Coverage Summary for Class: AccountsManageViewModel (com.georgeci.moneysurfer.feature.account.manage)

 package com.georgeci.moneysurfer.feature.account.manage
 
 import arrow.optics.optics
 import com.georgeci.moneysurfer.domain.formatter.MoneyFormatter
 import com.georgeci.moneysurfer.domain.model.Account
 import com.georgeci.moneysurfer.domain.model.formattedTotalsByCurrency
 import com.georgeci.moneysurfer.domain.primitives.AccountId
 import com.georgeci.moneysurfer.domain.primitives.AccountType
 import com.georgeci.moneysurfer.domain.usecase.ArchiveAccountUseCase
 import com.georgeci.moneysurfer.domain.usecase.DeleteAccountUseCase
 import com.georgeci.moneysurfer.domain.usecase.GetAccountsUseCase
 import com.georgeci.moneysurfer.domain.usecase.ReorderAccountsUseCase
 import com.georgeci.moneysurfer.domain.usecase.RestoreAccountUseCase
 import com.georgeci.moneysurfer.feature.account.generated.resources.Res
 import com.georgeci.moneysurfer.feature.account.generated.resources.accounts_manage_action_failed
 import com.georgeci.moneysurfer.feature.account.generated.resources.accounts_manage_archive_undo
 import com.georgeci.moneysurfer.feature.account.generated.resources.accounts_manage_archived_snackbar
 import com.georgeci.moneysurfer.feature.account.generated.resources.accounts_manage_deleted_snackbar
 import com.georgeci.moneysurfer.navigation.SnackbarController
 import com.georgeci.moneysurfer.utils.MviViewModel
 import kotlinx.coroutines.flow.MutableStateFlow
 import kotlinx.coroutines.flow.filterNotNull
 import kotlinx.datetime.LocalDate
 import kotlinx.datetime.TimeZone
 import kotlinx.datetime.toLocalDateTime
 import org.koin.core.annotation.KoinViewModel
 
 @KoinViewModel
 class AccountsManageViewModel(
     private val getAccounts: GetAccountsUseCase,
     private val deleteAccount: DeleteAccountUseCase,
     private val archiveAccount: ArchiveAccountUseCase,
     private val restoreAccount: RestoreAccountUseCase,
     private val reorderAccounts: ReorderAccountsUseCase,
     private val snackbar: SnackbarController,
 ) : MviViewModel<AccountsManageState, AccountsManageEvent, AccountsManageEffect>(
     initialState = AccountsManageState.Loading,
 ) {
 
     /**
      * The order the user has dragged the active accounts into, or null while the database is the
      * only authority on it. A drag is persisted on drop, so between the first move and the write
      * landing the stored order is stale — and even afterwards an unrelated emission (a balance
      * recalculation, a sync pull) can carry the old one. Without this overlay either would snap
      * the rows back out from under the finger.
      */
     private var userOrder: List<AccountId>? = null
 
     /**
      * The order waiting to be written, or null until something is dropped. Each drop would
      * otherwise start its own write coroutine, and two of those can read the table before either
      * has written it: the second then finds a row already sitting at its target position, skips
      * it, and leaves the list in an order nobody chose. One writer draining a conflated flow
      * keeps the last drop last.
      */
     private val pendingOrder = MutableStateFlow<List<AccountId>?>(null)
 
     init {
         observeAccounts()
         launch {
             pendingOrder.filterNotNull().collect { order ->
                 reorderAccounts(order).onLeft { snackbar.show(Res.string.accounts_manage_action_failed) }
             }
         }
     }
 
     override fun onEvent(event: AccountsManageEvent) {
         when (event) {
             AccountsManageEvent.OnBackClick -> postSideEffect(AccountsManageEffect.NavigateBack)
             AccountsManageEvent.OnAddAccountClick -> postSideEffect(AccountsManageEffect.NavigateToAccountCreation)
             AccountsManageEvent.OnToggleEditMode -> toggleEditMode()
             is AccountsManageEvent.OnAccountClick -> handleAccountClick(event.accountId)
             is AccountsManageEvent.OnArchiveAccountClick -> requestArchive(event.accountId)
             AccountsManageEvent.OnArchiveCancel -> dismissArchive()
             AccountsManageEvent.OnArchiveConfirm -> confirmArchive()
             is AccountsManageEvent.OnRestoreAccountClick -> performRestore(event.accountId)
             is AccountsManageEvent.OnRemoveAccountClick -> requestDelete(event.accountId)
             AccountsManageEvent.OnDeleteCancel -> dismissDelete()
             AccountsManageEvent.OnDeleteConfirm -> confirmDelete()
             is AccountsManageEvent.OnAccountMove -> moveAccount(from = event.from, to = event.to)
             AccountsManageEvent.OnAccountMoveEnd -> persistUserOrder()
         }
     }
 
