package app

import (
	"bytes"
	"crypto/rand"
	"encoding/json"
	"io"
	"os"
	"path/filepath"
	"testing"
	"time"

	"github.com/skidoodle/safebin/internal/crypto"
	"go.etcd.io/bbolt"
)

func TestCleanup_AbandonedChunks(t *testing.T) {
	tmpDir := t.TempDir()
	tmpStorage := filepath.Join(tmpDir, TempDirName)
	if err := os.MkdirAll(tmpStorage, 0700); err != nil {
		t.Fatalf("MkdirAll failed: %v", err)
	}

	db, err := InitDB(tmpDir)
	if err != nil {
		t.Fatalf("InitDB failed: %v", err)
	}
	defer func() {
		if err := db.Close(); err != nil {
			t.Errorf("Failed to close DB: %v", err)
		}
	}()

	app := &App{
		Conf:   Config{StorageDir: tmpDir},
		Logger: discardLogger(),
		DB:     db,
	}

	chunkDir := filepath.Join(tmpStorage, "some_upload_id")
	if err := os.MkdirAll(chunkDir, 0700); err != nil {
		t.Fatalf("MkdirAll chunkDir failed: %v", err)
	}
	if err := os.WriteFile(filepath.Join(chunkDir, "0"), []byte("chunk data"), 0600); err != nil {
		t.Fatalf("WriteFile chunk failed: %v", err)
	}

	oldTime := time.Now().Add(-TempExpiry - time.Hour)
	if err := os.Chtimes(chunkDir, oldTime, oldTime); err != nil {
		t.Fatalf("Chtimes failed: %v", err)
	}

	app.CleanTemp(tmpStorage)

	if _, err := os.Stat(chunkDir); !os.IsNotExist(err) {
		t.Error("Cleanup failed to remove abandoned chunk directory")
	}
}

func TestCleanup_ExpiredStorage(t *testing.T) {
	storageDir := t.TempDir()
	db, err := InitDB(storageDir)
	if err != nil {
		t.Fatalf("InitDB failed: %v", err)
	}
	defer func() {
		if err := db.Close(); err != nil {
			t.Errorf("Failed to close DB: %v", err)
		}
	}()

	app := &App{
		Conf: Config{
			StorageDir: storageDir,
			MaxMB:      100,
		},
		Logger: discardLogger(),
		DB:     db,
	}

	filename := "large_file_id"
	path := filepath.Join(storageDir, filename)
	f, err := os.Create(path)
	if err != nil {
		t.Fatalf("Create file failed: %v", err)
	}
	if err := f.Truncate(100 * MegaByte); err != nil {
		t.Fatalf("Truncate failed: %v", err)
	}
	if err := f.Close(); err != nil {
		t.Fatalf("Close file failed: %v", err)
	}

	expiredMeta := FileMeta{
		ID:        filename,
		Size:      100 * MegaByte,
		CreatedAt: time.Now().Add(-MinRetention - 2*time.Hour),
		ExpiresAt: time.Now().Add(-time.Hour),
	}

	if err := app.DB.Update(func(tx *bbolt.Tx) error {
		bFiles := tx.Bucket([]byte(DBBucketName))
		bIndex := tx.Bucket([]byte(DBBucketIndexName))

		data, _ := json.Marshal(expiredMeta)
		if err := bFiles.Put([]byte(filename), data); err != nil {
			return err
		}

		indexKey := []byte(expiredMeta.ExpiresAt.Format(time.RFC3339) + "_" + filename)
		return bIndex.Put(indexKey, []byte(filename))
	}); err != nil {
		t.Fatalf("DB Update failed: %v", err)
	}

	app.CleanStorage()

	if _, err := os.Stat(path); !os.IsNotExist(err) {
		t.Error("Cleanup failed to remove expired large file")
	}

	if err := app.DB.View(func(tx *bbolt.Tx) error {
		bFiles := tx.Bucket([]byte(DBBucketName))
		if v := bFiles.Get([]byte(filename)); v != nil {
			t.Error("Cleanup failed to remove metadata")
		}

		bIndex := tx.Bucket([]byte(DBBucketIndexName))
		indexKey := []byte(expiredMeta.ExpiresAt.Format(time.RFC3339) + "_" + filename)
		if v := bIndex.Get(indexKey); v != nil {
			t.Error("Cleanup failed to remove index entry")
		}
		return nil
	}); err != nil {
		t.Fatalf("DB View failed: %v", err)
	}
}

func TestSaveChunk_EncryptsData(t *testing.T) {
	tmpDir := t.TempDir()
	app := &App{
		Conf:   Config{StorageDir: tmpDir},
		Logger: discardLogger(),
	}

	uid := "test-encrypt-chunk"
	plaintext := make([]byte, 1024)
	if _, err := rand.Read(plaintext); err != nil {
		t.Fatal(err)
	}

	if err := app.saveChunk(uid, 0, bytes.NewReader(plaintext)); err != nil {
		t.Fatalf("saveChunk failed: %v", err)
	}

	path := filepath.Join(tmpDir, TempDirName, uid, "0")
	fileData, err := os.ReadFile(path)
	if err != nil {
		t.Fatalf("ReadFile failed: %v", err)
	}

	if bytes.Equal(fileData, plaintext) {
		t.Fatal("Chunk stored as plaintext!")
	}
	if bytes.Contains(fileData, plaintext) {
		t.Fatal("Chunk contains plaintext!")
	}

	expectedSize := crypto.KeySize + len(plaintext) + 16
	if len(fileData) != expectedSize {
		t.Errorf("Unexpected file size. Want %d, got %d", expectedSize, len(fileData))
	}
}

func TestGetChunkDecryptors_RestoresData(t *testing.T) {
	tmpDir := t.TempDir()
	app := &App{
		Conf:   Config{StorageDir: tmpDir},
		Logger: discardLogger(),
	}

	uid := "test-restore"
	data1 := []byte("chunk one data")
	data2 := []byte("chunk two data")

	if err := app.saveChunk(uid, 0, bytes.NewReader(data1)); err != nil {
		t.Fatal(err)
	}
	if err := app.saveChunk(uid, 1, bytes.NewReader(data2)); err != nil {
		t.Fatal(err)
	}

	decryptors, closeFn, err := app.getChunkDecryptors(uid, 2)
	if err != nil {
		t.Fatalf("getChunkDecryptors failed: %v", err)
	}
	defer closeFn()

	if len(decryptors) != 2 {
		t.Fatalf("Expected 2 decryptors, got %d", len(decryptors))
	}

	buf1, err := io.ReadAll(decryptors[0])
	if err != nil {
		t.Fatalf("Failed to read decryptor 1: %v", err)
	}
	if !bytes.Equal(buf1, data1) {
		t.Errorf("Chunk 1 mismatch. Want %s, got %s", data1, buf1)
	}

	buf2, err := io.ReadAll(decryptors[1])
	if err != nil {
		t.Fatalf("Failed to read decryptor 2: %v", err)
	}
	if !bytes.Equal(buf2, data2) {
		t.Errorf("Chunk 2 mismatch. Want %s, got %s", data2, buf2)
	}
}