107 lines
3.9 KiB
Swift
107 lines
3.9 KiB
Swift
import Foundation
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struct PlaybackQueue {
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struct Item: Identifiable {
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let id = UUID()
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let url: URL
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}
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private(set) var items: [Item] = []
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private(set) var currentID: UUID?
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var currentURL: URL? { items.first { $0.id == currentID }?.url }
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private var currentIndex: Int? { items.firstIndex { $0.id == currentID } }
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var canPrevious: Bool { currentIndex.map { $0 > 0 } ?? false }
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var canNext: Bool { currentIndex.map { $0 + 1 < items.count } ?? false }
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mutating func replace(_ urls: [URL]) {
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items = sortedFiles(urls).map { Item(url: $0) }
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currentID = items.first?.id
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}
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mutating func append(_ urls: [URL]) {
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items.append(contentsOf: sortedFiles(urls).map { Item(url: $0) })
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}
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mutating func select(_ id: UUID) {
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guard items.contains(where: { $0.id == id }) else { return }
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currentID = id
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}
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mutating func advance(_ offset: Int) -> URL? {
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guard let index = currentIndex else { return nil }
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let (target, overflow) = index.addingReportingOverflow(offset)
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guard !overflow, items.indices.contains(target) else { return nil }
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currentID = items[target].id
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return items[target].url
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}
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mutating func remove(_ id: UUID) -> URL? {
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guard let index = items.firstIndex(where: { $0.id == id }) else { return nil }
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let wasCurrent = currentID == id
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items.remove(at: index)
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guard wasCurrent else { return nil }
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currentID = items.indices.contains(index) ? items[index].id : nil
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return currentURL
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}
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mutating func move(fromOffsets offsets: IndexSet, toOffset destination: Int) {
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guard !offsets.isEmpty, offsets.allSatisfy(items.indices.contains),
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(0...items.count).contains(destination) else { return }
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let moving = offsets.map { items[$0] }
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for index in offsets.reversed() { items.remove(at: index) }
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let insertion = destination - offsets.filter { $0 < destination }.count
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items.insert(contentsOf: moving, at: insertion)
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}
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private func sortedFiles(_ urls: [URL]) -> [URL] {
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urls.filter(\.isFileURL).sorted {
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let order = $0.lastPathComponent.localizedStandardCompare($1.lastPathComponent)
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return order == .orderedSame ? $0.path < $1.path : order == .orderedAscending
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}
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}
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}
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// Geometry stays in the unshifted content coordinate space throughout a gesture.
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struct PlaybackQueueDrag {
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let source: Int
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let frames: [CGRect]
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let initialScrollOffset: CGFloat
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private(set) var scrollOffset: CGFloat
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private(set) var translation: CGFloat = 0
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private(set) var destination: Int
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var pointerY: CGFloat = 0
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init(source: Int, frames: [CGRect], scrollOffset: CGFloat) {
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self.source = source
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self.frames = frames
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initialScrollOffset = scrollOffset
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self.scrollOffset = scrollOffset
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destination = source
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}
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var offset: CGFloat { translation + scrollOffset - initialScrollOffset }
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func center(at index: Int) -> CGFloat {
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if index < source { return frames[index].minY + frames[source].height / 2 }
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if index > source { return frames[index].maxY - frames[source].height / 2 }
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return frames[source].midY
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}
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mutating func update(translation: CGFloat, scrollOffset: CGFloat) {
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self.translation = translation
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self.scrollOffset = scrollOffset
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let centerY = frames[source].midY + offset
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destination = frames.indices.min { abs(center(at: $0) - centerY) < abs(center(at: $1) - centerY) }!
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}
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var insertionOffset: Int { destination > source ? destination + 1 : destination }
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func offset(at index: Int) -> CGFloat {
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if index == source { return offset }
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let target = destination
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if source < index && index <= target { return -frames[source].height }
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if target <= index && index < source { return frames[source].height }
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return 0
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}
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}
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