feat(dm): 수신자 선택 상태를 추가한다

app/src/main/java/kr/co/vividnext/sodalive/v2/main/chat/recipient/DmRecipientPickerViewModel.kt

@@ -0,0 +1,97 @@
+package kr.co.vividnext.sodalive.v2.main.chat.recipient
+
+import androidx.lifecycle.LiveData
+import androidx.lifecycle.MutableLiveData
+import io.reactivex.rxjava3.core.Scheduler
+import io.reactivex.rxjava3.core.Single
+import io.reactivex.rxjava3.disposables.Disposable
+import io.reactivex.rxjava3.disposables.SerialDisposable
+import io.reactivex.rxjava3.schedulers.Schedulers
+import kr.co.vividnext.sodalive.base.BaseViewModel
+import java.util.concurrent.TimeUnit
+
+data class DmRecipientUiModel(
+    val id: Long,
+    val nickname: String,
+    val profileImageUrl: String
+)
+
+enum class DmRecipientPickerMode {
+    FOLLOWERS,
+    SEARCH
+}
+
+data class DmRecipientPickerUiState(
+    val mode: DmRecipientPickerMode = DmRecipientPickerMode.FOLLOWERS,
+    val recipients: List<DmRecipientUiModel> = emptyList(),
+    val searchResultCount: Int = 0,
+    val isSearchEmpty: Boolean = false,
+    val isError: Boolean = false
+)
+
+class DmRecipientPickerViewModel(
+    private val loadFollowers: () -> Single<List<DmRecipientUiModel>>,
+    private val searchUsers: (String) -> Single<List<DmRecipientUiModel>>,
+    private val debounceScheduler: Scheduler = Schedulers.computation()
+) : BaseViewModel() {
+
+    private val _recipientStateLiveData = MutableLiveData(DmRecipientPickerUiState())
+    val recipientStateLiveData: LiveData<DmRecipientPickerUiState> get() = _recipientStateLiveData
+    private var searchDisposable: Disposable? = null
+    private val requestDisposable = SerialDisposable().also(compositeDisposable::add)
+
+    fun enter() {
+        requestDisposable.set(null)
+        requestDisposable.set(
+            loadFollowers()
+                .subscribe({ recipients ->
+                    _recipientStateLiveData.value = DmRecipientPickerUiState(
+                        mode = DmRecipientPickerMode.FOLLOWERS,
+                        recipients = recipients
+                    )
+                }, {
+                    _recipientStateLiveData.value = DmRecipientPickerUiState(isError = true)
+                })
+        )
+    }
+
+    fun onSearchQueryChanged(query: String) {
+        val keyword = query.trim()
+        searchDisposable?.dispose()
+        requestDisposable.set(null)
+
+        if (keyword.length < MIN_SEARCH_QUERY_LENGTH) {
+            enter()
+            return
+        }
+
+        val scheduledSearch = debounceScheduler.scheduleDirect(
+            {
+                requestDisposable.set(
+                    searchUsers(keyword).subscribe({ recipients ->
+                        _recipientStateLiveData.value = DmRecipientPickerUiState(
+                            mode = DmRecipientPickerMode.SEARCH,
+                            recipients = recipients,
+                            searchResultCount = recipients.size,
+                            isSearchEmpty = recipients.isEmpty()
+                        )
+                    }, {
+                        _recipientStateLiveData.value = DmRecipientPickerUiState(
+                            mode = DmRecipientPickerMode.SEARCH,
+                            isError = true
+                        )
+                    })
+                )
+            },
+            SEARCH_DEBOUNCE_MILLIS,
+            TimeUnit.MILLISECONDS
+        )
+        searchDisposable = scheduledSearch
+        compositeDisposable.add(scheduledSearch)
+    }
+
+    private companion object {
+        const val MIN_SEARCH_QUERY_LENGTH = 2
+        const val SEARCH_DEBOUNCE_MILLIS = 500L
+    }
+}

