package ingress

import (
	"bytes"
	"context"
	"crypto/rand"
	"crypto/sha256"
	"encoding/base64"
	"encoding/json"
	"net/http"
	"net/http/httptest"
	"os"
	"path/filepath"
	"strconv"
	"testing"
	"time"

	"yovision/bell/contracts"
	"yovision/bell/internal/event"
)

type ingressIDs struct{}

func (ingressIDs) NewEventID() (string, error) {
	return "evt_01J8XQ2K7M3P5R9T0V4W6Y8Z2B", nil
}

type ingressPrivacy struct{}

func (ingressPrivacy) VideoAllowed(context.Context, int64, int64, int64) (bool, error) {
	return true, nil
}

type fakeRepository struct {
	replayResult Result
	replayFound  bool
	replayErr    error
	processErr   error
	processed    int
}

func (f *fakeRepository) Replay(context.Context, string, string, [sha256.Size]byte, string, string, [sha256.Size]byte) (Result, bool, error) {
	return f.replayResult, f.replayFound, f.replayErr
}

func (f *fakeRepository) ProcessEvent(_ context.Context, _, _ string, _ [sha256.Size]byte, producer string, _ [sha256.Size]byte, value event.Event) (Result, error) {
	f.processed++
	if f.processErr != nil {
		return Result{}, f.processErr
	}
	return Result{SchemaVersion: 1, ProducerID: producer, SourceEventID: value.SourceEventID(), EventID: value.ID(), Status: "accepted", HTTPStatus: 201}, nil
}

func ingressCandidate(t *testing.T) []byte {
	t.Helper()
	raw, err := os.ReadFile(filepath.Join("..", "..", "..", "docs", "raw", "contracts", "event-v0.1.example-current.json"))
	if err != nil {
		t.Fatal(err)
	}
	var object map[string]any
	if err := json.Unmarshal(raw, &object); err != nil {
		t.Fatal(err)
	}
	delete(object, "id")
	object["kind"] = "zone_entry"
	object["severity"] = "medium"
	object["evidence"] = map[string]any{"snapshot_uris": []any{}, "clip_uri": nil, "clip_range": nil}
	encoded, err := json.Marshal(object)
	if err != nil {
		t.Fatal(err)
	}
	return encoded
}

func newIngressHandler(t *testing.T, repository Repository) (*Handler, []byte) {
	t.Helper()
	guard, err := event.NewEvidenceGuard("private-customer")
	if err != nil {
		t.Fatal(err)
	}
	factory, err := event.NewFactory(contracts.EventV01Schema, ingressIDs{}, ingressPrivacy{}, guard)
	if err != nil {
		t.Fatal(err)
	}
	secret := make([]byte, 32)
	if _, err := rand.Read(secret); err != nil {
		t.Fatal(err)
	}
	handler, err := NewHandler(repository, map[string]Key{"brain-a": {ProducerID: "brain-main", Secret: secret}}, factory)
	if err != nil {
		t.Fatal(err)
	}
	handler.now = func() time.Time { return time.Unix(1_800_000_000, 0).UTC() }
	return handler, secret
}

func signedRequest(t *testing.T, secret []byte, producer string, candidate []byte) *http.Request {
	t.Helper()
	body, err := json.Marshal(map[string]any{"schema_version": 1, "producer_id": producer, "candidate": json.RawMessage(candidate)})
	if err != nil {
		t.Fatal(err)
	}
	request := httptest.NewRequest(http.MethodPost, Path, bytes.NewReader(body))
	timestamp := strconv.FormatInt(1_800_000_000, 10)
	nonce := base64.RawURLEncoding.EncodeToString([]byte("0123456789abcdef"))
	request.Header.Set(HeaderKeyID, "brain-a")
	request.Header.Set(HeaderTimestamp, timestamp)
	request.Header.Set(HeaderNonce, nonce)
	request.Header.Set(HeaderSignature, base64.RawURLEncoding.EncodeToString(signature(secret, canonicalString(http.MethodPost, Path, timestamp, nonce, body))))
	return request
}

func TestHandlerAcceptsSignedCandidateAndRejectsProducerSpoofing(t *testing.T) {
	repository := &fakeRepository{}
	handler, secret := newIngressHandler(t, repository)
	response := httptest.NewRecorder()
	handler.ServeHTTP(response, signedRequest(t, secret, "brain-main", ingressCandidate(t)))
	if response.Code != http.StatusCreated || repository.processed != 1 {
		t.Fatalf("signed candidate: status=%d body=%s processed=%d", response.Code, response.Body.String(), repository.processed)
	}
	var result Result
	if err := json.Unmarshal(response.Body.Bytes(), &result); err != nil || result.Status != "accepted" || result.EventID == "" {
		t.Fatalf("invalid accepted response: %+v %v", result, err)
	}

	response = httptest.NewRecorder()
	handler.ServeHTTP(response, signedRequest(t, secret, "brain-spoofed", ingressCandidate(t)))
	if response.Code != http.StatusUnauthorized || repository.processed != 1 {
		t.Fatalf("producer spoofing was not rejected: %d %s", response.Code, response.Body.String())
	}
}

func TestHandlerReturnsDurableReplayAndStableConflicts(t *testing.T) {
	repository := &fakeRepository{replayFound: true, replayResult: Result{
		SchemaVersion: 1, ProducerID: "brain-main", SourceEventID: "source-1",
		EventID: "evt_01J8XQ2K7M3P5R9T0V4W6Y8Z2B", Status: "duplicate", HTTPStatus: 200,
	}}
	handler, secret := newIngressHandler(t, repository)
	response := httptest.NewRecorder()
	handler.ServeHTTP(response, signedRequest(t, secret, "brain-main", ingressCandidate(t)))
	if response.Code != http.StatusOK || repository.processed != 0 {
		t.Fatalf("durable replay did not bypass factory persistence: %d", response.Code)
	}

	repository.replayFound = false
	repository.replayErr = ErrSourceConflict
	response = httptest.NewRecorder()
	handler.ServeHTTP(response, signedRequest(t, secret, "brain-main", ingressCandidate(t)))
	if response.Code != http.StatusConflict {
		t.Fatalf("source conflict status=%d body=%s", response.Code, response.Body.String())
	}
}

func TestHandlerRejectsInvalidSignatureAndUpstreamPlatformID(t *testing.T) {
	repository := &fakeRepository{}
	handler, secret := newIngressHandler(t, repository)
	request := signedRequest(t, secret, "brain-main", ingressCandidate(t))
	request.Header.Set(HeaderSignature, base64.RawURLEncoding.EncodeToString(make([]byte, 32)))
	response := httptest.NewRecorder()
	handler.ServeHTTP(response, request)
	if response.Code != http.StatusUnauthorized {
		t.Fatalf("invalid signature status=%d", response.Code)
	}

	var object map[string]any
	if err := json.Unmarshal(ingressCandidate(t), &object); err != nil {
		t.Fatal(err)
	}
	object["id"] = "evt_01J8XQ2K7M3P5R9T0V4W6Y8Z2B"
	withID, _ := json.Marshal(object)
	response = httptest.NewRecorder()
	handler.ServeHTTP(response, signedRequest(t, secret, "brain-main", withID))
	if response.Code != http.StatusUnprocessableEntity || repository.processed != 0 {
		t.Fatalf("upstream ID status=%d body=%s", response.Code, response.Body.String())
	}
}