#!/bin/bash
export TZ=UTC

envvars=(HTTP2IRC_GET_URL HTTP2IRC_POST_URL IA_S3_ACCESS IA_S3_SECRET)
for envvar in "${envvars[@]}"; do
	if [[ ! -v "${envvar}" ]]; then
		{ printf 'Error: one or more of the required environment variables (%s' "${envvars[0]}"; printf ', %s' "${envvars[@]:1}"; printf ') missing\n'; } >&2
		exit 1
	fi
done

# Optional env variables
declare -i timeout="${CODEARCHIVER_BOT_TIMEOUT:-0}"
declare -i nproclimit="${CODEARCHIVER_BOT_NPROC:-1}"
declare -i nproc=0

for dep in awk codearchiver curl ia-upload-stream python3 sha256sum tee zstd; do
	if ! command -v "${dep}" &>/dev/null; then
		printf 'Error: %s not found\n' "${dep}" >&2
		exit 1
	fi
done

function log {
	printf '%s %s\n' "${EPOCHREALTIME}" "$1" >&2
}

function log_loop {
	prefix="$1"
	# If there is output and it does not end with a LF, add one. Then replace CRLF with LF and replace remaining CR with LF.
	{ lastchar="$(tee /dev/fd/42 | tail -c 1 | xxd -p)"; if [[ "${lastchar}" && "${lastchar}" != '0a' ]]; then printf '\n'; fi } 42>&1 |
	  sed -u 's,\r$,,; s,\r,\n,g' |
	  while IFS= read -r line; do log "${prefix}${line}"; done
}

function send {
	local message="$1"
	log "Sending message: ${message}"
	curl --silent --verbose --max-time 10 --data "${message}" "${HTTP2IRC_POST_URL}" 2> >(log_loop 'curl http2irc POST: ') | log_loop 'http2irc POST response: '
}

function respond {
	local nick="$1"
	local message="$2"
	send "${nick}: ${message}"
}

function taint_block {
	message="Storage is tainted, not ${1}"
	if [[ -e '.tainted' ]]; then
		log "${message}"
		while [[ -e '.tainted' ]]; do
			sleep 1
		done
	fi
}

{ # Group the pipeline without requiring a backslash every time
	while :; do
		# Read from http2irc
		log 'Starting http2irc GET stream...'
		curl --silent --verbose --no-buffer "${HTTP2IRC_GET_URL}" 2> >(log_loop 'curl http2irc GET: ')
		printf '\n'  # Ensure that there's a trailing LF for `read`
	done |

	# Log all raw input
	tee >(log_loop 'Received http2irc line: ') |

	# Transform the JSONL data into a more suitable format for the following: lines of 'modes SP nick SP message'
	python3 -u -c 'import json, sys'$'\n''def json_parse_or_none(s):'$'\n'' try: return json.loads(s)'$'\n'' except json.JSONDecodeError as e:'$'\n''  print(f"Could not parse {s[:100]}…: {type(e).__name__}: {e!s}")'$'\n''{print(o["user"]["modes"] or "_", o["user"]["nick"], o["message"]) for o in map(json_parse_or_none, sys.stdin) if o and o.get("command") == "PRIVMSG"}' |

	# For valid bot commands with adequate permissions, assign a job ID and respond. Suppress everything else. Print lines of 'jobid SP nick SP URL' for the processing below.
	while read -r modes nick message; do
		if [[ "${message}" == '!help' ]]; then
			respond "${nick}" '`!a URL`: archives a single repository'
			respond "${nick}" '`!a < URL`: archives a list of repositories (no success/failure report, no warnings/errors report, check logs manually!)'
			continue
		fi
		if [[ "${message}" != '!a '* ]]; then
			continue
		fi
		if [[ "${modes}" != *[@+]* ]]; then
			respond "${nick}" 'Only voiced or opped users may use this command.'
			continue
		fi
		if [[ "${message}" =~ ^'!a '([a-z-]+\+)?[a-z]+://[^\ ]+$ ]]; then
			# Individual job
			jobs=("${message:3}")
			src="${message:3}"
		elif [[ "${message}" =~ ^'!a < 'https://transfer\.archivete\.am/[a-zA-Z0-9]+/.+$ ]]; then
			# List job
			jobs=()
			url="${message:5}"
			bad=
			log "Retrieving list job list: ${url}"
			while read -r line; do
				if [[ "${line}" =~ ^([a-z-]+\+)?[a-z]+://[^\ ]+$ ]]; then
					jobs+=("${line}")
				elif [[ "${line}" == '' ]]; then
					# Ignore empty lines
					continue
				else
					respond "${nick}" "Malformed line in ${url}: ${line}"
					bad=1
					break
				fi
			done < <({ curl --silent --verbose --fail --max-time 10 "${message:5}" 2> >(log_loop 'curl list job: '); printf '\n'; } | tee >(log_loop 'List input line: '))
			if [[ "${bad}" ]]; then
				continue
			fi
			src="${url}"
		else
			respond "${nick}" "I don't understand your command. Please forgive me."
			continue
		fi
		read -r jobid </proc/sys/kernel/random/uuid
		respond "${nick}" "Queueing job ${jobid} for ${src}"
		appendcounter=; if [[ ${#jobs[@]} -gt 1 ]]; then appendcounter=yes; fi
		for ((i=0; i<${#jobs[@]}; ++i)); do
			job="${jobs[${i}]}"
			singlejobid="${jobid}"; if [[ "${appendcounter}" ]]; then singlejobid+="_${i}"; fi
			printf '%s %s %s\n' "${singlejobid}" "${nick}" "${job}"
		done
		if [[ "${appendcounter}" ]]; then printf '%s %s end\n' "${jobid}" "${nick}"; fi  # Special value for sending a message when all list URLs have been processed
	done |

