Add a preview-kitty plugin (#577)

plugins/README.md

@@ -61,6 +61,7 @@ Plugins are installed to `${XDG_CONFIG_HOME:-$HOME/.config}/nnn/plugins`.
 | pdfread | Read a PDF or text file aloud | sh | pdftotext, mpv,<br>pico2wave |
 | pdfview | View PDF file in `$PAGER` | sh | pdftotext/<br>mupdf-tools |
 | picker | Pick files and list one per line (to pipe) | sh | nnn |
+| preview-kitty | File previewer in a kitty terminal pane | sh | [kitty](https://sw.kovidgoyal.net/kitty/), Optionally:<br>[exa](https://github.com/ogham/exa) [bat](https://github.com/sharkdp/bat) mediainfo |
 | preview-tabbed | `tabbed`/xembed based file previewer | bash | _see in-file docs_ |
 | preview-tui | Simple TUI file previewer (needs NNN_FIFO) | sh | tmux (>= 3.0)/xterm/<br>\$TERMINAL, file, tree |
 | pskill | Fuzzy list by name and kill process or zombie | sh | fzf, ps, sudo/doas |

plugins/preview-kitty

@@ -0,0 +1,71 @@
+#!/usr/bin/env sh
+
+# Description: File previewer for kitty term using NNN_FIFO
+#
+# Dependencies:
+#   - kitty (https://sw.kovidgoyal.net/kitty/) with allow_remote_control on
+#   - file
+#   - exa (https://github.com/ogham/exa) (fallback: ls)
+#   - bat (https://github.com/sharkdp/bat) (fallback: cat)
+#   - mediainfo (fallback: file)
+#
+# Usage:
+#   This plugin only works in kitty (https://sw.kovidgoyal.net/kitty/),
+#   and with kitty's 'allow_remote_control' option turned on.
+#   You need to set a NNN_FIFO path and set a key for the plugin,
+#   then start `nnn`:
+#
+#     $ NNN_FIFO=/tmp/nnn.fifo nnn
+#
+#   Then in `nnn`, launch the `preview-kitty` plugin.
+#
+#   If you provide the same NNN_FIFO to all nnn instances, there will be a
+#   single common preview window. I you provide different FIFO path, they
+#   will be independent.
+#
+# Shell: POSIX compliant
+# Authors: Léo Villeveygoux
+
+preview_file () {
+    clear
+    lines=$(($(tput lines)-1))
+    cols=$(tput cols)
+    mime="$(file -b --mime-type "$1")"
+
+    if [ -d "$1" ]; then
+        # Print directory tree
+        # shellcheck disable=SC2015
+        cd "$1" && \
+        COLUMNS=$cols exa -G --colour=always 2>/dev/null || ls --color=alway
+    elif [ "${mime%%/*}" = "text" ] ; then
+        # Print file head
+        bat --terminal-width="$cols" --paging=never --decorations=always \
+            --color=always "$1" 2>/dev/null || cat
+    elif [ "${mime%%/*}" = "image" ] ; then
+        kitty +kitten icat --silent --transfer-mode=stream --stdin=no "$1"
+    else
+        # Binary file
+        printf -- "-------- \033[1;31mBinary file\033[0m --------\n"
+        mediainfo "$1" 2>/dev/null || file -b "$1"
+    fi | head -n $lines
+}
+
+if [ "$PREVIEW_MODE" ] ; then
+    if [ ! -r "$NNN_FIFO" ] ; then
+        echo "No FIFO available! (\$NNN_FIFO='$NNN_FIFO')" >&2
+        read -r
+        exit 1
+    fi
+
+    preview_file "$1"
+
+    exec < "$NNN_FIFO"
+    while read -r selection ; do
+        preview_file "$selection"
+    done
+    exit 0
+fi
+
+kitty @ launch --no-response --title "nnn preview" --keep-focus \
+      --cwd="$PWD" --env "NNN_FIFO=$NNN_FIFO" --env "PREVIEW_MODE=1" \
+      "$0" "$1" > /dev/null