app/src/test/java/kr/co/vividnext/sodalive/v2/main/chat/recipient/DmRecipientPickerViewModelTest.kt

@@ -0,0 +1,215 @@
+package kr.co.vividnext.sodalive.v2.main.chat.recipient
+
+import android.app.Application
+import androidx.lifecycle.LiveData
+import io.reactivex.rxjava3.core.Single
+import io.reactivex.rxjava3.schedulers.TestScheduler
+import io.reactivex.rxjava3.subjects.SingleSubject
+import org.junit.Assert.assertEquals
+import org.junit.Before
+import org.junit.Test
+import org.junit.runner.RunWith
+import org.robolectric.RobolectricTestRunner
+import org.robolectric.annotation.Config
+import java.util.concurrent.TimeUnit
+
+@RunWith(RobolectricTestRunner::class)
+@Config(sdk = [28], application = Application::class)
+class DmRecipientPickerViewModelTest {
+
+    private lateinit var debounceScheduler: TestScheduler
+    private lateinit var source: FakeRecipientSource
+    private lateinit var viewModel: DmRecipientPickerViewModel
+
+    @Before
+    fun setUp() {
+        debounceScheduler = TestScheduler()
+        source = FakeRecipientSource()
+        viewModel = DmRecipientPickerViewModel(
+            loadFollowers = source::loadFollowers,
+            searchUsers = source::searchUsers,
+            debounceScheduler = debounceScheduler
+        )
+    }
+
+    @Test
+    fun `진입 시 팔로우 목록을 1회 로드한다`() {
+        source.followers = listOf(recipient(id = 1L, nickname = "팬A"))
+
+        viewModel.enter()
+
+        assertEquals(1, source.followerCalls)
+        assertEquals(emptyList<String>(), source.searchQueries)
+        assertEquals(
+            DmRecipientPickerUiState(
+                mode = DmRecipientPickerMode.FOLLOWERS,
+                recipients = source.followers
+            ),
+            viewModel.recipientStateLiveData.requireValue()
+        )
+    }
+
+    @Test
+    fun `검색어가 0에서 1자이면 검색하지 않고 팔로우 목록으로 복귀한다`() {
+        source.followers = listOf(recipient(id = 1L, nickname = "팬A"))
+        viewModel.enter()
+
+        viewModel.onSearchQueryChanged("가")
+
+        assertEquals(2, source.followerCalls)
+        assertEquals(emptyList<String>(), source.searchQueries)
+        assertEquals(
+            DmRecipientPickerUiState(
+                mode = DmRecipientPickerMode.FOLLOWERS,
+                recipients = source.followers
+            ),
+            viewModel.recipientStateLiveData.requireValue()
+        )
+    }
+
+    @Test
+    fun `검색어 2자 이상은 500ms 후 마지막 검색어만 요청한다`() {
+        source.searchResults = listOf(recipient(id = 2L, nickname = "팬B"))
+
+        viewModel.onSearchQueryChanged("가나")
+        debounceScheduler.advanceTimeBy(499L, TimeUnit.MILLISECONDS)
+        viewModel.onSearchQueryChanged("가나다")
+        debounceScheduler.advanceTimeBy(499L, TimeUnit.MILLISECONDS)
+
+        assertEquals(emptyList<String>(), source.searchQueries)
+
+        debounceScheduler.advanceTimeBy(1L, TimeUnit.MILLISECONDS)
+
+        assertEquals(listOf("가나다"), source.searchQueries)
+        assertEquals(
+            DmRecipientPickerUiState(
+                mode = DmRecipientPickerMode.SEARCH,
+                recipients = source.searchResults,
+                searchResultCount = source.searchResults.size
+            ),
+            viewModel.recipientStateLiveData.requireValue()
+        )
+    }
+
+    @Test
+    fun `검색 결과가 없으면 empty 상태를 표시한다`() {
+        source.searchResults = emptyList()
+
+        viewModel.onSearchQueryChanged("없는팬")
+        debounceScheduler.advanceTimeBy(500L, TimeUnit.MILLISECONDS)
+
+        assertEquals(
+            DmRecipientPickerUiState(
+                mode = DmRecipientPickerMode.SEARCH,
+                recipients = emptyList(),
