Added option to discard hunks

src/main/kotlin/app/extensions/StringExtensions.kt

@@ -29,3 +29,14 @@ val String.dirPath: String
         } else
             this
     }
+
+
+val String.lineDelimiter: String?
+    get() {
+        return if (this.contains("\r\n"))
+            "\r\n"
+        else if (this.contains("\n"))
+            "\n"
+        else
+            null
+    }

src/main/kotlin/app/git/StatusManager.kt

@@ -20,6 +20,8 @@ import org.eclipse.jgit.lib.FileMode
 import org.eclipse.jgit.lib.ObjectInserter
 import org.eclipse.jgit.lib.Repository
 import java.io.ByteArrayInputStream
+import java.io.File
+import java.io.FileWriter
 import java.io.IOException
 import java.nio.ByteBuffer
 import java.time.Instant
@@ -145,6 +147,10 @@ class StatusManager @Inject constructor(
         val content = rawFile.rawContent.toString(Charsets.UTF_8)//.removeSuffix(rawFile.lineDelimiter)
         val lineDelimiter: String? = rawFile.lineDelimiter
 
+        return getTextLines(content, lineDelimiter)
+    }
+
+    private fun getTextLines(content: String, lineDelimiter: String?): List<String> {
         var splitted: List<String> = if (lineDelimiter != null) {
             content.split(lineDelimiter).toMutableList().apply {
                 if (this.last() == "")
@@ -344,6 +350,52 @@ class StatusManager @Inject constructor(
             addCommand.call()
         }
     }
+
+    suspend fun resetHunk(git: Git, diffEntry: DiffEntry, hunk: Hunk) = withContext(Dispatchers.IO) {
+        val repository = git.repository
+
+        try {
+            val file = File(repository.directory.parent, diffEntry.oldPath)
+
+            val content = file.readText()
+            val textLines = getTextLines(content, content.lineDelimiter).toMutableList()
+            val hunkLines = hunk.lines.filter { it.lineType != LineType.CONTEXT }
+
+            val addedLines = hunkLines
+                .filter { it.lineType == LineType.ADDED }
+                .sortedBy { it.newLineNumber }
+            val removedLines = hunkLines
+                .filter { it.lineType == LineType.REMOVED }
+                .sortedBy { it.newLineNumber }
+
+            var linesRemoved = 0
+
+            // Start by removing the added lines to the index
+            for (line in addedLines) {
+                textLines.removeAt(line.newLineNumber + linesRemoved)
+                linesRemoved--
+            }
+
+            var linesAdded = 0
+
+            // Restore previously removed lines to the index
+            for (line in removedLines) {
+                // Check how many lines before this one have been deleted
+                val previouslyRemovedLines = addedLines.count { it.newLineNumber < line.newLineNumber }
+                textLines.add(line.newLineNumber + linesAdded - previouslyRemovedLines, line.text)
+                linesAdded++
+            }
+
+            val stagedFileText = textLines.joinToString("")
+
+
+            FileWriter(file).use { fw ->
+                fw.write(stagedFileText)
+            }
+        } catch (ex: Exception) {
+            throw Exception("Discard hunk failed. Check if the file still exists and has the write permissions set", ex)
+        }
+    }
 }
 
 

src/main/kotlin/app/ui/Diff.kt

@@ -105,9 +105,13 @@ fun Diff(
                         onUnstageHunk = { entry, hunk ->
                             diffViewModel.unstageHunk(entry, hunk)
                         },
-                    ) { entry, hunk ->
-                        diffViewModel.stageHunk(entry, hunk)
-                    }
+                        onStageHunk = { entry, hunk ->
+                            diffViewModel.stageHunk(entry, hunk)
+                        },
+                        onResetHunk = { entry, hunk ->
+                            diffViewModel.resetHunk(entry, hunk)
+                        }
+                    )
                 } else if (diffResult is DiffResult.NonText) {
                     NonTextDiff(diffResult)
                 }
@@ -220,6 +224,7 @@ fun TextDiff(
     diffResult: DiffResult.Text,
     onUnstageHunk: (DiffEntry, Hunk) -> Unit,
     onStageHunk: (DiffEntry, Hunk) -> Unit,
+    onResetHunk: (DiffEntry, Hunk) -> Unit,
 ) {
     val hunks = diffResult.hunks
 
@@ -237,6 +242,7 @@ fun TextDiff(
                             diffEntryType = diffEntryType,
                             onUnstageHunk = { onUnstageHunk(diffResult.diffEntry, hunk) },
                             onStageHunk = { onStageHunk(diffResult.diffEntry, hunk) },
+                            onResetHunk = { onResetHunk(diffResult.diffEntry, hunk) },
                         )
                     }
                 }
@@ -261,6 +267,7 @@ fun HunkHeader(
     diffEntryType: DiffEntryType,
     onUnstageHunk: () -> Unit,
     onStageHunk: () -> Unit,
+    onResetHunk: () -> Unit,
 ) {
     Row(
         modifier = Modifier
@@ -293,6 +300,14 @@ fun HunkHeader(
                 color = MaterialTheme.colors.stageButton
             }
 
+            if(diffEntryType is DiffEntryType.UnstagedDiff) {
+                SecondaryButton(
+                    text = "Discard hunk",
+                    backgroundButton = MaterialTheme.colors.error,
+                    onClick = onResetHunk
+                )
+            }
+
             SecondaryButton(
                 text = buttonText,
                 backgroundButton = color,

src/main/kotlin/app/ui/FileHistory.kt

@@ -173,7 +173,8 @@ fun HistoryContentLoaded(
                         scrollState = scrollState,
                         diffResult = diffResult,
                         onUnstageHunk = { _, _ -> },
-                        onStageHunk = { _, _ -> }
+                        onStageHunk = { _, _ -> },
+                        onResetHunk = { _, _ -> },
                     )
                 } else {
                     Box(

src/main/kotlin/app/viewmodels/DiffViewModel.kt

@@ -73,6 +73,13 @@ class DiffViewModel @Inject constructor(
         statusManager.stageHunk(git, diffEntry, hunk)
     }
 
+    fun resetHunk(diffEntry: DiffEntry, hunk: Hunk) = tabState.runOperation(
+        refreshType = RefreshType.UNCOMMITED_CHANGES,
+        showError = true,
+    ) { git ->
+        statusManager.resetHunk(git, diffEntry, hunk)
+    }
+
     fun unstageHunk(diffEntry: DiffEntry, hunk: Hunk) = tabState.runOperation(
         refreshType = RefreshType.UNCOMMITED_CHANGES,
     ) { git ->