# Undo Tree

The undo tree shows the full history of changes to a file as a branching tree, rather than a linear undo/redo stack. This lets you explore and restore any past state, even across different edit branches.

![Undo Tree view showing a branching edit history](https://raw.githubusercontent.com/Nimaoth/NevScreenshots/main/undo-tree.gif)

## Opening

Press `gK` in normal mode to open the undo tree panel for the current file. It appears in the left sidebar.

The tree is drawn as an ASCII graph:
- `(*)` - the current position in the history
- `+` - inactive branch

Each node shows a sequence number, relative timestamp, and a `>` marker if it matches the saved file state.

## Editor Keybindings (normal mode)

| Key | Command | Description |
|-----|---------|-------------|
| `gK` | `undotree.toggle` | Toggle undo tree panel |
| `u` | `vim.undo` | Undo |
| `U` | `vim.redo` | Redo |
| `<C-z>` | `undo` | Undo (VSCode keybindings) |

## Undo Tree Panel Keybindings

### Navigation

| Key | Command | Description |
|-----|---------|-------------|
| `<UP>` | `next-change` | Move to newer change |
| `<DOWN>` | `prev-change` | Move to older change |
| `<LEFT>` | `left-change` | Jump to left branch (when on branch line) |
| `<RIGHT>` | `right-change` | Jump to right branch (when on branch line) |
| `<S-UP>` | `active-child` | Go to active child |
| `<S-DOWN>` | `parent-change` | Go to parent node |
| `<HOME>` | `last-change` | Jump to newest change |
| `<END>` | `first-change` | Jump to oldest change |
| `c` | `select-current` | Select current (active) change |

### Applying Changes

| Key | Command | Description |
|-----|---------|-------------|
| `<ENTER>` | `apply-selected` | Make selected change the current one |
| `a` | `toggle-auto-apply` | Toggle auto-apply (live preview while navigating) |

### Time-Based Jumps

Jump forward or backward by a time interval. Use count prefixes (e.g. `3sg` to jump 3 seconds forward).

| Key | Command | Argument | Description |
|-----|---------|----------|-------------|
| `g` | `next-change-time` | `1s` | Forward 1 second |
| `r` | `prev-change-time` | `1s` | Back 1 second |
| `G` | `next-change-time` | `10m` | Forward 10 minutes |
| `R` | `prev-change-time` | `10m` | Back 10 minutes |
| `<PAGE_UP>` | `next-change-time` | `5s` | Forward 5 seconds |
| `<PAGE_DOWN>` | `prev-change-time` | `5s` | Back 5 seconds |
| `<?>-count>sg` | `next-change-time` | `<#count>s` | Forward N seconds |
| `<?>-count>sr` | `prev-change-time` | `<#count>s` | Back N seconds |
| `<?>-count>mg` | `next-change-time` | `<#count>m` | Forward N minutes |
| `<?>-count>mr` | `prev-change-time` | `<#count>m` | Back N minutes |
| `<?>-count>hg` | `next-change-time` | `<#count>h` | Forward N hours |
| `<?>-count>hr` | `prev-change-time` | `<#count>h` | Back N hours |
| `<?>-count>dg` | `next-change-time` | `<#count>d` | Forward N days |
| `<?>-count>dr` | `prev-change-time` | `<#count>d` | Back N days |

## Auto-Apply Mode

When auto-apply is off (default), navigating the tree only moves the selection highlight. Press `<ENTER>` to apply the selected state.

When auto-apply is on (toggle with `a`), the editor instantly switches to whichever node is selected. This is useful for quickly browsing through edit history.