Initial rendering of the node tree

node.go

@@ -0,0 +1,124 @@
+package main
+
+import (
+	// External
+	"github.com/jmoiron/sqlx"
+
+	// Standard
+	"time"
+)
+
+type Node struct {
+	ID   int
+	Name string
+
+	ParentID int `db:"parent_id"`
+
+	TypeID   int    `db:"type_id"`
+	TypeName string `db:"type_name"`
+	TypeIcon string `db:"type_icon"`
+
+	Updated time.Time
+	Data    any
+	RawData []byte `db:"raw_data"`
+
+	NumChildren int `db:"num_children"`
+	Children    []*Node
+}
+
+func GetNode(startNodeID, maxDepth int) (topNode *Node, err error) {
+	nodes := make(map[int]*Node)
+	var rows *sqlx.Rows
+	rows, err = GetNodeRows(startNodeID, maxDepth)
+	if err != nil {
+		return
+	}
+	defer rows.Close()
+
+	first := true
+	for rows.Next() {
+		var node Node
+		err = rows.StructScan(&node)
+		if err != nil {
+			return
+		}
+
+		if first {
+			topNode = &node
+			first = false
+		}
+
+		ComposeTree(nodes, &node)
+	}
+
+	return
+}
+
+func GetNodeRows(startNodeID, maxDepth int) (rows *sqlx.Rows, err error) {
+	rows, err = db.Queryx(`
+		WITH RECURSIVE nodes AS (
+			SELECT
+				COALESCE(
+					(SELECT parent FROM connection WHERE child = $1),
+					0
+				) AS parent_id,
+				$1::int AS id,
+				0 AS depth
+
+			UNION
+
+			SELECT
+				c.parent,
+				c.child,
+				ns.depth+1 AS depth
+			FROM connection c
+			INNER JOIN nodes ns ON ns.depth < $2 AND c.parent = ns.id
+		)
+
+		SEARCH DEPTH FIRST BY id SET ordercol
+
+		SELECT
+			ns.parent_id,
+			n.id,
+			n.name,
+			n.type_id,
+			t.name AS type_name,
+			COALESCE(t.schema->>'icon', '') AS type_icon,
+			n.updated,
+			n.data AS raw_data,
+			COUNT(c.child) AS num_children
+		FROM nodes ns
+		INNER JOIN public.node n ON ns.id = n.id
+		INNER JOIN public.type t ON n.type_id = t.id
+		LEFT JOIN public.connection c ON c.parent = n.id
+		GROUP BY
+			ns.depth,
+			ns.parent_id,
+			n.id,
+			t.name,
+			t.schema,
+			ns.ordercol
+		ORDER BY ordercol
+	`,
+		startNodeID,
+		maxDepth,
+	)
+	return
+}
+
+func ComposeTree(nodes map[int]*Node, node *Node) {
+	if node.Children == nil {
+		node.Children = []*Node{}
+	}
+
+	parentNode, found := nodes[node.ParentID]
+	if found {
+		if parentNode.Children == nil {
+			parentNode.Children = []*Node{node}
+		} else {
+			parentNode.Children = append(parentNode.Children, node)
+		}
+	}
+
+	nodes[node.ID] = node
+}