// Copyright 2011 The Go Authors.  All rights reserved.

// Use of this source code is governed by a BSD-style

// license that can be found in the LICENSE file.

package xmpp

// This file contains data structures.

import (

	"bytes"

	"encoding/xml"

	"errors"

	"flag"

	"fmt"

	"io"

	"regexp"

	"strings"

)

// JID represents an entity that can communicate with other

// entities. It looks like node@domain/resource. Node and resource are

// sometimes optional.

type JID struct {

	Node     string

	Domain   string

	Resource string

}

var _ fmt.Stringer = &JID{}

var _ flag.Value = &JID{}

// XMPP's <stream:stream> XML element

type stream struct {

	To      string `xml:"to,attr"`

	From    string `xml:"from,attr"`

	Id      string `xml:"id,attr"`

	Lang    string `xml:"lang,attr"`

	Version string `xml:"version,attr"`

}

var _ xml.Marshaler = &stream{}

var _ fmt.Stringer = &stream{}

// <stream:error>

type streamError struct {

	Any  Generic `xml:",any"`

	Text *errText `xml:"text"`

}

var _ xml.Marshaler = &streamError{}

type errText struct {

	Lang string `xml:"lang,attr"`

	Text string `xml:",chardata"`

}

var _ xml.Marshaler = &errText{}

type Features struct {

	Starttls   *starttls `xml:"starttls"`

	Mechanisms mechs `xml:"mechanisms"`

	Bind       *bindIq `xml:"bind"`

	Session    *Generic `xml:"session"`

	Any        *Generic `xml:",any"`

}

type starttls struct {

	XMLName  xml.Name

	Required *string `xml:"required"`

}

type mechs struct {

	Mechanism []string `xml:"mechanism"`

}

type auth struct {

	XMLName   xml.Name

	Chardata  string `xml:",chardata"`

	Mechanism string `xml:"mechanism,attr"`

	Any       *Generic `xml:",any"`

}

// One of the three core XMPP stanza types: iq, message, presence. See

// RFC3920, section 9.

type Stanza interface {

	// Returns "iq", "message", or "presence".

	GetName() string

	// The to attribute.

	GetTo() string

	// The from attribute.

	GetFrom() string

	// The id attribute.

	GetId() string

	// The type attribute.

	GetType() string

	// The xml:lang attribute.

	GetLang() string

	// A nested error element, if any.

	GetError() *Error

	// Zero or more (non-error) nested elements. These will be in

	// namespaces managed by extensions.

	GetNested() []interface{}

	addNested(interface{})

	innerxml() string

}

// message stanza

type Message struct {

	To       string `xml:"to,attr"`

	From     string `xml:"from,attr"`

	Id       string `xml:"id,attr"`

	Type     string `xml:"type,attr"`

	Lang     string `xml:"lang,attr"`

	Innerxml string `xml:",innerxml"`

	Error    *Error `xml:"error"`

	Subject  *Generic `xml:"subject"`

	Body     *Generic `xml:"body"`

	Thread   *Generic `xml:"thread"`

	Nested   []interface{}

}

var _ xml.Marshaler = &Message{}

var _ Stanza = &Message{}

// presence stanza

type Presence struct {

	To       string `xml:"to,attr"`

	From     string `xml:"from,attr"`

	Id       string `xml:"id,attr"`

	Type     string `xml:"type,attr"`

	Lang     string `xml:"lang,attr"`

	Innerxml string `xml:",innerxml"`

	Error    *Error `xml:"error"`

	Show     *Generic `xml:"show"`

	Status   *Generic `xml:"status"`

	Priority *Generic `xml:"priority"`

	Nested   []interface{}

}

var _ xml.Marshaler = &Presence{}

var _ Stanza = &Presence{}

// iq stanza

type Iq struct {

	To       string `xml:"to,attr"`

	From     string `xml:"from,attr"`

	Id       string `xml:"id,attr"`

	Type     string `xml:"type,attr"`

	Lang     string `xml:"lang,attr"`

	Innerxml string `xml:",innerxml"`

	Error    *Error `xml:"error"`

	Nested   []interface{}

}

var _ xml.Marshaler = &Iq{}

var _ Stanza = &Iq{}

// Describes an XMPP stanza error. See RFC 3920, Section 9.3.

type Error struct {

	XMLName xml.Name `xml:"error"`

	// The error type attribute.

	Type string `xml:"type,attr"`

	// Any nested element, if present.

