Coverage Summary for Class: SurferWindowGeometry (com.georgeci.moneysurfer.uikit.window)

 package com.georgeci.moneysurfer.uikit.window
 
 import androidx.compose.runtime.Composable
 import androidx.compose.ui.platform.LocalDensity
 import androidx.compose.ui.platform.LocalWindowInfo
 import androidx.compose.ui.unit.Dp
 import androidx.compose.ui.unit.dp
 
 /**
  * The Material 3 window *width* breakpoints, named once for the whole app.
  *
  * Before this existed every caller reached for `androidx.window.core.layout` constants directly,
  * so "wide" meant whatever each screen happened to compare against. Features depend on this enum
  * instead; `androidx.window` stays an implementation detail of the windowing libraries.
  *
  * Entries are declared narrow-to-wide, so the natural enum ordering is also the width ordering:
  * `currentSurferWindowSize() >= SurferWindowSize.Medium` reads as "at least Medium".
  *
  * Height breakpoints are deliberately absent: Material scales layouts by width, and a second set of
  * named bands would double the vocabulary for no screen that wants it. The one thing height *is*
  * needed for — telling a wide-because-landscape window from a wide-because-large one — is the
  * single [SurferWindowGeometry.isLandscape] flag rather than a band of its own.
  */
 enum class SurferWindowSize {
     /** `< 600 dp` — phones in portrait, and the narrow pane of a split-screen window. */
     Compact,
 
     /** `600–839 dp` — large phones in landscape, small tablets, resized desktop windows. */
     Medium,
 
     /** `840–1199 dp` — tablets in landscape, most desktop windows. */
     Expanded,
 
     /** `>= 1200 dp` — maximised desktop windows and large external displays. */
     Large,
 
     ;
 
     companion object {
         /** Lower bound of [Medium]. */
         val MediumLowerBound: Dp = 600.dp
 
         /** Lower bound of [Expanded]. */
         val ExpandedLowerBound: Dp = 840.dp
 
         /** Lower bound of [Large]. */
         val LargeLowerBound: Dp = 1200.dp
 
         /** Buckets a window [width] into a breakpoint. Widest bound first — the order matters. */
         fun ofWidth(width: Dp): SurferWindowSize = when {
             width >= LargeLowerBound -> Large
             width >= ExpandedLowerBound -> Expanded
             width >= MediumLowerBound -> Medium
             else -> Compact
         }
     }
 }
 
 /**
  * Both axes of the window, for the few layouts that cannot decide on width alone.
  *
  * Reach for [sizeClass] by default. [isLandscape] exists because "expanded" answers *how much* room
  * there is but not *what shape* it is: a 1024 dp tablet reports the same width lying down and stood
  * up, and a layout that puts two columns side by side wants the first and not the second.
  */
 data class SurferWindowGeometry(val width: Dp, val height: Dp) {
 
     /** The width band, i.e. what [currentSurferWindowSize] returns. */
     val sizeClass: SurferWindowSize = SurferWindowSize.ofWidth(width)
 
     /** Whether the window is wider than it is tall. */
     val isLandscape: Boolean = width > height
 }
 
 /**
  * The [SurferWindowGeometry] of the window this composition is hosted in, recomposing when the
  * window is resized.
  *
  * Measures `LocalWindowInfo.containerSize` in the current density — the same input
  * `currentWindowAdaptiveInfo()` derives its `WindowSizeClass` from, minus the dependency on the
  * `androidx.window` breakpoint sets (whose default set stops at Expanded and would collapse
  * [SurferWindowSize.Large] into it).
  *
  * Prefer this over measuring a `BoxWithConstraints` at a screen root: the window is what both
  * values are about, reading it costs no subcomposition, and it does not shrink when the keyboard
  * opens — so a layout chosen from it cannot flip while the user is typing.
  */
 @Composable
 fun currentSurferWindowGeometry(): SurferWindowGeometry {
     val containerSize = LocalWindowInfo.current.containerSize
     return with(LocalDensity.current) {
         SurferWindowGeometry(width = containerSize.width.toDp(), height = containerSize.height.toDp())
     }
 }
 
 /** The width band of the window this composition is hosted in. */
 @Composable
 fun currentSurferWindowSize(): SurferWindowSize = currentSurferWindowGeometry().sizeClass