// This file is part of the happyDomain (R) project.
// Copyright (c) 2020-2026 happyDomain
// Authors: Pierre-Olivier Mercier, et al.
//
// This program is offered under a commercial and under the AGPL license.
// For commercial licensing, contact us at <contact@happydomain.org>.
//
// For AGPL licensing:
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program.  If not, see <https://www.gnu.org/licenses/>.

// Package checker implements the generic SRV records checker for happyDomain.
//
// TLS/certificate testing is intentionally out of scope: it is handled by a
// dedicated TLS checker.
package checker

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

const ObservationKeySRV sdk.ObservationKey = "srv_records"

const (
	protoTCP = "tcp"
	protoUDP = "udp"
)

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"`

	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"`

	Probes []ProbeResult `json:"probes,omitempty"`
}

type ProbeResult struct {
	Address string `json:"address"`
	Proto   string `json:"proto"`
	// Connected reports whether the probe should be treated as reachable.
	// For TCP this is a true handshake. For UDP, where silent drops are
	// indistinguishable from a working service, a timeout also sets
	// Connected=true and populates Error with an explanatory note: the
	// rule treats "no ICMP unreachable" as best-effort reachable.
	Connected bool    `json:"connected"`
	LatencyMs float64 `json:"latencyMs,omitempty"`
	Error     string  `json:"error,omitempty"`
}

type SRVData struct {
	ServiceDomain string      `json:"serviceDomain"`
	Records       []SRVRecord `json:"records"`
}