import files, add README & LICENSE

list.go

@@ -0,0 +1,83 @@
+package cursor
+
+import (
+	"fmt"
+
+	"gitea.auvem.com/go-toolkit/dbx"
+	"github.com/go-jet/jet/v2/mysql"
+)
+
+// PageQuery runs a paginated SELECT and builds a Connection from the results.
+type PageQuery[T any, IE mysql.Expression, IC mysql.Column] struct {
+	Sqlo    dbx.Queryable
+	Stmt    mysql.SelectStatement
+	Conds   mysql.BoolExpression
+	Cursor  *Cursor[IE, IC]
+	Default func() *Cursor[IE, IC]
+	Limit   int
+	CountFn QueryCountFn
+	ToEdge  func(active *Cursor[IE, IC], item *T) (GenericCursor, error)
+	// Scan runs the paginated query into dest. When nil, Run uses Stmt.Query.
+	Scan func(stmt mysql.SelectStatement, dest *[]*T) error
+	// AfterScan optionally transforms rows after the query and before building edges.
+	AfterScan func(items []*T) ([]*T, error)
+}
+
+// Run executes the paginated query and returns a Connection.
+func (q PageQuery[T, IE, IC]) Run() (*Connection[T], error) {
+	active := q.Cursor
+	if active == nil {
+		active = q.Default()
+	}
+
+	stmt := q.Stmt
+	stmt.WHERE(q.Conds.AND(PaginateConds(q.Cursor)))
+	stmt.ORDER_BY(OrderByClauses(active)...)
+	if q.Limit > 0 {
+		stmt = stmt.LIMIT(int64(q.Limit))
+	}
+
+	var items []*T
+	scan := q.Scan
+	if scan == nil {
+		scan = func(s mysql.SelectStatement, dest *[]*T) error {
+			return s.Query(q.Sqlo, dest)
+		}
+	}
+	if err := scan(stmt, &items); err != nil {
+		return nil, fmt.Errorf("failed to run paginated query: %w", err)
+	}
+
+	if q.AfterScan != nil {
+		var err error
+		items, err = q.AfterScan(items)
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	return BuildEdges(q.Sqlo, q.CountFn, items, func(item *T) (GenericCursor, error) {
+		return q.ToEdge(active, item)
+	})
+}
+
+// ConnectionFromRelayArgs parses Relay pagination args and calls list with the
+// decoded cursor and limit. newZero supplies the cursor template for decoding
+// (same as NewXCursor).
+func ConnectionFromRelayArgs[T any, IE mysql.Expression, IC mysql.Column](
+	after *string,
+	first *int,
+	newZero func() *Cursor[IE, IC],
+	list func(cursor *Cursor[IE, IC], limit int) (*Connection[T], error),
+) (*Connection[T], error) {
+	limit := 0
+	if first != nil {
+		limit = *first
+	}
+
+	c, err := NewCursorFromAfterPtr(newZero, after)
+	if err != nil {
+		return nil, err
+	}
+	return list(c, limit)
+}