package knowledge

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

	"github.com/example/glpi-ai-agent/internal/model"
)

func TestLoadSearchesOnlyAllowedSources(t *testing.T) {
	dir := t.TempDir()
	data := filepath.Join(dir, "data")
	if err := os.MkdirAll(data, 0o755); err != nil {
		t.Fatal(err)
	}
	internal := `{"id":"I1","title":"VPN intern","text":"gateway vpn","answer":"x","source":"internal-kb","language":"de-DE","communication_style":"formal"}`
	vendor := `{"id":"V1","title":"VPN vendor","text":"gateway vpn","answer":"x","source":"vendor-docs","language":"de-DE","communication_style":"formal"}`
	if err := os.WriteFile(filepath.Join(dir, "internal.json"), []byte(internal), 0o644); err != nil {
		t.Fatal(err)
	}
	if err := os.WriteFile(filepath.Join(dir, "vendor.json"), []byte(vendor), 0o644); err != nil {
		t.Fatal(err)
	}
	s, err := Load(context.Background(), dir, data, nil, false, []string{"internal-kb"})
	if err != nil {
		t.Fatal(err)
	}
	if s.Count() != 1 {
		t.Fatalf("count=%d", s.Count())
	}
	hits, err := s.Search(context.Background(), "vpn gateway", 10)
	if err != nil {
		t.Fatal(err)
	}
	if len(hits) != 1 || hits[0].Doc.Source != "internal-kb" {
		t.Fatalf("unexpected hits: %+v", hits)
	}
}

func TestLoadRequiresSourceMetadata(t *testing.T) {
	dir := t.TempDir()
	data := filepath.Join(dir, "data")
	if err := os.MkdirAll(data, 0o755); err != nil {
		t.Fatal(err)
	}
	if err := os.WriteFile(filepath.Join(dir, "bad.json"), []byte(`{"id":"I1","title":"Missing source"}`), 0o644); err != nil {
		t.Fatal(err)
	}
	if _, err := Load(context.Background(), dir, data, nil, false, []string{"internal-kb"}); err == nil {
		t.Fatal("expected missing source to fail")
	}
}

func TestLoadMissingDirectoryReturnsHelpfulError(t *testing.T) {
	missing := filepath.Join(t.TempDir(), "does-not-exist")
	_, err := Load(context.Background(), missing, t.TempDir(), nil, false, []string{"internal-kb"})
	if err == nil {
		t.Fatal("expected missing knowledge directory to fail")
	}
	if got := err.Error(); !strings.Contains(got, "read knowledge directory") || !strings.Contains(got, missing) {
		t.Fatalf("unexpected error: %v", err)
	}
}

func TestNilStoreHelpersDoNotPanic(t *testing.T) {
	var s *Store
	if got := s.Count(); got != 0 {
		t.Fatalf("Count()=%d, want 0", got)
	}
	if _, ok := s.ByID("KB1"); ok {
		t.Fatal("nil store unexpectedly returned a document")
	}
	if _, err := s.Search(context.Background(), "vpn", 1); err == nil {
		t.Fatal("expected Search on nil store to return an error")
	}
}

func TestRAGRequiresEmbedderWhenDocumentsExist(t *testing.T) {
	dir := t.TempDir()
	doc := `{"id":"I1","title":"VPN intern","text":"gateway vpn","answer":"x","source":"internal-kb","language":"de-DE","communication_style":"formal"}`
	if err := os.WriteFile(filepath.Join(dir, "internal.json"), []byte(doc), 0o644); err != nil {
		t.Fatal(err)
	}
	if _, err := Load(context.Background(), dir, t.TempDir(), nil, true, []string{"internal-kb"}); err == nil {
		t.Fatal("expected RAG without embedder to fail")
	}
}

func TestUpsertDelete(t *testing.T) {
	dir := t.TempDir()
	data := t.TempDir()
	s, err := Load(context.Background(), dir, data, nil, false, []string{"internal-kb"})
	if err != nil {
		t.Fatal(err)
	}
	d := model.KnowledgeDoc{ID: "KB-1", Title: "Test", Text: "Wissen", Source: "internal-kb", Language: "de-DE", CommunicationStyle: "formal", MinScore: 0.8}
	if err := s.Upsert(context.Background(), d); err != nil {
		t.Fatal(err)
	}
	if s.Count() != 1 {
		t.Fatalf("count=%d", s.Count())
	}
	if _, ok := s.ByID("KB-1"); !ok {
		t.Fatal("missing")
	}
	if err := s.Delete("KB-1"); err != nil {
		t.Fatal(err)
	}
	if s.Count() != 0 {
		t.Fatalf("count=%d", s.Count())
	}
}

func TestExternalKnowledgeIsReadOnly(t *testing.T) {
	dir := t.TempDir()
	data := t.TempDir()
	s, err := Load(context.Background(), dir, data, nil, false, []string{"internal-kb", "glpi-kb"})
	if err != nil {
		t.Fatal(err)
	}
	d := model.KnowledgeDoc{ID: "GLPI-KB-1", Title: "Extern", Text: "Wissen", Source: "glpi-kb", Language: "de-DE", CommunicationStyle: "formal"}
	if err := s.ReplaceExternalSource(context.Background(), "glpi-kb", []model.KnowledgeDoc{d}); err != nil {
		t.Fatal(err)
	}
	if s.Count() != 1 || s.Origin("GLPI-KB-1") != "glpi-kb" {
		t.Fatalf("unexpected external store state")
	}
	if err := s.Upsert(context.Background(), d); err == nil {
		t.Fatal("expected external document to be read-only")
	}
}