tui/README.md

# TUI

A small keyboard-driven terminal UI for browsing directories and executing
ordinary shell commands defined in `.tui` files.

The important design choice is that **TUI does not execute actions inside a
Python subprocess**. It hands the generated commands back to the Bash process
that started `tui`. This keeps the commands visible in Bash history and gives
actions the normal shell environment.

## Requirements

- Debian/Linux with Bash
- Python 3
- PyYAML (`python3-yaml` on Debian)
- `curses` from the normal Python installation

Install the Debian dependency if necessary:

```bash
sudo apt install python3-yaml
```

## Installation

Unpack the project and run:

```bash
./install.sh
```

The installer installs TUI under:

```text
~/.local/lib/tui/
```

and adds the shell integration to:

```text
~/.bashrc
```

The integration is therefore loaded automatically for interactive Bash
sessions, including the normal Debian login/terminal startup path.

After installation, start a new terminal/login session, or run:

```bash
source ~/.bashrc
```

Then:

```bash
tui
```

Use `-a` to include hidden files and directories:

```bash
tui -a
```

The installer does not overwrite an existing `~/.tui`.

`-a` / `--all` is a command-line option, so the shell integration preserves it
when the TUI restarts after an action.

## `.tui` configuration

TUI searches for the nearest `.tui` starting in the current directory and
walking upwards, but never above `$HOME`.

A configuration contains `keys` and `actions`:

```yaml
keys:
  up: up
  down: down
  left: parent
  right:
    folder: enter
    file:
      - "*.zip": list-zip

  ctrl-k:
    b: mark-begin
    k: mark-end
    m:
      file:
        - "*": move

actions:
  list-zip:
    command:
      - unzip -l <path>
      - read -rp "Tryck Enter för att fortsätta..."

  move:
    command: mv -v <path> <dir>
```

Rules are evaluated from top to bottom; the first matching glob wins.

### Substitutions

| Token | Meaning |
|---|---|
| `<name>` | basename of the target |
| `<path>` | full path of the target |
| `<dir>` | directory currently displayed by TUI, with trailing `/` |

## Navigation

The default example configuration uses:

- `↑` / `↓` — move cursor
- `Enter` / `→` — execute the configured action
- `../` — synthetic parent-directory entry at the top of every listing
- `←` — move the cursor to `../`; pressing `←` again enters the parent directory
- `Enter` on `../` — enter the parent directory
- navigation cannot move above the directory containing the applicable `.tui` file
- hidden files and directories are hidden by default; `tui -a` shows them
- file and directory colors follow the usual GNU `ls --color=yes` conventions for common file types
- `Ctrl-K B` — set selection start
- `Ctrl-K K` — set selection end
- `Ctrl-K C` — copy marked files/folders
- `Ctrl-K M` — move marked files
- `Ctrl-K Y` — delete marked files/folders
- `Ctrl-C` — quit

## Marking

Marks are stored as absolute paths and belong to the TUI session, not to the
current directory.

For example:

```text
/home/joakim/notes/
  A.txt   *
  B.txt   *
  work/
```

Entering `work/` does not clear the marks. Returning to the parent directory
shows `A.txt` and `B.txt` as marked again.

Marks in different directories can coexist. If `A.txt` is marked, then TUI
is moved to `work/`, `Ctrl-K M` operates on the original absolute path while
using the **current directory** as the destination:

```bash
mv -v /home/joakim/notes/A.txt .
```

A mark is removed automatically only when its target no longer exists.

`Ctrl-K B` and `Ctrl-K K` define a contiguous selection in the directory being
viewed. Changing directory clears the temporary selection endpoints but does
not clear the already marked paths.

## Shell integration

When an action is triggered, TUI writes the generated commands to a temporary
file and exits with a private handoff status. The `tui()` Bash function then
executes them.

For example:

```yaml
actions:
  list-zip:
    command:
      - unzip -l <path>
      - read -rp "Tryck Enter för att fortsätta..."
```

The flow is:

```text
TUI
  ↓
unzip -l archive.zip
  ↓
read -rp "Tryck Enter..."
  ↓
TUI
```

TUI is **not redrawn between commands belonging to the same action**.

Every command is also inserted into Bash history. If one command fails, the
remaining commands in that action are not executed. TUI prints the exit code
and waits for:

```text
Tryck Enter för att fortsätta...
```

before returning to TUI, so an error cannot disappear immediately.

The shell wrapper uses `pushd`/`popd` so the command runs in the directory
shown by TUI without permanently changing the user's Bash working directory.

## Security note

Action strings are intentionally ordinary Bash commands and are executed with
`eval` by the user's Bash shell. `.tui` files should therefore be treated as
executable configuration and only used from directories/configurations you
trust.

## Development

Run a syntax check with:

```bash
python3 -m py_compile tui/tui.py
```

For development without installing:

```bash
source tui/tui-shell.bash
tui
```

The example configuration is in `tui/example.tui`.

### Cursor and block selection

There is an empty cursor position immediately below the last object in a directory. This makes range selection behave like a text editor.

`Ctrl+K K` follows joe-style semantics: the end of the selection is the row immediately above the cursor. Thus, when the cursor is on the empty line below the final object, `Ctrl+K K` includes the final object.