#!/bin/bash
# Usage: wpull2-requeue [ACTION] [FILENAME] ( [--where] URLPATTERN_OR_WHERE | --urls-from-stdin )
#  ACTION can be 'count' (default), 'print', or 'write'. On 'write', the number of modified records is printed.
#  FILENAME defaults to 'wpull.db'
#  URLPATTERN_OR_WHERE is URLPATTERN if --where isn't used or WHERE if it is.
#  URLPATTERN uses SQLite's LIKE syntax with ESCAPE "\", i.e. % matches any number of characters, _ matches exactly one character, and a backslash can be used to escape these special characters.
#    Must not contain quotes.
#  WHERE is an arbitrary SQLite 'WHERE' condition. The available tables are 'queued_urls' and 'url_strings', already joined together.
#  When --urls-from-stdin is used, one URL per line is expected on stdin. The URL must be in normalised format and not contain any double quotes.

if [[ $# -eq 4 || ( $# -ge 2 && $# -le 3 && ( "$1" == 'count' || "$1" == 'print' || "$1" == 'write' )) ]]
then
	action="$1"
	shift
else
	action=count
fi

if [[ $# -eq 3 || ( $# -eq 2 && "$1" != '--where' ) ]]
then
	filename="$1"
	shift
else
	filename=wpull.db
fi
if [[ ! -f "${filename}" ]]
then
	echo "Error: ${filename} does not exist or is not a regular file" >&2
	exit 1
fi

urlsfromstdin=
if [[ "$1" == '--urls-from-stdin' ]]
then
	urlsfromstdin=1
	shift
	if [[ $# -ne 0 ]]
	then
		echo "Error: invalid arguments" >&2
		exit 1
	fi
fi

where=
if [[ "$1" == '--where' ]]
then
	where=1
	shift
fi

if [[ "$1" == --* ]]
then
	echo "Error: Unknown option $1" >&2
	exit 1
fi

if [[ "${where}" ]]
then
	where="$1"
elif [[ "${urlsfromstdin}" ]]
then
	urls="$(sed 's/^/"/; s/$/", /' | tr -d '\n' | sed 's/, $//')"
	if [[ -z "${urls}" ]]
	then
		exit 0
	fi
	where="url IN (${urls})"
else
	where='url LIKE "'"$1"'" ESCAPE "\" AND status = "skipped" AND try_count > 3'
fi

query='FROM queued_urls JOIN url_strings ON url_string_id = url_strings.id WHERE '"${where}"

if [[ "${action}" == 'write' ]]
then
	sqlite3 "${filename}" <<<'UPDATE queued_urls SET status = "todo", try_count = 0, status_code = NULL WHERE id IN (SELECT queued_urls.id '"${query}"'); SELECT changes()'
elif [[ "${action}" == 'print' ]]
then
	sqlite3 "${filename}" <<<"SELECT queued_urls.*, url_strings.* ${query}"
else
	sqlite3 "${filename}" <<<"SELECT COUNT(queued_urls.id) ${query}"
fi