#!/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.


# hydra [args...]
#
# Show the first few lines of all input(s) given. The name comes from the
# multi-headed monster of ancient mythology, a nod to the standard cmd-line
# app `head`, which also limits inputs up to the number of lines given.
#
# The default line limit is 10, but you can change it with non-negative
# integer numbers you pass along the arguments, letting you use different
# max-numbers of lines for different files/inputs.


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

cmd="bat"
# debian linux uses a different name for the `bat` app
if [ -e "/usr/bin/batcat" ]; then
    cmd="batcat"
fi

first=1
maxlines=10

for a in "$@"; do
    # non-negative-integer arguments change the line limit
    if echo "${a}" | grep -E -q '^\+?[0-9]+$'; then
        maxlines="${a}"
        continue
    fi

    # visually separate results with extra empty lines
    if [ "${first}" -eq 0 ]; then
        printf "\n"
    fi
    first=0

    # show file using syntax-coloring, if available
    "${cmd}" --style=plain,header,numbers \
        --theme='Monokai Extended Light' \
        --wrap=never \
        --color=always \
        --paging=never \
        --line-range :"${maxlines}" "${a}" |
            # make colors readable on a wide range of backgrounds
            sed 's-\x1b\[38;5;70m-\x1b\[38;5;28m-g'

    # the previous way, kept for reference... or preference
    # printf "\e[7m%-80s\e[0m\n" "${a}"
    # head -n "${maxlines}" "${a}" | cat -n
done