dotfiles/programs/lf/previewer

#!/bin/bash
# shellcheck disable=SC2222

# File preview handler for lf.
# Dependencies:
#	- GNU 'file' or similar (file detection)
#	- bat (text)
#	- uebergzug (images, videos, pdf, fonts)
#	- ffmpegthumbnailer (videos)
#	- exiftool (metadata/audio, and file detection for .webm files)
#	- jq (json and metadata)
#	- lynx (html/web pages)
#	- pdftoppm (pdf)
#	- odt2txt (odt)
#	- convert from imagemagick (fonts)
#	- atool (archives)
#	- gpg (PGP encrypted files)
#	- man (troff manuals)
#	- Other: stat, cut, sha256sum

# Notes:
#	- If using alacritty's same process: 'alacritty msg create-window', previews only show in first window

set -C -f
IFS='
'

# Display an image with certain path, width, height, x, y
# Usage: image "$path_to_image" "$width" "$height" "$x" "$y" "$fallback_path"
image() {
  # shellcheck disable=all
  set +u
  set +e
	if [ -f "$1" ] && [ "$DISPLAY" ] && [ ! "$WAYLAND_DISPLAY" ]
	then
		printf '{"action": "add", "identifier": "PREVIEW", "path": "%s", "width": "%s", "height": "%s", "scaler": "contain", "x": "%s", "y": "%s"}\n' \
			"$1" "$(($2-1))" "$(($3-1))" "$4" "$5" > "$FIFO_UEBERZUG"
	else
		exiftool -j "$6" | jq -C
	fi
}

ifub() {
  # shellcheck disable=all
	if [ "$DISPLAY" ] && [ -z "$WAYLAND_DISPLAY" ]; then
		command -V ueberzug >/dev/null 2>&1
	fi
}

# Note that the cache file name is a function of file information, meaning if
# an image appears in multiple places across the machine, it will not have to
# be regenerated once seen.

create_cache() {
  # shellcheck disable=all
	CACHE="${XDG_CACHE_HOME:-"$HOME/.cache"}/lf/thumb.$(stat --printf '%n\0%i\0%F\0%s\0%W\0%Y' \
		-- "$(readlink -f "$1" || realpath "$1" )" \
		| sha256sum \
		| cut -d' ' -f1)"
}

