// Copyright 2026 Beacon Contributors
// SPDX-License-Identifier: AGPL-3.0-or-later

package ingest

import (
	"context"
	"crypto/ed25519"
	"encoding/binary"
	"encoding/hex"
	"encoding/json"
	"strings"
	"testing"
	"time"

	"github.com/MeshCore-Beacon/beacon-server/internal/hub"
	"github.com/MeshCore-Beacon/beacon-server/internal/keystore"
	"github.com/meshcore-go/meshcore-go"
)

// mapKeys is a ChannelKeyStore stub that returns a fixed set of entries for
// any hash, letting tests control whether a channel's key is "known".
type mapKeys struct {
	entries map[byte][]keystore.Entry
}

func (k *mapKeys) GetKey(hash []byte) []keystore.Entry {
	if len(hash) == 0 {
		return nil
	}
	return k.entries[hash[0]]
}

// buildAdvertPacket signs (or, if tamper is true, signs then mutates) an
// advert payload and wraps it in a minimal Packet with no path (zero-hop).
func buildAdvertPacket(t *testing.T, tamper bool) *meshcore.Packet {
	return buildAdvertPacketWithData(t, []byte{meshcore.AdvertTypeRepeater}, tamper)
}

func buildAdvertPacketWithData(t *testing.T, data []byte, tamper bool) *meshcore.Packet {
	t.Helper()
	pub, priv, err := ed25519.GenerateKey(nil)
	if err != nil {
		t.Fatalf("generate key: %v", err)
	}
	id, err := meshcore.NewIdentityFromBytes(pub)
	if err != nil {
		t.Fatalf("new identity: %v", err)
	}
	advert := &meshcore.Advert{
		PublicKey:  id,
		Timestamp:  12345,
		RawAppData: data,
	}
	advert.Sign(priv)
	if tamper {
		// Flip the device-role bits after signing, as if a relay (or an
		// attacker) altered the payload in transit.
		advert.RawAppData = []byte{meshcore.AdvertTypeRoom}
	}
	payload, err := advert.ToBytes()
	if err != nil {
		t.Fatalf("advert to bytes: %v", err)
	}
	return &meshcore.Packet{
		Header:  meshcore.MakeHeader(meshcore.RouteTypeFlood, meshcore.PayloadTypeAdvert, 0),
		Payload: payload,
	}
}

func TestAdvertLocationPresence(t *testing.T) {
	for _, tc := range []struct {
		name                   string
		present, tamper, clear bool
		lat, lon               int32
	}{
		{"ordinary location", true, false, false, 45000000, -75000000},
		{"explicit reset", true, false, true, 0, 0},
		{"zero latitude", true, false, false, 0, -75000000},
		{"zero longitude", true, false, false, 45000000, 0},
		{"no location", false, false, false, 0, 0},
		{"tampered reset", true, true, false, 0, 0},
	} {
		t.Run(tc.name, func(t *testing.T) {
			data := []byte{meshcore.AdvertTypeRepeater}
			if tc.present {
				// Preserve the wire presence bit even for zero coordinates; the
				// library's AppData encoder omits location when both values are zero.
				data[0] |= meshcore.AdvertLatLonMask
				data = binary.LittleEndian.AppendUint32(data, uint32(tc.lat))
				data = binary.LittleEndian.AppendUint32(data, uint32(tc.lon))
			}
			worker, store := newTestWorker()
			packet := buildAdvertPacketWithData(t, data, tc.tamper)
			worker.handlePayloadTypeSideEffects(context.Background(), packet, "YOW", []byte{1}, RadioSettings{}, nil, nil, nil, 0)
			if tc.tamper {
				if store.upsertNodeCalls != 0 {
					t.Fatal("invalid signature updated the node")
				}
				return
			}
			if store.upsertNodeCalls != 1 {
				t.Fatal("signed advert did not update the node")
			}
			got := store.upsertNodeParams
			if got.ClearLocation != tc.clear {
				t.Fatalf("ClearLocation = %v, want %v", got.ClearLocation, tc.clear)
			}
			if !tc.present || tc.clear {
				if got.Latitude != nil || got.Longitude != nil {
					t.Fatal("absent location became an update")
				}
				return
			}
			if got.Latitude == nil || got.Longitude == nil || *got.Latitude != float64(tc.lat)/1e6 || *got.Longitude != float64(tc.lon)/1e6 {
				t.Fatal("advertised coordinates did not reach the node update")
			}
		})
	}
}

