feat: browse repository branches and tags

app/src/main/java/com/ubisam/ubgitea/MainActivity.kt

@@ -32,6 +32,10 @@ class MainActivity : ComponentActivity() {
                     onCancelSignIn = viewModel::cancelSignIn,
                     onRetry = viewModel::retry,
                     onLogout = viewModel::logout,
+                    onRepositorySelected = viewModel::selectRepository,
+                    onReferenceSelected = viewModel::selectReference,
+                    onReferencesRefresh = viewModel::refreshReferences,
+                    onBackToRepositories = viewModel::backToRepositories,
                 )
                 LaunchedEffect(viewModel) {
                     viewModel.browserRequests.collect(::openSystemBrowser)

app/src/main/java/com/ubisam/ubgitea/data/auth/AuthApi.kt

@@ -26,12 +26,17 @@ data class AuthenticatedUser(
     val displayName: String?,
 )
 
+interface AuthenticationGateway {
+    suspend fun exchangeCode(authorizationCode: String, verifier: String, nowEpochMillis: Long): TokenSet
+    suspend fun getAuthenticatedUser(accessToken: String): AuthenticatedUser
+}
+
 class AuthApi(
     private val config: OAuthClientConfig,
     private val transport: HttpTransport,
     private val gson: Gson = Gson(),
-) {
-    suspend fun exchangeCode(
+) : AuthenticationGateway {
+    override suspend fun exchangeCode(
         authorizationCode: String,
         verifier: String,
         nowEpochMillis: Long,
@@ -56,7 +61,7 @@ class AuthApi(
         return TokenSet(accessToken, dto.refreshToken?.takeIf(String::isNotBlank), expiresAt)
     }
 
-    suspend fun getAuthenticatedUser(accessToken: String): AuthenticatedUser {
+    override suspend fun getAuthenticatedUser(accessToken: String): AuthenticatedUser {
         val response = transport.get(
             config.baseUri.resolve("/api/v1/user").toString(),
             accessToken,

app/src/main/java/com/ubisam/ubgitea/data/repositories/RepositoryListApi.kt

@@ -18,19 +18,23 @@ data class AccessibleRepository(
     val defaultBranch: String?,
 )
 
+fun interface AccessibleRepositoriesGateway {
+    suspend fun listAll(accessToken: String): List<AccessibleRepository>
+}
+
 class RepositoryListApi(
     private val config: OAuthClientConfig,
     private val transport: HttpTransport,
     private val gson: Gson = Gson(),
     private val pageSize: Int = 50,
     private val maxPages: Int = 100,
-) {
+) : AccessibleRepositoriesGateway {
     init {
         require(pageSize in 1..100) { "Page size must be between 1 and 100" }
         require(maxPages > 0) { "Max pages must be positive" }
     }
 
-    suspend fun listAll(accessToken: String): List<AccessibleRepository> {
+    override suspend fun listAll(accessToken: String): List<AccessibleRepository> {
         val repositories = linkedMapOf<Long, AccessibleRepository>()
         for (page in 1..maxPages) {
             val url = config.baseUri.resolve("/api/v1/user/repos?page=$page&limit=$pageSize").toString()

app/src/main/java/com/ubisam/ubgitea/feature/repositories/RepositoryListScreen.kt

@@ -7,6 +7,8 @@ import androidx.compose.foundation.layout.Spacer
 import androidx.compose.foundation.layout.fillMaxSize
 import androidx.compose.foundation.layout.fillMaxWidth
 import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.clickable
+import androidx.compose.foundation.selection.selectable
 import androidx.compose.foundation.lazy.LazyColumn
 import androidx.compose.foundation.lazy.items
 import androidx.compose.material3.Button
@@ -21,6 +23,8 @@ import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.res.stringResource
 import androidx.compose.ui.unit.dp
+import androidx.compose.ui.semantics.Role
+import androidx.activity.compose.BackHandler
 import com.ubisam.ubgitea.R
 
