Coverage Summary for Class: AccountBalanceChartUi (com.georgeci.moneysurfer.feature.account.details)

 package com.georgeci.moneysurfer.feature.account.details
 
 import arrow.optics.optics
 import com.georgeci.moneysurfer.domain.config.HostCapabilities
 import com.georgeci.moneysurfer.domain.formatter.MoneyFormatter
 import com.georgeci.moneysurfer.domain.model.Account
 import com.georgeci.moneysurfer.domain.model.AccountBalanceSeries
 import com.georgeci.moneysurfer.domain.model.AccountExtraDetail
 import com.georgeci.moneysurfer.domain.model.Transaction
 import com.georgeci.moneysurfer.domain.primitives.AccountId
 import com.georgeci.moneysurfer.domain.primitives.AccountType
 import com.georgeci.moneysurfer.domain.primitives.CurrencyCode
 import com.georgeci.moneysurfer.domain.primitives.Money
 import com.georgeci.moneysurfer.domain.primitives.TransactionId
 import com.georgeci.moneysurfer.domain.primitives.TransactionType
 import com.georgeci.moneysurfer.domain.usecase.GetAccountBalanceSeriesUseCase
 import com.georgeci.moneysurfer.domain.usecase.GetAccountByIdUseCase
 import com.georgeci.moneysurfer.domain.usecase.GetTransactionsByAccountUseCase
 import com.georgeci.moneysurfer.feature.account.generated.resources.Res
 import com.georgeci.moneysurfer.feature.account.generated.resources.account_details_transaction_delete_undo
 import com.georgeci.moneysurfer.feature.account.generated.resources.account_details_transaction_deleted_snackbar
 import com.georgeci.moneysurfer.navigation.DeleteTransactionWithUndo
 import com.georgeci.moneysurfer.utils.MviViewModel
 import org.koin.core.annotation.KoinViewModel
 
 @KoinViewModel
 class AccountDetailsViewModel(
     accountId: AccountId,
     private val getAccountById: GetAccountByIdUseCase,
     private val getTransactionsByAccount: GetTransactionsByAccountUseCase,
     private val getAccountBalanceSeries: GetAccountBalanceSeriesUseCase,
     private val hostCapabilities: HostCapabilities,
     private val deleteWithUndo: DeleteTransactionWithUndo,
 ) : MviViewModel<AccountDetailsState, AccountDetailsEvent, AccountDetailsEffect>(
     initialState = AccountDetailsState.Loading(accountId),
 ) {
 
     init {
         loadData()
     }
 
     override fun onEvent(event: AccountDetailsEvent) {
         when (event) {
             AccountDetailsEvent.OnBackClick -> postSideEffect(AccountDetailsEffect.NavigateBack)
             is AccountDetailsEvent.OnTransactionClick ->
                 postSideEffect(AccountDetailsEffect.NavigateToTransactionDetails(event.transactionId))
             AccountDetailsEvent.OnAddTransactionClick ->
                 postSideEffect(AccountDetailsEffect.NavigateToTransactionCreation)
             AccountDetailsEvent.OnEditClick ->
                 postSideEffect(AccountDetailsEffect.NavigateToAccountEdit(currentState.accountId))
             AccountDetailsEvent.OnSeeAllTransactionsClick ->
                 postSideEffect(AccountDetailsEffect.NavigateToTransactionsList(currentState.accountId))
             is AccountDetailsEvent.OnFilterChanged ->
                 updateState {
                     AccountDetailsState.content.filter.modify(this) { event.filter }
                 }
             // The list is a database Flow, so the row leaves — and returns on Undo — on its own.
             is AccountDetailsEvent.OnDeleteTransaction -> launch {
                 deleteWithUndo(
                     transactionId = event.transactionId,
                     message = Res.string.account_details_transaction_deleted_snackbar,
                     undoLabel = Res.string.account_details_transaction_delete_undo,
                 )
             }
         }
     }
 
     private fun loadData() {
         launch {
             val accountId = currentState.accountId
             getTransactionsByAccount(accountId).collect { transactions ->
                 // Re-read per emission rather than once up front: deleting a row from this screen
                 // moves the account's balance, and a value captured before the flow started would
                 // leave the hero card printing the pre-delete number until the screen is reopened.
                 val account = getAccountById(accountId)
                 val currency = account?.currencyCode ?: CurrencyCode("USD")
                 val visible = transactions.filter { it.type != TransactionType.OPENING_BALANCE }
                 val totals = visible.formatTotals(currency)
                 val txnUi = visible.map { it.toUi(currency) }
                 // The chart is anchored on the same balance the hero card prints, and folds the
                 // history already collected above rather than issuing a second query.
                 val series = getAccountBalanceSeries(
                     accountId = accountId,
                     currentBalance = account?.balance ?: Money.zero(),
                     transactions = transactions,
                 )
                 val chart = series.toUi(currency)
                 updateState {
                     when (this) {
                         is AccountDetailsState.Loading ->
                             account.toContent(accountId, txnUi, totals, chart)
                         is AccountDetailsState.Content -> copy(
                             transactions = txnUi,
                             formattedBalance = account
                                 ?.let { MoneyFormatter.format(it.balance, it.currencyCode) }
                                 ?: formattedBalance,
                             formattedIncome = totals.income,
                             formattedExpenses = totals.expenses,
                             chart = chart,
                         )
                     }
                 }
             }
         }
     }
 