     /**
      * Moves [from] into the slot [to] holds right now. State only — a drag reports a move every
      * half row, and the order is written once, when the row is dropped.
      */
     private fun moveAccount(from: AccountId, to: AccountId) {
         val content = currentState as? AccountsManageState.Content ?: return
         val reordered = content.activeAccounts.moved(from = from, to = to) ?: return
         userOrder = reordered.map { it.id }
         updateState { AccountsManageState.content.activeAccounts.modify(this) { reordered } }
     }
 
     private fun persistUserOrder() {
         pendingOrder.value = userOrder ?: return
     }
 
     private fun toggleEditMode() = updateState {
         AccountsManageState.content.isEditing.modify(this) { !it }
     }
 
     private fun handleAccountClick(accountId: AccountId) {
         val isEditing = (currentState as? AccountsManageState.Content)?.isEditing == true
         val effect = if (isEditing) {
             AccountsManageEffect.NavigateToAccountEdit(accountId)
         } else {
             AccountsManageEffect.NavigateToAccountDetails(accountId)
         }
         postSideEffect(effect)
     }
 
     private fun requestArchive(accountId: AccountId) {
         val content = currentState as? AccountsManageState.Content ?: return
         val target = content.activeAccounts.firstOrNull { it.id == accountId } ?: return
         updateState {
             AccountsManageState.content.pendingArchive.modify(this) {
                 AccountsManagePendingArchive(id = target.id, name = target.name)
             }
         }
     }
 
     private fun dismissArchive() = updateState {
         AccountsManageState.content.pendingArchive.modify(this) { null }
     }
 
     private fun confirmArchive() {
         val content = currentState as? AccountsManageState.Content ?: return
         val target = content.pendingArchive ?: return
         updateState { AccountsManageState.content.pendingArchive.modify(this) { null } }
         launch {
             archiveAccount(target.id).fold(
                 ifLeft = { snackbar.show(Res.string.accounts_manage_action_failed) },
                 ifRight = {
                     snackbar.show(
                         message = Res.string.accounts_manage_archived_snackbar,
                         messageArgs = listOf(target.name),
                         actionLabel = Res.string.accounts_manage_archive_undo,
                         onAction = { restoreArchived(target.id) },
                     )
                 },
             )
         }
     }
 
     private fun performRestore(accountId: AccountId) {
         launch { restoreArchived(accountId) }
     }
 
     private suspend fun restoreArchived(accountId: AccountId) {
         restoreAccount(accountId).onLeft {
             snackbar.show(Res.string.accounts_manage_action_failed)
         }
     }
 
     private fun requestDelete(accountId: AccountId) {
         val content = currentState as? AccountsManageState.Content ?: return
         val target = content.activeAccounts.firstOrNull { it.id == accountId }
             ?: content.archivedAccounts.firstOrNull { it.id == accountId }
             ?: return
         updateState {
             AccountsManageState.content.pendingDelete.modify(this) {
                 AccountsManagePendingDelete(id = target.id, name = target.name)
             }
         }
     }
 
     private fun dismissDelete() = updateState {
         AccountsManageState.content.pendingDelete.modify(this) { null }
     }
 
     private fun confirmDelete() {
         val content = currentState as? AccountsManageState.Content ?: return
         val target = content.pendingDelete ?: return
         updateState { AccountsManageState.content.pendingDelete.modify(this) { null } }
         launch {
             deleteAccount(target.id).fold(
                 ifLeft = { snackbar.show(Res.string.accounts_manage_action_failed) },
                 ifRight = {
                     snackbar.show(Res.string.accounts_manage_deleted_snackbar, listOf(target.name))
                 },
             )
         }
     }
 
     private fun observeAccounts() {
         launch {
             getAccounts().collect { accounts ->
                 val stored = accounts.filterNot { it.archived }
                 val activeAccounts = userOrder?.let(stored::orderedBy) ?: stored
                 // Once the database agrees with the drag, it is the authority again — including
                 // when it agrees only because an account the drag named has since been deleted.
                 if (activeAccounts == stored) userOrder = null
                 val active = activeAccounts.map { it.toUi() }
                 val archived = accounts.filter { it.archived }.map { it.toUi() }
                 val totals = activeAccounts.formattedTotalsByCurrency()
                 updateState {
                     when (this) {
                         is AccountsManageState.Loading -> AccountsManageState.Content(
                             isEditing = false,
                             activeAccounts = active,
                             archivedAccounts = archived,
                             formattedTotal = totals.firstOrNull(),
                             otherCurrencyTotals = totals.drop(1),
                         )
                         is AccountsManageState.Content -> copy(
                             activeAccounts = active,
                             archivedAccounts = archived,
                             formattedTotal = totals.firstOrNull(),
                             otherCurrencyTotals = totals.drop(1),
                         )
                     }
                 }
             }
         }
     }
 }
 
