package checker

import (
	"context"
	"encoding/json"
	"fmt"

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

// fakeObs is a tiny ObservationGetter that returns a single payload regardless
// of the key requested. Tests use it to feed canned ResolverPropagationData
// into rules.
type fakeObs struct {
	payload any
	err     error
}

func newFakeObs(payload any) *fakeObs { return &fakeObs{payload: payload} }

func (f *fakeObs) Get(_ context.Context, _ sdk.ObservationKey, dest any) error {
	if f.err != nil {
		return f.err
	}
	raw, err := json.Marshal(f.payload)
	if err != nil {
		return fmt.Errorf("fakeObs marshal: %w", err)
	}
	return json.Unmarshal(raw, dest)
}

func (f *fakeObs) GetRelated(_ context.Context, _ sdk.ObservationKey) ([]sdk.RelatedObservation, error) {
	return nil, nil
}

// errObs always fails Get; used to verify error-path branches in rules.
type errObs struct{ err error }

func (e *errObs) Get(_ context.Context, _ sdk.ObservationKey, _ any) error { return e.err }
func (e *errObs) GetRelated(_ context.Context, _ sdk.ObservationKey) ([]sdk.RelatedObservation, error) {
	return nil, nil
}

// mkProbe is a small constructor used in many tests.
func mkProbe(rcode, sig string, records ...string) *RRProbe {
	return &RRProbe{Rcode: rcode, Signature: sig, Records: records, Transport: TransportUDP}
}

// mkResolver builds a ResolverView with a single probe.
func mkResolver(id, region string, filtered, reachable bool, probes map[string]*RRProbe) *ResolverView {
	return &ResolverView{
		ID: id, Name: id, IP: "0.0.0.0", Region: region,
		Filtered: filtered, Reachable: reachable, Transport: TransportUDP,
		Probes: probes,
	}
}

// statesByCode reorganises a slice of CheckState by Code for easy lookup.
func statesByCode(states []sdk.CheckState) map[string][]sdk.CheckState {
	out := map[string][]sdk.CheckState{}
	for _, s := range states {
		out[s.Code] = append(out[s.Code], s)
	}
	return out
}