Added tabs drag and drop

Still requires some work to improve the animations as they flicker a bit.

Fixes #82

src/main/kotlin/com/jetpackduba/gitnuro/App.kt

@@ -201,6 +201,9 @@ class App {
                 onTabClosed = onCloseTab,
                 onAddNewTab = onAddedTab,
                 tabsHeight = 40.dp,
+                onMoveTab = { fromIndex, toIndex ->
+                    tabsManager.onMoveTab(fromIndex, toIndex)
+                },
             )
         }
     }

src/main/kotlin/com/jetpackduba/gitnuro/git/log/GetLogUseCase.kt

@@ -9,9 +9,12 @@ import kotlinx.coroutines.withContext
 import org.eclipse.jgit.api.Git
 import org.eclipse.jgit.lib.Constants
 import org.eclipse.jgit.lib.Ref
+import org.eclipse.jgit.lib.Repository
 import javax.inject.Inject
 
 class GetLogUseCase @Inject constructor() {
+    private var graphWalkCached: GraphWalk? = null
+
     suspend operator fun invoke(git: Git, currentBranch: Ref?, hasUncommitedChanges: Boolean, commitsLimit: Int) =
         withContext(Dispatchers.IO) {
             val commitList = GraphCommitList()
@@ -20,7 +23,6 @@ class GetLogUseCase @Inject constructor() {
             if (currentBranch != null || repositoryState.isRebasing) { // Current branch is null when there is no log (new repo) or rebasing
                 val logList = git.log().setMaxCount(1).call().toList()
 
-                //TODO: Perhaps cache GraphWalk when the commitsLimit is too big? This would ensure a fast traversal of the commits graph but would use more memory. Benchmark it and perhaps offer the option as a setting
                 val walk = GraphWalk(git.repository)
 
                 walk.use {
@@ -47,4 +49,17 @@ class GetLogUseCase @Inject constructor() {
 
             return@withContext commitList
         }
+
+    private fun cachedGraphWalk(repository: Repository): GraphWalk {
+        val graphWalkCached = this.graphWalkCached
+
+        return if(graphWalkCached != null) {
+            graphWalkCached
+        } else {
+            val newGraphWalk = GraphWalk(repository)
+            this.graphWalkCached = newGraphWalk
+
+            newGraphWalk
+        }
+    }
 }

src/main/kotlin/com/jetpackduba/gitnuro/main.kt

@@ -2,8 +2,6 @@ package com.jetpackduba.gitnuro
 
 import com.jetpackduba.gitnuro.preferences.initPreferencesPath
 
-private const val TAG = "main"
-
 fun main(args: Array<String>) {
     initLogging()
     initPreferencesPath()

src/main/kotlin/com/jetpackduba/gitnuro/ui/TabsManager.kt

@@ -133,4 +133,14 @@ class TabsManager @Inject constructor(
             appComponent = appComponent,
         )
     }
+
+    fun onMoveTab(fromIndex: Int, toIndex: Int) {
+        _tabsFlow.update {
+            it.toMutableList().apply {
+                add(toIndex, removeAt(fromIndex))
+            }
+        }
+
+        updatePersistedTabs()
+    }
 }

