Coverage Summary for Class: SurferBalanceTrend (com.georgeci.moneysurfer.uikit.widgets)

 package com.georgeci.moneysurfer.uikit.widgets
 
 import androidx.compose.foundation.layout.Arrangement
 import androidx.compose.foundation.layout.Box
 import androidx.compose.foundation.layout.Column
 import androidx.compose.foundation.layout.Row
 import androidx.compose.foundation.layout.Spacer
 import androidx.compose.foundation.layout.fillMaxWidth
 import androidx.compose.foundation.layout.height
 import androidx.compose.foundation.layout.padding
 import androidx.compose.foundation.layout.size
 import androidx.compose.foundation.layout.width
 import androidx.compose.material.icons.Icons
 import androidx.compose.material.icons.automirrored.filled.TrendingDown
 import androidx.compose.material.icons.automirrored.filled.TrendingUp
 import androidx.compose.material3.Card
 import androidx.compose.material3.CardDefaults
 import androidx.compose.material3.Icon
 import androidx.compose.material3.Text
 import androidx.compose.runtime.Composable
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.text.style.TextOverflow
 import androidx.compose.ui.tooling.preview.Preview
 import androidx.compose.ui.unit.Dp
 import androidx.compose.ui.unit.dp
 import com.georgeci.moneysurfer.uikit.components.base.SurferSparkline
 import com.georgeci.moneysurfer.uikit.components.base.SurferSplitAmount
 import com.georgeci.moneysurfer.uikit.components.base.SurferSplitAmountTier
 import com.georgeci.moneysurfer.uikit.components.base.sparklinePoints
 import com.georgeci.moneysurfer.uikit.preview.SurferComponentPreview
 import com.georgeci.moneysurfer.uikit.semantics.SurferSemantics
 import com.georgeci.moneysurfer.uikit.theme.AppTheme
 import com.georgeci.moneysurfer.uikit.theme.SurferContainerStyle
 
 /**
  * Bottom line of [SurferBalanceWidget]. The two variants are mutually exclusive by construction —
  * passing them as independent nullable strings let callers ask for combinations the widget silently
  * dropped.
  *
  * The period delta is *not* one of them: it is [SurferBalanceTrend], because a card can honestly
  * carry both "up €412 this month" and "converted at rates from yesterday" at once, and forcing them
  * into one slot meant a workspace holding two currencies never saw its trend.
  */
 sealed interface SurferBalanceFootnote {
 
     /**
      * Secondary line carrying what the single headline figure cannot say — e.g. the balances
      * held in other currencies, which no rate-free sum may fold into it.
      */
     data class Note(val text: String) : SurferBalanceFootnote
 
     /**
      * Nothing to total yet. Also switches the headline to plain text and drops the trend: there is
      * no amount to split and no curve to draw.
      */
     data class Empty(val text: String) : SurferBalanceFootnote
 }
 
 /**
  * Where the balance has been and what moved it over the newest period.
  *
  * Both halves are optional and independent: a workspace one month old has a delta and no curve
  * worth drawing, and a curve is still worth drawing over a month that netted out to nothing. With
  * neither, pass no trend at all.
  */
 data class SurferBalanceTrend(
     /** The delta as a sentence, already formatted and signed by the caller. */
     val text: String? = null,
     /**
      * The balance at the close of each charted period, oldest first. Fewer than two points draws
      * nothing — see [SurferSparkline].
      */
     val series: List<Float> = emptyList(),
     /**
      * Whether the balance fell. Picks the arrow only: the card sits on `primaryContainer`, where an
      * error red would fail contrast, so the direction is carried by the icon and by the sign the
      * caller already put in [text].
      */
     val isNegative: Boolean = false,
 )
 
 /**
  * Presentation treatment of the balance card — six of them, the A–F set of the dashboard mockups.
  * The container, its colours and the footnote are the same in all six, so the choice reads as a
  * style rather than as six different widgets; what changes is the arrangement, the type scale of
  * the title and the amount, and how much room the trend curve gets.
  *
  * The entry names double as the persisted keys of a dashboard card style, which is why
  * [fromKey] is lenient: a layout written by a newer build may name a treatment this one has never
  * heard of, and falling back to [Classic] beats refusing to draw the balance.
  */
 enum class SurferBalanceVariant {
 
     /** Label above the amount — the dashboard default. */
     Classic,
 
     /** Amount first, label demoted to a caption under it. */
     Stacked,
 
     /** Label and amount on one line, the amount a tier smaller so both fit. */
     Inline,
 
