Improvements to accuracy of universal captcha detection

app/src/main/java/exh/patch/NetworkPatches.kt

@@ -0,0 +1,41 @@
+package exh.patch
+
+import okhttp3.OkHttpClient
+import okhttp3.Request
+import okhttp3.Response
+
+typealias EHInterceptor = (request: Request, response: Response, sourceId: Long) -> Response
+
+fun OkHttpClient.Builder.injectPatches(sourceIdProducer: () -> Long): OkHttpClient.Builder {
+    return addInterceptor { chain ->
+        val req = chain.request()
+        val response = chain.proceed(req)
+        val sourceId = sourceIdProducer()
+        findAndApplyPatches(sourceId)(req, response, sourceId)
+    }
+}
+
+fun findAndApplyPatches(sourceId: Long): EHInterceptor {
+    return ((EH_INTERCEPTORS[sourceId] ?: emptyList()) +
+            (EH_INTERCEPTORS[EH_UNIVERSAL_INTERCEPTOR] ?: emptyList())).merge()
+}
+
+fun List<EHInterceptor>.merge(): EHInterceptor {
+    return { request, response, sourceId ->
+        fold(response) { acc, int ->
+            int(request, acc, sourceId)
+        }
+    }
+}
+
+private const val EH_UNIVERSAL_INTERCEPTOR = -1L
+private val EH_INTERCEPTORS: Map<Long, List<EHInterceptor>> = mapOf(
+        EH_UNIVERSAL_INTERCEPTOR to listOf(
+                CAPTCHA_DETECTION_PATCH // Auto captcha detection
+        ),
+
+        // MangaDex login support
+        *MANGADEX_SOURCE_IDS.map { id ->
+            id to listOf(MANGADEX_LOGIN_PATCH)
+        }.toTypedArray()
+)