36 lines
1.2 KiB
Dart
36 lines
1.2 KiB
Dart
/// Manages focus memory for one browse surface.
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///
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/// Tracks two things:
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/// 1. Per-hub memory: Each hub remembers which item was last focused
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/// 2. Last column hint: When entering a hub that hasn't been visited,
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/// we use the column position from the last focused hub as a hint
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class HubFocusMemory {
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final Map<String, int> _perHubMemory = {};
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int _lastColumnHint = 0;
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void setForHub(String hubKey, int index) {
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_perHubMemory[hubKey] = index;
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_lastColumnHint = index;
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}
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/// Get the remembered index for a hub, or fall back to column hint
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int getForHub(String hubKey, int itemCount) {
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if (itemCount <= 0) return 0;
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// If this hub has memory, use it
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if (_perHubMemory.containsKey(hubKey)) {
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return _perHubMemory[hubKey]!.clamp(0, itemCount - 1);
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}
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// Otherwise use the last column hint (clamped to this hub's item count)
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return _lastColumnHint.clamp(0, itemCount - 1);
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}
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/// Get only this hub's remembered index, without falling back to the last column hint.
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int getForHubOnly(String hubKey, int itemCount, {int fallback = 0}) {
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if (itemCount <= 0) return 0;
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final remembered = _perHubMemory[hubKey];
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return (remembered ?? fallback).clamp(0, itemCount - 1);
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}
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}
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