0.10.6

Sources/Shared/Models/MediaMetadata.swift

@@ -0,0 +1,76 @@
+import Foundation
+import UniformTypeIdentifiers
+
+enum MediaMetadata {
+    struct Inferred: Equatable, Sendable {
+        let kind: ChatMessage.Kind
+        let mimeType: String?
+        let duration: TimeInterval?
+    }
+
+    static func transportFilename(
+        originalFilename: String,
+        kind: ChatMessage.Kind,
+        duration: TimeInterval?
+    ) -> String {
+        let milliseconds = duration.flatMap { value -> Int? in
+            guard value.isFinite,
+                  value > 0,
+                  value <= Double(Int.max) / 1_000 else { return nil }
+            return Int((value * 1_000).rounded())
+        }
+        guard let milliseconds else { return originalFilename }
+
+        switch kind {
+        case .voice:
+            return "luma-voice-\(milliseconds)-\(originalFilename)"
+        case .videoNote:
+            return "luma-videonote-\(milliseconds)-\(originalFilename)"
+        default:
+            return originalFilename
+        }
+    }
+
+    static func infer(from transportFilename: String) -> Inferred {
+        let contentType = UTType(
+            filenameExtension: URL(fileURLWithPath: transportFilename).pathExtension
+        )
+        let kind: ChatMessage.Kind
+        if transportFilename.hasPrefix("luma-voice-") {
+            kind = .voice
+        } else if transportFilename.hasPrefix("luma-videonote-") {
+            kind = .videoNote
+        } else if contentType?.conforms(to: .image) == true {
+            kind = .photo
+        } else if contentType?.conforms(to: .movie) == true {
+            kind = .video
+        } else if contentType?.conforms(to: .audio) == true {
+            kind = .audio
+        } else {
+            kind = .attachment
+        }
+
+        return Inferred(
+            kind: kind,
+            mimeType: contentType?.preferredMIMEType,
+            duration: encodedDuration(from: transportFilename)
+        )
+    }
+
+    private static func encodedDuration(from filename: String) -> TimeInterval? {
+        let prefix: String
+        if filename.hasPrefix("luma-voice-") {
+            prefix = "luma-voice-"
+        } else if filename.hasPrefix("luma-videonote-") {
+            prefix = "luma-videonote-"
+        } else {
+            return nil
+        }
+
+        let remainder = filename.dropFirst(prefix.count)
+        guard let separator = remainder.firstIndex(of: "-"),
+              let milliseconds = Int(remainder[..<separator]),
+              milliseconds > 0 else { return nil }
+        return TimeInterval(milliseconds) / 1_000
+    }
+}