#!/bin/bash
# bash spinners - functions and demo
# Set of functions to create, start and stop a spinner as background task.
# Version: 2.0.2 -- Last update: Tue Jan 20 08:50:44 2026
# (C) 2023-2026 F-Hauri.ch - http://www.f-hauri.ch
# This version use collection of themes from a JSOM file. The idea and the
# original JSON was forked from https://github.com/sindresorhus/cli-spinners
# Extended by some growing snake themes (some require two lines!)
# Should be sourced! But run as a script, they will present a short fzf menu.
# This script depend on `coreutils`, `sed`, `fzf` and `jq` packages!

SRCDIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
export spinnerJson="$SRCDIR/spinners.json"

# --- Minimal code for simple backgrounded spinner without json begin here! ---
declare shapesInterval=.08
declare spinnerShapes=(  ⢎\   ⠎⠁  ⠊⠑  ⠈⠱  \ ⡱  ⢀⡰  ⢄⡠  ⢆⡀  )
declare -i doSpinner=0  # File descriptor to address spinner as background task
declare -i spinnerFD    # File descriptor for spinner output, in order to not
if ! [[ -t $spinnerFD ]]; then #     use any of STDOUT or STDERR
    exec {spinnerFD}>&1
    export spinnerFD
fi
spinner() { # spinner as job.  ( Use global spinnerShapes and shapesInterval )
    local -i pnt
    while ! read -rsn 1 -t "$shapesInterval" _; do # while no input
	# Save cursor position, render frame, restore cursor position
        printf >&$spinnerFD '\e7%b\e8' \
	       "${spinnerShapes[pnt++%${#spinnerShapes[@]}]}"
    done 
}
startSpinner() { # startSpinner          # no arguments
    printf '\e[?25l' >&$spinnerFD        # Cursor invisible
    exec {doSpinner}> >(spinner)    # Run spinner with dedicated FD to stop
}
stopSpinner() { # stopSpinner            # no arguments
    if (( doSpinner )) && echo >&"$doSpinner"; then # Echo newline in FD
	exec {doSpinner}>&-              # Close doSpinner FD
	doSpinner=0
	printf '\e[?25h\n' >&$spinnerFD  # Cursor visible
    fi
}
# --- Minimal code for simple backgrounded spinner without json end here! ---

spinnerShapeFromJSON() { # spinner <theme> [interval]
    local -i pnt
    { # Run jq once, retrieving interval and frames
        read -r shapesInterval
        mapfile -t spinnerShapes
    } < <(jq -r ".$1"' | "00\(.interval)" , .frames[]' <"$spinnerJson")
    shapesInterval=00${2:-$shapesInterval} # Convert milliseconds into seconds
    printf -v shapesInterval %.3f "${shapesInterval::-3}.${shapesInterval: -3}"
}
spinnerFramesList() {
    jq -r 'to_entries|.[].key' < "$spinnerJson"
}
testSpinner() { # testSpinner <theme> [loop] [userKeyVarname] [interval]
    local spinnerTheme=$1 spinnerLoop=${2:-3.5} userKey=${3:-_} toSleep
    local -i themeInterval themeFrames
    read -r themeInterval themeFrames twoLines toSleep < <(
	jq -r <"$spinnerJson" ".$spinnerTheme |
	    \"\(.interval) \(.frames|length) \(
			.frames[0] | test(\"\\u001b\\\\[A\")) \(
			(.frames|length)*(3+${4:-.interval})*.001*$spinnerLoop
		)\" " )
    (( themeInterval * themeFrames )) || return
    [[ $twoLines == true ]] && printf '\n'  # Scroll a 2nd line if needed
    printf '%-20s %4d frames, interval %4dms: ' \
	"$spinnerTheme" $themeFrames $themeInterval
    spinnerShapeFromJSON "$spinnerTheme" "${4:-$themeInterval}"
    startSpinner
    # shellcheck disable=SC2229  # $userKey hold a variable name or _ as garbage
    read -rsn 1 -t "$toSleep" "$userKey"
    stopSpinner
}
spinnerThemeDetail() { # spinnerThemeDetail <theme> # Intented to by used by fzf
    (
	echo -n "Theme: '$1', "
	jq -r <"$spinnerJson" "\"\( .$1.frames | length ) frames, interval: \(
            .$1.interval)ms, \( .$1.frames[0] |
	         if test( \"\\u001b\\\\[A\" ) then \"two lines\"
		 	else \"one line\" end
		 )\n\n\n\n\(.$1.frames|join(\"\n\"))\""
    ) |
	sed 's/\o33/\\E/g' |
	paste  - - - -
}
export -f spinnerThemeDetail
spinnerMenu() { # spinnerMenu [loop]
    testSpinner "$(
	fzf --preview "spinnerThemeDetail '{}'" --preview-window=80% \
		< <(spinnerFramesList) )" "${1:-5.5}"
}
showAllSpinners() { # showAllSpinners [loop]
    local theme uKey
    for theme in $(spinnerFramesList); do
	testSpinner "$theme" "${1:-3.5}" uKey
	[[ ${uKey,} == q ]] && break
    done
}

complete -W "$(spinnerFramesList)" spinnerShapeFromJSON \
	 testSpinner spinnerThemeDetail

# Exit gracefully here, if sourced
[[ $0 = "${BASH_SOURCE[0]}" ]] || { true; return 0; }

Quit() { exit 0 ;}

while :; do
    uCmd="$(fzf --preview-window=80% --preview "jq -r < '$spinnerJson' \
	'.[]| if has(\"comment\") then . else empty end|.comment' |
	    fold -sw 54" <<-eoMenu
		show All Spinners
		spinner Menu
		Quit
		eoMenu
    )"
    if [[ $uCmd ]]; then
	"${uCmd// }"
    else
	Quit
    fi
done
echo