feat: show optional SponsorBlock ranges on playback timeline

2026-10-25 03:01:40 +01:00
parent edb17f76e3
commit b04ed7fdc8
9 changed files with 666 additions and 24 deletions
@@ -0,0 +1,144 @@
+import Foundation
+import CryptoKit
+
+struct SponsorSegment: Sendable {
+    let start: Double
+    let end: Double
+    let videoDuration: Double
+
+    static func visibleRanges(_ segments: [SponsorSegment], duration: Double) -> [ClosedRange<Double>] {
+        guard duration.isFinite, duration > 0 else { return [] }
+        let ranges = segments.compactMap { segment -> ClosedRange<Double>? in
+            guard segment.start.isFinite, segment.end.isFinite,
+                  segment.start >= 0, segment.end > segment.start, segment.end <= duration,
+                  segment.videoDuration.isFinite, segment.videoDuration >= 0,
+                  segment.videoDuration == 0 || abs(segment.videoDuration - duration) < 1 else { return nil }
+            return segment.start...segment.end
+        }.sorted { $0.lowerBound < $1.lowerBound }
+        var merged: [ClosedRange<Double>] = []
+        for range in ranges {
+            if let previous = merged.last, range.lowerBound <= previous.upperBound {
+                merged[merged.count - 1] = previous.lowerBound...max(previous.upperBound, range.upperBound)
+            } else {
+                merged.append(range)
+            }
+        }
+        return merged
+    }
+}
+
+private enum SponsorBlockError: LocalizedError {
+    case invalidVideoID, invalidResponse, status(Int), tooLarge, malformedJSON
+
+    var errorDescription: String? {
+        switch self {
+        case .invalidVideoID: return "SponsorBlock requires a canonical YouTube video ID."
+        case .invalidResponse: return "SponsorBlock returned an invalid response."
+        case .status(let status): return "SponsorBlock returned HTTP \(status)."
+        case .tooLarge: return "SponsorBlock returned too much data."
+        case .malformedJSON: return "SponsorBlock returned malformed segment data."
+        }
+    }
+}
+
+private final class SponsorBlockRedirectPolicy: NSObject, URLSessionTaskDelegate, Sendable {
+    func urlSession(_ session: URLSession, task: URLSessionTask,
+                    willPerformHTTPRedirection response: HTTPURLResponse,
+                    newRequest request: URLRequest,
+                    completionHandler: @escaping (URLRequest?) -> Void) {
+        completionHandler(nil)
+    }
+}
+
+enum SponsorBlockResolver {
+    static let responseLimit = 2 * 1024 * 1024
+
+    private static func validID(_ id: String) -> Bool {
+        id.utf8.count == 11 && id.utf8.allSatisfy {
+            (65...90).contains($0) || (97...122).contains($0) || (48...57).contains($0) || $0 == 45 || $0 == 95
+        }
+    }
+
+    static func videoID(for url: URL) -> String? {
+        let prefix = "https://www.youtube.com/watch?v="
+        let text = url.absoluteString
+        guard text.hasPrefix(prefix) else { return nil }
+        let id = String(text.dropFirst(prefix.count))
+        return validID(id) ? id : nil
+    }
+
+    static func request(videoID: String) throws -> URLRequest {
+        guard validID(videoID) else { throw SponsorBlockError.invalidVideoID }
+        let prefix = SHA256.hash(data: Data(videoID.utf8)).prefix(2).map { String(format: "%02x", $0) }.joined()
+        let url = URL(string: "https://sponsor.ajay.app/api/skipSegments/\(prefix)?category=sponsor&actionType=skip&service=YouTube")!
+        var request = URLRequest(url: url, cachePolicy: .reloadIgnoringLocalAndRemoteCacheData, timeoutInterval: 10)
+        request.httpMethod = "GET"
+        request.httpShouldHandleCookies = false
+        return request
+    }
+
+    static func resolve(videoID: String, configuration: URLSessionConfiguration? = nil) async throws -> [SponsorSegment] {
+        let request = try request(videoID: videoID)
+        let configuration = (configuration?.copy() as? URLSessionConfiguration) ?? .ephemeral
+        configuration.httpCookieStorage = nil
+        configuration.httpShouldSetCookies = false
+        configuration.urlCredentialStorage = nil
+        configuration.urlCache = nil
+        configuration.requestCachePolicy = .reloadIgnoringLocalAndRemoteCacheData
+        configuration.httpAdditionalHeaders = nil
+        configuration.timeoutIntervalForRequest = 10
+        configuration.timeoutIntervalForResource = 15
+        let session = URLSession(configuration: configuration)
+        defer { session.invalidateAndCancel() }
+        try Task.checkCancellation()
+        let (bytes, response) = try await session.bytes(for: request, delegate: SponsorBlockRedirectPolicy())
+        try Task.checkCancellation()
+        guard let response = response as? HTTPURLResponse else { throw SponsorBlockError.invalidResponse }
+        if response.statusCode == 404 { return [] }
+        guard response.statusCode == 200 else { throw SponsorBlockError.status(response.statusCode) }
+        guard response.expectedContentLength <= Int64(responseLimit) else { throw SponsorBlockError.tooLarge }
+        var data = Data()
+        data.reserveCapacity(min(responseLimit, max(0, Int(response.expectedContentLength))))
+        for try await byte in bytes {
+            try Task.checkCancellation()
+            guard data.count < responseLimit else { throw SponsorBlockError.tooLarge }
+            data.append(byte)
+        }
+        try Task.checkCancellation()
+        return try decode(data, videoID: videoID)
+    }
+
+    static func decode(_ data: Data, videoID: String) throws -> [SponsorSegment] {
+        guard data.count <= responseLimit else { throw SponsorBlockError.tooLarge }
+        let buckets: [Lossy<Bucket>]
+        do { buckets = try JSONDecoder().decode([Lossy<Bucket>].self, from: data) }
+        catch { throw SponsorBlockError.malformedJSON }
+        return buckets.compactMap(\.value).filter { $0.videoID == videoID }.flatMap { bucket in
+            bucket.segments.compactMap { row in
+                guard let row = row.value, row.category == "sponsor", row.actionType == "skip",
+                      row.segment.count == 2,
+                      row.segment[0].isFinite, row.segment[1].isFinite,
+                      row.segment[0] >= 0, row.segment[1] > row.segment[0],
+                      row.videoDuration.isFinite, row.videoDuration >= 0 else { return nil }
+                return SponsorSegment(start: row.segment[0], end: row.segment[1], videoDuration: row.videoDuration)
+            }
+        }
+    }
+
+    private struct Lossy<Value: Decodable>: Decodable {
+        let value: Value?
+        init(from decoder: Decoder) throws { value = try? Value(from: decoder) }
+    }
+
+    private struct Bucket: Decodable {
+        let videoID: String
+        let segments: [Lossy<Row>]
+    }
+
+    private struct Row: Decodable {
+        let category: String
+        let actionType: String
+        let segment: [Double]
+        let videoDuration: Double
+    }
+}