     /** Amount alone, and no trend: the card's position on the dashboard is the label. */
     Minimal,
 
     /** Label and delta on one line facing each other, the amount below them. */
     Split,
 
     /** The curve is the hero: caption label, amount a tier down, and a chart twice as tall. */
     Chart,
 
     ;
 
     companion object {
         fun fromKey(key: String?): SurferBalanceVariant = entries.firstOrNull { it.name == key } ?: Classic
     }
 }
 
 @Composable
 fun SurferBalanceWidget(
     title: String,
     balance: String,
     modifier: Modifier = Modifier,
     size: SurferWidgetSize = LocalSurferWidgetSize.current,
     variant: SurferBalanceVariant = SurferBalanceVariant.Classic,
     footnote: SurferBalanceFootnote? = null,
     trend: SurferBalanceTrend? = null,
 ) {
     val hero = size == SurferWidgetSize.Expanded
     val isEmpty = footnote is SurferBalanceFootnote.Empty
     val elevated = AppTheme.containerStyle == SurferContainerStyle.Card
     // An empty balance has no trend by definition, and Minimal is the treatment that asked for the
     // figure and nothing else. Resolved once so the arrangement below and the curve agree.
     val shownTrend = trend?.takeUnless { isEmpty || variant == SurferBalanceVariant.Minimal }
 
     Card(
         modifier = modifier,
         shape = AppTheme.shapes.large,
         colors = CardDefaults.cardColors(
             containerColor = AppTheme.materialColors.primaryContainer,
             contentColor = AppTheme.materialColors.onPrimaryContainer,
         ),
         elevation = if (elevated) {
             CardDefaults.elevatedCardElevation()
         } else {
             CardDefaults.cardElevation(
                 defaultElevation = 0.dp,
                 pressedElevation = 0.dp,
                 focusedElevation = 0.dp,
                 hoveredElevation = 0.dp,
                 draggedElevation = 0.dp,
                 disabledElevation = 0.dp,
             )
         },
     ) {
         Column(modifier = Modifier.fillMaxWidth()) {
             Column(
                 modifier = Modifier
                     .fillMaxWidth()
                     .padding(horizontal = if (hero) 20.dp else 16.dp, vertical = if (hero) 18.dp else 14.dp),
                 verticalArrangement = Arrangement.spacedBy(if (hero) 8.dp else 4.dp),
             ) {
                 val tier = variant.amountTier(hero)
                 when (variant) {
                     SurferBalanceVariant.Classic -> {
                         Title(text = title, hero = hero)
                         Amount(balance = balance, tier = tier, isEmpty = isEmpty)
                     }
                     SurferBalanceVariant.Stacked -> {
                         Amount(balance = balance, tier = tier, isEmpty = isEmpty)
                         Title(text = title, hero = hero, caption = true)
                     }
                     SurferBalanceVariant.Inline -> Row(verticalAlignment = Alignment.CenterVertically) {
                         Title(text = title, hero = hero, modifier = Modifier.weight(1f))
                         Amount(balance = balance, tier = tier, isEmpty = isEmpty)
                     }
                     SurferBalanceVariant.Minimal -> Amount(balance = balance, tier = tier, isEmpty = isEmpty)
                     SurferBalanceVariant.Split -> {
                         Row(verticalAlignment = Alignment.Bottom) {
                             Title(text = title, hero = hero, modifier = Modifier.weight(1f))
                             TrendLabel(trend = shownTrend, hero = hero)
                         }
                         Amount(balance = balance, tier = tier, isEmpty = isEmpty)
                     }
                     SurferBalanceVariant.Chart -> {
                         Title(text = title, hero = hero, caption = true)
                         Amount(balance = balance, tier = tier, isEmpty = isEmpty)
                     }
                 }
                 // Split has already drawn the delta on the title's line; drawing it again below
                 // would state the same figure twice.
                 if (variant != SurferBalanceVariant.Split) {
                     TrendRow(trend = shownTrend, hero = hero)
                 }
                 Footnote(footnote = footnote)
             }
             // Outside the padded column so the curve bleeds to the card's edges, the way the
             // mockups draw it — a sparkline inset from the sides reads as a chart that was cropped.
             Sparkline(trend = shownTrend, variant = variant, hero = hero)
         }
     }
 }
 
