feat(organizations): join and leave, with a last-owner guard (#81)

app/src/main/java/com/interlinedlist/android/navigation/InterlinedListNavHost.kt

@@ -607,6 +607,8 @@ private fun MainShell(
                 OrganizationDetailRoute(
                     onBack = { tabNav.popBackStack() },
                     onDeleted = { tabNav.popBackStack() },
+                    // Leaving drops access to the org, so return to the index.
+                    onLeft = { tabNav.popBackStack() },
                 )
             }
 

feature/organizations/src/androidTest/kotlin/com/interlinedlist/android/feature/organizations/ui/detail/OrganizationDetailScreenTest.kt

@@ -28,6 +28,8 @@ class OrganizationDetailScreenTest {
         state: OrganizationDetailUiState,
         onRemoveMember: (OrgMember) -> Unit = {},
         onDelete: () -> Unit = {},
+        onJoin: () -> Unit = {},
+        onLeave: () -> Unit = {},
     ) {
         composeRule.setContent {
             InterlinedListTheme {
@@ -40,6 +42,8 @@ class OrganizationDetailScreenTest {
                     onRemoveMember = onRemoveMember,
                     onSaveEdit = { _, _, _ -> },
                     onDelete = onDelete,
+                    onJoin = onJoin,
+                    onLeave = onLeave,
                 )
             }
         }
@@ -97,4 +101,105 @@ class OrganizationDetailScreenTest {
 
         composeRule.onNodeWithTag(OrganizationDetailTestTags.EMPTY).assertIsDisplayed()
     }
+
+    @Test
+    fun nonMember_seesJoinPrompt_andNoMemberTools() {
+        setScreen(
+            state = OrganizationDetailUiState(
+                // No role: the API reports membership only for the caller's own orgs.
+                organization = Organization("o1", "Metals", null, null, true, 1, null, null),
+                isLoading = false,
+            ),
+        )
+
+        composeRule.onNodeWithTag(OrganizationDetailTestTags.JOIN_PROMPT).assertIsDisplayed()
+        composeRule.onNodeWithTag(OrganizationDetailTestTags.JOIN).assertIsDisplayed()
+        composeRule.onNodeWithTag(OrganizationDetailTestTags.SEARCH).assertDoesNotExist()
+    }
+
+    @Test
+    fun nonMember_join_reportsTheAction() {
+        var joined = false
+        setScreen(
+            state = OrganizationDetailUiState(
+                organization = Organization("o1", "Metals", null, null, true, 1, null, null),
+                isLoading = false,
+            ),
+            onJoin = { joined = true },
+        )
+
+        composeRule.onNodeWithTag(OrganizationDetailTestTags.JOIN).performClick()
+        assert(joined)
+    }
+
+    @Test
+    fun nonMemberOfPrivateOrg_isNotOfferedJoin() {
+        setScreen(
+            state = OrganizationDetailUiState(
+                organization = Organization("o1", "Acme", null, null, false, 2, null, null),
+                isLoading = false,
+            ),
+        )
+
+        composeRule.onNodeWithTag(OrganizationDetailTestTags.JOIN_PROMPT).assertIsDisplayed()
+        composeRule.onNodeWithTag(OrganizationDetailTestTags.JOIN).assertDoesNotExist()
+    }
+
+    @Test
+    fun member_leaveFlow_confirmsBeforeLeaving() {
+        var left = false
+        setScreen(
+            state = OrganizationDetailUiState(
+                organization = Organization("o1", "Bikey Life", null, null, true, 3, OrgRole.MEMBER, null),
+                members = listOf(
+                    OrgMember("u1", "ada", "Ada", null, OrgRole.OWNER, active = true),
+                    OrgMember("me", "me", null, null, OrgRole.MEMBER, active = true),
+                ),
+                isLoading = false,
+            ),
+            onLeave = { left = true },
+        )
+
+        composeRule.onNodeWithTag(OrganizationDetailTestTags.OVERFLOW).performClick()
+        composeRule.onNodeWithTag(OrganizationDetailTestTags.LEAVE).performClick()
+        composeRule.onNodeWithTag(OrganizationDetailTestTags.LEAVE_DIALOG).assertIsDisplayed()
+        composeRule.onNodeWithTag(OrganizationDetailTestTags.LEAVE_CONFIRM).performClick()
+        assert(left)
+    }
+
+    @Test
+    fun soleOwner_isExplainedInsteadOfBeingAllowedToLeave() {
+        var left = false
+        setScreen(
+            state = OrganizationDetailUiState(
+                organization = Organization("o1", "Acme", null, null, false, 2, OrgRole.OWNER, null),
+                members = listOf(
+                    OrgMember("me", "me", null, null, OrgRole.OWNER, active = true),
+                    OrgMember("u2", "grace", null, null, OrgRole.MEMBER, active = true),
+                ),
+                isLoading = false,
+            ),
+            onLeave = { left = true },
+        )
+
+        composeRule.onNodeWithTag(OrganizationDetailTestTags.OVERFLOW).performClick()
+        composeRule.onNodeWithTag(OrganizationDetailTestTags.LEAVE).performClick()
+        // The dialog explains why, and offers no destructive confirm at all.
+        composeRule.onNodeWithTag(OrganizationDetailTestTags.LAST_OWNER_NOTICE).assertIsDisplayed()
+        composeRule.onNodeWithTag(OrganizationDetailTestTags.LEAVE_CONFIRM).assertDoesNotExist()
+        assert(!left)
+    }
+
+    @Test
+    fun nonMember_isNotOfferedLeave() {
+        setScreen(
+            state = OrganizationDetailUiState(
+                organization = Organization("o1", "Metals", null, null, true, 1, null, null),
+                isLoading = false,
+            ),
+        )
+
+        composeRule.onNodeWithTag(OrganizationDetailTestTags.OVERFLOW).performClick()
+        composeRule.onNodeWithTag(OrganizationDetailTestTags.LEAVE).assertDoesNotExist()
+    }
 }

