#!/bin/bash -ex

# Tool for documenting sql with graphviz
# Usage:
# $ cat sql_file.sql | tools/doc_sql.sh -flags -passed -to -dot > output_file.svg
# Outputs a subgraph and some edges that can be grouped togeather in a full graph

flags=$@
input_file=$(cat -)
# First, find the table name
table_name=$(echo "${input_file}" "SELECT name FROM sqlite_master WHERE type='table';" | sqlite3 | head -n 1)
# And get the data we need to display
table_schema=$(echo "${input_file}" "
SELECT
	info.name,
	info.type,
	info.pk,
	info.\"notnull\",
	fk_from.\"from\" AS fk_from_col,
	fk_from.\"on_delete\" AS fk_on_delete,
	fk_from.\"table\" AS fk_from_tbl,
	fk_from.\"to\" AS fk_from_to
FROM
	pragma_table_info('$table_name') info
	LEFT JOIN pragma_foreign_key_list('$table_name') fk_from
		ON fk_from.\"from\" = info.\"name\"
ORDER BY
	info.\"notnull\" DESC
;" | sqlite3 )
table_pk_1=$(echo "$table_schema" | head -n 1)
table_pk=$(echo "$table_schema" | head -n 1 | awk '
BEGIN {FS="|"}
{print $1}
')
#foreign_keys=$(echo "${input_file}" "pragma foreign_key_list('$table_name');" | sqlite3)

echo "$table_name ["
echo "    shape=\"plaintext\""
echo "    label=<<table>"
echo "    <tr><td colspan=\"3\"><b>" $table_name "</b></td></tr>"
echo "$table_schema" | awk '
BEGIN {FS="|"}
{
	if ($4)
		print "<tr><td port=\"" $1 "\">PK</td>";
	else if ($5)
		print "<tr><td port=\"" $1 "\">FK</td>";
	else
		print "<tr><td></td>";
	print "<td>" $1 "</td>";
	printf "<td";
	if($4)
		printf " port=\"" $1 "\">";
	else
		printf ">";
	if($2)
		print $2;
	else
		print $2 "ON DELETE CASCADE";
	print "</td></tr>";
}'
echo "</table>> ];"
echo "$table_schema" | awk -v "table_name=$table_name" -v "table_pk=$table_pk" '
BEGIN {FS="|"}
{
	if ($5) {
		print table_name ":" $5 "->" $7 ":" $8 ;
	}
}
'