Add proxy password interceptor.

It passes request chain either to hex password interceptor or
to md5+salt interceptor depending on current protocol version.

dependencies.gradle

@@ -21,6 +21,7 @@ ext.versions = [
         okhttp               : "3.9.0",
 
         junit                : "4.12",
+        mockito              : "2.12.0",
         mockitoKotlin        : "1.5.0",
         kluent               : "1.26",
         apacheCodecs         : "1.10",
@@ -53,6 +54,8 @@ ext.testing = [
         junit         : "junit:junit:$versions.junit",
         kotlinJunit   : "org.jetbrains.kotlin:kotlin-test-junit:$versions.kotlin",
         mockitoKotlin : "com.nhaarman:mockito-kotlin:$versions.mockitoKotlin",
+        mockito       : "org.mockito:mockito-core:$versions.mockito",
+        mockitoInline : "org.mockito:mockito-inline:$versions.mockito",
         kluent        : "org.amshove.kluent:kluent:$versions.kluent",
         mockWebServer : "com.squareup.okhttp3:mockwebserver:$versions.okhttp",
         apacheCodecs  : "commons-codec:commons-codec:$versions.apacheCodecs",

subsonic-api/build.gradle

@@ -21,6 +21,8 @@ dependencies {
 
     testImplementation testing.junit
     testImplementation testing.kotlinJunit
+    testImplementation testing.mockito
+    testImplementation testing.mockitoInline
     testImplementation testing.mockitoKotlin
     testImplementation testing.kluent
     testImplementation testing.mockWebServer

subsonic-api/src/main/kotlin/org/moire/ultrasonic/api/subsonic/interceptors/ProxyPasswordInterceptor.kt

@@ -0,0 +1,23 @@
+package org.moire.ultrasonic.api.subsonic.interceptors
+
+import okhttp3.Interceptor
+import okhttp3.Interceptor.Chain
+import okhttp3.Response
+import org.moire.ultrasonic.api.subsonic.SubsonicAPIVersions
+
+/**
+ * Proxy [Interceptor] that uses one of [hexInterceptor] or [mD5Interceptor] depends on [apiVersion].
+ */
+internal class ProxyPasswordInterceptor(
+        initialAPIVersions: SubsonicAPIVersions,
+        private val hexInterceptor: PasswordHexInterceptor,
+        private val mD5Interceptor: PasswordMD5Interceptor) : Interceptor {
+    var apiVersion: SubsonicAPIVersions = initialAPIVersions
+
+    override fun intercept(chain: Chain): Response =
+            if (apiVersion < SubsonicAPIVersions.V1_13_0) {
+                hexInterceptor.intercept(chain)
+            } else {
+                mD5Interceptor.intercept(chain)
+            }
+}

subsonic-api/src/test/kotlin/org/moire/ultrasonic/api/subsonic/interceptors/ProxyPasswordInterceptorTest.kt

@@ -0,0 +1,36 @@
+package org.moire.ultrasonic.api.subsonic.interceptors
+
+import com.nhaarman.mockito_kotlin.mock
+import com.nhaarman.mockito_kotlin.verify
+import okhttp3.Interceptor.Chain
+import org.junit.Test
+import org.moire.ultrasonic.api.subsonic.SubsonicAPIVersions.V1_12_0
+import org.moire.ultrasonic.api.subsonic.SubsonicAPIVersions.V1_13_0
+
+/**
+ * Unit test for [ProxyPasswordInterceptor].
+ */
+class ProxyPasswordInterceptorTest {
+    private val mockPasswordHexInterceptor = mock<PasswordHexInterceptor>()
+    private val mockPasswordMd5Interceptor = mock<PasswordMD5Interceptor>()
+    private val mockChain = mock<Chain>()
+
+    private val proxyInterceptor = ProxyPasswordInterceptor(V1_12_0,
+            mockPasswordHexInterceptor, mockPasswordMd5Interceptor)
+
+    @Test
+    fun `Should use hex password on versions less then 1 13 0`() {
+        proxyInterceptor.intercept(mockChain)
+
+        verify(mockPasswordHexInterceptor).intercept(mockChain)
+    }
+
+    @Test
+    fun `Should use md5 password on version 1 13 0`() {
+        proxyInterceptor.apiVersion = V1_13_0
+
+        proxyInterceptor.intercept(mockChain)
+
+        verify(mockPasswordMd5Interceptor).intercept(mockChain)
+    }
+}