src/main/kotlin/com/jetpackduba/gitnuro/ui/components/RepositoriesTabPanel.kt

@@ -1,20 +1,14 @@
 package com.jetpackduba.gitnuro.ui.components
 
-import androidx.compose.foundation.HorizontalScrollbar
+import androidx.compose.foundation.*
-import androidx.compose.foundation.background
-import androidx.compose.foundation.hoverable
 import androidx.compose.foundation.interaction.MutableInteractionSource
 import androidx.compose.foundation.interaction.collectIsHoveredAsState
 import androidx.compose.foundation.layout.*
 import androidx.compose.foundation.lazy.LazyRow
-import androidx.compose.foundation.lazy.items
+import androidx.compose.foundation.lazy.itemsIndexed
 import androidx.compose.foundation.lazy.rememberLazyListState
-import androidx.compose.foundation.rememberScrollbarAdapter
 import androidx.compose.foundation.v2.maxScrollOffset
-import androidx.compose.material.Icon
+import androidx.compose.material.*
-import androidx.compose.material.IconButton
-import androidx.compose.material.MaterialTheme
-import androidx.compose.material.Text
 import androidx.compose.material.icons.Icons
 import androidx.compose.material.icons.filled.Add
 import androidx.compose.runtime.*
@@ -25,8 +19,7 @@ import androidx.compose.ui.res.painterResource
 import androidx.compose.ui.text.style.TextOverflow
 import androidx.compose.ui.unit.Dp
 import androidx.compose.ui.unit.dp
-import com.jetpackduba.gitnuro.AppIcons
+import com.jetpackduba.gitnuro.*
-import com.jetpackduba.gitnuro.LocalTabScope
 import com.jetpackduba.gitnuro.di.AppComponent
 import com.jetpackduba.gitnuro.di.DaggerTabComponent
 import com.jetpackduba.gitnuro.di.TabComponent
@@ -34,6 +27,9 @@ import com.jetpackduba.gitnuro.extensions.handMouseClickable
 import com.jetpackduba.gitnuro.extensions.handOnHover
 import com.jetpackduba.gitnuro.extensions.onMiddleMouseButtonClick
 import com.jetpackduba.gitnuro.managers.AppStateManager
+import com.jetpackduba.gitnuro.ui.drag_sorting.DraggableItem
+import com.jetpackduba.gitnuro.ui.drag_sorting.dragContainer
+import com.jetpackduba.gitnuro.ui.drag_sorting.rememberDragDropState
 import com.jetpackduba.gitnuro.viewmodels.TabViewModel
 import com.jetpackduba.gitnuro.viewmodels.TabViewModelsHolder
 import kotlinx.coroutines.delay
@@ -42,6 +38,7 @@ import javax.inject.Inject
 import kotlin.io.path.Path
 import kotlin.io.path.name
 
+@OptIn(ExperimentalFoundationApi::class)
 @Composable
 fun RepositoriesTabPanel(
     tabs: List<TabInformation>,
@@ -49,6 +46,7 @@ fun RepositoriesTabPanel(
     tabsHeight: Dp,
     onTabSelected: (TabInformation) -> Unit,
     onTabClosed: (TabInformation) -> Unit,
+    onMoveTab: (Int, Int) -> Unit,
     onAddNewTab: () -> Unit,
 ) {
     val stateHorizontal = rememberLazyListState()
@@ -89,25 +87,37 @@ fun RepositoriesTabPanel(
             }
         }
 
+
+        val dragDropState = rememberDragDropState(stateHorizontal) { fromIndex, toIndex ->
+            onMoveTab(fromIndex, toIndex)
+        }
+
         Row {
             LazyRow(
                 modifier = Modifier
                     .height(tabsHeight)
-                    .weight(1f, false),
+                    .weight(1f, false)
+                    .dragContainer(dragDropState),
                 state = stateHorizontal,
             ) {
-                items(items = tabs, key = { it.tabViewModel }) { tab ->
+                itemsIndexed(
-                    Tooltip(tab.path) {
+                    items = tabs,
-                        Tab(
+                    key = { _, tab -> tab.tabViewModel }
-                            title = tab.tabName,
+                ) { index, tab ->
-                            isSelected = currentTab == tab,
+                    DraggableItem(dragDropState, index) { _ ->
-                            onClick = {
+                        Tooltip(tab.path) {
-                                onTabSelected(tab)
+                            Tab(
-                            },
+                                modifier = Modifier,
-                            onCloseTab = {
+                                title = tab.tabName,
-                                onTabClosed(tab)
+                                isSelected = currentTab == tab,
-                            }
+                                onClick = {
-                        )
+                                    onTabSelected(tab)
+                                },
+                                onCloseTab = {
+                                    onTabClosed(tab)
+                                }
+                            )
+                        }
                     }
                 }
             }
@@ -145,6 +155,7 @@ fun RepositoriesTabPanel(
 