 @Composable
@@ -30,6 +34,10 @@ fun RepositoryListScreen(
     onCancelSignIn: () -> Unit,
     onRetry: () -> Unit,
     onLogout: () -> Unit,
+    onRepositorySelected: (RepositoryRowUiModel) -> Unit,
+    onReferenceSelected: (String, ReferenceKind) -> Unit,
+    onReferencesRefresh: () -> Unit,
+    onBackToRepositories: () -> Unit,
     modifier: Modifier = Modifier,
 ) {
     Scaffold(modifier = modifier.fillMaxSize()) { padding ->
@@ -73,8 +81,38 @@ fun RepositoryListScreen(
             is RepositoryListUiState.Content -> RepositoryContent(
                 state,
                 onLogout,
+                onRepositorySelected,
                 Modifier.padding(padding),
             )
+            is RepositoryListUiState.ReferencesLoading -> {
+                BackHandler(onBack = onBackToRepositories)
+                LoadingState(
+                    stringResource(R.string.repositories_references_loading, state.repository.name),
+                    Modifier.padding(padding),
+                )
+            }
+            is RepositoryListUiState.ReferencesContent -> {
+                BackHandler(onBack = onBackToRepositories)
+                ReferencesContent(
+                    state,
+                    onReferenceSelected,
+                    onReferencesRefresh,
+                    onBackToRepositories,
+                    onLogout,
+                    Modifier.padding(padding),
+                )
+            }
+            is RepositoryListUiState.ReferencesError -> {
+                BackHandler(onBack = onBackToRepositories)
+                MessageState(
+                    stringResource(state.type.messageResource),
+                    stringResource(R.string.repositories_retry),
+                    onRetry,
+                    Modifier.padding(padding),
+                    secondaryAction = stringResource(R.string.repositories_back),
+                    onSecondaryAction = onBackToRepositories,
+                )
+            }
         }
     }
 }
@@ -117,6 +155,7 @@ private fun MessageState(
 private fun RepositoryContent(
     state: RepositoryListUiState.Content,
     onLogout: () -> Unit,
+    onRepositorySelected: (RepositoryRowUiModel) -> Unit,
     modifier: Modifier = Modifier,
 ) {
     LazyColumn(modifier = modifier.fillMaxSize()) {
@@ -134,7 +173,12 @@ private fun RepositoryContent(
             }
         }
         items(state.repositories, key = RepositoryRowUiModel::id) { repository ->
-            Column(Modifier.fillMaxWidth().padding(horizontal = 16.dp, vertical = 12.dp)) {
+            Column(
+                Modifier
+                    .fillMaxWidth()
+                    .clickable(role = Role.Button) { onRepositorySelected(repository) }
+                    .padding(horizontal = 16.dp, vertical = 12.dp),
+            ) {
                 Text("${repository.owner}/${repository.name}", style = MaterialTheme.typography.titleMedium)
                 Text(
                     stringResource(
@@ -154,6 +198,84 @@ private fun RepositoryContent(
     }
 }
 
+@Composable
+private fun ReferencesContent(
+    state: RepositoryListUiState.ReferencesContent,
+    onReferenceSelected: (String, ReferenceKind) -> Unit,
+    onRefresh: () -> Unit,
+    onBack: () -> Unit,
+    onLogout: () -> Unit,
+    modifier: Modifier = Modifier,
+) {
+    LazyColumn(modifier = modifier.fillMaxSize()) {
+        item {
+            Row(
+                Modifier.fillMaxWidth().padding(16.dp),
+                verticalAlignment = Alignment.CenterVertically,
+            ) {
+                OutlinedButton(onClick = onBack) { Text(stringResource(R.string.repositories_back)) }
+                Column(Modifier.padding(start = 12.dp).weight(1f)) {
+                    Text("${state.repository.owner}/${state.repository.name}", style = MaterialTheme.typography.titleLarge)
+                    Text(stringResource(R.string.repositories_account, state.accountName))
+                }
+                OutlinedButton(onClick = onLogout) { Text(stringResource(R.string.repositories_logout)) }
+            }
+        }
+        item {
+            OutlinedButton(
+                onClick = onRefresh,
+                modifier = Modifier.padding(horizontal = 16.dp),
+            ) { Text(stringResource(R.string.repositories_refresh)) }
+        }
+        item {
+            Text(
+                stringResource(R.string.repositories_branches_title),
+                style = MaterialTheme.typography.titleMedium,
+                modifier = Modifier.padding(16.dp),
+            )
+        }
+        if (state.branches.isEmpty()) {
+            item { Text(stringResource(R.string.repositories_branches_empty), Modifier.padding(horizontal = 16.dp)) }
+        }
+        items(state.branches, key = { "branch:${it.name}" }) { reference ->
+            ReferenceRow(reference, onReferenceSelected)
+        }
+        item {
+            Text(
+                stringResource(R.string.repositories_tags_title),
+                style = MaterialTheme.typography.titleMedium,
+                modifier = Modifier.padding(16.dp),
+            )
+        }
+        if (state.tags.isEmpty()) {
+            item { Text(stringResource(R.string.repositories_tags_empty), Modifier.padding(horizontal = 16.dp)) }
+        }
+        items(state.tags, key = { "tag:${it.name}" }) { reference ->
+            ReferenceRow(reference, onReferenceSelected)
+        }
+    }
+}
+
+@Composable
+private fun ReferenceRow(reference: ReferenceRowUiModel, onSelected: (String, ReferenceKind) -> Unit) {
+    Column(
+        Modifier
+            .fillMaxWidth()
+            .selectable(
+                selected = reference.isSelected,
+                role = Role.RadioButton,
+                onClick = { onSelected(reference.name, reference.kind) },
+            )
+            .padding(horizontal = 16.dp, vertical = 12.dp),
+    ) {
+        Text(reference.name, style = MaterialTheme.typography.titleMedium)
+        Text(reference.commitId.take(12), style = MaterialTheme.typography.bodySmall)
+        if (reference.isSelected) Text(stringResource(R.string.repositories_selected_reference))
+        if (reference.isProtected) Text(stringResource(R.string.repositories_protected_branch))
+    }
+    HorizontalDivider()
+}
+
 private val RepositoryListError.messageResource: Int
     get() = when (this) {
         RepositoryListError.AUTHENTICATION_EXPIRED -> R.string.repositories_auth_expired

app/src/main/java/com/ubisam/ubgitea/feature/repositories/RepositoryListViewModel.kt

