sq/libsq/ast/join.go

package ast

import (
	"fmt"

	"github.com/neilotoole/sq/libsq/ast/internal/slq"

	"github.com/antlr/antlr4/runtime/Go/antlr/v4"
)

var _ Node = (*JoinNode)(nil)

// JoinNode models a SQL JOIN node. It has a child of type JoinConstraint.
type JoinNode struct {
	seg        *SegmentNode
	ctx        antlr.ParseTree
	constraint *JoinConstraint
	leftTbl    *TblSelectorNode
	rightTbl   *TblSelectorNode
}

// LeftTbl is the selector for the left table of the join.
func (jn *JoinNode) LeftTbl() *TblSelectorNode {
	return jn.leftTbl
}

// RightTbl is the selector for the right table of the join.
func (jn *JoinNode) RightTbl() *TblSelectorNode {
	return jn.rightTbl
}

// Tabler implements the Tabler marker interface.
func (jn *JoinNode) tabler() {
	// no-op
}

func (jn *JoinNode) Parent() Node {
	return jn.seg
}

func (jn *JoinNode) SetParent(parent Node) error {
	seg, ok := parent.(*SegmentNode)
	if !ok {
		return errorf("%T requires parent of type %s", jn, typeSegmentNode)
	}
	jn.seg = seg
	return nil
}

func (jn *JoinNode) Children() []Node {
	if jn.constraint == nil {
		return []Node{}
	}

	return []Node{jn.constraint}
}

func (jn *JoinNode) AddChild(node Node) error {
	jc, ok := node.(*JoinConstraint)
	if !ok {
		return errorf("JOIN() child must be *JoinConstraint, but got: %T", node)
	}

	if jn.constraint != nil {
		return errorf("JOIN() has max 1 child: failed to add: %T", node)
	}

	jn.constraint = jc
	return nil
}

func (jn *JoinNode) SetChildren(children []Node) error {
	if len(children) == 0 {
		jn.constraint = nil
		return nil
	}

	if len(children) > 1 {
		return errorf("JOIN() can have only one child: failed to add %d children", len(children))
	}

	expr, ok := children[0].(*JoinConstraint)
	if !ok {
		return errorf("JOIN() child must be *FnJoinExpr, but got: %T", children[0])
	}

	jn.constraint = expr
	return nil
}

func (jn *JoinNode) Context() antlr.ParseTree {
	return jn.ctx
}

func (jn *JoinNode) SetContext(ctx antlr.ParseTree) error {
	jn.ctx = ctx
	return nil
}

func (jn *JoinNode) Text() string {
	return jn.ctx.GetText()
}

func (jn *JoinNode) Segment() *SegmentNode {
	return jn.seg
}

func (jn *JoinNode) String() string {
	text := nodeString(jn)

	leftTblName := ""
	rightTblName := ""

	if jn.leftTbl != nil {
		leftTblName, _ = jn.leftTbl.SelValue()
	}
	if jn.rightTbl != nil {
		rightTblName, _ = jn.rightTbl.SelValue()
	}

	text += fmt.Sprintf(" |  left_table: {%s}  |  right_table: {%s}", leftTblName, rightTblName)
	return text
}

var _ Node = (*JoinConstraint)(nil)

// JoinConstraint models a join's constraint.
// For example the elements inside the parentheses
// in "join(.uid == .user_id)".
type JoinConstraint struct {
	// join is the parent node
	join     *JoinNode
	ctx      antlr.ParseTree
	children []Node
}

func (n *JoinConstraint) Parent() Node {
	return n.join
}

func (n *JoinConstraint) SetParent(parent Node) error {
	join, ok := parent.(*JoinNode)
	if !ok {
		return errorf("%T requires parent of type %s", n, typeJoinNode)
	}
	n.join = join
	return nil
}

func (n *JoinConstraint) Children() []Node {
	return n.children
}

func (n *JoinConstraint) AddChild(child Node) error {
	nodeCtx := child.Context()

	switch nodeCtx.(type) {
	case *antlr.TerminalNodeImpl:
	case *slq.SelectorContext:
	default:
		return errorf("cannot add child node %T to %T", nodeCtx, n.ctx)
	}

	n.children = append(n.children, child)
	return nil
}

func (n *JoinConstraint) SetChildren(children []Node) error {
	for _, child := range children {
		nodeCtx := child.Context()

		switch nodeCtx.(type) {
		case *antlr.TerminalNodeImpl:
		case *slq.SelectorContext:
		default:
			return errorf("cannot add child node %T to %T", nodeCtx, n.ctx)
		}
	}

	if len(children) == 0 {
		n.children = children
		return nil
	}

	n.children = children
	return nil
}

func (n *JoinConstraint) Context() antlr.ParseTree {
	return n.ctx
}

func (n *JoinConstraint) SetContext(ctx antlr.ParseTree) error {
	n.ctx = ctx // TODO: check for correct type
	return nil
}

func (n *JoinConstraint) Text() string {
	return n.ctx.GetText()
}

func (n *JoinConstraint) String() string {
	return nodeString(n)
}