Redesign Hope iOS UI, harden playback, and document project handoff

Sources/Media/PinnedMediaResourceLoader.swift

@@ -1,5 +1,6 @@
 import AVFoundation
 import Foundation
+import UniformTypeIdentifiers
 import os
 
 private let logger = Logger(subsystem: "dev.shane.voice", category: "media")
@@ -114,21 +115,29 @@ final class PinnedMediaResourceLoader: NSObject, AVAssetResourceLoaderDelegate {
         shouldWaitForLoadingOfRequestedResource loadingRequest: AVAssetResourceLoadingRequest
     ) -> Bool {
         // All state access is on the main queue (the delegate queue).
-        guard let dataRequest = loadingRequest.dataRequest else { return false }
+        guard loadingRequest.dataRequest != nil else { return false }
         guard let url = loaderURLs[ObjectIdentifier(resourceLoader)] else {
             logger.log("no resolved URL for resource loader")
             loadingRequest.finishLoading(with: URLError(.badURL))
             return false
         }
 
+        fetchChunk(loadingRequest, url: url)
+        return true
+    }
+
+    /// Return bounded chunks promptly instead of buffering an entire song before
+    /// AVPlayer receives its first usable bytes. The same loading request stays
+    /// open until its requested range (or EOF) has been delivered.
+    private func fetchChunk(_ loadingRequest: AVAssetResourceLoadingRequest, url: URL) {
+        guard !loadingRequest.isCancelled, let dataRequest = loadingRequest.dataRequest else { return }
         var upstream = URLRequest(url: url)
-        let offset = dataRequest.requestedOffset
+        let offset = max(dataRequest.requestedOffset, dataRequest.currentOffset)
         let length = Int64(dataRequest.requestedLength)
-        if length > 0 {
-            upstream.setValue("bytes=\(offset)-\(offset + length - 1)", forHTTPHeaderField: "Range")
-        } else {
-            upstream.setValue("bytes=\(offset)-", forHTTPHeaderField: "Range")
-        }
+        let requestedEnd = dataRequest.requestedOffset + length
+        let end = dataRequest.requestsAllDataToEndOfResource || length == 0
+            ? offset + 262_143 : min(requestedEnd - 1, offset + 262_143)
+        upstream.setValue("bytes=\(offset)-\(end)", forHTTPHeaderField: "Range")
         logger.log("fetching \(url.absoluteString, privacy: .public) range=\(upstream.value(forHTTPHeaderField: "Range") ?? "-", privacy: .public)")
 
         // Key the task by the loading request's identity directly — no hash
@@ -140,6 +149,7 @@ final class PinnedMediaResourceLoader: NSObject, AVAssetResourceLoaderDelegate {
             // Runs on .main (the session's delegateQueue), same domain as all
             // other map mutations.
             self.activeTasks[requestKey] = nil
+            guard !loadingRequest.isCancelled else { return }
 
             if let error {
                 logger.log("fetch failed \(url.absoluteString, privacy: .public): \(error.localizedDescription, privacy: .public)")
@@ -158,7 +168,8 @@ final class PinnedMediaResourceLoader: NSObject, AVAssetResourceLoaderDelegate {
                 return
             }
             if let info = loadingRequest.contentInformationRequest {
-                info.contentType = http.mimeType ?? "application/octet-stream"
+                // AVFoundation requires a UTI, not the HTTP MIME string.
+                info.contentType = http.mimeType.flatMap { UTType(mimeType: $0)?.identifier }
                 // Content-length handling (Iteration 05 Item 7):
                 // - For 206: set full content length ONLY when Content-Range
                 //   provides a known total. Never fall back to the range's
@@ -180,14 +191,21 @@ final class PinnedMediaResourceLoader: NSObject, AVAssetResourceLoaderDelegate {
                 }
                 info.isByteRangeAccessSupported = true
             }
-            if let data {
+            if let data, !data.isEmpty {
                 dataRequest.respond(with: data)
+                let nextOffset = offset + Int64(data.count)
+                let total = Self.parseTotalLength(http)
+                let reachedEOF = total.map { nextOffset >= $0 } ?? (nextOffset <= end)
+                let needsMore = dataRequest.requestsAllDataToEndOfResource || nextOffset < requestedEnd
+                if http.statusCode == 206, !reachedEOF, needsMore {
+                    self.fetchChunk(loadingRequest, url: url)
+                    return
+                }
             }
             loadingRequest.finishLoading()
         }
         activeTasks[requestKey] = task
         task.resume()
-        return true
     }
 
     func resourceLoader(