Emit OSC 9;4 progress bar escape sequences

osc-progress

#!/usr/bin/env bash
# osc-progress - Emit OSC 9;4 progress bar escape sequences
#
# Usage:
#   osc-progress <value>           # set progress (0-100)
#   osc-progress normal:60         # same as above (at 60%)
#   osc-progress info:60           # same as above (at 60%)
#   osc-progress indeterminate     # set indeterminate/pulsing state
#   osc-progress paused            # set paused state
#   osc-progress paused:60         # set paused state at 60%
#   osc-progress error             # set error state
#   osc-progress error:60          # set error state at 60%
#   osc-progress clear             # clear progress bar
#
#   echo "42" | osc-progress       # read value from stdin
#   echo "error:42" | osc-progress # same format as command line argument
#
# States: 0=clear, 1=normal, 2=error, 3=indeterminate, 4=paused

set -euo pipefail

_emit() {
    local seq="$1"
    if [[ -n "${TMUX:-}" ]]; then
        printf '\033Ptmux;\033%s\033\\' "$seq"
    else
        printf '%s' "$seq"
    fi
}

_progress() {
    local state="$1"
    local value="${2:-}"
    if [[ -n "$value" ]]; then
        _emit $'\033]9;4;'"${state};${value}"$'\007'
    else
        _emit $'\033]9;4;'"${state}"$'\007'
    fi
}

_usage() {
    sed -n '2,18p' "$0" | sed 's/^# \{0,1\}//'
    exit 1
}

# Read from stdin if piped
if [[ ! -t 0 ]] && [[ $# -eq 0 ]]; then
    read -r value
    set -- "$value"
fi

[[ $# -eq 0 ]] && _usage

arg="${1:-}"
cmd="${arg%%:*}"
val="${arg#*:}"
[[ "$val" == "$arg" ]] && val=""  # no colon present

case "$cmd" in
    clear)         _progress 0 ;;
    normal|info)   _progress 1 "$val" ;;
    error)         _progress 2 "$val" ;;
    indeterminate) _progress 3 ;;
    paused)        _progress 4 "$val" ;;
    [0-9]|[0-9][0-9]|100)
                   _progress 1 "$cmd" ;;
    *)
        echo "osc-progress: invalid argument: $arg" >&2
        _usage ;;
esac