// 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"

	"flag"

	"fmt"

	"io"

	"os"

	"regexp"

	"strings"

	"xml"

)

// 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:"attr"`

	From string `xml:"attr"`

	Id string `xml:"attr"`

	Lang string `xml:"attr"`

	Version string `xml:"attr"`

}

var _ xml.Marshaler = &stream{}

var _ fmt.Stringer = &stream{}

// <stream:error>

type streamError struct {

	Any Generic

	Text *errText

}

var _ xml.Marshaler = &streamError{}

type errText struct {

	Lang string `xml:"attr"`

	Text string `xml:"chardata"`

}

var _ xml.Marshaler = &errText{}

type Features struct {

	Starttls *starttls

	Mechanisms mechs

	Bind *bindIq

	Session *Generic

	Any *Generic

}

type starttls struct {

	XMLName xml.Name

	Required *string

}

type mechs struct {

	Mechanism []string

}

type auth struct {

	XMLName xml.Name

	Chardata string `xml:"chardata"`

	Mechanism string `xml:"attr"`

	Any *Generic

}

// 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

	// A (non-error) nested element, if any.

	GetNested() interface{}

	setNested(interface{})

	generic() *Generic

	innerxml() string

}

// message stanza

type Message struct {

	To string `xml:"attr"`

	From string `xml:"attr"`

	Id string `xml:"attr"`

	Type string `xml:"attr"`

	Lang string `xml:"attr"`

	Innerxml string `xml:"innerxml"`

	Error *Error

	Subject *Generic

	Body *Generic

	Thread *Generic

	Any *Generic

	Nested interface{}

}

var _ xml.Marshaler = &Message{}

var _ Stanza = &Message{}

// presence stanza

type Presence struct {

	To string `xml:"attr"`

	From string `xml:"attr"`

	Id string `xml:"attr"`

	Type string `xml:"attr"`

	Lang string `xml:"attr"`

	Innerxml string `xml:"innerxml"`

	Error *Error

	Show *Generic

	Status *Generic

	Priority *Generic

	Any *Generic

	Nested interface{}

}

var _ xml.Marshaler = &Presence{}

var _ Stanza = &Presence{}

// iq stanza

type Iq struct {

	To string `xml:"attr"`

	From string `xml:"attr"`

	Id string `xml:"attr"`

	Type string `xml:"attr"`

	Lang string `xml:"attr"`

	Innerxml string `xml:"innerxml"`

	Error *Error

	Any *Generic

	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:"attr"`

	// Any nested element, if present.

	Any *Generic

}

var _ os.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

	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) bool {

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

	parts := r.FindStringSubmatch(val)

	if parts == nil {

		return false

	}

	jid.Node = parts[2]

	jid.Domain = parts[3]

	jid.Resource = parts[5]

	return true

}

func (s *stream) MarshalXML() ([]byte, os.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, os.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, os.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, os.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, os.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 st.GetNested() != nil {

		xml.Marshal(buf, st.GetNested())

	} else if st.generic() != nil {

		xml.Marshal(buf, st.generic())

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

		buf.WriteString(st.innerxml())

	}

	buf.WriteString("</")

	buf.WriteString(st.GetName())

	buf.WriteString(">")

	return buf.Bytes(), nil

}