#!/bin/sh -e
f='
ssg.html
ssg/ssg.png
ssg/ssg.sh
ssg/txt2img.sh
ssg/ssg.test.sh
ssg/.ssg.sitemap.sh
ssg/.ssg.logo.sh
ssg/.ssg.example.sh
'

test $# -ne 2 && { echo "$f" && exit; }

SRC="$1"
DST="$2"
ssg_png="$DST/ssg/ssg.png"

mkdir -p "$DST/ssg"


echo '<meta http-equiv="refresh" content="0;url=https://romanzolotarev.com/ssg/">' > "$DST/ssg.html"

cp "$SRC/.ssg.sitemap.sh" "$DST/ssg/.ssg.sitemap.sh"
cp "$SRC/.ssg.logo.sh" "$DST/ssg/.ssg.logo.sh"
cp "$SRC/ssg/.ssg.sh" "$DST/ssg/.ssg.example.sh"
cp "$(which ssg.sh)" "$DST/ssg/ssg.sh"
cp "$(which txt2img.sh)" "$DST/ssg/txt2img.sh"
cp "$(which ssg.test.sh)" "$DST/ssg/ssg.test.sh"

if command -v magick >/dev/null 2>&1; then im='magick'; else im='convert'; fi

create_image() {
	"$im" \
		-background black \
		-fill white \
		-font 'spleen-6x12' \
		-pointsize 12 \
		-size '480x' \
		-gravity northwest \
		label:@- \
		-depth 1 \
		"$1"
}

cut_pages() {
	pages=$1
	out=$2

	content=$(cat)
	total=$(echo "$content" | wc -l)
	per=$(((total + pages - 1) / pages))
	i=1
	while test "$i" -le "$pages"; do
		start=$(((i - 1) * per + 1))
		end=$((i * per))
		page=$(echo "$content" | sed -n "${start},${end}p")
		# shellcheck disable=2059
		printf '%s\n' "$page" | create_image "$(printf "$out" "$i")"
		i=$((i + 1))
	done
}

tile_pages() {
	o="$1" && shift
	montage "$@" -tile x1 -geometry +0+0 -gravity north -background black "$o"
}

rm_pages() { rm -f "$@"; }
trim() { "$im" "$1" -trim +repage "$1"; }
optimize_png() { pngquant --strip --force --ext .png "$1"; }

cut_pages 4 "$DST/ssg/ssg_%d.png" <"$DST/ssg/ssg.sh"
tile_pages "$ssg_png" "$DST"/ssg/ssg_*.png
rm_pages "$DST"/ssg/ssg_*.png
trim "$ssg_png"
optimize_png "$ssg_png"

echo "$f"