 /**
  * The accounts of the receiver arranged the way [order] names them. Accounts [order] says nothing
  * about — created since the drag — keep the position they came in with, after the placed ones.
  */
 private fun List<Account>.orderedBy(order: List<AccountId>): List<Account> {
     val positions = order.withIndex().associate { (index, id) -> id to index }
     return sortedBy { positions[it.id] ?: Int.MAX_VALUE }
 }
 
 private fun List<AccountManageUi>.moved(from: AccountId, to: AccountId): List<AccountManageUi>? {
     if (from == to) return null
     val fromIndex = indexOfFirst { it.id == from }
     val toIndex = indexOfFirst { it.id == to }
     if (fromIndex < 0 || toIndex < 0) return null
     return toMutableList().apply { add(toIndex, removeAt(fromIndex)) }
 }
 
 private fun Account.toUi() = AccountManageUi(
     id = id,
     name = name,
     type = type,
     formattedBalance = MoneyFormatter.format(balance, currencyCode),
     currency = currencyCode.value,
     archivedOn = archivedAt?.toLocalDateTime(TimeZone.currentSystemDefault())?.date,
 )
 
 @optics
 sealed interface AccountsManageState {
     data object Loading : AccountsManageState
 
     @optics
     data class Content(
         val isEditing: Boolean,
         val activeAccounts: List<AccountManageUi>,
         val archivedAccounts: List<AccountManageUi>,
         /** Total for the most-used currency, or null when there are no active accounts. */
         val formattedTotal: String?,
         /**
          * Totals for every other currency in play. Rendered beside [formattedTotal] rather than
          * folded into it — without FX rates a single number would just hide these balances.
          */
         val otherCurrencyTotals: List<String> = emptyList(),
         val pendingDelete: AccountsManagePendingDelete? = null,
         val pendingArchive: AccountsManagePendingArchive? = null,
     ) : AccountsManageState {
         companion object
     }
 
     companion object
 }
 
 data class AccountsManagePendingDelete(
     val id: AccountId,
     val name: String,
 )
 
 data class AccountsManagePendingArchive(
     val id: AccountId,
     val name: String,
 )
 
 data class AccountManageUi(
     val id: AccountId,
     val name: String,
     val type: AccountType,
     val formattedBalance: String,
     val currency: String,
     /** Date the account was archived, or null when it is active (or was archived pre-#307). */
     val archivedOn: LocalDate? = null,
 )
 
 sealed interface AccountsManageEvent {
     data object OnBackClick : AccountsManageEvent
     data object OnAddAccountClick : AccountsManageEvent
     data object OnToggleEditMode : AccountsManageEvent
     data class OnAccountClick(val accountId: AccountId) : AccountsManageEvent
     data class OnArchiveAccountClick(val accountId: AccountId) : AccountsManageEvent
     data object OnArchiveConfirm : AccountsManageEvent
     data object OnArchiveCancel : AccountsManageEvent
     data class OnRestoreAccountClick(val accountId: AccountId) : AccountsManageEvent
     data class OnRemoveAccountClick(val accountId: AccountId) : AccountsManageEvent
     data object OnDeleteConfirm : AccountsManageEvent
     data object OnDeleteCancel : AccountsManageEvent
 
     /** [from] was dragged onto the slot [to] occupies right now, among the active accounts. */
     data class OnAccountMove(val from: AccountId, val to: AccountId) : AccountsManageEvent
 
     /** The dragged row was dropped — write the order the moves have built up. */
     data object OnAccountMoveEnd : AccountsManageEvent
 }
 
 sealed interface AccountsManageEffect {
     data object NavigateBack : AccountsManageEffect
     data object NavigateToAccountCreation : AccountsManageEffect
     data class NavigateToAccountDetails(val accountId: AccountId) : AccountsManageEffect
     data class NavigateToAccountEdit(val accountId: AccountId) : AccountsManageEffect
 }