package rrdformat

import (
	"encoding/xml"
	"strconv"
)

//const XMLNS = "https://oss.oetiker.ch/rrdtool/rrdtool-dump.xml"

func xmlStart(name string) xml.StartElement {
	return xml.StartElement{
		Name: xml.Name{
			Local: name,
		},
	}
}

func (rrd RRD) MarshalXML(e *xml.Encoder, start xml.StartElement) error {
	if err := e.EncodeToken(xml.Comment(" Round Robin Database Dump ")); err != nil {
		return err
	}
	if err := e.EncodeToken(xml.CharData("\n")); err != nil {
		return err
	}
	if err := e.EncodeToken(start); err != nil {
		return err
	}

	// 1. Version
	if err := e.EncodeElement(rrd.Header.Version, xmlStart("version")); err != nil {
		return err
	}
	// 2. Step
	if err := e.EncodeElement(rrd.Header.PDPStep, xmlStart("step")); err != nil {
		return err
	}
	if err := e.EncodeToken(xml.CharData(" ")); err != nil {
		return err
	}
	if err := e.EncodeToken(xml.Comment(" Seconds ")); err != nil {
		return err
	}
	// 3. Last Update
	if err := e.EncodeElement(rrd.LastUpdated, xmlStart("lastupdate")); err != nil {
		return err
	}
	// blank line
	if err := e.EncodeToken(xml.CharData("\n")); err != nil {
		return err
	}
	// 3. Data Sources
	for _, ds := range rrd.DSDefs {
		if err := e.EncodeElement(ds, xmlStart("ds")); err != nil {
			return err
		}
	}

	// 4. Round Robin Archives
	for _, rra := range rrd.RRADefs {
		if err := e.EncodeElement(rra, xmlStart("rra")); err != nil {
			return err
		}
	}

	if err := e.EncodeToken(start.End()); err != nil {
		return err
	}
	return nil
}

func (t TimeWithUsec) MarshalXML(e *xml.Encoder, start xml.StartElement) error {
	if err := e.EncodeToken(start); err != nil {
		return err
	}
	if err := e.EncodeToken(xml.CharData(strconv.FormatInt(int64(t.Sec), 10))); err != nil {
		return err
	}
	if err := e.EncodeToken(start.End()); err != nil {
		return err
	}
	if err := e.EncodeToken(xml.CharData(" ")); err != nil {
		return err
	}
	if err := e.EncodeToken(xml.Comment(t.Time().Format(" 2006-01-02 15:04:05 MST "))); err != nil {
		return err
	}
	return nil
}

func (ds DSDef) MarshalXML(e *xml.Encoder, start xml.StartElement) error {
	if err := e.EncodeToken(start); err != nil {
		return err
	}
	if err := e.EncodeElement(" "+ds.DSName+" ", xmlStart("name")); err != nil {
		return err
	}
	if err := e.EncodeElement(" "+ds.DSType+" ", xmlStart("type")); err != nil {
		return err
	}

	switch ds.DSType {
	case DST_CDEF:
		var rpnps []rrdbinary.RPNToken
		for _, param := range ds.Params {
			rpnps = append(rpnps, param.AsRPNTokens()...)
		}
		strs := make([]string, len(rpnps))
		for _, rpnp := range rpnps {
			switch Op(rpnp.Op) {
			case OP_NUMBER:
				strs = append(strs, fmt.Sprintf("%d", rpnp.Val))
			case OP_VARIABLE:
				if rpnp.Val < 0 || rpnp.Val >= len(rrd.DSDefs) {
					return fmt.Errorf("out-of-bounds %s %d", Op(rpnp.Op), rpnp.Val)
				}
				strs = append(strs, rrd.DSDefs[int(rpnp.Val)].Name)
			case OP_PREV_OTHER:
				if rpnp.Val < 0 || rpnp.Val >= len(rrd.DSDefs) {
					return fmt.Errorf("out-of-bounds %s %d", Op(rpnp.Op), rpnp.Val)
				}
				strs = append(strs, fmt.Sprintf("PREV(%s)", rrd.DSDefs[int(rpnp.Val)].Name))
			default:
				strs = append(strs, rpnp.Op.String())
			}
		}
		if err := e.EncodeElement(strings.Join(strs, ","), xmlStart("cdef")); err != nil {
			return err
		}
	default:

	}

	if err := e.EncodeToken(start.End()); err != nil {
		return err
	}
}