package checker

import (
	"fmt"
	"time"

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

// Version is overridden at build time via -ldflags by main.go and plugin.go.
var Version = "built-in"

func Definition() *sdk.CheckerDefinition {
	def := &sdk.CheckerDefinition{
		ID:      "alias",
		Name:    "CNAME / DNAME / ALIAS chain",
		Version: Version,
		Availability: sdk.CheckerAvailability{
			ApplyToService: true,
			LimitToServices: []string{
				"svcs.CNAME",
				"svcs.SpecialCNAME",
			},
		},
		ObservationKeys: []sdk.ObservationKey{ObservationKeyAlias},
		Options: sdk.CheckerOptionsDocumentation{
			UserOpts: []sdk.CheckerOptionDocumentation{
				{
					Id:          "allowApexCNAME",
					Type:        "bool",
					Label:       "Allow CNAME at apex",
					Description: "Shared by cname_at_apex and cname_coexistence: when enabled, a CNAME at a zone apex (and its coexistence violations) are downgraded to warnings. RFC 1912 forbids this, so leaving it off is strongly recommended.",
					Default:     defaultAllowApexCNAME,
				},
				{
					Id:          "recognizeApexFlattening",
					Type:        "bool",
					Label:       "Recognize ALIAS/ANAME flattening",
					Description: "Shared by apex_flattening and cname_coexistence: when enabled, providers that serve A/AAAA at the apex (ALIAS/ANAME pseudo-records) are recognised as intentional and excused from coexistence violations.",
					Default:     defaultRecognizeApexFlattening,
				},
			},
			DomainOpts: []sdk.CheckerOptionDocumentation{
				{
					Id:       "domain_name",
					Label:    "Parent domain name",
					AutoFill: sdk.AutoFillDomainName,
				},
				{
					Id:       "subdomain",
					Label:    "Subdomain",
					AutoFill: sdk.AutoFillSubdomain,
				},
			},
			ServiceOpts: []sdk.CheckerOptionDocumentation{
				{
					Id:       "service_type",
					Label:    "Service type",
					AutoFill: sdk.AutoFillServiceType,
				},
				{
					Id:       "service",
					Label:    "Service",
					AutoFill: sdk.AutoFillService,
				},
				{
					Id:       "domain_name",
					Label:    "Parent domain name",
					AutoFill: sdk.AutoFillDomainName,
				},
			},
		},
		Rules: []sdk.CheckRule{
			apexLookupRule{},
			chainLoopRule{},
			chainLengthRule{},
			chainQueryErrorRule{},
			chainRcodeRule{},
			hopTTLRule{},
			cnameAtApexRule{},
			apexFlatteningRule{},
			cnameCoexistenceRule{},
			cnameDnssecRule{},
			targetResolvableRule{},
			multipleRecordsRule{},
		},
		HasHTMLReport: true,
		Interval: &sdk.CheckIntervalSpec{
			Min:     5 * time.Minute,
			Max:     24 * time.Hour,
			Default: 1 * time.Hour,
		},
	}
	def.BuildRulesInfo()
	return def
}

// ValidateOptions runs on the host before Collect so bad options are rejected
// up-front rather than producing an unhelpful runtime error mid-walk.
func (p *aliasProvider) ValidateOptions(opts sdk.CheckerOptions) error {
	if v, ok := opts["maxChainLength"]; ok {
		f, ok := v.(float64)
		if !ok {
			return fmt.Errorf("maxChainLength must be a number")
		}
		if f < 1 {
			return fmt.Errorf("maxChainLength must be >= 1")
		}
	}
	if v, ok := opts["minTargetTTL"]; ok {
		f, ok := v.(float64)
		if !ok {
			return fmt.Errorf("minTargetTTL must be a number")
		}
		if f < 0 {
			return fmt.Errorf("minTargetTTL must be >= 0")
		}
	}
	return nil
}