// Package checker detects dangling pointer records (CNAME/MX/SRV/NS) whose external targets
// may have expired or been re-registered, enabling subdomain takeover.
package checker

import (
	"encoding/json"
)

const ObservationKeyDangling = "dangling_records"

// DanglingData is the raw observation payload; one Pointer per (owner, rrtype, target) triple.
type DanglingData struct {
	Zone            string    `json:"zone,omitempty"`
	ServicesScanned int       `json:"services_scanned"`
	Pointers        []Pointer `json:"pointers,omitempty"`
	// CollectErrors surfaces non-fatal scan problems so silent skips don't masquerade as a clean pass.
	CollectErrors []string `json:"collect_errors,omitempty"`
}

// Pointer is one (owner, rrtype, target) triple from the zone, with its DNS resolution verdict.
type Pointer struct {
	Owner     string `json:"owner"`
	Subdomain string `json:"subdomain"`
	Rrtype    string `json:"rrtype"`
	Target    string `json:"target"`
	// External flags takeover risk: Target's registrable domain differs from the zone's.
	External    bool   `json:"external"`
	Registrable string `json:"registrable,omitempty"`
	// ServiceType identifies the happyDomain service for linking back to the edit screen.
	ServiceType      string `json:"service_type,omitempty"`
	Resolution       string `json:"resolution"`
	ResolutionDetail string `json:"resolution_detail,omitempty"`
}

// rawZone is a partial Zone type redeclared here to avoid importing the happyDomain module.
type rawZone struct {
	DomainName string                  `json:"domain_name,omitempty"`
	Services   map[string][]rawService `json:"services"`
}

type rawService struct {
	Type    string          `json:"_svctype"`
	Domain  string          `json:"_domain"`
	Service json.RawMessage `json:"Service"`
}

type cnameBody struct {
	Record struct {
		Hdr struct {
			Name string `json:"Name"`
		} `json:"Hdr"`
		Target string `json:"Target"`
	} `json:"cname"`
}

type mxRecord struct {
	Hdr struct {
		Name string `json:"Name"`
	} `json:"Hdr"`
	Mx string `json:"Mx"`
}

type mxsBody struct {
	MXs []mxRecord `json:"mx"`
}

type srvRecord struct {
	Hdr struct {
		Name string `json:"Name"`
	} `json:"Hdr"`
	Target string `json:"Target"`
}

type srvsBody struct {
	Records []srvRecord `json:"srv"`
}

// orphanRecord wraps an svcs.Orphan body; Hdr.Rrtype is sniffed to pick the right field.
type orphanRecord struct {
	Record struct {
		Hdr struct {
			Name   string `json:"Name"`
			Rrtype uint16 `json:"Rrtype"`
		} `json:"Hdr"`
		// Optional fields, populated for the relevant rrtype.
		Target string `json:"Target,omitempty"`
		Mx     string `json:"Mx,omitempty"`
		Ns     string `json:"Ns,omitempty"`
	} `json:"record"`
}