#!/bin/sh

# The MIT License (MIT)
#
# Copyright © 2025 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.


# vrt [option...] [files...]
#
#
# View Rich Text is a simple non-interactive plain-text file viewer, which
# handles ANSI-codes and renders pictures out of data-URI lines.
#
# The options are, available in single and double-dashed versions
#
#   -h           show this help message
#   -help        show this help message
#
#   -header=n    always show first `n` lines at the top
#
#   -n           show line numbers for overall results
#   -N           show line numbers for overall results
#
#   -s           show pictures using the sixel format (experimental)
#   -sixel       show pictures using the sixel format (experimental)
#
#   -t           show first line at the top at all times
#   -top         show first line at the top at all times


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

width=0
sixels=0
# less_options='-MKiCRS'
less_options='-MKiCS'

for arg in "$@"; do
    if [ "${arg}" = '--' ]; then
        shift
        break
    fi

    case "${arg}" in
        -n|--n|-N|--N)
            less_options="${less_options} -N"
            shift
        ;;

        --header=*)
            less_options="${less_options} ${arg}"
            shift
        ;;

        -s|--s|-sixel|--sixel|-sixels|--sixels)
            sixels=1
            # less_options="${less_options} -r"
            shift
        ;;

        -t|--t|-top|--top)
            less_options="${less_options} --header=1"
            shift
        ;;

        -w|--w|-width|--width)
            shift
            if [ $# -eq 0 ]; then
                printf "expected number after width option\n" >&2
                exit 1
            fi
            width="$1"
            shift
        ;;
    esac
done

if [ "${sixels}" -eq 0 ]; then
    less_options="${less_options} -R"
fi

if [ "${width}" -eq 0 ]; then
    width="$(tput cols)"
fi

command='awk'
if [ -e /usr/bin/gawk ]; then
    command='gawk'
fi

if [ $# -eq 0 ]; then
    less "${less_options}" -f -
    exit $?
fi

if [ $# -lt 2 ]; then
    less_options="${less_options} --header=1"
fi

# show all non-existing files given
failed=0
for arg in "$@"; do
    if [ "${arg}" = "-" ]; then
        continue
    fi
    if [ ! -e "${arg}" ]; then
        printf "no file named \"%s\"\n" "${arg}" > /dev/stderr
        failed=1
    fi
done

if [ "${failed}" -gt 0 ]; then
    exit 2
fi

view_pic=''
if [ -e /usr/bin/chafa ]; then
    view_pic='chafa'
    if [ "${sixels}" -eq 1 ]; then
        view_pic='chafa --format sixels'
    fi
fi

${command} -v width="${width}" -v view_pic="${view_pic}" '
    BEGIN {
        if (width >= 170) width = (width - 10) / 2
        fmt = "sh -c \"base64 -d | %s --size %dx\""
        render_pic_cmd = sprintf(fmt, view_pic, width)
    }

    FNR == 1 {
        if (files++ > 0) print ""
        printf "\x1b[7m%-80s\x1b[0m\n", FILENAME
    }

    { gsub(/\r$/, "") }

    /^data:image\/[a-z]+;base64,[A-Za-z0-9/+]*=*$/ {
        if (view_pic == "") {
            print "image renderer \"chafa\" not found" > "/dev/stderr"
            exit 1
        }

        gsub(/^data:image\/[a-z]+;base64,/, "")
        print | render_pic_cmd
        close(render_pic_cmd)
        next
    }

    # { print; next }

    /\t/ { print; next }

    {
        pos = 0

        for (i = 1; i <= NF; i++) {
            plain = $i
            gsub(/\x1b\[[0-9;]*[A-Za-z]/, "", plain)
            w = length(plain) + (i > 1)

            if (pos + w >= width || w >= width) {
                print ""
                pos = 0
            }

            pos += w

            if (i == 1) printf "%s", $i
            else printf " %s", $i
        }

        if (pos > 0 || NF == 0) print ""
    }
' "$@" | less "${less_options}"