 /**
  * How big the amount is set. [SurferBalanceVariant.Inline] shares its line with the title and
  * [SurferBalanceVariant.Chart] shares its card with a tall curve, so neither can keep the hero
  * tier; the rest have the full width of the card to themselves.
  */
 private fun SurferBalanceVariant.amountTier(hero: Boolean): SurferSplitAmountTier = when (this) {
     SurferBalanceVariant.Inline,
     SurferBalanceVariant.Chart,
     -> if (hero) SurferSplitAmountTier.Stat else SurferSplitAmountTier.Body
     else -> if (hero) SurferSplitAmountTier.Hero else SurferSplitAmountTier.Stat
 }
 
 /**
  * Height the curve gets, or null for the treatments that draw none.
  * [SurferBalanceVariant.Chart] is the one that leads with it; elsewhere it is a band under the
  * figures.
  */
 private fun SurferBalanceVariant.sparklineHeight(hero: Boolean): Dp? = when (this) {
     SurferBalanceVariant.Minimal -> null
     SurferBalanceVariant.Chart -> if (hero) 96.dp else 64.dp
     else -> if (hero) 56.dp else 40.dp
 }
 
 @Composable
 private fun Title(
     text: String,
     hero: Boolean,
     modifier: Modifier = Modifier,
     caption: Boolean = false,
 ) {
     Text(
         text = text,
         style = when {
             caption -> if (hero) AppTheme.typography.labelMedium else AppTheme.typography.labelSmall
             hero -> AppTheme.typography.labelLarge
             else -> AppTheme.typography.labelMedium
         },
         color = AppTheme.materialColors.onPrimaryContainer.copy(alpha = 0.8f),
         // Inline puts the title on the amount's line, where the amount is measured first: a long
         // balance leaves the title a narrow column, and it must shorten rather than stack up.
         maxLines = 1,
         overflow = TextOverflow.Ellipsis,
         modifier = modifier,
     )
 }
 
 /** The headline figure. An empty balance is a dash, not an amount, so it is plain text. */
 @Composable
 private fun Amount(
     balance: String,
     tier: SurferSplitAmountTier,
     isEmpty: Boolean,
 ) {
     if (isEmpty) {
         Text(
             text = balance,
             style = when (tier) {
                 SurferSplitAmountTier.Hero -> AppTheme.typography.displaySmall
                 SurferSplitAmountTier.Stat -> AppTheme.typography.headlineSmall
                 SurferSplitAmountTier.Body -> AppTheme.typography.titleLarge
             },
             color = AppTheme.materialColors.onPrimaryContainer,
         )
     } else {
         SurferSplitAmount(
             formattedAmount = balance,
             tier = tier,
             color = AppTheme.materialColors.onPrimaryContainer,
             signAlpha = 0.7f,
             fractionAlpha = 0.55f,
         )
     }
 }
 
 /** The delta with its direction arrow, on a line of its own. */
 @Composable
 private fun TrendRow(trend: SurferBalanceTrend?, hero: Boolean) {
     val text = trend?.text ?: return
     Row(verticalAlignment = Alignment.CenterVertically) {
         Icon(
             imageVector = trend.icon(),
             contentDescription = SurferSemantics.Decorative,
             tint = AppTheme.materialColors.onPrimaryContainer,
             modifier = Modifier.size(if (hero) 16.dp else 14.dp),
         )
         Spacer(Modifier.width(6.dp))
         Text(
             text = text,
             style = if (hero) AppTheme.typography.bodyMedium else AppTheme.typography.bodySmall,
             color = AppTheme.materialColors.onPrimaryContainer,
         )
     }
 }
 
 /**
  * The delta alone, for [SurferBalanceVariant.Split], where it faces the title across the card and
  * the arrow would crowd the gap between them.
  *
  * The unweighted child of that row, so it is measured first against the card's whole width — a long
  * enough delta squeezes the title rather than running off the edge, and shortens rather than clips
  * once even that is not enough.
  */
 @Composable
 private fun TrendLabel(trend: SurferBalanceTrend?, hero: Boolean) {
     val text = trend?.text ?: return
     Text(
         text = text,
         style = if (hero) AppTheme.typography.labelLarge else AppTheme.typography.labelMedium,
         color = AppTheme.materialColors.onPrimaryContainer,
         maxLines = 1,
         overflow = TextOverflow.Ellipsis,
     )
 }
 
 private fun SurferBalanceTrend.icon() =
     if (isNegative) Icons.AutoMirrored.Filled.TrendingDown else Icons.AutoMirrored.Filled.TrendingUp
 
