package carddav

import (
	"context"
	"io"
	"log/slog"
	"path/filepath"
	"strings"
	"testing"

	vcard "github.com/emersion/go-vcard"
	"github.com/yourusername/caldav-server/internal/auth"
	"github.com/yourusername/caldav-server/internal/config"
	"github.com/yourusername/caldav-server/internal/db"
	"github.com/yourusername/caldav-server/internal/store"
)

func newTestBackend(t *testing.T) (*Backend, *db.DB) {
	t.Helper()
	dir := t.TempDir()

	st, err := store.NewStore(filepath.Join(dir, "data"))
	if err != nil {
		t.Fatalf("NewStore: %v", err)
	}
	dbase, err := db.Open(filepath.Join(dir, "test.db"))
	if err != nil {
		t.Fatalf("db.Open: %v", err)
	}
	t.Cleanup(func() { dbase.Close() })

	cfg := &config.Config{}
	if err := dbase.CreateUser("alice", "pw", "", ""); err != nil {
		t.Fatalf("CreateUser alice: %v", err)
	}
	if err := dbase.CreateUser("bob", "pw", "", ""); err != nil {
		t.Fatalf("CreateUser bob: %v", err)
	}
	if err := dbase.CreateAddressBook("alice", "contacts"); err != nil {
		t.Fatalf("CreateAddressBook alice/contacts: %v", err)
	}
	if err := dbase.CreateAddressBook("bob", "personal"); err != nil {
		t.Fatalf("CreateAddressBook bob/personal: %v", err)
	}
	logger := slog.New(slog.NewTextHandler(io.Discard, nil))
	return NewBackend(cfg, st, dbase, logger), dbase
}

func ctxFor(username string) context.Context {
	return auth.NewContext(context.Background(), &auth.Principal{Username: username})
}

// minimalCard returns a minimal, valid vCard for use in tests.
func minimalCard() vcard.Card {
	const raw = "BEGIN:VCARD\r\n" +
		"VERSION:3.0\r\n" +
		"UID:card1@nidus.test\r\n" +
		"FN:Test Person\r\n" +
		"END:VCARD\r\n"
	card, err := vcard.NewDecoder(strings.NewReader(raw)).Decode()
	if err != nil {
		panic("minimalCard: " + err.Error())
	}
	return card
}

func TestListAddressBooksIncludesSharedBook(t *testing.T) {
	b, dbase := newTestBackend(t)

	if err := dbase.ShareAddressBook("alice", "contacts", "bob", db.PermRead); err != nil {
		t.Fatalf("ShareAddressBook: %v", err)
	}
	// The shared book must exist on disk for it to be listed; normally this
	// happens when alice's own ListAddressBooks runs and ensures it.
	if _, err := b.ListAddressBooks(ctxFor("alice")); err != nil {
		t.Fatalf("ListAddressBooks(alice): %v", err)
	}

	books, err := b.ListAddressBooks(ctxFor("bob"))
	if err != nil {
		t.Fatalf("ListAddressBooks: %v", err)
	}

	var found bool
	wantName := sharedBookName("alice", "contacts")
	for _, book := range books {
		if book.Name == wantName {
			found = true
		}
	}
	if !found {
		t.Errorf("shared address book %q not found in ListAddressBooks result: %+v", wantName, books)
	}
}

func TestSharedAddressBookReadOnlyRejectsWrite(t *testing.T) {
	b, dbase := newTestBackend(t)

	if err := dbase.ShareAddressBook("alice", "contacts", "bob", db.PermRead); err != nil {
		t.Fatalf("ShareAddressBook: %v", err)
	}

	localName := sharedBookName("alice", "contacts")
	objPath := cardObjectPath(localName, "card1.vcf")

	_, err := b.PutAddressObject(ctxFor("bob"), objPath, minimalCard(), nil)
	if err == nil {
		t.Fatal("expected error writing to read-only shared address book, got nil")
	}
}

func TestSharedAddressBookWriteAllowed(t *testing.T) {
	b, dbase := newTestBackend(t)

	if err := dbase.ShareAddressBook("alice", "contacts", "bob", db.PermWrite); err != nil {
		t.Fatalf("ShareAddressBook: %v", err)
	}

	localName := sharedBookName("alice", "contacts")
	objPath := cardObjectPath(localName, "card1.vcf")

	if _, err := b.PutAddressObject(ctxFor("bob"), objPath, minimalCard(), nil); err != nil {
		t.Fatalf("PutAddressObject with write share: %v", err)
	}

	// The object should now be visible under alice's own address book too,
	// since it's stored in her namespace.
	obj, err := b.GetAddressObject(ctxFor("alice"), cardObjectPath("contacts", "card1.vcf"), nil)
	if err != nil {
		t.Fatalf("GetAddressObject as owner: %v", err)
	}
	if obj == nil {
		t.Fatal("expected non-nil object")
	}
}

func TestUnauthorizedUserCannotAccessUnsharedBook(t *testing.T) {
	b, _ := newTestBackend(t)

	localName := sharedBookName("alice", "contacts")
	_, err := b.GetAddressBook(ctxFor("bob"), cardHomePath()+localName+"/")
	if err == nil {
		t.Fatal("expected error accessing unshared address book, got nil")
	}
}