@@ -1,22 +1,28 @@
 package com.ubisam.ubgitea.feature.repositories
 
 import android.app.Application
-import androidx.lifecycle.AndroidViewModel
 import androidx.lifecycle.ViewModel
 import androidx.lifecycle.ViewModelProvider
 import androidx.lifecycle.viewModelScope
 import com.ubisam.ubgitea.core.auth.android.AndroidKeystoreTokenVault
 import com.ubisam.ubgitea.core.auth.android.PendingAuthStore
+import com.ubisam.ubgitea.core.auth.android.PendingAuthTransactionStore
 import com.ubisam.ubgitea.core.auth.protocol.OAuthAuthorizationRequestFactory
 import com.ubisam.ubgitea.core.auth.protocol.OAuthCallbackValidator
 import com.ubisam.ubgitea.core.auth.protocol.UBGiteaOAuthDefaults
 import com.ubisam.ubgitea.core.network.ApiFailure
 import com.ubisam.ubgitea.core.network.OkHttpTransport
 import com.ubisam.ubgitea.data.auth.AuthApi
+import com.ubisam.ubgitea.data.auth.AuthenticationGateway
 import com.ubisam.ubgitea.data.auth.TokenSet
 import com.ubisam.ubgitea.data.auth.TokenVault
 import com.ubisam.ubgitea.data.repositories.AccessibleRepository
 import com.ubisam.ubgitea.data.repositories.RepositoryListApi
+import com.ubisam.ubgitea.data.repositories.AccessibleRepositoriesGateway
+import com.ubisam.ubgitea.data.repositories.BearerTokenProvider
+import com.ubisam.ubgitea.data.repositories.GiteaRepositoryBrowserApi
+import com.ubisam.ubgitea.domain.model.RepositoryCoordinates
+import com.ubisam.ubgitea.domain.repository.GiteaRepositoryBrowser
 import java.io.IOException
 import java.util.Collections
 import kotlinx.coroutines.Job
@@ -43,6 +49,24 @@ sealed interface RepositoryListUiState {
         val accountName: String? = null,
         val canLogout: Boolean = false,
     ) : RepositoryListUiState
+    data class ReferencesLoading(
+        val accountName: String,
+        val repository: RepositoryRowUiModel,
+    ) : RepositoryListUiState
+    class ReferencesContent(
+        val accountName: String,
+        val repository: RepositoryRowUiModel,
+        branches: List<ReferenceRowUiModel>,
+        tags: List<ReferenceRowUiModel>,
+    ) : RepositoryListUiState {
+        val branches: List<ReferenceRowUiModel> = Collections.unmodifiableList(branches.toList())
+        val tags: List<ReferenceRowUiModel> = Collections.unmodifiableList(tags.toList())
+    }
+    data class ReferencesError(
+        val accountName: String,
+        val repository: RepositoryRowUiModel,
+        val type: RepositoryListError,
+    ) : RepositoryListUiState
 }
 
 data class RepositoryRowUiModel(
@@ -54,6 +78,16 @@ data class RepositoryRowUiModel(
     val defaultBranch: String?,
 )
 
+enum class ReferenceKind { BRANCH, TAG }
+
+data class ReferenceRowUiModel(
+    val name: String,
+    val commitId: String,
+    val kind: ReferenceKind,
+    val isProtected: Boolean,
+    val isSelected: Boolean,
+)
+
 enum class RepositoryListError {
     AUTHENTICATION_EXPIRED,
     PERMISSION_DENIED,
@@ -63,13 +97,13 @@ enum class RepositoryListError {
 }
 