 @Composable
 fun Tab(
+    modifier: Modifier,
     title: MutableState<String>,
     isSelected: Boolean,
     onClick: () -> Unit,
@@ -159,7 +170,7 @@ fun Tab(
     val isHovered by hoverInteraction.collectIsHoveredAsState()
 
     Box(
-        modifier = Modifier
+        modifier = modifier
             .widthIn(min = 200.dp)
             .width(IntrinsicSize.Max)
             .fillMaxHeight()

src/main/kotlin/com/jetpackduba/gitnuro/ui/components/Tooltip.kt

@@ -15,8 +15,9 @@ import com.jetpackduba.gitnuro.theme.onBackgroundSecondary
 
 @OptIn(ExperimentalFoundationApi::class)
 @Composable
-fun Tooltip(text: String?, content: @Composable () -> Unit) {
+fun Tooltip(text: String?, modifier: Modifier = Modifier, content: @Composable () -> Unit) {
     TooltipArea(
+        modifier = modifier,
         tooltip = {
             if (text != null) {
                 val border = if (MaterialTheme.colors.isDark) {

src/main/kotlin/com/jetpackduba/gitnuro/ui/drag_sorting/RowDragSorting.kt

@@ -0,0 +1,195 @@
+package com.jetpackduba.gitnuro.ui.drag_sorting
+
+import androidx.compose.animation.core.Animatable
+import androidx.compose.animation.core.Spring
+import androidx.compose.animation.core.spring
+import androidx.compose.foundation.ExperimentalFoundationApi
+import androidx.compose.foundation.gestures.detectDragGestures
+import androidx.compose.foundation.gestures.scrollBy
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.ColumnScope
+import androidx.compose.foundation.lazy.LazyItemScope
+import androidx.compose.foundation.lazy.LazyListItemInfo
+import androidx.compose.foundation.lazy.LazyListState
+import androidx.compose.runtime.*
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.geometry.Offset
+import androidx.compose.ui.graphics.graphicsLayer
+import androidx.compose.ui.input.pointer.pointerInput
+import androidx.compose.ui.zIndex
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.channels.Channel
+import kotlinx.coroutines.launch
+
+
+@Composable
+fun rememberDragDropState(
+    lazyListState: LazyListState,
+    @Suppress("PrimitiveInLambda")
+    onMove: (Int, Int) -> Unit
+): DragDropState {
+    val scope = rememberCoroutineScope()
+    val state = remember(lazyListState) {
+        DragDropState(
+            state = lazyListState,
+            onMove = onMove,
+            scope = scope
+        )
+    }
+    LaunchedEffect(state) {
+        while (true) {
+            val diff = state.scrollChannel.receive()
+            lazyListState.scrollBy(diff)
+        }
+    }
+    return state
+}
+
+class DragDropState internal constructor(
+    private val state: LazyListState,
+    private val scope: CoroutineScope,
+    @Suppress("PrimitiveInLambda")
+    private val onMove: (Int, Int) -> Unit
+) {
+    var draggingItemIndex by mutableStateOf<Int?>(null)
+        private set
+
+    internal val scrollChannel = Channel<Float>()
+
+    private var draggingItemDraggedDelta by mutableStateOf(0f)
+    private var draggingItemInitialOffset by mutableStateOf(0)
+    internal val draggingItemOffset: Float
+        get() = draggingItemLayoutInfo?.let { item ->
+            draggingItemInitialOffset + draggingItemDraggedDelta - item.offset
+        } ?: 0f
+
+    private val draggingItemLayoutInfo: LazyListItemInfo?
+        get() = state.layoutInfo.visibleItemsInfo
+            .firstOrNull { it.index == draggingItemIndex }
+
+    internal var previousIndexOfDraggedItem by mutableStateOf<Int?>(null)
+        private set
+    internal var previousItemOffset = Animatable(0f)
+        private set
+
+    internal fun onDragStart(offset: Offset) {
+        state.layoutInfo.visibleItemsInfo
+            .firstOrNull { item ->
+                offset.x.toInt() in item.offset..(item.offset + item.size)
+            }?.also {
+                draggingItemIndex = it.index
+                draggingItemInitialOffset = it.offset
+            }
+    }
+
+    internal fun onDragInterrupted() {
+        if (draggingItemIndex != null) {
+            previousIndexOfDraggedItem = draggingItemIndex