	Any *Generic `xml:",any"`

}

var _ error = &Error{}

// Used for resource binding as a nested element inside <iq/>.

type bindIq struct {

	XMLName  xml.Name `xml:"urn:ietf:params:xml:ns:xmpp-bind bind"`

	Resource *string  `xml:"resource"`

	Jid      *string  `xml:"jid"`

}

// Holds an XML element not described by the more specific types.

type Generic struct {

	XMLName  xml.Name

	Any      *Generic `xml:",any"`

	Chardata string `xml:",chardata"`

}

var _ fmt.Stringer = &Generic{}

func (jid *JID) String() string {

	result := jid.Domain

	if jid.Node != "" {

		result = jid.Node + "@" + result

	}

	if jid.Resource != "" {

		result = result + "/" + jid.Resource

	}

	return result

}

// Set implements flag.Value. It returns true if it successfully

// parses the string.

func (jid *JID) Set(val string) error {

	r := regexp.MustCompile("^(([^@/]+)@)?([^@/]+)(/([^@/]+))?$")

	parts := r.FindStringSubmatch(val)

	if parts == nil {

		return errors.New("Can't parse as JID: " + val)

	}

	jid.Node = parts[2]

	jid.Domain = parts[3]

	jid.Resource = parts[5]

	return nil

}

func (s *stream) MarshalXML() ([]byte, error) {

	buf := bytes.NewBuffer(nil)

	buf.WriteString("<stream:stream")

	writeField(buf, "xmlns", "jabber:client")

	writeField(buf, "xmlns:stream", NsStream)

	writeField(buf, "to", s.To)

	writeField(buf, "from", s.From)

	writeField(buf, "id", s.Id)

	writeField(buf, "xml:lang", s.Lang)

	writeField(buf, "version", s.Version)

	buf.WriteString(">")

	// We never write </stream:stream>

	return buf.Bytes(), nil

}

func (s *stream) String() string {

	result, _ := s.MarshalXML()

	return string(result)

}

func parseStream(se xml.StartElement) (*stream, error) {

	s := &stream{}

	for _, attr := range se.Attr {

		switch strings.ToLower(attr.Name.Local) {

		case "to":

			s.To = attr.Value

		case "from":

			s.From = attr.Value

		case "id":

			s.Id = attr.Value

		case "lang":

			s.Lang = attr.Value

		case "version":

			s.Version = attr.Value

		}

	}

	return s, nil

}

func (s *streamError) MarshalXML() ([]byte, error) {

	buf := bytes.NewBuffer(nil)

	buf.WriteString("<stream:error>")

	xml.Marshal(buf, s.Any)

	if s.Text != nil {

		xml.Marshal(buf, s.Text)

	}

	buf.WriteString("</stream:error>")

	return buf.Bytes(), nil

}

func (e *errText) MarshalXML() ([]byte, error) {

	buf := bytes.NewBuffer(nil)

	buf.WriteString("<text")

	writeField(buf, "xmlns", NsStreams)

	writeField(buf, "xml:lang", e.Lang)

	buf.WriteString(">")

	xml.Escape(buf, []byte(e.Text))

	buf.WriteString("</text>")

	return buf.Bytes(), nil

}

func writeField(w io.Writer, field, value string) {

	if value != "" {

		io.WriteString(w, " ")

		io.WriteString(w, field)

		io.WriteString(w, `="`)

		xml.Escape(w, []byte(value))

		io.WriteString(w, `"`)

	}

}

func (u *Generic) String() string {

	if u == nil {

		return "nil"

	}

	var sub string

	if u.Any != nil {

		sub = u.Any.String()

	}

	return fmt.Sprintf("<%s %s>%s%s</%s %s>", u.XMLName.Space,

		u.XMLName.Local, sub, u.Chardata, u.XMLName.Space,

		u.XMLName.Local)

}

func marshalXML(st Stanza) ([]byte, error) {

	buf := bytes.NewBuffer(nil)

	buf.WriteString("<")

	buf.WriteString(st.GetName())

	if st.GetTo() != "" {

		writeField(buf, "to", st.GetTo())

	}

	if st.GetFrom() != "" {

		writeField(buf, "from", st.GetFrom())

	}

	if st.GetId() != "" {

		writeField(buf, "id", st.GetId())

	}

	if st.GetType() != "" {

		writeField(buf, "type", st.GetType())

	}

	if st.GetLang() != "" {

		writeField(buf, "xml:lang", st.GetLang())

	}

	buf.WriteString(">")

	if m, ok := st.(*Message); ok {

		err := xml.Marshal(buf, m.Subject)

		if err != nil {

			return nil, err

		}

		err = xml.Marshal(buf, m.Body)

		if err != nil {

			return nil, err

		}

		err = xml.Marshal(buf, m.Thread)

		if err != nil {

			return nil, err

		}

	}

	if p, ok := st.(*Presence); ok {

		err := xml.Marshal(buf, p.Show)

		if err != nil {

			return nil, err

		}

		err = xml.Marshal(buf, p.Status)

		if err != nil {

			return nil, err

		}

		err = xml.Marshal(buf, p.Priority)

		if err != nil {

			return nil, err

		}

	}

	if nested := st.GetNested(); nested != nil {

		for _, n := range nested {

			xml.Marshal(buf, n)

		}

	} else if st.innerxml() != "" {

		buf.WriteString(st.innerxml())

	}