Skip to content

Instantly share code, notes, and snippets.

@kafri8889
Created February 19, 2023 10:46
Show Gist options
  • Save kafri8889/ac0f9a35737eaf83a81dde9867666bdc to your computer and use it in GitHub Desktop.
Save kafri8889/ac0f9a35737eaf83a81dde9867666bdc to your computer and use it in GitHub Desktop.
Undo redo feature
class Unre<T> {
private var listener: UnreListener<T>? = null
val stacks: ArrayList<UnreData<T>> = arrayListOf()
var currentStack: Int = -1
private fun modifyStack() {
val newStacks = arrayListOf<UnreData<T>>()
stacks.forEachIndexed { i, ud ->
if (ud.stack == currentStack) {
currentStack = i
}
newStacks.add(ud.copy(stack = i))
}
stacks.apply {
clear()
addAll(newStacks)
}
}
private fun toUnreData(vararg data: T): List<UnreData<T>> {
val newStacks = arrayListOf<UnreData<T>>()
data.forEachIndexed { i, t ->
newStacks.add(UnreData(i, t))
}
return newStacks
}
fun swap(vararg newData: T) {
stacks.apply {
clear()
newData.forEach { t ->
addStack(t)
}
}
}
fun addStack(t: T) {
val lastStack = stacks.lastOrNull()?.stack ?: -1
val newStack = UnreData(
stack = if (currentStack == -1) 0 else lastStack + 1,
data = t
)
val lastCurrentStack = currentStack
currentStack = newStack.stack
println("sem wit las: ${lastCurrentStack} == ${lastStack}")
println("sem: ${currentStack} == ${lastStack + 1}")
if (lastCurrentStack!= lastStack) {
// val newStacks = stacks.dropLast((lastCurrentStack?.stack ?: -1) + 1)
val newStacks = ArrayList(stacks).slice(0..lastCurrentStack)
println("nyu staks: $newStacks")
stacks.apply {
clear()
addAll(newStacks)
}
}
stacks.add(newStack)
modifyStack()
println("siz: ${stacks.size} -> ${stacks.map { it.stack }}")
stacks.forEachIndexed { i, t ->
println("$i = ${t.stack} -> ${t.data}")
}
println("cur stak: ${currentStack}")
}
fun undo() {
val previousStack = stacks.getOrNull(currentStack - 1)
println("undo | prev: ${previousStack?.stack}, cur: ${currentStack}")
if (previousStack != null) {
currentStack = previousStack.stack
listener?.onUndo(previousStack.data)
}
}
fun redo() {
val nextStack = stacks.getOrNull(currentStack + 1)
if (nextStack != null) {
currentStack = nextStack.stack
listener?.onRedo(nextStack.data)
}
}
fun setListener(l: UnreListener<T>) {
listener = l
}
interface UnreListener<T> {
fun onUndo(data: T)
fun onRedo(data: T)
}
}
data class UnreData<T>(
val stack: Int,
val data: T
)
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment