// Package checker implements the generic SRV records checker for happyDomain.
//
// For each SRV record attached to the target service it performs:
//
//   - DNS resolution of every SRV target (A/AAAA, CNAME detection)
//   - TCP connectivity test on target:port (_tcp SRVs)
//   - UDP probe on target:port (_udp SRVs)
//
// TLS/certificate testing is intentionally out of scope: it is handled by a
// dedicated TLS checker.
//
// Checks are performed natively using the Go standard library (no external
// testsuite).
package checker

import (
	sdk "git.happydns.org/checker-sdk-go/checker"
)

const ObservationKeySRV sdk.ObservationKey = "srv_records"

type SRVRecord struct {
	Service  string `json:"service"`
	Proto    string `json:"proto"`
	Owner    string `json:"owner"`
	Target   string `json:"target"`
	Port     uint16 `json:"port"`
	Priority uint16 `json:"priority"`
	Weight   uint16 `json:"weight"`

	// DNS resolution results
	IsNullTarget bool     `json:"isNullTarget,omitempty"` // target == "." means "no service"
	IsCNAME      bool     `json:"isCNAME,omitempty"`      // RFC 2782: MUST NOT be CNAME
	CNAMEChain   []string `json:"cnameChain,omitempty"`
	Addresses    []string `json:"addresses,omitempty"`
	ResolveError string   `json:"resolveError,omitempty"`

	// Reachability checks per address
	Probes []ProbeResult `json:"probes,omitempty"`
}

type ProbeResult struct {
	Address   string  `json:"address"`
	Proto     string  `json:"proto"` // "tcp" or "udp"
	Connected bool    `json:"connected"`
	LatencyMs float64 `json:"latencyMs,omitempty"`
	Error     string  `json:"error,omitempty"`
}

type SRVData struct {
	ServiceDomain string      `json:"serviceDomain"` // e.g. _sip._tcp.example.com
	Records       []SRVRecord `json:"records"`
	CollectError  string      `json:"collectError,omitempty"`
}