#!/bin/bash

usage() {
	echo "Usage: $0 --method [size|full] --output-dir DIR --url URL"
	echo "Options:"
	echo "  --method         Method to use (allowed values: size, full)"
	echo "  --output-dir     Output directory (will be created if it doesn't exist)"
	echo "  --url            URL to process"
	echo "  --help           Display this help message"
	exit 1
}


[ $# -eq 0 ] && usage
METHOD=
OUTPUT_DIR=
URL=

while [[ $# -gt 0 ]]; do
    key="$1"

    case $key in
        --method)
			METHOD="$2"
			if [[ "$METHOD" != "size" && "$METHOD" != "full" ]]; then
				echo "Error: invalid value for --method. Allowed values are 'size' or 'full'."
				exit 1
			fi
			shift
			;;
        --output-dir)
			OUTPUT_DIR="$2"
			shift
			;;
        --url)
			URL="$2"
			shift
			;;
        --help)
			usage
			;;
    *)
        echo "Error: unknown option $1"
        usage
        ;;
    esac
	shift
done

if [ -z "$METHOD" ] || [ -z "$OUTPUT_DIR" ] || [ -z "$URL" ]; then
    echo "Error: missing required arguments."
    usage
fi

if [ ! -d "$OUTPUT_DIR" ]; then
    mkdir -p "$OUTPUT_DIR"
    if [ $? -ne 0 ]; then
        echo "Error: failed to create directory '$OUTPUT_DIR'."
        exit 1
    fi
fi

cd "$OUTPUT_DIR"
if [ ! -f data.json ]; then
	echo "> fetching json data..."
	curl -s "$URL" | sed -n 's|.*<script id="__NEXT_DATA__" type="application/json">\([^<]*\)</script>.*|\1|p' \
		| jq '{width: .props.pageProps.compressedTransformedManifest.compressedCanvases.width, height: .props.pageProps.compressedTransformedManifest.compressedCanvases.height, prefix: .props.pageProps.compressedTransformedManifest.compressedCanvases.imageServiceId.prefix, suffix: .props.pageProps.compressedTransformedManifest.compressedCanvases.imageServiceId.suffix, remainders: .props.pageProps.compressedTransformedManifest.compressedCanvases.imageServiceId.remainders}' > data.json
fi

echo "> deleting junk files..."
find . -type f -size 111c -exec rm {} +

prefix=$(cat data.json | jq -r '.prefix')
suffix=$(cat data.json | jq -r '.suffix')

echo "> downloading missing pages..."
cat data.json | jq -r '.remainders[]' | while read -r page; do
	[ -e "$page.jpg" ] && continue
	url="${prefix}${page}${suffix}"
	case $METHOD in
		full)
			url="${url}/full/full/0/default.jpg"
			;;
		size)
			jpage=$(echo $page | sed 's/^0*//')
			jpage=$(( jpage-1 ))
			w=$(cat sizes.json | jq ".width[$jpage]")
			h=$(cat sizes.json | jq ".height[$jpage]")
			url="${url}/0,0,${w},${h}/${w},${h}/0/default.jpg"
			;;
	esac
	output="${page}.jpg"
	curl --silent "$url" -H 'User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:127.0) Gecko/20100101 Firefox/127.0' -H 'Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,*/*;q=0.8' -H 'Accept-Language: en-US,en;q=0.5' -H 'Accept-Encoding: gzip, deflate, br, zstd' -H 'DNT: 1' -H 'Connection: keep-alive' -H 'Upgrade-Insecure-Requests: 1' -H 'Sec-Fetch-Dest: document' -H 'Sec-Fetch-Mode: navigate' -H 'Sec-Fetch-Site: same-site' -H 'Priority: u=1' -H 'Pragma: no-cache' -H 'Cache-Control: no-cache' -H 'TE: trailers' -o "$output"
	if [ $(stat -c%s "$output") -eq 111 ]; then
		echo "> $page FAIL"
	else
		echo "> $page OK"
	fi
done