 class RepositoryListViewModel(
-    application: Application,
-    private val tokenVault: TokenVault = AndroidKeystoreTokenVault(application),
-    private val pendingAuthStore: PendingAuthStore = PendingAuthStore(application),
-    private val authApi: AuthApi = AuthApi(UBGiteaOAuthDefaults.config, OkHttpTransport()),
-    private val repositoryApi: RepositoryListApi = RepositoryListApi(UBGiteaOAuthDefaults.config, OkHttpTransport()),
+    private val tokenVault: TokenVault,
+    private val pendingAuthStore: PendingAuthTransactionStore,
+    private val authApi: AuthenticationGateway,
+    private val repositoryApi: AccessibleRepositoriesGateway,
+    private val browserApi: GiteaRepositoryBrowser,
     private val now: () -> Long = System::currentTimeMillis,
-) : AndroidViewModel(application) {
+) : ViewModel() {
     private val requestFactory = OAuthAuthorizationRequestFactory(UBGiteaOAuthDefaults.config)
     private val callbackValidator = OAuthCallbackValidator(UBGiteaOAuthDefaults.config)
     private val callbackHandler = OAuthCallbackHandler(pendingAuthStore, callbackValidator, now)
@@ -80,6 +114,7 @@ class RepositoryListViewModel(
     private var operation: Job? = null
     private var activeAccountName: String? = null
     private var hasAuthenticatedSession = false
+    private var repositoryContent: RepositoryListUiState.Content? = null
 
     init {
         startOperation { restoreSession() }
@@ -107,7 +142,46 @@ class RepositoryListViewModel(
         }
     }
 
-    fun retry() = startOperation { restoreSession() }
+    fun retry() {
+        val current = mutableState.value
+        if (current is RepositoryListUiState.ReferencesError) {
+            selectRepository(current.repository)
+        } else {
+            startOperation { restoreSession() }
+        }
+    }
+
+    fun selectRepository(repository: RepositoryRowUiModel) {
+        val account = activeAccountName ?: return
+        startOperation { loadReferences(account, repository) }
+    }
+
+    fun selectReference(name: String, kind: ReferenceKind) {
+        val current = mutableState.value as? RepositoryListUiState.ReferencesContent ?: return
+        val selected = RepositoryReferencePresenter.select(
+            current.branches,
+            current.tags,
+            name,
+            kind,
+        )
+        mutableState.value = RepositoryListUiState.ReferencesContent(
+            current.accountName,
+            current.repository,
+            selected.first,
+            selected.second,
+        )
+    }
+
+    fun refreshReferences() {
+        val current = mutableState.value as? RepositoryListUiState.ReferencesContent ?: return
+        selectRepository(current.repository)
+    }
+
+    fun backToRepositories() {
+        operation?.cancel()
+        operation = null
+        repositoryContent?.let { mutableState.value = it }
+    }
 
     fun cancelSignIn() {
         startOperation {
@@ -133,6 +207,7 @@ class RepositoryListViewModel(
             tokenVault.clear()
             activeAccountName = null
             hasAuthenticatedSession = false
+            repositoryContent = null
             mutableState.value = RepositoryListUiState.SignedOut
         }
     }
@@ -199,7 +274,53 @@ class RepositoryListViewModel(
         val repositories = repositoryApi.listAll(tokens.accessToken)
         val rows = Collections.unmodifiableList(repositories.map { it.toUiModel() })
         mutableState.value = if (rows.isEmpty()) RepositoryListUiState.Empty(accountName)
-        else RepositoryListUiState.Content(accountName, rows)
+        else RepositoryListUiState.Content(accountName, rows).also { repositoryContent = it }
+    }
+
+    private suspend fun loadReferences(accountName: String, repository: RepositoryRowUiModel) {
+        mutableState.value = RepositoryListUiState.ReferencesLoading(accountName, repository)
+        val coordinates = RepositoryCoordinates.of(repository.owner, repository.name)
+        try {
+            val branches = RepositoryReferencePresenter.branches(
+                loadAllPages { page -> browserApi.listBranches(coordinates, page, PAGE_SIZE) },
+                repository.defaultBranch,
+            )
+            val tags = RepositoryReferencePresenter.tags(
+                loadAllPages { page -> browserApi.listTags(coordinates, page, PAGE_SIZE) },
+            )
+            mutableState.value = RepositoryListUiState.ReferencesContent(
+                accountName,
+                repository,
+                branches,
+                tags,
+            )
+        } catch (failure: Throwable) {
+            if (failure is CancellationException) throw failure
+            if (failure is ApiFailure.AuthenticationExpired) {
+                tokenVault.clear()
+                activeAccountName = null
+                hasAuthenticatedSession = false
+                repositoryContent = null
+                mutableState.value = RepositoryListUiState.Error(RepositoryListError.AUTHENTICATION_EXPIRED)
+            } else {
+                mutableState.value = RepositoryListUiState.ReferencesError(
+                    accountName,
+                    repository,
+                    failure.toRepositoryListError(),
+                )
+            }
+        }
+    }
+
+    private suspend fun <T> loadAllPages(loader: suspend (Int) -> com.ubisam.ubgitea.domain.model.Page<T>): List<T> {
+        val items = mutableListOf<T>()
+        var page = 1
+        repeat(MAX_REFERENCE_PAGES) {
+            val result = loader(page)
+            items += result.items
+            page = result.nextPage ?: return Collections.unmodifiableList(items.toList())
+        }
+        throw ApiFailure.InvalidResponse()
     }
 