	# The actual work loop
	while IFS= read -r line; do
		singlejobid="${line%% *}"
		line="${line#* }"
		nick="${line%% *}"
		url="${line#* }"

		# Handle marker for end of list job: tell the user it's done and move on.
		if [[ "${url}" == 'end' ]]; then
			# No status code reflection here because the start of the list job might not even have been in this batch.
			respond "${nick}" "Job ${singlejobid} finished."
			continue
		fi

		# Block until there's a free slot
		while [[ "${nproc}" -ge "${nproclimit}" ]]; do
			# Wait for one subshell to exit
			wait -n
			nproc+=-1
		done

		taint_block 'continuing with work loop'

		# Find nonexistent filename for log file with lock
		# mkdir is pretty much always atomic, creating files might not be depending on the underlying file system (e.g. networked ones like NFS).
		while ! mkdir '.loglock' 2> >(log_loop 'mkdir loglock (work) err: '); do
			sleep 1
		done
		trap 'rmdir ".loglock"' EXIT  # Unlock if something below fails
		logbasename="$(printf '%(%Y%m%dT%H%M%SZ)T')_${singlejobid}"
		if [[ -e "${logbasename}_codearchiver.log" || -e "${logbasename}_codearchiver.log.zst" ]]; then
			for ((j=0; ; ++j)); do
				if [[ ! -e "${logbasename}_coll${j}_codearchiver.log" || -e "${logbasename}_coll${j}_codearchiver.log.zst" ]]; then
					break
				fi
			done
			logbasename="${logbasename}_coll${j}"
		fi
		logname="${logbasename}_codearchiver.log"
		artefactsname="${logbasename}_codearchiver_artefacts.txt"
		# Create the log file already in case spawning the tee process for it below is too slow
		touch "${logname}"
		trap - EXIT  # Reset trap
		rmdir '.loglock'  # Unlock

		# Run codearchiver in a background shell, duplicating WARNINGs and higher in the bot output
		# Produces lines of filenames to upload on stdout
		log "Running ${url} (${singlejobid}), logging into ${logname}"
		(
			taint_block "launching job ${singlejobid}"

			timeout --signal=INT "${timeout}" \
				codearchiver --verbose --write-artefacts-fd-3 "${url}" \
				3> >(tee "${artefactsname}" | log_loop "Artefact from codearchiver ${singlejobid}: ") \
				> >(log_loop "codearchiver ${singlejobid} out: ") \
				2> >(tee "${logname}" | grep -Fv -e '  INFO  ' | log_loop "codearchiver ${singlejobid} err: ")
			status="$?"
			log "codearchiver ${url} finished with status code ${status}"
			#TODO Integrate this into the pipe from codearchiver above to avoid rereading the entire log file
			declare -i badcount=$(awk '! ($3 ~ /^INFO$/) { cnt += 1; }  END { printf "%d\n", cnt; }' "${logname}")

			# Compress log file with zstd -19
			log "Compressing log file ${logname}"
			zstd -19 --rm "${logname}" 2> >(log_loop 'zstd err: ')
			if [[ -e "${logname}.zst" && ! -e "${logname}" ]]; then
				# Compression successful
				logname="${logname}.zst"
			fi

			# Verify that there are no artefacts if codearchiver exited non-zero
			# Since codearchiver handles errors internally normally, this should not usually happen, but it could occur e.g. if running out of disk space and leaving partial files in the storage.
			# With parallelism, this could in theory lead to artefacts of a successful run depending on artefacts from a failed run, which we wouldn't want.
			# So, if there are artefacts of a failed process, touch the .tainted file to stop the uploader and new processes starting and send a warning to IRC.
			# Emit the log filename for upload always (even on tainted storage), artefacts list and artefacts only on zero exit.
			readarray -t artefacts <"${artefactsname}"
			if [[ "${status}" -ne 0 && "${#artefacts[@]}" -ne 0 ]]; then
				touch '.tainted'
				send "Job ${singlejobid} exited non-zero but left artefacts behind!"
				msg="$(printf 'Artefact files by non-zero exit process: '; printf ' %q' "${artefacts[@]}")"
				log "${msg}"
			elif [[ "${status}" -eq 0 ]]; then
				for file in "${artefacts[@]}"; do
					printf '%s\n' "${file}"
				done
				printf '%s\n' "${artefactsname}"
			fi
			printf '%s\n' "${logname}"

