// Package api speaks the AutoDNS XML gateway that Schlundtech exposes at
// gateway.schlundtech.de. It is the only place in this program that performs
// HTTP.
//
// The gateway answers HTTP 200 even when a task fails, so every response is
// parsed and judged on result/status/type and result/msg — never on the HTTP
// status code. A non-2xx status from this host is an nginx 404 for a wrong
// path, not an application error.
package api

import "encoding/xml"

// Request is the AutoDNS request envelope: one auth block plus one or more
// task blocks.
type Request struct {
	XMLName  xml.Name `xml:"request"`
	Auth     Auth     `xml:"auth"`
	Language string   `xml:"language,omitempty"`
	Task     []Task   `xml:"task"`
}

// Auth carries the gateway credentials. Context is the project the records
// belong to; for Schlundtech it is 10.
type Auth struct {
	User     string `xml:"user"`
	Password string `xml:"password"`
	Context  string `xml:"context"`
	// Token is the optional second-factor token, when the account has 2FA on.
	Token string `xml:"token,omitempty"`
}

// Task is a single task block. The API is task-specific below the code
// element, so only the sub-structures a task can carry are modelled and the
// caller populates the one it needs.
type Task struct {
	Code string `xml:"code"`

	// Zone identifies the zone for a zone info or zone update task. Its Name
	// is empty for a zone list.
	Zone *ZoneRef `xml:"zone,omitempty"`

	// View, Where and Key belong to a list query.
	View  *View    `xml:"view,omitempty"`
	Where *Where   `xml:"where,omitempty"`
	Key   []string `xml:"key,omitempty"`

	// Default is the payload of a zone update.
	Default *Update `xml:"default,omitempty"`
}

// ZoneRef names a zone and the name server that serves it. SystemNS is
// mandatory on updates — the gateway refuses the task without it.
type ZoneRef struct {
	Name      string `xml:"name"`
	SystemNS  string `xml:"system_ns"`
	VirtualNS string `xml:"virtual_name_server,omitempty"`
}

// View bounds a list query.
type View struct {
	Offset   int `xml:"offset"`
	Limit    int `xml:"limit"`
	Children int `xml:"children,omitempty"`
}

// Where filters a list query.
type Where struct {
	Key      string `xml:"key"`
	Operator string `xml:"operator"`
	Value    string `xml:"value"`
}

// Update is the payload of a zone update. rr_add and rr_rem are repeated
// elements: one sibling per record, not one element with children.
type Update struct {
	RRAdd []Record `xml:"rr_add"`
	RRRem []Record `xml:"rr_rem"`
}

// Record is one resource record. Name is relative to the zone; the zone apex
// is the empty string.
type Record struct {
	Name  string `xml:"name"`
	Type  string `xml:"type"`
	Value string `xml:"value"`
	TTL   int    `xml:"ttl,omitempty"`
	Pref  int    `xml:"pref,omitempty"`
}

// Response is the AutoDNS response envelope. Result is repeated because a
// multi-zone task answers once per zone.
type Response struct {
	XMLName xml.Name `xml:"response"`
	Result  []Result `xml:"result"`
	Stid    string   `xml:"stid"`
}

// Result is the per-task outcome.
type Result struct {
	Data   *Data  `xml:"data,omitempty"`
	Status Status `xml:"status"`
	Msg    []Msg  `xml:"msg,omitempty"`
}

// Status is the overall task status. Type is "success", "error" or
// "notification".
type Status struct {
	Code string `xml:"code"`
	Type string `xml:"type"`
	Text string `xml:"text"`
}

// Msg is a system message. On failure this is where the actionable code and
// text live; status stays generic (E00000).
type Msg struct {
	Code   string  `xml:"code"`
	Type   string  `xml:"type"`
	Text   string  `xml:"text"`
	Object *Object `xml:"object,omitempty"`
}

// Object names what a Msg refers to.
type Object struct {
	Type  string `xml:"type"`
	Value string `xml:"value"`
}

// Data is the payload of an info or list task.
type Data struct {
	Summary int    `xml:"summary"`
	Zone    []Zone `xml:"zone"`
}

// Zone is a DNS zone. The list task returns the summary fields; an info task
// additionally returns every record in RRs.
type Zone struct {
	Name     string   `xml:"name"`
	Origin   string   `xml:"origin,omitempty"`
	SystemNS string   `xml:"system_ns"`
	SOA      *SOA     `xml:"soa,omitempty"`
	RRs      []Record `xml:"rr"`
}

// SOA is a zone's start-of-authority record.
type SOA struct {
	TTL     int    `xml:"ttl,omitempty"`
	Refresh int    `xml:"refresh,omitempty"`
	Retry   int    `xml:"retry,omitempty"`
	Expire  int    `xml:"expire,omitempty"`
	Email   string `xml:"email,omitempty"`
}