     /** Per-direction sums over the visible transactions, already formatted for display. */
     private fun List<Transaction>.formatTotals(currency: CurrencyCode): FormattedTotals {
         val income = sumOf(TransactionType.INCOME)
         val expenses = sumOf(TransactionType.EXPENSE)
         return FormattedTotals(
             income = MoneyFormatter.format(income, currency),
             expenses = MoneyFormatter.format(expenses, currency),
         )
     }
 
     private fun List<Transaction>.sumOf(type: TransactionType): Money =
         fold(Money.zero()) { acc, t -> if (t.type == type) acc + t.money.abs() else acc }
 
     /** First resolved state for the screen. A null account means it was deleted underneath us. */
     private fun Account?.toContent(
         accountId: AccountId,
         transactions: List<AccountTransactionUi>,
         totals: FormattedTotals,
         chart: AccountBalanceChartUi,
     ) = AccountDetailsState.Content(
         accountId = accountId,
         name = this?.name.orEmpty(),
         formattedBalance = this?.let { MoneyFormatter.format(it.balance, it.currencyCode) }.orEmpty(),
         type = this?.type,
         formattedIncome = totals.income,
         formattedExpenses = totals.expenses,
         chart = chart,
         transactions = transactions,
         filter = TransactionFilter.All,
         // Mirrors the creation screen: the offline build has no place to put these, so it does
         // not offer to collect them and does not show them.
         extraDetails = if (hostCapabilities.isOffline) emptyList() else this?.extraDetails.orEmpty(),
     )
 
     /**
      * The card scales its own axes, so the y values stay in major units and x is just the day
      * index — the series is evenly spaced by construction.
      */
     private fun AccountBalanceSeries.toUi(currency: CurrencyCode): AccountBalanceChartUi {
         val formatted = MoneyFormatter.format(delta, currency)
         return AccountBalanceChartUi(
             points = points.mapIndexed { index, point ->
                 index.toFloat() to (point.balance.minor / Money.MINOR_PER_MAJOR).toFloat()
             },
             // Locale formatting only signs negatives; a flat period reads as "+" too, since
             // "no change" is not a loss.
             formattedDelta = if (delta.isNegative()) formatted else "+$formatted",
             isDeltaNegative = delta.isNegative(),
         )
     }
 
     private fun Transaction.toUi(currency: CurrencyCode) = AccountTransactionUi(
         id = id,
         title = note.ifBlank { "No description" },
         formattedAmount = MoneyFormatter.format(money.abs(), currency),
         isExpense = type == TransactionType.EXPENSE,
         categoryHueSeed = categoryId?.value.orEmpty(),
         isTransfer = transferId != null,
         isSplitLeg = splitId != null,
     )
 }
 
 @optics
 sealed interface AccountDetailsState {
     val accountId: AccountId
 
     @optics
     data class Loading(override val accountId: AccountId) : AccountDetailsState {
         companion object
     }
 
     @optics
     data class Content(
         override val accountId: AccountId,
         val name: String,
         val formattedBalance: String,
         /** Drives the hero meta line. Null only while the account row is still being read. */
         val type: AccountType?,
         val formattedIncome: String,
         val formattedExpenses: String,
         val chart: AccountBalanceChartUi,
         val transactions: List<AccountTransactionUi>,
         val filter: TransactionFilter,
         /** User-entered key–value details; empty when there are none or in the offline build. */
         val extraDetails: List<AccountExtraDetail> = emptyList(),
     ) : AccountDetailsState {
         companion object
     }
 
     companion object
 }
 
 /** Display-ready income/expense totals for the quick-stats row. */
 private data class FormattedTotals(val income: String, val expenses: String)
 
 enum class TransactionFilter { All, Expenses, Income }
 
 /** Balance curve for the details chart: `x to y` pairs the card plots, plus its signed delta. */
 data class AccountBalanceChartUi(
     val points: List<Pair<Float, Float>>,
     val formattedDelta: String,
     val isDeltaNegative: Boolean,
 )
 
 data class AccountTransactionUi(
     val id: TransactionId,
     val title: String,
     val formattedAmount: String,
     val isExpense: Boolean,
     val categoryHueSeed: String,
     /** One leg of a transfer, which deleting takes down together with its sibling. */
     val isTransfer: Boolean = false,
     /**
      * One leg of a receipt split across categories. This screen deliberately lists the legs
      * separately — a leg is its own row under its own category here — but deleting one still takes
      * the whole receipt, so the confirmation has to say so.
      */
     val isSplitLeg: Boolean = false,
 )
 
 sealed interface AccountDetailsEvent {
     data object OnBackClick : AccountDetailsEvent
     data object OnEditClick : AccountDetailsEvent
     data class OnTransactionClick(val transactionId: TransactionId) : AccountDetailsEvent
     data object OnAddTransactionClick : AccountDetailsEvent
     data object OnSeeAllTransactionsClick : AccountDetailsEvent
     data class OnFilterChanged(val filter: TransactionFilter) : AccountDetailsEvent
 
     /** A row was swiped away and the confirmation accepted; the Undo rides on the snackbar. */
     data class OnDeleteTransaction(val transactionId: TransactionId) : AccountDetailsEvent
 }
 
 sealed interface AccountDetailsEffect {
     data object NavigateBack : AccountDetailsEffect
     data class NavigateToTransactionDetails(val transactionId: TransactionId) : AccountDetailsEffect
     data object NavigateToTransactionCreation : AccountDetailsEffect
     data class NavigateToAccountEdit(val accountId: AccountId) : AccountDetailsEffect
     data class NavigateToTransactionsList(val accountId: AccountId) : AccountDetailsEffect
 }