#!/bin/bash
set -e

if [[ $# -ne 1 || "$1" == '-h' || "$1" == '--help' ]]
then
	echo 'Usage: transfer.notkiska.pw-check-ia TKPPATH'
	echo 'TKPPATH is the path of a file on transfer.notkiska.pw, e.g. "123F3V/twitter-#qanon"'
	echo 'Checks that the file is archived correctly on IA by downloading both copies and comparing the SHA-1.'
	echo 'If the TKPCHECK_CACHE_DIR environment variable is set, it is used as a cache for the CDXs to avoid redownloading them from IA on every check.'
	exit 1
fi

if [[ "${TKPCHECK_CACHE_DIR}" ]]
then
	if [[ -e "${TKPCHECK_CACHE_DIR}" && ! -d "${TKPCHECK_CACHE_DIR}" ]]
	then
		echo "Error: ${TKPCHECK_CACHE_DIR} is not a directory." >&2
		exit 1
	fi
fi

file="$1"
fileid="${file%/*}"
filename="${file#*/}"

echo "Downloading from transfer.notkiska.pw" >&2
tkphash="$(curl "https://transfer.notkiska.pw/${file}" | sha1sum | tee /dev/fd/2)"

echo "Retrieving WARC list from viewer" >&2
mapfile -t warcs < <(curl -s "https://archive.fart.website/archivebot/viewer/api/v1/search.json?q=urls-transfer.notkiska.pw-transfer.notkiska.pw-" | python3 -c 'import json,sys; [print(x["job_id"]) for x in json.loads(sys.stdin.read())["results"]]' | sed 's,^,https://archive.fart.website/archivebot/viewer/job/,' | xargs curl -s | grep -Po 'href="\Khttps://archive.org/download/[^/"]+/[^/"]+-\d\d\d\d\d\.warc\.gz(?=")')

cdxLines=()
for warc in "${warcs[@]}"
do
	cdx="${warc::-3}.os.cdx.gz"
	mapfile -t -O ${#cdxLines[@]} cdxLines < <(
		{
			if [[ "${TKPCHECK_CACHE_DIR}" ]]
			then
				cdxfn="${cdx:29}"
				mkdir -p "${TKPCHECK_CACHE_DIR}/${cdxfn%/*}"
				if [[ ! -e "${TKPCHECK_CACHE_DIR}/${cdxfn}" ]]
				then
					echo "Fetching ${cdx} into local cache" >&2
					curl -L "${cdx}" >"${TKPCHECK_CACHE_DIR}/${cdxfn}"
				fi
				cat "${TKPCHECK_CACHE_DIR}/${cdxfn}"
			else
				echo "Fetching ${cdx}" >&2
				curl -L "${cdx}"
			fi
		} | zgrep -F "/${fileid}/" 2>/dev/null | tee /dev/fd/2
	 )
done

if [[ ${#cdxLines[@]} -ne 1 ]]
then
	echo "Not exactly one matching CDX line found, cannot continue" >&2
	exit 1
fi

read -r length offset iapath < <(awk '{print $9 " " $10 " " $11}' <<<"${cdxLines[0]}")
echo "Fetching ${offset}-$((${offset}+${length})) from IA ${iapath}" >&2
iahash="$(curl -L --range "${offset}-$((${offset}+${length}))" "https://archive.org/download/${iapath}" | zcat 2>/dev/null | awk '/^\r$/ {empty+=1; next}  (empty >= 2)' | sha1sum | tee /dev/fd/2)"

if [[ "${tkphash}" == "${iahash}" ]]
then
	echo OK >&2
	exit 0
else
	echo "Hash mismatch!" >&2
	exit 1
fi