			# For individual jobs, tell the user about warnings and success/failure
			if [[ "${singlejobid}" != *_* ]]; then
				if [[ "${status}" -eq 0 ]]; then
					respond "${nick}" "Job ${singlejobid} succeeded."
				else
					respond "${nick}" "Job ${singlejobid} failed."
				fi

				if [[ ${badcount} -gt 0 ]]; then
					respond "${nick}" "Job ${singlejobid} produced ${badcount} warnings or errors."
				fi
			fi
		) &
		nproc+=1
	done |

	# Upload
	while :; do
		# Process in batches for efficiency of parallel IA upload processing
		declare -a filenames=()
		while read -r -t 1 filename; do
			filenames+=("${filename}")
		done
		if [[ ${#filenames[@]} -eq 0 ]]; then
			continue
		fi

		log 'Starting upload batch'

		# Record SHA-256 hashes for new files
		sha256sum "${filenames[@]}" > >(log_loop 'sha256sum: ')

		taint_block 'uploading anything'

		# Upload
		date="$(printf '%(%Y-%m-%d)T')"
		identifier="codearchiver_${date//-/}"
		if [[ -z "${CODEARCHIVER_BOT_TEST}" ]]; then
			collection='archiveteam_codearchiver'
		else
			identifier="test_${identifier}"
			collection='test_collection'
		fi
		uploadsfine=y
		for f in "${filenames[@]}"; do
			taint_block "starting upload for $(printf '%q' "${f}")"

			log "Uploading $(printf '%q' "${f}") to ${identifier}"
			ia-upload-stream --no-derive "${identifier}" "${f}" \
				"collection:${collection}" \
				'mediatype:software' \
				"date:${date}" \
				'noarchivetorrent:true' \
				<"${f}" 2> >(log_loop 'ia-upload-stream: ')
			status="$?"
			if [[ "${status}" -ne 0 ]]; then
				log "Upload failed: exit status ${status}"
				if [[ "${uploadsfine}" ]]; then
					send "Upload failed: exit status ${status}"
				fi
				uploadsfine=
			fi
		done

		if [[ -z "${uploadsfine}" ]]; then
			log 'At least one upload in the batch failed, not removing anything'
			continue
		fi

		# Wait until all tasks for the item are done
		while :; do
			tasks="$(python3 -c 'import json, sys; o = json.load(sys.stdin); totalTasks = sum(o["value"]["summary"].values()); virusChecks = sum(1 for task in o["value"]["catalog"] if task.get("cmd") == "book_op.php" and task.get("args", {}).get("op10") == "VirusCheck"); print(f"Expected exactly 0 or 1 VirusCheck tasks, got {virusChecks}", file = sys.stderr) if virusChecks not in (0, 1) else None; print("Ignoring VirusCheck book_op task", file = sys.stderr) if virusChecks > 0 else None; print(totalTasks - min(virusChecks, 1))' < <({ curl --silent --verbose --fail --max-time 10 --header "Authorization: LOW ${IA_S3_ACCESS}:${IA_S3_SECRET}" "https://archive.org/services/tasks.php?identifier=${identifier}&catalog=1&history=0" 2> >(log_loop 'curl IA tasks err: '); } | tee >(log_loop 'curl IA tasks out: ')))"
			if [[ "${tasks}" == '0' ]]; then
				break
			fi
			sleep 60
		done

		taint_block 'removing any files after upload'

		# Replace non-metadata files with a symlink to .uploaded dummy file
		# No locking with codearchiver processes is necessary because those will only read metadata (which is left alone) or write files.
		# However, a lock with the log filename finding is required.
		while ! mkdir '.loglock' 2> >(log_loop 'mkdir loglock (upload) err: '); do
			sleep 1.1  # Slightly longer than above to minimise repeated collisions
		done
		trap 'rmdir ".loglock"' EXIT
		touch '.uploaded'
		for f in "${filenames[@]}"; do
			if [[ "${f}" != *_codearchiver_metadata.txt ]]; then
				log "Replacing $(printf '%q' "${f}") with symlink to .uploaded"
				{ rm --verbose -- "${f}" && ln --symbolic --verbose '.uploaded' "${f}"; } |& log_loop 'rm/ln: '
			fi
		done
		trap - EXIT
		rmdir '.loglock'
	done
}