feature/organizations/src/androidTest/kotlin/com/interlinedlist/android/feature/organizations/ui/list/OrganizationsScreenTest.kt

@@ -6,6 +6,7 @@ import androidx.compose.ui.test.onNodeWithTag
 import androidx.compose.ui.test.performClick
 import androidx.test.ext.junit.runners.AndroidJUnit4
 import com.interlinedlist.android.core.designsystem.theme.InterlinedListTheme
+import com.interlinedlist.android.feature.organizations.domain.OrgRole
 import com.interlinedlist.android.feature.organizations.domain.Organization
 import org.junit.Rule
 import org.junit.Test
@@ -25,6 +26,7 @@ class OrganizationsScreenTest {
     private fun setScreen(
         state: OrganizationsUiState,
         onOpenOrg: (String) -> Unit = {},
+        onJoinOrg: (String) -> Unit = {},
     ) {
         composeRule.setContent {
             InterlinedListTheme {
@@ -33,6 +35,7 @@ class OrganizationsScreenTest {
                     onOpenOrg = onOpenOrg,
                     onBack = {},
                     onLoadMore = {},
+                    onJoinOrg = onJoinOrg,
                     onCreateOrganization = { _, _, _ -> },
                 )
             }
@@ -86,4 +89,51 @@ class OrganizationsScreenTest {
         composeRule.onNodeWithTag(OrganizationsTestTags.CREATE_FAB).performClick()
         composeRule.onNodeWithTag(OrganizationsTestTags.CREATE_NAME).assertIsDisplayed()
     }
+
+    @Test
+    fun rendersMembershipState_joinForNonMembers_roleForMembers() {
+        setScreen(
+            state = OrganizationsUiState(
+                organizations = listOf(
+                    // Public, no role -> not a member: offer Join.
+                    Organization("1", "Metals", null, null, true, 1, null, null),
+                    // A membership reports a role: show it, never offer Join.
+                    Organization("2", "Bikey Life", null, null, true, 3, OrgRole.MEMBER, null),
+                ),
+                isRefreshing = false,
+            ),
+        )
+
+        composeRule.onNodeWithTag(OrganizationsTestTags.join("1")).assertIsDisplayed()
+        composeRule.onNodeWithTag(OrganizationsTestTags.membership("1")).assertDoesNotExist()
+        composeRule.onNodeWithTag(OrganizationsTestTags.membership("2")).assertIsDisplayed()
+        composeRule.onNodeWithTag(OrganizationsTestTags.join("2")).assertDoesNotExist()
+    }
+
+    @Test
+    fun joinButton_reportsTheOrgId() {
+        var joined: String? = null
+        setScreen(
+            state = OrganizationsUiState(
+                organizations = listOf(Organization("1", "Metals", null, null, true, 1, null, null)),
+                isRefreshing = false,
+            ),
+            onJoinOrg = { joined = it },
+        )
+
+        composeRule.onNodeWithTag(OrganizationsTestTags.join("1")).performClick()
+        assert(joined == "1")
+    }
+
+    @Test
+    fun privateOrgsTheUserIsNotIn_offerNoJoin() {
+        setScreen(
+            state = OrganizationsUiState(
+                organizations = listOf(Organization("1", "Acme", null, null, false, 2, null, null)),
+                isRefreshing = false,
+            ),
+        )
+
+        composeRule.onNodeWithTag(OrganizationsTestTags.join("1")).assertDoesNotExist()
+    }
 }

feature/organizations/src/main/kotlin/com/interlinedlist/android/feature/organizations/data/CurrentUserIdProvider.kt