+                searchResultCount = 0,
+                isSearchEmpty = true
+            ),
+            viewModel.recipientStateLiveData.requireValue()
+        )
+    }
+
+    @Test
+    fun `검색 결과 개수는 검색 결과가 0개여도 상태에 포함된다`() {
+        source.searchResults = emptyList()
+
+        viewModel.onSearchQueryChanged("홍길동")
+        debounceScheduler.advanceTimeBy(500L, TimeUnit.MILLISECONDS)
+
+        assertEquals(0, viewModel.recipientStateLiveData.requireValue()?.searchResultCount)
+    }
+
+    @Test
+    fun `팔로워 요청 실패는 오류 상태로 전달한다`() {
+        val model = DmRecipientPickerViewModel(
+            loadFollowers = { Single.error(IllegalStateException()) },
+            searchUsers = source::searchUsers,
+            debounceScheduler = debounceScheduler
+        )
+
+        model.enter()
+
+        assertEquals(true, model.recipientStateLiveData.value?.isError)
+    }
+
+    @Test
+    fun `검색 요청 실패는 빈 결과 대신 오류 상태로 전달한다`() {
+        val model = DmRecipientPickerViewModel(
+            loadFollowers = source::loadFollowers,
+            searchUsers = { Single.error(IllegalStateException()) },
+            debounceScheduler = debounceScheduler
+        )
+
+        model.onSearchQueryChanged("검색")
+        debounceScheduler.advanceTimeBy(500L, TimeUnit.MILLISECONDS)
+
+        assertEquals(true, model.recipientStateLiveData.value?.isError)
+        assertEquals(false, model.recipientStateLiveData.value?.isSearchEmpty)
+    }
+
+    @Test
+    fun `팔로워로 복귀하면 이전 검색 응답은 목록을 덮어쓰지 않는다`() {
+        val pendingSearch = SingleSubject.create<List<DmRecipientUiModel>>()
+        val model = DmRecipientPickerViewModel(
+            source::loadFollowers,
+            { pendingSearch },
+            debounceScheduler
+        )
+        model.onSearchQueryChanged("검색")
+        debounceScheduler.advanceTimeBy(500L, TimeUnit.MILLISECONDS)
+
+        model.onSearchQueryChanged("")
+        pendingSearch.onSuccess(listOf(recipient(2L, "지난검색")))
+
+        assertEquals(DmRecipientPickerMode.FOLLOWERS, model.recipientStateLiveData.value?.mode)
+        assertEquals(source.followers, model.recipientStateLiveData.value?.recipients)
+    }
+
+    @Test
+    fun `검색으로 전환하면 늦은 팔로워 응답은 검색 결과를 덮어쓰지 않는다`() {
+        val pendingFollowers = SingleSubject.create<List<DmRecipientUiModel>>()
+        val model = DmRecipientPickerViewModel(
+            { pendingFollowers },
+            source::searchUsers,
+            debounceScheduler
+        )
+        model.enter()
+
+        model.onSearchQueryChanged("검색")
+        debounceScheduler.advanceTimeBy(500L, TimeUnit.MILLISECONDS)
+        pendingFollowers.onSuccess(listOf(recipient(1L, "팔로워")))
+
+        assertEquals(DmRecipientPickerMode.SEARCH, model.recipientStateLiveData.value?.mode)
+        assertEquals(source.searchResults, model.recipientStateLiveData.value?.recipients)
+    }
+
+    private class FakeRecipientSource {
+        var followers = emptyList<DmRecipientUiModel>()
+        var searchResults = emptyList<DmRecipientUiModel>()
+        var followerCalls = 0
+        val searchQueries = mutableListOf<String>()
+
+        fun loadFollowers(): Single<List<DmRecipientUiModel>> {
+            followerCalls += 1
+            return Single.just(followers)
+        }
+
+        fun searchUsers(query: String): Single<List<DmRecipientUiModel>> {
+            searchQueries += query
+            return Single.just(searchResults)
+        }
+    }
+}
+
+private fun recipient(
+    id: Long,
+    nickname: String
+) = DmRecipientUiModel(
+    id = id,
+    nickname = nickname,
+    profileImageUrl = "https://example.com/$id.png"
+)
+
+private fun <T> LiveData<T>.requireValue(): T? {
+    return value
+}