Redesign alphabet picker to fit all letters on screen (#480)

- Switch to tv.material3.Button with ButtonDefaults for better styling
- Add opacity changes based on focus (0.85f focused, 0.2f unfocused)
- Keep selected letter fully visible when picker is unfocused
- Reduce button size from 24.dp to 14.dp to fit all letters
- Reduce spacing between letters (1.1.dp vertical, 2.dp horizontal)
- Use transparent backgrounds for unfocused letters
- Use border color for selected letter when focused, tertiary when
unfocused
- Add Box with CircleShape clip to prevent focus indicator overflow
- Reduce font size by 15%
- Add 16.dp end padding to push picker away from screen edge

When using the 'Show details' view option, the alphabet picker will
still overflow the bottom edge of the screen. I find this an acceptable
option though, as the backdrop pushes the card grid further down the
page.

Closes https://github.com/damontecres/Wholphin/issues/386

>[!NOTE]
> AI was used in the making of this PR

---------

Co-authored-by: Damontecres <damontecres@gmail.com>

app/src/main/java/com/github/damontecres/wholphin/ui/detail/CardGrid.kt

@@ -22,6 +22,7 @@ import androidx.compose.foundation.lazy.grid.LazyVerticalGrid
 import androidx.compose.foundation.lazy.grid.rememberLazyGridState
 import androidx.compose.foundation.lazy.layout.LazyLayoutCacheWindow
 import androidx.compose.foundation.lazy.rememberLazyListState
+import androidx.compose.foundation.shape.CircleShape
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.LaunchedEffect
 import androidx.compose.runtime.getValue
@@ -33,11 +34,14 @@ import androidx.compose.runtime.saveable.rememberSaveable
 import androidx.compose.runtime.setValue
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
+import androidx.compose.ui.draw.alpha
+import androidx.compose.ui.draw.clip
 import androidx.compose.ui.focus.FocusRequester
 import androidx.compose.ui.focus.focusProperties
 import androidx.compose.ui.focus.focusRequester
 import androidx.compose.ui.focus.focusRestorer
 import androidx.compose.ui.focus.onFocusChanged
+import androidx.compose.ui.graphics.Color
 import androidx.compose.ui.input.key.Key
 import androidx.compose.ui.input.key.KeyEventType
 import androidx.compose.ui.input.key.key
@@ -49,6 +53,8 @@ import androidx.compose.ui.res.stringResource
 import androidx.compose.ui.text.style.TextAlign
 import androidx.compose.ui.unit.Dp
 import androidx.compose.ui.unit.dp
+import androidx.tv.material3.Button
+import androidx.tv.material3.ButtonDefaults
 import androidx.tv.material3.LocalContentColor
 import androidx.tv.material3.MaterialTheme
 import androidx.tv.material3.Text
@@ -57,8 +63,6 @@ import com.github.damontecres.wholphin.data.model.BaseItem
 import com.github.damontecres.wholphin.ui.AppColors
 import com.github.damontecres.wholphin.ui.FontAwesome
 import com.github.damontecres.wholphin.ui.cards.GridCard
-import com.github.damontecres.wholphin.ui.components.Button
-import com.github.damontecres.wholphin.ui.components.TextButton
 import com.github.damontecres.wholphin.ui.ifElse
 import com.github.damontecres.wholphin.ui.playback.isBackwardButton
 import com.github.damontecres.wholphin.ui.playback.isForwardButton
@@ -366,7 +370,11 @@ fun CardGrid(
             AlphabetButtons(
                 letters = letters,
                 currentLetter = currentLetter,
-                modifier = Modifier.align(Alignment.CenterVertically),
+                modifier =
+                    Modifier
+                        .align(Alignment.CenterVertically)
+                        .padding(end = 16.dp),
+                // Add end padding to push away from edge
                 letterClicked = { letter ->
                     scope.launch(ExceptionHandler()) {
                         val jumpPosition =
@@ -375,6 +383,7 @@ fun CardGrid(
                             }
                         Timber.d("Alphabet jump to $jumpPosition")
                         if (jumpPosition >= 0) {
+                            pager.getOrNull(jumpPosition)
                             gridState.scrollToItem(jumpPosition)
                             focusOn(jumpPosition)
                             alphabetFocus = true
@@ -428,7 +437,6 @@ fun AlphabetButtons(
     letterClicked: (Char) -> Unit,
     modifier: Modifier = Modifier,
 ) {
-    val context = LocalContext.current
     val scope = rememberCoroutineScope()
     val listState = rememberLazyListState()
 
