package vectorstore_test

import (
	"context"
	"errors"
	"os"
	"path/filepath"
	"testing"

	"github.com/mathiasbq/hyperguild/ingestion/internal/vectorstore"
	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"
)

type stubStore struct {
	known    map[string]struct{}
	upserts  map[string][]float32
	deletes  []string
	failNext error
}

func (s *stubStore) KnownPaths(_ context.Context) (map[string]struct{}, error) {
	out := make(map[string]struct{}, len(s.known))
	for k := range s.known {
		out[k] = struct{}{}
	}
	return out, nil
}

func (s *stubStore) Upsert(_ context.Context, path string, v []float32) error {
	if s.failNext != nil {
		err := s.failNext
		s.failNext = nil
		return err
	}
	if s.upserts == nil {
		s.upserts = make(map[string][]float32)
	}
	s.upserts[path] = v
	return nil
}

func (s *stubStore) Delete(_ context.Context, path string) error {
	s.deletes = append(s.deletes, path)
	return nil
}

type stubEmbedder struct {
	vec []float32
	err error
}

func (e stubEmbedder) Embed(_ context.Context, _ string) ([]float32, error) {
	return e.vec, e.err
}

func writeNote(t *testing.T, dir, rel, body string) {
	t.Helper()
	full := filepath.Join(dir, rel)
	require.NoError(t, os.MkdirAll(filepath.Dir(full), 0o755))
	require.NoError(t, os.WriteFile(full, []byte(body), 0o644))
}

func TestSync_AddsNewFiles(t *testing.T) {
	dir := t.TempDir()
	writeNote(t, dir, "wiki/jepa-fx/facts/x.md", "body of x")
	writeNote(t, dir, "wiki/jepa-fx/facts/y.md", "body of y")

	store := &stubStore{known: map[string]struct{}{}}
	emb := stubEmbedder{vec: make([]float32, 768)}
	res, err := vectorstore.Sync(context.Background(), dir, store, emb)
	require.NoError(t, err)
	assert.Equal(t, 2, res.Added)
	assert.Empty(t, res.Deleted)
	assert.Contains(t, store.upserts, "wiki/jepa-fx/facts/x.md")
	assert.Contains(t, store.upserts, "wiki/jepa-fx/facts/y.md")
}

func TestSync_SkipsAlreadyKnown(t *testing.T) {
	dir := t.TempDir()
	writeNote(t, dir, "wiki/a/facts/x.md", "x")

	store := &stubStore{known: map[string]struct{}{"wiki/a/facts/x.md": {}}}
	emb := stubEmbedder{vec: make([]float32, 768)}
	res, err := vectorstore.Sync(context.Background(), dir, store, emb)
	require.NoError(t, err)
	assert.Equal(t, 0, res.Added)
	assert.Empty(t, store.upserts)
}

func TestSync_DeletesDisappearedFiles(t *testing.T) {
	dir := t.TempDir()
	require.NoError(t, os.MkdirAll(filepath.Join(dir, "wiki"), 0o755))
	// store has a path that doesn't exist on disk anymore
	store := &stubStore{known: map[string]struct{}{"wiki/old/facts/ghost.md": {}}}
	res, err := vectorstore.Sync(context.Background(), dir, &stubStoreWithDelete{stubStore: store}, stubEmbedder{vec: make([]float32, 768)})
	require.NoError(t, err)
	assert.Equal(t, 1, res.Deleted)
}

// stubStoreWithDelete is a thin wrapper to capture Delete calls;
// stubStore already implements Delete but we need the wrapper to mix
// store interfaces with sync-specific expectations.
type stubStoreWithDelete struct {
	*stubStore
}

func TestSync_SkipsIndexFiles(t *testing.T) {
	dir := t.TempDir()
	writeNote(t, dir, "wiki/a/_index.md", "moc")
	writeNote(t, dir, "wiki/a/facts/real.md", "body")

	store := &stubStore{known: map[string]struct{}{}}
	res, err := vectorstore.Sync(context.Background(), dir, store, stubEmbedder{vec: make([]float32, 768)})
	require.NoError(t, err)
	assert.Equal(t, 1, res.Added)
	assert.NotContains(t, store.upserts, "wiki/a/_index.md")
}

func TestSync_NoOpWhenComponentsNil(t *testing.T) {
	dir := t.TempDir()
	writeNote(t, dir, "wiki/a/facts/x.md", "x")
	res, err := vectorstore.Sync(context.Background(), dir, nil, nil)
	require.NoError(t, err)
	assert.Equal(t, 0, res.Added)
}

func TestSync_CollectsEmbedderErrors(t *testing.T) {
	dir := t.TempDir()
	writeNote(t, dir, "wiki/a/facts/x.md", "x")
	store := &stubStore{known: map[string]struct{}{}}
	emb := stubEmbedder{err: errors.New("upstream down")}
	res, err := vectorstore.Sync(context.Background(), dir, store, emb)
	require.NoError(t, err)
	assert.Equal(t, 0, res.Added)
	assert.Len(t, res.Errors, 1)
}