Downloading extensions from Github Repo. (#1101)

Downloading extensions from Github Repo.

app/src/main/java/eu/kanade/tachiyomi/extension/api/ExtensionGithubApi.kt

@@ -0,0 +1,55 @@
+package eu.kanade.tachiyomi.extension.api
+
+import com.github.salomonbrys.kotson.fromJson
+import com.github.salomonbrys.kotson.get
+import com.github.salomonbrys.kotson.int
+import com.github.salomonbrys.kotson.string
+import com.google.gson.Gson
+import com.google.gson.JsonArray
+import eu.kanade.tachiyomi.extension.model.Extension
+import eu.kanade.tachiyomi.network.GET
+import eu.kanade.tachiyomi.network.NetworkHelper
+import eu.kanade.tachiyomi.network.asObservableSuccess
+import okhttp3.Response
+import rx.Observable
+import uy.kohesive.injekt.injectLazy
+
+internal class ExtensionGithubApi {
+
+    private val network: NetworkHelper by injectLazy()
+
+    private val client get() = network.client
+
+    private val gson: Gson by injectLazy()
+
+    private val repoUrl = "https://raw.githubusercontent.com/inorichi/tachiyomi-extensions/repo"
+
+    fun findExtensions(): Observable<List<Extension.Available>> {
+        val call = GET("$repoUrl/index.json")
+
+        return client.newCall(call).asObservableSuccess()
+                .map(::parseResponse)
+    }
+
+    private fun parseResponse(response: Response): List<Extension.Available> {
+        val text = response.body()?.use { it.string() } ?: return emptyList()
+
+        val json = gson.fromJson<JsonArray>(text)
+
+        return json.map { element ->
+            val name = element["name"].string.substringAfter("Tachiyomi: ")
+            val pkgName = element["pkg"].string
+            val apkName = element["apk"].string
+            val versionName = element["version"].string
+            val versionCode = element["code"].int
+            val lang = element["lang"].string
+            val icon = "$repoUrl/icon/${apkName.replace(".apk", ".png")}"
+
+            Extension.Available(name, pkgName, versionName, versionCode, lang, apkName, icon)
+        }
+    }
+
+    fun getApkUrl(extension: Extension.Available): String {
+        return "$repoUrl/apk/${extension.apkName}"
+    }
+}