@@ -0,0 +1,12 @@
+package com.interlinedlist.android.feature.organizations.data
+
+/**
+ * Supplies the signed-in user's id. Leaving an organization is expressed by the
+ * API as deleting your own membership row
+ * (`DELETE /api/organizations/{id}/members/{userId}`), so the repository needs it.
+ * Abstracted from `SessionStore` (which is Android-backed) so the repository stays
+ * unit-testable on the plain JVM.
+ */
+fun interface CurrentUserIdProvider {
+    fun currentUserId(): String?
+}

feature/organizations/src/main/kotlin/com/interlinedlist/android/feature/organizations/data/DefaultOrganizationsRepository.kt

@@ -9,6 +9,7 @@ import com.interlinedlist.android.feature.organizations.data.local.OrganizationD
 import com.interlinedlist.android.feature.organizations.data.remote.OrganizationsApi
 import com.interlinedlist.android.feature.organizations.data.remote.dto.AddMemberRequest
 import com.interlinedlist.android.feature.organizations.data.remote.dto.CreateOrganizationRequest
+import com.interlinedlist.android.feature.organizations.data.remote.dto.JoinOrganizationRequest
 import com.interlinedlist.android.feature.organizations.data.remote.dto.OrganizationsResponse
 import com.interlinedlist.android.feature.organizations.data.remote.dto.UpdateMemberRequest
 import com.interlinedlist.android.feature.organizations.data.remote.dto.UpdateOrganizationRequest
@@ -32,6 +33,7 @@ class DefaultOrganizationsRepository @Inject constructor(
     private val api: OrganizationsApi,
     private val dao: OrganizationDao,
     private val json: kotlinx.serialization.json.Json,
+    private val currentUserId: CurrentUserIdProvider,
     private val dispatchers: DispatcherProvider,
 ) : OrganizationsRepository {
 
@@ -142,6 +144,47 @@ class DefaultOrganizationsRepository @Inject constructor(
             }
         }
 
+    override suspend fun joinOrganization(orgId: String): ApiResult<Unit> =
+        withContext(dispatchers.io) {
+            when (val result = safeApiCall(json) { api.joinOrganization(JoinOrganizationRequest(orgId)) }) {
+                // Re-read the org so the cached row carries the new role and member
+                // count; the index then renders "Member" instead of "Join".
+                is ApiResult.Success -> {
+                    getOrganization(orgId)
+                    ApiResult.Success(Unit)
+                }
+                is ApiResult.Failure -> result
+            }
+        }
+
+    override suspend fun leaveOrganization(orgId: String): ApiResult<Unit> =
+        withContext(dispatchers.io) {
+            val userId = currentUserId.currentUserId()?.takeIf { it.isNotBlank() }
+                ?: return@withContext ApiResult.Failure(
+                    AppError.Unauthorized("We couldn't confirm who you're signed in as. Sign in again and retry."),
+                )
+            when (val result = safeApiCall(json) { api.removeMember(orgId, userId) }) {
+                is ApiResult.Success -> {
+                    refreshAfterLeaving(orgId)
+                    ApiResult.Success(Unit)
+                }
+                is ApiResult.Failure -> result
+            }
+        }
+
+    /**
+     * Re-reads an org just left so the cache drops the membership. A private org is
+     * invisible to a non-member, so a 403/404 means it should leave the cache too.
+     */
+    private suspend fun refreshAfterLeaving(orgId: String) {
+        val refreshed = getOrganization(orgId)
+        if (refreshed is ApiResult.Failure &&
+            (refreshed.error is AppError.Forbidden || refreshed.error is AppError.NotFound)
+        ) {
+            dao.deleteById(orgId)
+        }
+    }
+
     override suspend fun getMembers(orgId: String, limit: Int): ApiResult<List<OrgMember>> =
         withContext(dispatchers.io) {
             safeApiCall(json) { api.getMembers(orgId, limit = limit, offset = 0) }

feature/organizations/src/main/kotlin/com/interlinedlist/android/feature/organizations/data/OrganizationMapper.kt

@@ -15,7 +15,7 @@ object OrganizationMapper {
         avatarUrl = dto.resolvedAvatar,
         isPublic = dto.resolvedPublic,
         memberCount = dto.resolvedMemberCount,
-        role = dto.role?.let(OrgRole::fromApi),
+        role = dto.resolvedRole?.let(OrgRole::fromApi),
         updatedAt = dto.updatedAt,
     )
 

feature/organizations/src/main/kotlin/com/interlinedlist/android/feature/organizations/data/OrganizationsRepository.kt