func TestAdvertClearEmitsNullLocation(t *testing.T) {
	w, _ := newTestWorker()
	go w.hub.Run()
	client := w.hub.NewClient()
	defer w.hub.Remove(client)
	w.hub.AddScope(client, "clear", hub.Scope{Events: []hub.EventType{hub.EventNodeUpdate, hub.EventObserverStatus}})
	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
	defer cancel()
	waitForSummarySubscriber(t, ctx, w.hub, client)
	for _, tc := range []struct {
		name          string
		present, want bool
		lat, lon      int32
		wantLat       string
		wantLng       string
	}{
		{"explicit reset sends null", true, true, 0, 0, "null", "null"},
		{"omission sends nothing", false, false, 0, 0, "", ""},
		{"real location sends coordinates", true, true, 45000000, -75000000, "45", "-75"},
	} {
		t.Run(tc.name, func(t *testing.T) {
			data := []byte{meshcore.AdvertTypeRepeater}
			if tc.present {
				data[0] |= meshcore.AdvertLatLonMask
				data = binary.LittleEndian.AppendUint32(data, uint32(tc.lat))
				data = binary.LittleEndian.AppendUint32(data, uint32(tc.lon))
			}
			w.handlePayloadTypeSideEffects(ctx, buildAdvertPacketWithData(t, data, false), "AAA", []byte{1}, RadioSettings{}, nil, nil, nil, 0)
			for {
				select {
				case event := <-client.Send:
					if event.Type != hub.EventNodeUpdate {
						continue
					}
					payload := string(event.Payload)
					for field, want := range map[string]string{`"lat"`: tc.wantLat, `"lng"`: tc.wantLng} {
						if tc.want && !strings.Contains(payload, field+":"+want+",") {
							t.Fatalf("%s != %s: %s", field, want, payload)
						}
						if !tc.want && strings.Contains(payload, field) {
							t.Fatalf("%s present on omission: %s", field, payload)
						}
					}
					return
				case <-ctx.Done():
					t.Fatal("node update not received")
				}
			}
		})
	}
}

func TestHandlePayloadTypeSideEffects_Advert_ValidSignature_UpsertsNode(t *testing.T) {
	w, db := newTestWorker()
	packet := buildAdvertPacket(t, false)

	w.handlePayloadTypeSideEffects(context.Background(), packet, "TEST", []byte{0x01}, RadioSettings{}, nil, nil, nil, 0)

	if db.upsertNodeCalls != 1 {
		t.Errorf("expected UpsertNode to be called once for a validly-signed advert, got %d", db.upsertNodeCalls)
	}
}

func TestHandlePayloadTypeSideEffects_Advert_InvalidSignature_SkipsUpsert(t *testing.T) {
	w, db := newTestWorker()
	packet := buildAdvertPacket(t, true)

	w.handlePayloadTypeSideEffects(context.Background(), packet, "TEST", []byte{0x01}, RadioSettings{}, nil, nil, nil, 0)

	if db.upsertNodeCalls != 0 {
		t.Errorf("expected UpsertNode NOT to be called for a tampered advert, got %d calls", db.upsertNodeCalls)
	}
}

func buildGrpTxtPacket(t *testing.T, channelHash byte, psk []byte) *meshcore.Packet {
	t.Helper()
	grpTxt, err := (&meshcore.GroupTextPayload{
		Timestamp: 1000,
		Sender:    "ded",
		Text:      "hello",
	}).Encrypt(channelHash, psk)
	if err != nil {
		t.Fatalf("encrypt group text: %v", err)
	}
	payload, err := grpTxt.ToBytes()
	if err != nil {
		t.Fatalf("group text to bytes: %v", err)
	}
	return &meshcore.Packet{
		Header:  meshcore.MakeHeader(meshcore.RouteTypeFlood, meshcore.PayloadTypeGrpTxt, 0),
		Payload: payload,
	}
}

func TestHandlePayloadTypeSideEffects_GrpTxt_KnownKey_OnlyUpsertsKeyedChannel(t *testing.T) {
	w, db := newTestWorker()
	psk := make([]byte, 16)
	channelHash := byte(0x42)
	w.keys = &mapKeys{entries: map[byte][]keystore.Entry{
		channelHash: {{Key: psk, Fingerprint: []byte{0xAA}, Name: "Public", Hashtag: "public"}},
	}}
	packet := buildGrpTxtPacket(t, channelHash, psk)

	w.handlePayloadTypeSideEffects(context.Background(), packet, "TEST", []byte{0x02}, RadioSettings{}, nil, nil, nil, 0)

	if db.upsertChannelCalls != 1 {
		t.Errorf("expected UpsertChannel to be called once, got %d", db.upsertChannelCalls)
	}
	if db.upsertChannelHashOnlyCalls != 0 {
		t.Errorf("expected UpsertChannelHashOnly NOT to be called when the key is known, got %d calls", db.upsertChannelHashOnlyCalls)
	}
}

