooks/useTuning.ts

@@ -0,0 +1,82 @@
+/**
+ * Hook for managing selected tuning state.
+ * Persists selection to localStorage.
+ */
+
+import { useState, useEffect } from 'react';
+import type { InstrumentType } from '../../domain/types';
+import type { Tuning } from '../../domain/tunings';
+import { getDefaultTuning, getTuningsForInstrument, getTuningById } from '../../domain/tunings';
+
+const STORAGE_KEY = 'tuner-selected-tunings';
+
+export function useTuning(instrumentType: InstrumentType) {
+    const [selectedTuning, setSelectedTuning] = useState<Tuning>(() => {
+        // Try to load from localStorage
+        const stored = localStorage.getItem(STORAGE_KEY);
+        if (stored) {
+            try {
+                const tunings = JSON.parse(stored);
+                const tuningId = tunings[instrumentType];
+                if (tuningId) {
+                    const tuning = getTuningById(tuningId);
+                    if (tuning) return tuning;
+                }
+            } catch {
+                // Fall through to default
+            }
+        }
+        return getDefaultTuning(instrumentType);
+    });
+
+    // Update tuning when instrument changes
+    useEffect(() => {
+        const stored = localStorage.getItem(STORAGE_KEY);
+        let tuningId: string | null = null;
+
+        if (stored) {
+            try {
+                const tunings = JSON.parse(stored);
+                tuningId = tunings[instrumentType];
+            } catch {
+                // Ignore parsing errors
+            }
+        }
+
+        if (tuningId) {
+            const tuning = getTuningById(tuningId);
+            if (tuning) {
+                setSelectedTuning(tuning);
+                return;
+            }
+        }
+
+        // Fall back to default
+        setSelectedTuning(getDefaultTuning(instrumentType));
+    }, [instrumentType]);
+
+    const changeTuning = (tuning: Tuning) => {
+        setSelectedTuning(tuning);
+
+        // Persist to localStorage
+        const stored = localStorage.getItem(STORAGE_KEY);
+        let tunings: Record<string, string> = {};
+
+        if (stored) {
+            try {
+                tunings = JSON.parse(stored);
+            } catch {
+                // Start fresh
+            }
+        }
+
+        tunings[instrumentType] = tuning.id;
+        localStorage.setItem(STORAGE_KEY, JSON.stringify(tunings));
+    };
+
+    return {
+        tuning: selectedTuning,
+        availableTunings: getTuningsForInstrument(instrumentType),
+        changeTuning,
+    };
+}