model: import API related classes

Signed-off-by: Harsh Shandilya <me@msfjarvis.dev>

model/src/main/java/dev/msfjarvis/lobsters/data/api/KtorLobstersApi.kt

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+package dev.msfjarvis.lobsters.data.api
+
+import dev.msfjarvis.lobsters.data.api.LobstersApi.Companion.BASE_URL
+import dev.msfjarvis.lobsters.model.LobstersPost
+import io.ktor.client.HttpClient
+import io.ktor.client.request.get
+import javax.inject.Inject
+
+/**
+ * Ktor backed implementation of [LobstersApi]
+ */
+class KtorLobstersApi @Inject constructor(private val client: HttpClient) : LobstersApi {
+  override suspend fun getHottestPosts(page: Int): List<LobstersPost> {
+    return client.get("${BASE_URL}/hottest.json?page=$page")
+  }
+}

model/src/main/java/dev/msfjarvis/lobsters/data/api/LobstersApi.kt

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+package dev.msfjarvis.lobsters.data.api
+
+import dev.msfjarvis.lobsters.model.LobstersPost
+
+/**
+ * Simple interface defining an API for lobste.rs
+ */
+interface LobstersApi {
+
+  suspend fun getHottestPosts(page: Int): List<LobstersPost>
+
+  companion object {
+    const val BASE_URL = "https://lobste.rs"
+  }
+}

model/src/main/java/dev/msfjarvis/lobsters/injection/KtorApiModule.kt

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+package dev.msfjarvis.lobsters.injection
+
+import dagger.Binds
+import dagger.Module
+import dagger.hilt.InstallIn
+import dagger.hilt.android.components.ActivityComponent
+import dev.msfjarvis.lobsters.data.api.KtorLobstersApi
+import dev.msfjarvis.lobsters.data.api.LobstersApi
+
+@Module
+@InstallIn(ActivityComponent::class)
+abstract class KtorApiModule {
+  @Binds abstract fun bindLobstersApi(realApi: KtorLobstersApi): LobstersApi
+}

model/src/main/java/dev/msfjarvis/lobsters/injection/KtorClientModule.kt

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+package dev.msfjarvis.lobsters.injection
+
+import dagger.Module
+import dagger.Provides
+import dagger.hilt.InstallIn
+import dagger.hilt.components.SingletonComponent
+import io.ktor.client.HttpClient
+import io.ktor.client.engine.okhttp.OkHttp
+import io.ktor.client.features.json.JsonFeature
+import io.ktor.client.features.json.serializer.KotlinxSerializer
+
+@Module
+@InstallIn(SingletonComponent::class)
+object KtorClientModule {
+  @Provides
+  fun provideClient() = HttpClient(OkHttp) {
+    install(JsonFeature) {
+      serializer = KotlinxSerializer()
+    }
+    engine {
+      config {
+        followSslRedirects(true)
+      }
+    }
+  }
+}

model/src/test/java/dev/msfjarvis/lobsters/data/api/KtorLobstersApiTest.kt

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+package dev.msfjarvis.lobsters.data.api
+
+import dev.msfjarvis.lobsters.util.TestUtils
+import io.ktor.client.HttpClient
+import io.ktor.client.engine.mock.MockEngine
+import io.ktor.client.engine.mock.respond
+import io.ktor.client.features.json.JsonFeature
+import io.ktor.client.features.json.serializer.KotlinxSerializer
+import io.ktor.http.fullPath
+import io.ktor.http.headersOf
+import org.junit.Assert.assertEquals
+import org.junit.Assert.assertTrue
+import kotlinx.coroutines.runBlocking
+import org.junit.AfterClass
+import org.junit.BeforeClass
+import org.junit.Test
+
+class KtorLobstersApiTest {
+
+  companion object {
+    @JvmStatic
+    private lateinit var client: HttpClient
+    @JvmStatic
+    private lateinit var apiClient: LobstersApi
+
+    @JvmStatic
+    @BeforeClass
+    fun setUp() {
+      client = HttpClient(MockEngine) {
+        install(JsonFeature) {
+          serializer = KotlinxSerializer()
+        }
+        engine {
+          addHandler { request ->
+            when (request.url.fullPath) {
+              "/hottest.json?page=1" -> {
+                val responseHeaders = headersOf("Content-Type" to listOf("application/json"))
+                respond(TestUtils.getJson("hottest.json"), headers = responseHeaders)
+              }
+              else -> error("Unhandled ${request.url.fullPath}")
+            }
+          }
+        }
+      }
+      apiClient = KtorLobstersApi(client)
+    }
+
+    @JvmStatic
+    @AfterClass
+    fun tearDown() {
+      client.close()
+    }
+  }
+
+  @Test
+  fun `api gets correct number of items`() = runBlocking {
+    val posts = apiClient.getHottestPosts(1)
+    assertEquals(25, posts.size)
+  }
+
+  @Test
+  fun `no moderator posts in test data`() = runBlocking {
+    val posts = apiClient.getHottestPosts(1)
+    val moderatorPosts = posts.asSequence()
+      .filter { it.submitterUser.isModerator }
+      .toSet()
+    assertTrue(moderatorPosts.isEmpty())
+  }
+
+  @Test
+  fun `posts with no urls`() = runBlocking {
+    val posts = apiClient.getHottestPosts(1)
+    val commentsOnlyPosts = posts.asSequence()
+      .filter { it.url.isEmpty() }
+      .toSet()
+    assertEquals(2, commentsOnlyPosts.size)
+  }
+}

model/src/test/java/dev/msfjarvis/lobsters/util/TestUtils.kt

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+package dev.msfjarvis.lobsters.util
+
+import java.io.File
+
+object TestUtils {
+  fun getJson(path: String): String {
+    // Load the JSON response
+    val uri = javaClass.classLoader.getResource(path)
+    val file = File(uri.path)
+    return String(file.readBytes())
+  }
+}