package service

import (
	"bytes"
	"errors"
	"mime/multipart"
	"os"
	"path/filepath"
	"testing"

	"github.com/vaultdrop/backend/repository"
)

func multipartFileHeader(t *testing.T, filename string, content []byte) *multipart.FileHeader {
	t.Helper()
	var body bytes.Buffer
	writer := multipart.NewWriter(&body)
	part, err := writer.CreateFormFile("file", filename)
	if err != nil {
		t.Fatalf("create form: %v", err)
	}
	if _, err := part.Write(content); err != nil {
		t.Fatalf("write: %v", err)
	}
	if err := writer.Close(); err != nil {
		t.Fatalf("close: %v", err)
	}

	reader := multipart.NewReader(&body, writer.Boundary())
	form, err := reader.ReadForm(1 << 20)
	if err != nil {
		t.Fatalf("read form: %v", err)
	}
	files := form.File["file"]
	if len(files) == 0 {
		t.Fatal("aucun fichier dans la forme")
	}
	return files[0]
}

func TestUploadPersistsPhysicalFile(t *testing.T) {
	s := newServiceStore(t)
	userID := mustCreateUser(t, s.Repository, "upload-happy")

	dto, err := s.Upload(userID, multipartFileHeader(t, "docs.txt", []byte("hello")), "", "")
	if err != nil {
		t.Fatalf("upload: %v", err)
	}
	if dto.ID == "" || dto.Name != "docs.txt" {
		t.Errorf("dto inattendu: %+v", dto)
	}

	// Le fichier physique existe sous UploadDir/<user>/<id>.<ext>.
	path := filepath.Join(s.UploadDir, userID, dto.ID+".txt")
	info, err := os.Stat(path)
	if err != nil {
		t.Fatalf("fichier physique absent: %v", err)
	}
	if info.Size() != 5 {
		t.Errorf("taille physique = %d, attendu 5", info.Size())
	}
}

func TestUploadRemovesPhysicalFileOnNameConflict(t *testing.T) {
	s := newServiceStore(t)
	userID := mustCreateUser(t, s.Repository, "upload-conflict")
	folderID := repository.NewID()
	if err := s.Repository.Resources.InsertFolder(userID, folderID, "Docs", ""); err != nil {
		t.Fatalf("insert folder: %v", err)
	}

	target := multipartFileHeader(t, "dupe.txt", []byte("hello"))
	first, err := s.Upload(userID, target, folderID, "")
	if err != nil {
		t.Fatalf("premier upload: %v", err)
	}
	if first.ID == "" {
		t.Fatal("aucun id au premier upload")
	}

	// Même nom, même dossier → NAME_CONFLICT et pas de second fichier physique.
	if _, err := s.Upload(userID, target, folderID, ""); !errors.Is(err, repository.ErrNameConflict) {
		t.Fatalf("second upload : attendu ErrNameConflict, got %v", err)
	}

	entries, err := os.ReadDir(filepath.Join(s.UploadDir, userID))
	if err != nil {
		t.Fatalf("readdir: %v", err)
	}
	if len(entries) != 1 {
		t.Errorf("fichier orphelin laissé après NAME_CONFLICT : %d fichiers", len(entries))
	}
}

func TestUploadTargetsExistingResource(t *testing.T) {
	s := newServiceStore(t)
	userID := mustCreateUser(t, s.Repository, "upload-target")

	// Fiche metadata-only créée par l'outbox côté client.
	resourceID := repository.NewID()
	ext := "png"
	if err := s.Repository.Resources.InsertFile(userID, resourceID, "scan.png", "", 0, nil, &ext); err != nil {
		t.Fatalf("insert metadata-only file: %v", err)
	}

	// Re-upload ciblé : mêmes octets, même resource_id, pas de doublon.
	dto, err := s.Upload(userID, multipartFileHeader(t, "scan.png", []byte("PNGDATA")), "", resourceID)
	if err != nil {
		t.Fatalf("targeted upload: %v", err)
	}
	if dto.ID != resourceID {
		t.Errorf("id attendu %s, got %s", resourceID, dto.ID)
	}
	if dto.Size != 7 {
		t.Errorf("taille = %d, attendu 7 (rafraîchie)", dto.Size)
	}

	path := filepath.Join(s.UploadDir, userID, resourceID+".png")
	info, err := os.Stat(path)
	if err != nil {
		t.Fatalf("fichier physique absent: %v", err)
	}
	if info.Size() != 7 {
		t.Errorf("taille physique = %d, attendu 7", info.Size())
	}

	// Une seule ligne serveur (pas de doublon créé par le re-upload).
	rows, total, err := s.Repo.ListFiles(userID, "", 50, 0, "", "")
	if err != nil {
		t.Fatalf("list: %v", err)
	}
	if total != 1 || len(rows) != 1 || rows[0].ID != resourceID {
		t.Errorf("liste après re-upload: total=%d rows=%+v", total, rows)
	}
}

func TestUploadTargetsOwnedResourceOnly(t *testing.T) {
	s := newServiceStore(t)
	userID := mustCreateUser(t, s.Repository, "upload-owner")
	otherUser := mustCreateUser(t, s.Repository, "upload-owner-other")

	resourceID := repository.NewID()
	if err := s.Repository.Resources.InsertFile(otherUser, resourceID, "mine.png", "", 0, nil, nil); err != nil {
		t.Fatalf("insert other's file: %v", err)
	}

	// Un resource_id d'un autre user → ErrNotFound, aucun octet écrit.
	if _, err := s.Upload(userID, multipartFileHeader(t, "mine.png", []byte("DATA")), "", resourceID); !errors.Is(err, repository.ErrNotFound) {
		t.Fatalf("upload cross-user : attendu ErrNotFound, got %v", err)
	}
	// Le dossier upload du user ne doit pas avoir été créé (échec avant écriture).
	if _, err := os.Stat(filepath.Join(s.UploadDir, userID)); !os.IsNotExist(err) {
		t.Errorf("dossier upload créé à tort ou erreur inattendue: %v", err)
	}
}

func TestUploadTargetUnknownIsNotFound(t *testing.T) {
	s := newServiceStore(t)
	userID := mustCreateUser(t, s.Repository, "upload-unknown")

	if _, err := s.Upload(userID, multipartFileHeader(t, "ghost.png", []byte("DATA")), "", repository.NewID()); !errors.Is(err, repository.ErrNotFound) {
		t.Fatalf("upload inconnu : attendu ErrNotFound, got %v", err)
	}
}