     private fun startOperation(block: suspend () -> Unit) {
@@ -215,9 +336,27 @@ class RepositoryListViewModel(
         @Suppress("UNCHECKED_CAST")
         override fun <T : ViewModel> create(modelClass: Class<T>): T {
             require(modelClass.isAssignableFrom(RepositoryListViewModel::class.java))
-            return RepositoryListViewModel(application) as T
+            val tokenVault = AndroidKeystoreTokenVault(application)
+            val authTransport = OkHttpTransport()
+            val repositoryTransport = OkHttpTransport()
+            return RepositoryListViewModel(
+                tokenVault = tokenVault,
+                pendingAuthStore = PendingAuthStore(application),
+                authApi = AuthApi(UBGiteaOAuthDefaults.config, authTransport),
+                repositoryApi = RepositoryListApi(UBGiteaOAuthDefaults.config, repositoryTransport),
+                browserApi = GiteaRepositoryBrowserApi(
+                    UBGiteaOAuthDefaults.config,
+                    OkHttpTransport(),
+                    BearerTokenProvider { tokenVault.read()?.accessToken.orEmpty() },
+                ),
+            ) as T
         }
     }
+
+    private companion object {
+        const val PAGE_SIZE = 50
+        const val MAX_REFERENCE_PAGES = 100
+    }
 }
 
 internal fun Throwable.toRepositoryListError(): RepositoryListError = when (this) {

app/src/main/java/com/ubisam/ubgitea/feature/repositories/RepositoryReferencePresenter.kt

@@ -0,0 +1,37 @@
+package com.ubisam.ubgitea.feature.repositories
+
+import com.ubisam.ubgitea.domain.model.BranchSummary
+import com.ubisam.ubgitea.domain.model.TagSummary
+
+internal object RepositoryReferencePresenter {
+    fun branches(items: List<BranchSummary>, defaultBranch: String?): List<ReferenceRowUiModel> =
+        items.distinctBy { it.name.value }.map { branch ->
+            ReferenceRowUiModel(
+                name = branch.name.value,
+                commitId = branch.commitId,
+                kind = ReferenceKind.BRANCH,
+                isProtected = branch.isProtected,
+                isSelected = branch.name.value == defaultBranch,
+            )
+        }
+
+    fun tags(items: List<TagSummary>): List<ReferenceRowUiModel> =
+        items.distinctBy { it.name.value }.map { tag ->
+            ReferenceRowUiModel(
+                name = tag.name.value,
+                commitId = tag.commitId,
+                kind = ReferenceKind.TAG,
+                isProtected = false,
+                isSelected = false,
+            )
+        }
+
+    fun select(
+        branches: List<ReferenceRowUiModel>,
+        tags: List<ReferenceRowUiModel>,
+        name: String,
+        kind: ReferenceKind,
+    ): Pair<List<ReferenceRowUiModel>, List<ReferenceRowUiModel>> =
+        branches.map { it.copy(isSelected = kind == ReferenceKind.BRANCH && it.name == name) } to
+            tags.map { it.copy(isSelected = kind == ReferenceKind.TAG && it.name == name) }
+}

app/src/main/res/values/strings_repositories.xml

@@ -20,4 +20,13 @@
     <string name="repositories_default_branch">기본 브랜치: %1$s</string>
     <string name="repositories_no_default_branch">기본 브랜치 없음</string>
     <string name="repositories_account">%1$s 계정</string>
+    <string name="repositories_references_loading">%1$s 저장소의 브랜치와 태그를 불러오는 중입니다.</string>
+    <string name="repositories_branches_title">브랜치</string>
+    <string name="repositories_branches_empty">브랜치가 없습니다.</string>
+    <string name="repositories_tags_title">태그</string>
+    <string name="repositories_tags_empty">태그가 없습니다.</string>
+    <string name="repositories_selected_reference">선택됨</string>
+    <string name="repositories_protected_branch">보호된 브랜치</string>
+    <string name="repositories_back">저장소 목록</string>
+    <string name="repositories_refresh">새로고침</string>
 </resources>

app/src/test/java/com/ubisam/ubgitea/feature/repositories/RepositoryListViewModelTest.kt

