feat(*): subsonic client with avfoundation playback and apple music ui

Packages/AmphlifyKit/Sources/SourceSubsonic/SubsonicClient.swift

@@ -0,0 +1,100 @@
+import CryptoKit
+import Foundation
+
+public enum SubsonicError: Error, Equatable, Sendable {
+    case server(code: Int, message: String)
+    case http(Int)
+    case malformed
+}
+
+typealias SubsonicTransport = @Sendable (URLRequest) async throws -> (Data, URLResponse)
+
+struct SubsonicClient: Sendable {
+    let baseURL: URL
+    let username: String
+    let password: String
+    let transport: SubsonicTransport
+
+    init(baseURL: URL, username: String, password: String, transport: @escaping SubsonicTransport) {
+        self.baseURL = baseURL
+        self.username = username
+        self.password = password
+        self.transport = transport
+    }
+
+    init(baseURL: URL, username: String, password: String, session: URLSession) {
+        self.init(baseURL: baseURL, username: username, password: password) { request in
+            try await session.data(for: request)
+        }
+    }
+
+    func url(_ method: String, _ params: [String: String] = [:]) -> URL {
+        let endpoint = baseURL.appending(path: "rest/\(method).view")
+        var components = URLComponents(url: endpoint, resolvingAgainstBaseURL: false) ?? URLComponents()
+        components.queryItems = (params.sorted { $0.key < $1.key } + authParams()).map { URLQueryItem(name: $0.key, value: $0.value) }
+        return components.url ?? endpoint
+    }
+
+    func call<Payload: Decodable>(_ method: String, _ params: [String: String] = [:], as _: Payload.Type) async throws -> Payload {
+        let request = URLRequest(url: url(method, params))
+        let (data, response) = try await transport(request)
+        if let http = response as? HTTPURLResponse, http.statusCode >= 400 {
+            throw SubsonicError.http(http.statusCode)
+        }
+        return try Self.decode(data, as: Payload.self)
+    }
+
+    func call(_ method: String, _ params: [String: String] = [:]) async throws {
+        _ = try await call(method, params, as: EmptyPayload.self)
+    }
+
+    static func decode<Payload: Decodable>(_ data: Data, as _: Payload.Type) throws -> Payload {
+        let decoder = JSONDecoder()
+        let status: Wrapper<EnvelopeStatus>
+        do {
+            status = try decoder.decode(Wrapper<EnvelopeStatus>.self, from: data)
+        } catch {
+            throw SubsonicError.malformed
+        }
+        if status.response.status != "ok" {
+            let error = status.response.error
+            throw SubsonicError.server(code: error?.code ?? 0, message: error?.message ?? "")
+        }
+        do {
+            return try decoder.decode(Wrapper<Payload>.self, from: data).response
+        } catch {
+            throw SubsonicError.malformed
+        }
+    }
+
+    private func authParams() -> [(key: String, value: String)] {
+        let salt = Self.salt()
+        let token = Insecure.MD5.hash(data: Data((password + salt).utf8)).map { String(format: "%02x", $0) }.joined()
+        return [("u", username), ("t", token), ("s", salt), ("v", "1.16.1"), ("c", "Amphlify"), ("f", "json")]
+    }
+
+    private static func salt() -> String {
+        let alphabet = Array("abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789")
+        return String((0 ..< 12).compactMap { _ in alphabet.randomElement() })
+    }
+}
+
+private struct Wrapper<Payload: Decodable>: Decodable {
+    let response: Payload
+
+    enum CodingKeys: String, CodingKey {
+        case response = "subsonic-response"
+    }
+}
+
+private struct EnvelopeStatus: Decodable {
+    struct Failure: Decodable {
+        let code: Int
+        let message: String?
+    }
+
+    let status: String
+    let error: Failure?
+}
+
+struct EmptyPayload: Decodable {}