mime_preview() {
  # shellcheck disable=all
	# The 'ran_guard' variable is there in case I need to do recursion
	# because the initial mime_type variable wasn't enough to determine
	# an adequate preview
	case "$mime_type","$ran_guard" in
	(image/svg+xml,0 | image/svg)
		create_cache "$1"
		[ -f "$CACHE.png" ] \
			|| rsvg-convert  -o "$CACHE.png" -a -w "1000" -b '#1f2430' "$1"
		image "$CACHE.png" "$2" "$3" "$4" "$5" "$1"
	;;
	(image/*,0)
		image "$1" "$2" "$3" "$4" "$5" "$1"
	;;
	(text/html,0)
		lynx -width="$4" -display_charset=utf-8 -dump -- "$1"
	;;
	(text/troff,0)
		case "${1##*.}" in
		([0-9] | [01]p | [23]*)
			man ./ "$1" | col -b
		;;
		(*)
			bat --terminal-width "$(($4*7/9))" -f "$1" --style=numbers
		esac
	;;
	(text/*,0 | */xml,0 | application/javascript,0 | application/x-subrip,0 )
		bat --terminal-width "$(($4*7/9))" -f "$1" --style=numbers
	;;
	( application/x-pie-executable,0 | application/x-executable,0 | \
	application/x-sharedlib,0)
		objdump -d "$1" -M intel
		#readelf -WCa "$1"
		#hexdump -C "$1" || xxd "$1"
	;;
	(application/json,0)
		case "${1##*.}" in
		(ipynb)
			# Needs my fork of ipynb-py-convert
			ipynb-py-convert --stdout "$1" \
				| bat --terminal-width "$(($4*7/9))" --color=always -l python --style=numbers
		;;
		(*) jq -C < "$1" ;;
		esac
	;;
	(application/zip,0 | application/x-7z-compressed,0 )
		atool --list -- "$1"
	;;
	(audio/*,[01])
		exiftool -j "$1" | jq -C
	;;
	(video/webm,0)
		# file --mime-type doesn't distinguish well between "video/webm"
		# actual webm videos or webm audios, but exiftool does, thus
		# re-run this function with new mimetype
		mime_type="$(exiftool -s3 -MIMEType "$1")" \
		ran_guard=$((ran_guard+1))
		mime_preview "$@"
		;;
	(video/*,[01])
		create_cache "$1"
		[ -f "$CACHE" ] \
			|| ffmpegthumbnailer -i "$1" -o "$CACHE" -s 0
		image "$CACHE" "$2" "$3" "$4" "$5" "$1"
	;;
	(*/pdf,0 | */postscript,0)  # .pdf, .ps
		create_cache "$1"
		[ -f "$CACHE.jpg" ] \
			|| pdftoppm -jpeg -f 1 -singlefile "$1" "$CACHE"
		image "$CACHE.jpg" "$2" "$3" "$4" "$5" "$1"
	;;
	(application/font*,0 | application/*opentype,0 | font/sfnt,0)  # .ttf, .otf
		create_cache "$1"
		[ -f "$CACHE.png" ] \
			|| convert -size "800x800" "xc:#000000" -fill "#ffffff" \
				-pointsize "72" -font "$1" -gravity center -annotate +0+0 \
				"ABCDEFGHIJKLM\nNOPQRSTUVWXYZ\nabcdefghijklm\nnopqrstuvwxyz\n1234567890\n!@#$\%^&*,.;:\n_-=+'\"|\\(){}[]" \
				"$CACHE.png"
		image "$CACHE.png" "$2" "$3" "$4" "$5" "$1"
	;;
	(*opendocument*,0) # .odt, .ods
		CCt='	' \
		bytes=$(du -sb "$1") bytes="${bytes%%"$CCt"*}"
		if [ "$bytes" -lt 150000 ]; then
			odt2txt "$1"
		else
			printf "file too big too preview quickly\n"
		fi
	;;
	(*ms-excel,0)  # .xls
		xls2csv -- "$1" \
			| bat --terminal-width "$(($4*7/9))" --color=always -l csv --style=numbers
	;;
	#(application/vnd.openxmlformats-officedocument.spreadsheetml.sheet)  # .xslx
		# https://github.com/dilshod/xlsx2csv
		#xlsx2csv -- "$1"
	#;;
	#(text/rtf,0 | *msword,0 )  # .doc, doesn't always work
		#catdoc -- "$1"
	#;;
	#(*wordprocessingml.document|*/epub+zip|*/x-fictionbook+xml)  # .docx
		#pandoc -s -t markdown -- "$1"
	#;;
	#(message/rfc822)
		# https://github.com/djcb/mu
		#mu view -- "${FILE_PATH}" && exit 5
	#;;
	# TODO: add lf command to decrypt it and show the decrypted file in preview window
	(application/pgp-encrypted,0)
		printf "PGP armored ASCII \033[1;31mencrypted\033[m file,\ntry using gpg to decrypt it\n\n"
		cat "$1"
		#gpg -d -- "$1"
	;;
	(application/octet-stream,0)
		#extension="${1##*.}" extension="${extension%"$1"}"
		case "${1##*.}" in
		(gpg)
			printf "OpenPGP \033[1;31mencrypted\033[m file,\ntry using gpg to decrypt it\n\n"
		;;
		(*) exiftool -j "$1" | jq -C
		esac
	;;
	(application/vnd.sqlite3,0)
		# TODO: handle multiple tables, maybe it's better to show tables and columns in a tree format
		table=$(sqlite3 "$1" '.tables')
		sqlite3 "$1" ".headers on" ".mode markdown" "select * from $table"
		;;
	esac
	return 1
}

main() {
  # shellcheck disable=all
	mime_type="$(file --dereference -b --mime-type -- "$1")"
  "echo hiiiiiiiiiiiiiiiiii $mime_type"
	ran_guard=0
	mime_preview "$@" || return $?
}

main "$@" || exit $?