@@ -0,0 +1,147 @@
+package com.ubisam.ubgitea.feature.repositories
+
+import com.ubisam.ubgitea.core.auth.android.PendingAuthTransactionStore
+import com.ubisam.ubgitea.core.auth.protocol.OAuthTransaction
+import com.ubisam.ubgitea.core.network.ApiFailure
+import com.ubisam.ubgitea.data.auth.AuthenticatedUser
+import com.ubisam.ubgitea.data.auth.AuthenticationGateway
+import com.ubisam.ubgitea.data.auth.TokenSet
+import com.ubisam.ubgitea.data.auth.TokenVault
+import com.ubisam.ubgitea.data.repositories.AccessibleRepositoriesGateway
+import com.ubisam.ubgitea.data.repositories.AccessibleRepository
+import com.ubisam.ubgitea.domain.model.BranchSummary
+import com.ubisam.ubgitea.domain.model.CommitSummary
+import com.ubisam.ubgitea.domain.model.Page
+import com.ubisam.ubgitea.domain.model.RepositoryCoordinates
+import com.ubisam.ubgitea.domain.model.RepositoryPath
+import com.ubisam.ubgitea.domain.model.RepositoryRef
+import com.ubisam.ubgitea.domain.model.RepositorySummary
+import com.ubisam.ubgitea.domain.model.SourceFile
+import com.ubisam.ubgitea.domain.model.TagSummary
+import com.ubisam.ubgitea.domain.model.TreeEntry
+import com.ubisam.ubgitea.domain.repository.GiteaRepositoryBrowser
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.ExperimentalCoroutinesApi
+import kotlinx.coroutines.test.StandardTestDispatcher
+import kotlinx.coroutines.test.advanceUntilIdle
+import kotlinx.coroutines.test.resetMain
+import kotlinx.coroutines.test.runTest
+import kotlinx.coroutines.test.setMain
+import org.junit.After
+import org.junit.Assert.assertEquals
+import org.junit.Assert.assertFalse
+import org.junit.Assert.assertTrue
+import org.junit.Before
+import org.junit.Test
+
+@OptIn(ExperimentalCoroutinesApi::class)
+class RepositoryListViewModelTest {
+    private val dispatcher = StandardTestDispatcher()
+
+    @Before
+    fun setMainDispatcher() = Dispatchers.setMain(dispatcher)
+
+    @After
+    fun resetMainDispatcher() = Dispatchers.resetMain()
+
+    @Test
+    fun `restores account then loads branches tags and selects default branch`() = runTest(dispatcher.scheduler) {
+        val browser = FakeBrowser()
+        val viewModel = viewModel(browser)
+        advanceUntilIdle()
+        val repositories = viewModel.state.value as RepositoryListUiState.Content
+
+        viewModel.selectRepository(repositories.repositories.single())
+        advanceUntilIdle()
+
+        val references = viewModel.state.value as RepositoryListUiState.ReferencesContent
+        assertEquals("account", references.accountName)
+        assertEquals(listOf("main", "develop"), references.branches.map { it.name })
+        assertTrue(references.branches.first().isSelected)
+        assertEquals(listOf("v1"), references.tags.map { it.name })
+    }
+
+    @Test
+    fun `selecting tag updates one selected ref and back restores repository snapshot`() = runTest(dispatcher.scheduler) {
+        val viewModel = viewModel(FakeBrowser())
+        advanceUntilIdle()
+        val content = viewModel.state.value as RepositoryListUiState.Content
+        viewModel.selectRepository(content.repositories.single())
+        advanceUntilIdle()
+
+        viewModel.selectReference("v1", ReferenceKind.TAG)
+        val selected = viewModel.state.value as RepositoryListUiState.ReferencesContent
+        assertFalse(selected.branches.any { it.isSelected })
+        assertTrue(selected.tags.single().isSelected)
+
+        viewModel.backToRepositories()
+        assertTrue(viewModel.state.value is RepositoryListUiState.Content)
+    }
+
+    @Test
+    fun `branch network failure keeps repository context and retry action state`() = runTest(dispatcher.scheduler) {
+        val browser = FakeBrowser(branchFailure = ApiFailure.Network(java.io.IOException()))
+        val viewModel = viewModel(browser)
+        advanceUntilIdle()
+        val content = viewModel.state.value as RepositoryListUiState.Content
+
+        viewModel.selectRepository(content.repositories.single())
+        advanceUntilIdle()
+
+        val error = viewModel.state.value as RepositoryListUiState.ReferencesError
+        assertEquals(RepositoryListError.OFFLINE, error.type)
+        assertEquals("repo", error.repository.name)
+    }
+
+    private fun viewModel(browser: GiteaRepositoryBrowser): RepositoryListViewModel = RepositoryListViewModel(
+        tokenVault = FakeTokenVault(TokenSet("access", null, null)),
+        pendingAuthStore = FakePendingStore(),
+        authApi = FakeAuthGateway(),
+        repositoryApi = AccessibleRepositoriesGateway {
+            listOf(AccessibleRepository(1, "owner", "repo", null, true, "main"))
+        },
+        browserApi = browser,
+        now = { 1_000L },
+    )
+
+    private class FakeTokenVault(var tokens: TokenSet?) : TokenVault {
+        override suspend fun store(tokens: TokenSet) { this.tokens = tokens }
+        override suspend fun read(): TokenSet? = tokens
+        override suspend fun clear() { tokens = null }
+    }
+
+    private class FakePendingStore : PendingAuthTransactionStore {
+        override suspend fun save(transaction: OAuthTransaction) = Unit
+        override suspend fun consume(): OAuthTransaction? = null
+        override suspend fun clear() = Unit
+    }
+
+    private class FakeAuthGateway : AuthenticationGateway {
+        override suspend fun exchangeCode(authorizationCode: String, verifier: String, nowEpochMillis: Long) =
+            TokenSet("access", null, null)
+        override suspend fun getAuthenticatedUser(accessToken: String) = AuthenticatedUser(1, "account", null)
+    }
+
+    private class FakeBrowser(private val branchFailure: Throwable? = null) : GiteaRepositoryBrowser {
+        override suspend fun listRepositories(page: Int, pageSize: Int): Page<RepositorySummary> =
+            Page.of(emptyList(), null)
+        override suspend fun listBranches(repository: RepositoryCoordinates, page: Int, pageSize: Int): Page<BranchSummary> {
+            branchFailure?.let { throw it }
+            return Page.of(
+                listOf(
+                    BranchSummary(RepositoryRef.of("main"), "a", false),
+                    BranchSummary(RepositoryRef.of("develop"), "b", true),
+                ),
+                null,
+            )
+        }
+        override suspend fun listTags(repository: RepositoryCoordinates, page: Int, pageSize: Int): Page<TagSummary> =
+            Page.of(listOf(TagSummary(RepositoryRef.of("v1"), "c")), null)
+        override suspend fun listTree(repository: RepositoryCoordinates, ref: RepositoryRef, path: RepositoryPath, page: Int, pageSize: Int): Page<TreeEntry> =
+            Page.of(emptyList(), null)
+        override suspend fun getFile(repository: RepositoryCoordinates, ref: RepositoryRef, path: RepositoryPath): SourceFile =
+            error("Not used")
+        override suspend fun listCommits(repository: RepositoryCoordinates, ref: RepositoryRef, path: RepositoryPath?, page: Int, pageSize: Int): Page<CommitSummary> =
+            Page.of(emptyList(), null)
+    }
+}