@@ -440,17 +448,27 @@ fun AlphabetButtons(
                 listState.layoutInfo.visibleItemsInfo
                     .lastOrNull()
                     ?.index ?: -1
-            if (index < firstVisibleItemIndex || index > lastVisibleItemIndex) {
+            if (index !in firstVisibleItemIndex..lastVisibleItemIndex) {
                 listState.animateScrollToItem(index)
             }
         }
     }
+    // Focus & interaction states for each letter button
     val focusRequesters = remember { List(letters.length) { FocusRequester() } }
+    val interactionSources = remember { List(letters.length) { MutableInteractionSource() } }
+
+    // Track if the entire alphabet picker component has focus
+    var alphabetPickerFocused by remember { mutableStateOf(false) }
+
     LazyColumn(
-        contentPadding = PaddingValues(4.dp),
+        contentPadding = PaddingValues(vertical = 1.1.dp, horizontal = 2.dp),
+        verticalArrangement = Arrangement.spacedBy(1.1.dp),
         state = listState,
         modifier =
-            modifier.focusProperties {
+            modifier
+                .onFocusChanged { focusState ->
+                    alphabetPickerFocused = focusState.hasFocus
+                }.focusProperties {
                     onEnter = {
                         focusRequesters[index.coerceIn(0, letters.length - 1)].tryRequestFocus()
                     }
@@ -460,32 +478,68 @@ fun AlphabetButtons(
             letters.length,
             key = { letters[it] },
         ) { index ->
-            val interactionSource = remember { MutableInteractionSource() }
+            val interactionSource = interactionSources[index]
             val focused by interactionSource.collectIsFocusedAsState()
-            TextButton(
+
+            val isCurrentLetter = letters[index] == currentLetter
+            // Apply alpha to individual items, but keep selected letter fully visible when picker is unfocused
+            val itemAlpha =
+                when {
+                    isCurrentLetter && !alphabetPickerFocused -> 1f
+                    alphabetPickerFocused -> .85f
+                    else -> .25f
+                }
+
+            // Only show circle background for the current letter (or when focused)
+            // Wrap in Box with clipping to prevent focus indicator from overflowing
+            Box(
                 modifier =
                     Modifier
-                        .size(24.dp)
+                        .size(14.dp)
+                        .clip(CircleShape)
+                        .alpha(itemAlpha),
+            ) {
+                Button(
+                    modifier =
+                        Modifier
+                            .size(14.dp)
                             .focusRequester(focusRequesters[index]),
-                contentPadding = PaddingValues(2.dp),
+                    contentPadding = PaddingValues(0.dp), // No padding to maximize text space
                     interactionSource = interactionSource,
                     onClick = {
                         letterClicked.invoke(letters[index])
                     },
-            ) {
-                val color =
-                    if (!focused && letters[index] == currentLetter) {
-                        MaterialTheme.colorScheme.tertiary
+                    colors =
+                        if (isCurrentLetter || focused) {
+                            // Use default button colors for current letter or focused
+                            ButtonDefaults.colors()
                         } else {
-                        LocalContentColor.current
+                            // Transparent background for non-current letters (no circle)
+                            ButtonDefaults.colors(
+                                containerColor = Color.Transparent,
+                                contentColor = MaterialTheme.colorScheme.onSurface,
+                                focusedContainerColor = MaterialTheme.colorScheme.primaryContainer,
+                                focusedContentColor = MaterialTheme.colorScheme.onPrimaryContainer,
+                            )
+                        },
+                ) {
+                    // Use border color for selected letter when focused, tertiary for unfocused-selected
+                    val color =
+                        when {
+                            isCurrentLetter && focused -> MaterialTheme.colorScheme.border
+                            isCurrentLetter -> MaterialTheme.colorScheme.tertiary
+                            focused -> LocalContentColor.current
+                            else -> MaterialTheme.colorScheme.onSurface
                         }
                     Text(
                         text = letters[index].toString(),
                         color = color,
                         textAlign = TextAlign.Center,
                         modifier = Modifier.fillMaxWidth(),
+                        style = MaterialTheme.typography.bodySmall,
                     )
                 }
             }
         }
+    }
 }