 @Composable
 private fun Sparkline(trend: SurferBalanceTrend?, variant: SurferBalanceVariant, hero: Boolean) {
     val series = trend?.series ?: return
     if (series.size < 2) return
     val height = variant.sparklineHeight(hero) ?: return
     SurferSparkline(
         points = sparklinePoints(series),
         color = AppTheme.materialColors.onPrimaryContainer,
         modifier = Modifier
             .fillMaxWidth()
             .height(height),
     )
 }
 
 /**
  * Takes no size: the two remaining footnotes are qualifying prose either way, and only the delta —
  * now [TrendRow]'s job — ever scaled with the card.
  */
 @Composable
 private fun Footnote(footnote: SurferBalanceFootnote?) {
     when (footnote) {
         null -> Unit
         is SurferBalanceFootnote.Note -> Text(
             text = footnote.text,
             style = AppTheme.typography.bodySmall,
             color = AppTheme.materialColors.onPrimaryContainer.copy(alpha = 0.85f),
         )
         is SurferBalanceFootnote.Empty -> Text(
             text = footnote.text,
             style = AppTheme.typography.bodyMedium,
             color = AppTheme.materialColors.onPrimaryContainer.copy(alpha = 0.85f),
         )
     }
 }
 
 /** Shared preview copy, so the galleries below differ only in the treatment they show. */
 private const val PREVIEW_TITLE = "Total balance"
 
 private const val PREVIEW_BALANCE = "€11,575.32"
 
 private val PREVIEW_TREND = SurferBalanceTrend(
     text = "+€412 this month",
     series = listOf(9_800f, 10_240f, 9_950f, 10_610f, 11_160f, 11_575f),
 )
 
 @Preview
 @Composable
 private fun SurferBalanceWidgetHeroPreview() {
     SurferComponentPreview {
         Box(modifier = Modifier.padding(16.dp)) {
             SurferBalanceWidget(
                 title = PREVIEW_TITLE,
                 balance = PREVIEW_BALANCE,
                 trend = PREVIEW_TREND,
                 modifier = Modifier.fillMaxWidth(),
             )
         }
     }
 }
 
 @Preview
 @Composable
 private fun SurferBalanceWidgetCompactPreview() {
     SurferComponentPreview {
         Box(modifier = Modifier.padding(16.dp)) {
             SurferBalanceWidget(
                 title = PREVIEW_TITLE,
                 balance = PREVIEW_BALANCE,
                 size = SurferWidgetSize.Compact,
                 trend = PREVIEW_TREND.copy(text = "+€412"),
                 modifier = Modifier.width(220.dp),
             )
         }
     }
 }
 
 @Preview
 @Composable
 private fun SurferBalanceWidgetVariantsPreview() {
     SurferComponentPreview {
         Column(
             modifier = Modifier.padding(16.dp),
             verticalArrangement = Arrangement.spacedBy(12.dp),
         ) {
             SurferBalanceVariant.entries.forEach { variant ->
                 SurferBalanceWidget(
                     title = PREVIEW_TITLE,
                     balance = PREVIEW_BALANCE,
                     variant = variant,
                     trend = PREVIEW_TREND,
                     modifier = Modifier.fillMaxWidth(),
                 )
             }
         }
     }
 }
 
 @Preview
 @Composable
 private fun SurferBalanceWidgetFallingPreview() {
     SurferComponentPreview {
         Box(modifier = Modifier.padding(16.dp)) {
             SurferBalanceWidget(
                 title = PREVIEW_TITLE,
                 balance = "€9,140.08",
                 trend = SurferBalanceTrend(
                     text = "−€612 this month",
                     series = listOf(11_575f, 11_160f, 10_610f, 9_950f, 10_240f, 9_140f),
                     isNegative = true,
                 ),
                 footnote = SurferBalanceFootnote.Note("Plus £820.00 no rate could convert"),
                 modifier = Modifier.fillMaxWidth(),
             )
         }
     }
 }
 
 @Preview
 @Composable
 private fun SurferBalanceWidgetEmptyPreview() {
     SurferComponentPreview {
         Box(modifier = Modifier.padding(16.dp)) {
             SurferBalanceWidget(
                 title = PREVIEW_TITLE,
                 balance = "—",
                 footnote = SurferBalanceFootnote.Empty("Add your first account to see balance."),
                 modifier = Modifier.fillMaxWidth(),
             )
         }
     }
 }