+            val startOffset = draggingItemOffset
+            scope.launch {
+                previousItemOffset.snapTo(startOffset)
+                previousItemOffset.animateTo(
+                    0f,
+                    spring(
+                        stiffness = Spring.StiffnessMediumLow,
+                        visibilityThreshold = 1f
+                    )
+                )
+                previousIndexOfDraggedItem = null
+            }
+        }
+        draggingItemDraggedDelta = 0f
+        draggingItemIndex = null
+        draggingItemInitialOffset = 0
+    }
+
+    internal fun onDrag(offset: Offset) {
+        draggingItemDraggedDelta += offset.x
+
+        val draggingItem = draggingItemLayoutInfo ?: return
+        val startOffset = draggingItem.offset + draggingItemOffset
+        val endOffset = startOffset + draggingItem.size
+        val middleOffset = startOffset + (endOffset - startOffset) / 2f
+        println("Middle offset is $middleOffset")
+
+        val targetItem = state.layoutInfo.visibleItemsInfo.find { item ->
+            middleOffset.toInt() in item.offset..item.offsetEnd &&
+                    draggingItem.index != item.index
+        }
+        if (targetItem != null) {
+            val scrollToIndex = if (targetItem.index == state.firstVisibleItemIndex) {
+                draggingItem.index
+            } else if (draggingItem.index == state.firstVisibleItemIndex) {
+                targetItem.index
+            } else {
+                null
+            }
+            if (scrollToIndex != null) {
+                scope.launch {
+                    // this is needed to neutralize automatic keeping the first item first.
+                    state.scrollToItem(scrollToIndex, state.firstVisibleItemScrollOffset)
+                    onMove.invoke(draggingItem.index, targetItem.index)
+                }
+            } else {
+                onMove.invoke(draggingItem.index, targetItem.index)
+            }
+            draggingItemIndex = targetItem.index
+        } else {
+            val overscroll = when {
+                draggingItemDraggedDelta > 0 ->
+                    (endOffset - state.layoutInfo.viewportEndOffset).coerceAtLeast(0f)
+                draggingItemDraggedDelta < 0 ->
+                    (startOffset - state.layoutInfo.viewportStartOffset).coerceAtMost(0f)
+                else -> 0f
+            }
+            if (overscroll != 0f) {
+                scrollChannel.trySend(overscroll)
+            }
+        }
+    }
+
+    private val LazyListItemInfo.offsetEnd: Int
+        get() = this.offset + this.size
+}
+
+fun Modifier.dragContainer(dragDropState: DragDropState): Modifier {
+    return pointerInput(dragDropState) {
+        detectDragGestures(
+            onDrag = { change, offset ->
+                change.consume()
+                dragDropState.onDrag(offset = offset)
+            },
+            onDragStart = { offset -> dragDropState.onDragStart(offset) },
+            onDragEnd = { dragDropState.onDragInterrupted() },
+            onDragCancel = { dragDropState.onDragInterrupted() }
+        )
+    }
+}
+
+@ExperimentalFoundationApi
+@Composable
+fun LazyItemScope.DraggableItem(
+    dragDropState: DragDropState,
+    index: Int,
+    modifier: Modifier = Modifier,
+    content: @Composable ColumnScope.(isDragging: Boolean) -> Unit
+) {
+    val dragging = index == dragDropState.draggingItemIndex
+    val draggingModifier = if (dragging) {
+        Modifier
+            .zIndex(1f)
+            .graphicsLayer {
+                translationX = dragDropState.draggingItemOffset
+            }
+    } else if (index == dragDropState.previousIndexOfDraggedItem) {
+        Modifier.zIndex(1f)
+            .graphicsLayer {
+                translationX = dragDropState.previousItemOffset.value
+            }
+    } else {
+        Modifier.animateItemPlacement()
+    }
+    Column(modifier = modifier.then(draggingModifier)) {
+        content(dragging)
+    }
+}