func TestHandlePayloadTypeSideEffects_GrpTxt_UnknownKey_OnlyUpsertsHashOnlyChannel(t *testing.T) {
	w, db := newTestWorker() // default stubKeys returns no entries for any hash
	channelHash := byte(0x99)
	packet := buildGrpTxtPacket(t, channelHash, make([]byte, 16))

	w.handlePayloadTypeSideEffects(context.Background(), packet, "TEST", []byte{0x03}, RadioSettings{}, nil, nil, nil, 0)

	if db.upsertChannelHashOnlyCalls != 1 {
		t.Errorf("expected UpsertChannelHashOnly to be called once for an unknown-key channel, got %d", db.upsertChannelHashOnlyCalls)
	}
	if db.upsertChannelCalls != 0 {
		t.Errorf("expected UpsertChannel NOT to be called when the key is unknown, got %d calls", db.upsertChannelCalls)
	}
}

// packetEnvelope wraps a packet in the minimal broker JSON that handlePacket expects.
func packetEnvelope(t *testing.T, packet *meshcore.Packet) []byte {
	t.Helper()
	raw, err := packet.ToBytes()
	if err != nil {
		t.Fatalf("packet to bytes: %v", err)
	}
	env, err := json.Marshal(map[string]string{
		"raw":       hex.EncodeToString(raw),
		"timestamp": time.Now().UTC().Format("2006-01-02T15:04:05.000000"),
	})
	if err != nil {
		t.Fatalf("marshal envelope: %v", err)
	}
	return env
}

func TestHandlePacket_GrpTxt_UpsertsChannelIATA(t *testing.T) {
	w, db := newTestWorker()
	db.observationInserted = true
	envelope := packetEnvelope(t, buildGrpTxtPacket(t, 0x1a, make([]byte, 16)))

	w.handlePacket(context.Background(), "YOW", "0102", envelope)

	if db.upsertChannelIATACalls != 1 {
		t.Errorf("expected UpsertChannelIATA to be called once for a stored group text, got %d", db.upsertChannelIATACalls)
	}
}

func TestHandlePacket_GrpTxt_DedupObservation_StillUpsertsChannelIATA(t *testing.T) {
	w, db := newTestWorker() // stub reports the observation as a duplicate
	envelope := packetEnvelope(t, buildGrpTxtPacket(t, 0x1a, make([]byte, 16)))

	w.handlePacket(context.Background(), "YOW", "0102", envelope)

	if db.upsertChannelIATACalls != 1 {
		t.Errorf("expected UpsertChannelIATA to run for a duplicate observation too, got %d calls", db.upsertChannelIATACalls)
	}
}

func TestHandlePacket_Advert_SkipsChannelIATA(t *testing.T) {
	w, db := newTestWorker()
	db.observationInserted = true
	envelope := packetEnvelope(t, buildAdvertPacket(t, false))

	w.handlePacket(context.Background(), "YOW", "0102", envelope)

	if db.upsertChannelIATACalls != 0 {
		t.Errorf("expected UpsertChannelIATA NOT to be called for a non-channel packet, got %d calls", db.upsertChannelIATACalls)
	}
	if len(db.traceHearings) != 0 {
		t.Errorf("expected RecordTrace NOT to be called for a non-trace packet, got %d calls", len(db.traceHearings))
	}
}

func buildTracePacket(t *testing.T) *meshcore.Packet {
	t.Helper()
	payload, err := (&meshcore.Trace{Tag: 0xdeadbeef, AuthCode: 1, PathHashes: []byte{0xaa, 0xbb}}).ToBytes()
	if err != nil {
		t.Fatalf("trace to bytes: %v", err)
	}
	return &meshcore.Packet{
		Header:  meshcore.MakeHeader(meshcore.RouteTypeFlood, meshcore.PayloadTypeTrace, 0),
		Payload: payload,
	}
}

func TestHandlePacket_Trace_RecordsTrace(t *testing.T) {
	w, db := newTestWorker()
	db.observationInserted = true
	db.packetIsNew = true
	envelope := packetEnvelope(t, buildTracePacket(t))

	w.handlePacket(context.Background(), "YOW", "0102", envelope)
	db.packetIsNew, db.observationInserted = false, false
	w.handlePacket(context.Background(), "YOW", "0102", envelope)

	if len(db.traceHearings) != 2 {
		t.Fatalf("expected RecordTrace for every hearing, got %d", len(db.traceHearings))
	}
	for _, h := range db.traceHearings {
		if h.IATA != "YOW" || h.HeardAt.IsZero() || hex.EncodeToString(h.TraceTag) != "efbeadde" {
			t.Errorf("unexpected hearing %+v", h)
		}
	}
}