package ast

import (
	"azalea/schema/token"
	"strconv"
	"strings"
)

type Schema ExprList
type ExprList []Expr
type Expr struct {
	Name  string
	Left  *Val
	Right *Val
}
type ValList []Val
type Val struct {
	string string
	number string
	name   string
	*Expr
}

func NewExprList(expr any) (ExprList, error) {
	return ExprList{expr.(Expr)}, nil
}

func NewStringVal(val *token.Token) (Val, error) {
	return Val{string: string(val.Lit)}, nil
}

func NewNumberVal(val *token.Token) (Val, error) {
	return Val{number: string(val.Lit)}, nil
}

func NewNameVal(val *token.Token) (Val, error) {
	return Val{name: string(val.Lit)}, nil
}

func NewExprVal(val any) (Val, error) {
	expr := val.(Expr)
	return Val{Expr: &expr}, nil
}

func AppendExpr(exprList, expr any) (ExprList, error) {
	return append(exprList.(ExprList), expr.(Expr)), nil
}

func NewValList(val any) (ValList, error) {
	return ValList{val.(Val)}, nil
}

func AppendVal(valList, val any) (ValList, error) {
	return append(valList.(ValList), val.(Val)), nil
}
func NewExpr(name *token.Token, left any, right any) (Expr, error) {
	var l Val
	var r Val
	if left != nil {
		l = left.(Val)
	}
	if right != nil {
		r = right.(Val)
	}

	return Expr{string(name.Lit), &l, &r}, nil
}
func ListExpr(val any) (Expr, error) {
	vals := val.(ValList)
	root := Expr{
		Name: ".",
	}
	current := &root
	for _, val := range vals[:len(vals)-2] {
		current.Left = &val
		current.Right = &Val{
			Expr: &Expr{
				Name: ".",
			}}
		current = current.Right.Expr
	}
	current.Left = &vals[len(vals)-2]
	current.Right = &vals[len(vals)-1]
	return root, nil
}

func (e Expr) String() string {
	sb := new(strings.Builder)
	sb.WriteRune('(')
	sb.WriteString(e.Name)
	sb.WriteRune(' ')
	if e.Left != nil {
		sb.WriteString(e.Left.String())
	}
	sb.WriteRune(' ')
	if e.Left != nil {
		sb.WriteString(e.Right.String())
	}
	sb.WriteRune(')')
	return sb.String()
}
func (v *Val) String() string {
	if v.string != "" {
		return v.string
	}
	if v.number != "" {
		num, _ := strconv.ParseInt(v.number, 0, 64)
		return strconv.FormatInt(num, 10)
	}
	if v.name != "" {
		return v.name
	}
	if v.Expr != nil {
		return v.Expr.String()
	}
	return "<nil>"
}