[Api] Implement caching invalid API signature response.

app/src/main/java/pl/szczodrzynski/edziennik/Extensions.kt

@@ -1112,7 +1112,7 @@ fun Throwable.toErrorCode() = when (this) {
     is SzkolnyApiException -> this.error?.toErrorCode()
     else -> null
 }
-private fun ApiResponse.Error.toErrorCode() = when (this.code) {
+fun ApiResponse.Error.toErrorCode() = when (this.code) {
     "PdoError" -> ERROR_API_PDO_ERROR
     "InvalidClient" -> ERROR_API_INVALID_CLIENT
     "InvalidArgument" -> ERROR_API_INVALID_ARGUMENT

app/src/main/java/pl/szczodrzynski/edziennik/config/Config.kt

@@ -115,6 +115,11 @@ class Config(val db: AppDb) : CoroutineScope, AbstractConfig {
         get() { mValidation = mValidation ?: values["buildValidation"]; return mValidation }
         set(value) { set("buildValidation", value); mValidation = value }
 
+    private var mApiInvalidCert: String? = null
+    var apiInvalidCert: String?
+        get() { mApiInvalidCert = mApiInvalidCert ?: values["apiInvalidCert"]; return mApiInvalidCert }
+        set(value) { set("apiInvalidCert", value); mApiInvalidCert = value }
+
     private var rawEntries: List<ConfigEntry> = db.configDao().getAllNow()
     private val profileConfigs: HashMap<Int, ProfileConfig> = hashMapOf()
     init {

app/src/main/java/pl/szczodrzynski/edziennik/data/api/szkolny/SzkolnyApi.kt

@@ -18,7 +18,9 @@ import pl.szczodrzynski.edziennik.*
 import pl.szczodrzynski.edziennik.data.api.ERROR_API_INVALID_SIGNATURE
 import pl.szczodrzynski.edziennik.data.api.szkolny.adapter.DateAdapter
 import pl.szczodrzynski.edziennik.data.api.szkolny.adapter.TimeAdapter
+import pl.szczodrzynski.edziennik.data.api.szkolny.interceptor.ApiCacheInterceptor
 import pl.szczodrzynski.edziennik.data.api.szkolny.interceptor.SignatureInterceptor
+import pl.szczodrzynski.edziennik.data.api.szkolny.interceptor.Signing
 import pl.szczodrzynski.edziennik.data.api.szkolny.request.*
 import pl.szczodrzynski.edziennik.data.api.szkolny.response.ApiResponse
 import pl.szczodrzynski.edziennik.data.api.szkolny.response.RegisterAvailabilityStatus
@@ -57,6 +59,7 @@ class SzkolnyApi(val app: App) : CoroutineScope {
         val okHttpClient: OkHttpClient = app.http.newBuilder()
                 .followRedirects(true)
                 .callTimeout(10, SECONDS)
+                .addInterceptor(ApiCacheInterceptor(app))
                 .addInterceptor(SignatureInterceptor(app))
                 .build()
 
@@ -158,6 +161,10 @@ class SzkolnyApi(val app: App) : CoroutineScope {
             }
         }
 
+        if (body?.errors?.any { it.toErrorCode() == ERROR_API_INVALID_SIGNATURE } == true) {
+            app.config.apiInvalidCert = Signing.appCertificate.md5()
+        }
+
         throw SzkolnyApiException(body?.errors?.firstOrNull())
     }
 

app/src/main/java/pl/szczodrzynski/edziennik/data/api/szkolny/interceptor/ApiCacheInterceptor.kt

@@ -0,0 +1,36 @@
+/*
+ * Copyright (c) Kuba Szczodrzyński 2021-3-29.
+ */
+
+package pl.szczodrzynski.edziennik.data.api.szkolny.interceptor
+
+import okhttp3.*
+import pl.szczodrzynski.edziennik.App
+import pl.szczodrzynski.edziennik.data.api.szkolny.response.ApiResponse
+import pl.szczodrzynski.edziennik.md5
+
+class ApiCacheInterceptor(val app: App) : Interceptor {
+
+    override fun intercept(chain: Interceptor.Chain): Response {
+        if (Signing.appCertificate.md5() == app.config.apiInvalidCert) {
+            val response = ApiResponse<Unit>(
+                success = false,
+                errors = listOf(ApiResponse.Error("InvalidSignature", ""))
+            )
+
+            return Response.Builder()
+                .request(chain.request())
+                .protocol(Protocol.HTTP_1_1)
+                .code(401)
+                .message("Unauthorized")
+                .addHeader("Content-Type", "application/json")
+                .body(ResponseBody.create(
+                    MediaType.parse("application/json"),
+                    app.gson.toJson(response)
+                ))
+                .build()
+        }
+
+        return chain.proceed(chain.request())
+    }
+}