#!/bin/sh

# The MIT License (MIT)
#
# Copyright © 2024 pacman64
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the “Software”), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
# SOFTWARE.


# leak [style-name...]
#
# Emit copies of stdin lines both to stdout and to stderr, thus `leaking`
# the contents going through a pipe of commands, using the leading argument
# as the style/color name to use to decorate the stderr output.
#
# If no style name is given, a default one is chosen.
#
# As its name suggests, its main use is to inspect/debug the intermediate
# stages of a `pipelined` shell command.
#
# Supported style names include
#
# - red     - orange    - bold     - underline
# - green   - magenta   - purple   - invert
# - blue    - gray      - italic
#
# Supported aliases for style names include
#
#   b    (blue)
#   g    (green)
#   h    (hilight/invert)
#   m    (magenta)
#   o    (orange)
#   p    (purple)
#   r    (red)
#   u    (underline)


# handle help options
case "$1" in
    -h|--h|-help|--help)
        awk '/^# +leak/, /^$/ { gsub(/^# ?/, ""); print }' "$0"
        exit 0
    ;;
esac

name="$(echo "${1:-gray}" | sed 's/^--?//')"
[ $# -gt 0 ] && shift

# handle special style-names
case "${name}" in
    plain)
        # the general case can't handle simply removing all styles
        awk '{
            print

            gsub(/\x1b\[([0-9]*[A-HJKST]|[0-9;]*m)/, "")
            print > "/dev/stderr"
        }'
        exit $?
    ;;

    keep)
        # the general case handles empty style-strings as errors
        awk '{
            printf "%s\x1b[0m\n", $0
            printf "%s\x1b[0m\n", $0 > "/dev/stderr"
        }'
        exit $?
    ;;
esac

# general case to handle actual styles
awk -v name="${name}" '
BEGIN {
    # pick a default style, when no style is given
    if (name == "") name = "gray"
    orig = name
    gsub(/^-{1,2}/, "", name)

    # alias-lookup table
    a["r"] = "red"
    a["g"] = "green"
    a["b"] = "blue"
    a["o"] = "orange"
    a["p"] = "purple"
    a["m"] = "magenta"
    a["h"] = "invert"
    a["i"] = "invert"
    a["u"] = "underline"
    a["or"] = "orange"
    a["ma"] = "magenta"
    a["hi"] = "invert"
    a["in"] = "invert"
    a["un"] = "underline"
    a["inv"] = "invert"
    a["mag"] = "magenta"
    a["grey"] = "gray"
    a["inverse"] = "invert"
    a["inverted"] = "invert"
    a["hilite"] = "invert"
    a["hilited"] = "invert"
    a["highlight"] = "invert"
    a["highlighted"] = "invert"
    a["underlined"] = "underline"
    a["bluebg"] = "blueback"
    a["graybg"] = "grayback"
    a["greenbg"] = "greenback"
    a["magentabg"] = "magentaback"
    a["orangebg"] = "orangeback"
    a["purplebg"] = "purpleback"
    a["redbg"] = "redback"
    a["magback"] = "magentaback"
    a["magbg"] = "magentaback"
    a["orback"] = "orangeback"
    a["orbg"] = "orangeback"
    a["purback"] = "purpleback"
    a["purbg"] = "purpleback"

    # style-lookup table
    s["red"] = "\x1b[38;5;1m"
    s["green"] = "\x1b[38;5;29m"
    s["blue"] = "\x1b[38;5;26m"
    s["orange"] = "\x1b[38;5;166m"
    s["purple"] = "\x1b[38;5;99m"
    s["magenta"] = "\x1b[38;5;165m"
    s["gray"] = "\x1b[38;5;248m"
    s["bold"] = "\x1b[1m"
    s["invert"] = "\x1b[7m"
    s["italic"] = "\x1b[3m"
    s["underline"] = "\x1b[4m"
    s["blueback"] = "\x1b[48;5;26m\x1b[38;5;15m"
    s["grayback"] = "\x1b[48;5;248m\x1b[38;5;15m"
    s["greenback"] = "\x1b[48;5;29m\x1b[38;5;15m"
    s["magentaback"] = "\x1b[48;5;165m\x1b[38;5;15m"
    s["orangeback"] = "\x1b[48;5;166m\x1b[38;5;15m"
    s["purpleback"] = "\x1b[48;5;99m\x1b[38;5;15m"
    s["redback"] = "\x1b[41m\x1b[38;5;15m"

    # resolve aliases
    if (a[name] != "") {
        name = a[name]
    }

    # handle unsupported style-names with an error
    if (s[name] == "") {
        fmt = "\x1b[31munsupported style/color name `%s`\x1b[0m\n"
        printf fmt, orig > "/dev/stderr"
        exit 1
    }

    # match ANSI-code to the name
    style = s[name]

    # make a style-reset replacement for already-styled lines
    rep = "\x1b[0m" style
}

# (re)style lines
{
    print
    fflush()
    gsub(/\x1b\[0m/, rep)
    printf "%s%s\x1b[0m\n", style, $0 > "/dev/stderr"
}
' "$@"