@@ -46,6 +46,19 @@ interface OrganizationsRepository {
     /** Deletes an organization and evicts it from the cache. */
     suspend fun deleteOrganization(id: String): ApiResult<Unit>
 
+    /**
+     * Joins a public organization (`POST /api/user/organizations`). On success the
+     * cached row is re-read so it carries the new role and member count.
+     */
+    suspend fun joinOrganization(orgId: String): ApiResult<Unit>
+
+    /**
+     * Leaves an organization by removing the signed-in user's own membership. The
+     * server refuses to orphan an organization: the last owner gets a 400
+     * ("Cannot remove the last owner"), which is reported as a failure.
+     */
+    suspend fun leaveOrganization(orgId: String): ApiResult<Unit>
+
     /** Members of an organization (users granted access), with their roles. */
     suspend fun getMembers(orgId: String, limit: Int = DEFAULT_PAGE_SIZE): ApiResult<List<OrgMember>>
 

feature/organizations/src/main/kotlin/com/interlinedlist/android/feature/organizations/data/remote/OrganizationsApi.kt

@@ -2,6 +2,7 @@ package com.interlinedlist.android.feature.organizations.data.remote
 
 import com.interlinedlist.android.feature.organizations.data.remote.dto.AddMemberRequest
 import com.interlinedlist.android.feature.organizations.data.remote.dto.CreateOrganizationRequest
+import com.interlinedlist.android.feature.organizations.data.remote.dto.JoinOrganizationRequest
 import com.interlinedlist.android.feature.organizations.data.remote.dto.MembersResponse
 import com.interlinedlist.android.feature.organizations.data.remote.dto.OrgUsersResponse
 import com.interlinedlist.android.feature.organizations.data.remote.dto.OrganizationEnvelope
@@ -33,6 +34,14 @@ interface OrganizationsApi {
     @GET("api/user/organizations")
     suspend fun getUserOrganizations(): OrganizationsResponse
 
+    /**
+     * Joins a public organization. Confirmed live: the body key is
+     * `organizationId`, the response is 201 `{ message, membership }`, a private
+     * org answers 403 and an existing membership answers 409.
+     */
+    @POST("api/user/organizations")
+    suspend fun joinOrganization(@Body body: JoinOrganizationRequest)
+
     @POST("api/organizations")
     suspend fun createOrganization(@Body body: CreateOrganizationRequest): OrganizationEnvelope
 
@@ -68,6 +77,10 @@ interface OrganizationsApi {
         @Body body: UpdateMemberRequest,
     )
 
+    /**
+     * Removes a membership. Used both for removing someone else and for *leaving*
+     * (passing the signed-in user's own id) — the API has no separate leave route.
+     */
     @DELETE("api/organizations/{id}/members/{userId}")
     suspend fun removeMember(
         @Path("id") id: String,

feature/organizations/src/main/kotlin/com/interlinedlist/android/feature/organizations/data/remote/dto/OrganizationDtos.kt

@@ -30,8 +30,11 @@ data class OrganizationDto(
     val memberCount: Int? = null,
     val membersCount: Int? = null,
     val members: Int? = null,
-    // The current user's role in this org, when the endpoint includes it.
+    // The current user's role in this org, when the endpoint includes it. The
+    // index reports it as `role`, the detail endpoint as `userRole` (explicitly
+    // null for a non-member), so both names are read.
     val role: String? = null,
+    val userRole: String? = null,
     val updatedAt: String? = null,
 ) {
     /** The avatar URL under whichever field name the API used. */
@@ -40,6 +43,12 @@ data class OrganizationDto(
     val resolvedPublic: Boolean get() = isPublic ?: public ?: false
     /** Member count under whichever name the API used, defaulting to zero. */
     val resolvedMemberCount: Int get() = memberCount ?: membersCount ?: members ?: 0
+
+    /**
+     * The caller's role under whichever name the endpoint used. `null` means the
+     * caller is not a member — that is how the API signals non-membership.
+     */
+    val resolvedRole: String? get() = role ?: userRole
 }
 
 /** Pagination block shared by list endpoints. */
@@ -84,6 +93,16 @@ data class CreateOrganizationRequest(
     val isPublic: String? = null,
 )
 
+/**
+ * Body for `POST /api/user/organizations` — joining a public organization.
+ * The server requires the key `organizationId` (it 400s with
+ * `{"error":"Organization ID is required"}` otherwise).
+ */
+@Serializable
+data class JoinOrganizationRequest(
+    val organizationId: String,
+)
+
 /** Body for `PUT /api/organizations/{id}` — partial metadata updates. */
 @Serializable
 data class UpdateOrganizationRequest(