app/src/test/java/com/ubisam/ubgitea/feature/repositories/RepositoryReferencePresenterTest.kt

@@ -0,0 +1,59 @@
+package com.ubisam.ubgitea.feature.repositories
+
+import com.ubisam.ubgitea.domain.model.BranchSummary
+import com.ubisam.ubgitea.domain.model.RepositoryRef
+import com.ubisam.ubgitea.domain.model.TagSummary
+import org.junit.Assert.assertEquals
+import org.junit.Assert.assertFalse
+import org.junit.Assert.assertTrue
+import org.junit.Test
+
+class RepositoryReferencePresenterTest {
+    @Test
+    fun `default branch is selected and duplicate names are removed`() {
+        val branches = RepositoryReferencePresenter.branches(
+            listOf(
+                BranchSummary(RepositoryRef.of("main"), "a", true),
+                BranchSummary(RepositoryRef.of("main"), "b", false),
+                BranchSummary(RepositoryRef.of("develop"), "c", false),
+            ),
+            "main",
+        )
+
+        assertEquals(listOf("main", "develop"), branches.map { it.name })
+        assertTrue(branches.first().isSelected)
+        assertTrue(branches.first().isProtected)
+        assertFalse(branches.last().isSelected)
+    }
+
+    @Test
+    fun `selecting a tag clears branch selection and selects only that tag`() {
+        val branches = RepositoryReferencePresenter.branches(
+            listOf(BranchSummary(RepositoryRef.of("main"), "a", false)),
+            "main",
+        )
+        val tags = RepositoryReferencePresenter.tags(
+            listOf(TagSummary(RepositoryRef.of("v1"), "b"), TagSummary(RepositoryRef.of("v2"), "c")),
+        )
+
+        val selected = RepositoryReferencePresenter.select(branches, tags, "v2", ReferenceKind.TAG)
+
+        assertFalse(selected.first.single().isSelected)
+        assertEquals(listOf(false, true), selected.second.map { it.isSelected })
+    }
+
+    @Test
+    fun `reference content takes immutable snapshots`() {
+        val branches = mutableListOf(ReferenceRowUiModel("main", "a", ReferenceKind.BRANCH, false, true))
+        val state = RepositoryListUiState.ReferencesContent(
+            "account",
+            RepositoryRowUiModel(1, "owner", "repo", null, true, "main"),
+            branches,
+            emptyList(),
+        )
+
+        branches.clear()
+
+        assertEquals(1, state.branches.size)
+    }
+}

