android: integrate with Paging

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

android/src/main/kotlin/dev/msfjarvis/claw/android/MainActivity.kt

@@ -4,21 +4,31 @@ import android.os.Bundle
 import androidx.activity.compose.setContent
 import androidx.appcompat.app.AppCompatActivity
 import androidx.compose.foundation.isSystemInDarkTheme
-import dev.msfjarvis.claw.common.posts.LobstersItem
-import dev.msfjarvis.claw.common.posts.TEST_POST
+import androidx.paging.Pager
+import androidx.paging.PagingConfig
+import androidx.paging.compose.collectAsLazyPagingItems
+import dagger.hilt.android.AndroidEntryPoint
+import dev.msfjarvis.claw.android.paging.LobstersPagingSource
+import dev.msfjarvis.claw.android.ui.NetworkPosts
+import dev.msfjarvis.claw.api.LobstersApi
 import dev.msfjarvis.claw.common.theme.LobstersTheme
+import dev.msfjarvis.claw.common.urllauncher.UrlLauncher
+import javax.inject.Inject
 
+@AndroidEntryPoint
 class MainActivity : AppCompatActivity() {
+  @Inject lateinit var api: LobstersApi
+  @Inject lateinit var urlLauncher: UrlLauncher
+
   override fun onCreate(savedInstanceState: Bundle?) {
     super.onCreate(savedInstanceState)
+    val pager = Pager(PagingConfig(20)) { LobstersPagingSource(api::getHottestPosts) }
     setContent {
       LobstersTheme(darkTheme = isSystemInDarkTheme()) {
-        LobstersItem(
-          post = TEST_POST,
-          isSaved = false,
-          {},
-          {},
-          {},
+        val items = pager.flow.collectAsLazyPagingItems()
+        NetworkPosts(
+          items = items,
+          urlLauncher = urlLauncher,
         )
       }
     }

android/src/main/kotlin/dev/msfjarvis/claw/android/ext/database.kt

@@ -0,0 +1,18 @@
+package dev.msfjarvis.claw.android.ext
+
+import dev.msfjarvis.claw.api.model.LobstersPost
+import dev.msfjarvis.claw.database.local.SavedPost
+
+/** Convert a [LobstersPost] object returned by the API into a [SavedPost] for persistence. */
+fun LobstersPost.toDbModel(): SavedPost {
+  return SavedPost(
+    shortId = shortId,
+    title = title,
+    url = url,
+    createdAt = createdAt,
+    commentsUrl = commentsUrl,
+    submitterName = submitter.username,
+    submitterAvatarUrl = submitter.avatarUrl,
+    tags = tags,
+  )
+}

android/src/main/kotlin/dev/msfjarvis/claw/android/ui/NetworkPosts.kt

@@ -0,0 +1,30 @@
+package dev.msfjarvis.claw.android.ui
+
+import androidx.compose.foundation.lazy.LazyColumn
+import androidx.compose.runtime.Composable
+import androidx.paging.compose.LazyPagingItems
+import androidx.paging.compose.items
+import dev.msfjarvis.claw.android.ext.toDbModel
+import dev.msfjarvis.claw.api.model.LobstersPost
+import dev.msfjarvis.claw.common.posts.LobstersItem
+import dev.msfjarvis.claw.common.urllauncher.UrlLauncher
+
+@Composable
+fun NetworkPosts(
+  items: LazyPagingItems<LobstersPost>,
+  urlLauncher: UrlLauncher,
+) {
+  LazyColumn {
+    items(items) { item ->
+      if (item != null) {
+        LobstersItem(
+          post = item.toDbModel(),
+          isSaved = false,
+          viewPost = { urlLauncher.launch(item.url.ifEmpty { item.commentsUrl }) },
+          viewComments = { urlLauncher.launch(item.commentsUrl) },
+          toggleSave = {},
+        )
+      }
+    }
+  }
+}