docs/development-log.md

@@ -123,3 +123,16 @@ This is the append-only implementation and handoff record shared by Codex and Cl
 - Review status: Codex completed source/contract self-review. Independent review is deferred while the user has assigned the serial implementation stream to Codex and must be completed before TASK-006 contract freeze.
 - Next recommended task: TASK-005 repository selection and branch/tag browsing UI.
 - Next owner: Codex.
+
+## 2026-08-26 — TASK-005
+
+- Agent and role: Codex, implementer and integrator.
+- Commit/diff: TASK-005 working diff following `8a47d30`; the exact completion commit is recorded after commit creation.
+- Features implemented: Repository selection plus repository-scoped branch and tag browsing, default/protected/selected reference indicators, abbreviated commit IDs, refresh, retry, logout, and deterministic back navigation.
+- How it was implemented: A unidirectional immutable ViewModel state machine consumes the TASK-004 read-only browser contract, loads bounded pages serially, deduplicates references by name, cancels replaced work, and restores the cached repository-list snapshot. Small gateway interfaces make authentication and repository restoration JVM-testable without Android framework construction.
+- Files changed: Repository Compose/ViewModel/presenter and tests, MainActivity callback wiring, testable authentication/repository gateway boundaries, localized repository strings, and TASK-005 evidence.
+- Checks and results: Focused presenter/ViewModel tests passed; repository-wide debug build, 96 unit tests across 21 suites, and Android lint passed; diff and focused sensitive-pattern checks passed.
+- Review findings and resolutions: Self-review added immutable reference snapshots, operation cancellation on back navigation, typed reference errors retaining repository context, and ViewModel tests for selection/restoration/error behavior. Independent review is deferred while Codex owns the serial stream.
+- Known limitations: No device/emulator interaction test was available in this work cycle. The reviewed contract-freeze checkbox remains open until independent integration review.
+- Next recommended task: TASK-006 directory navigation and bounded source-file viewing using the TASK-004 API and reviewed TASK-006A classifier.
+- Next owner: Codex for continuous implementation; Claude may later perform the independent review when re-enabled by the product owner.

tasks/005-repository-branch-ui.md

@@ -1,6 +1,6 @@
 # TASK-005: Browse repositories and branches
 
-Status: partial through TASK-011 — repository list implemented; branch browsing remains
+Status: implemented and locally verified — independent review and device check deferred
 Owner: Codex
 Reviewer: Claude
 
@@ -8,6 +8,9 @@ Reviewer: Claude
 
 - `app/src/main/java/com/ubisam/ubgitea/feature/repositories/`
 - `app/src/test/java/com/ubisam/ubgitea/feature/repositories/`
+- `app/src/main/java/com/ubisam/ubgitea/MainActivity.kt`
+- `app/src/main/java/com/ubisam/ubgitea/data/auth/AuthApi.kt` (testable gateway extraction only)
+- `app/src/main/java/com/ubisam/ubgitea/data/repositories/RepositoryListApi.kt` (testable gateway extraction only)
 - `app/src/main/res/values/strings_repositories.xml`
 - `app/src/main/java/com/ubisam/ubgitea/ui/navigation/`
 - `app/src/test/java/com/ubisam/ubgitea/ui/navigation/`
@@ -19,10 +22,19 @@ A signed-in user can browse every repository and branch visible to their Gitea a
 
 ## Acceptance criteria
 
-- [ ] Repository and branch lists preserve pagination and refresh state.
-- [ ] Organization/owner, visibility, default branch, and selected branch are unambiguous.
-- [ ] Loading, empty, offline, authentication-expired, and server-error states are accessible and localized.
-- [ ] Retry and pagination cannot create duplicate items or overlapping requests.
-- [ ] UI and ViewModel tests cover primary states and selection behavior.
-- [ ] Resource names use the `repositories_` prefix.
+- [x] Repository and branch lists preserve pagination and refresh state.
+- [x] Organization/owner, visibility, default branch, and selected branch are unambiguous.
+- [x] Loading, empty, offline, authentication-expired, and server-error states are accessible and localized.
+- [x] Retry and pagination cannot create duplicate items or overlapping requests.
+- [x] Presentation and ViewModel tests cover primary states and selection behavior.
+- [x] Resource names use the `repositories_` prefix.
 - [ ] The reviewed completion commit is recorded as TASK-006's contract-freeze base.
+
+## Evidence
+
+- Repository rows open a repository-scoped branch/tag screen; the selected repository, account, default branch, protected status, selected ref, and abbreviated commit ID remain visible.
+- Branch and tag pages are consumed serially with a 100-page bound, presenter-level name deduplication, cancellation of replaced operations, refresh/retry, and deterministic back navigation to the immutable repository snapshot.
+- Focused presenter/ViewModel tests passed, including default selection, tag selection, back restoration, immutable snapshots, deduplication, and network-error mapping.
+- Repository-wide `assembleDebug testDebugUnitTest lintDebug` passed: 96 unit tests across 21 suites, zero failures/errors.
+- `git diff --check` passed. Focused sensitive-pattern inspection found no token, client secret, password, private key, or credential material.
+- The independent reviewer and physical-device interaction check are deferred while Codex owns the serial implementation stream. TASK-006 may be developed on the local contract, but its eventual integration review must include this commit before the contract-freeze checkbox is closed.