package database_test

import (
	"context"
	"testing"
	"time"

	"sneak.berlin/go/vaultik/internal/database"
	"sneak.berlin/go/vaultik/internal/types"
)

const chunk4Hash = "chunk4"

// verifyChunkFilePair asserts that the chunk-file rows cover both test
// files at their expected offsets.
func verifyChunkFilePair(
	t *testing.T, chunkFiles []*database.ChunkFile,
	file1ID, file2ID types.FileID,
) {
	t.Helper()

	foundFile1 := false
	foundFile2 := false

	for _, cf := range chunkFiles {
		if cf.FileID == file1ID && cf.FileOffset == 0 {
			foundFile1 = true
		}

		if cf.FileID == file2ID && cf.FileOffset == 2048 {
			foundFile2 = true
		}
	}

	if !foundFile1 || !foundFile2 {
		t.Error("not all expected files found")
	}
}

// createChunkFileTestFiles creates the two files used by the chunk-file
// repository tests.
func createChunkFileTestFiles(
	t *testing.T, fileRepo *database.FileRepository,
) (*database.File, *database.File) {
	t.Helper()

	testTime := time.Now().Truncate(time.Second)
	file1 := &database.File{
		Path:       testFilePath1,
		MTime:      testTime,
		Size:       1024,
		Mode:       0644,
		UID:        1000,
		GID:        1000,
		LinkTarget: "",
	}
	file2 := &database.File{
		Path:       testFilePath2,
		MTime:      testTime,
		Size:       1024,
		Mode:       0644,
		UID:        1000,
		GID:        1000,
		LinkTarget: "",
	}

	mustCreateFile(t, fileRepo, file1)
	mustCreateFile(t, fileRepo, file2)

	return file1, file2
}

func TestChunkFileRepository(t *testing.T) {
	t.Parallel()

	db, cleanup := setupTestDB(t)
	defer cleanup()

	ctx := context.Background()
	repo := database.NewChunkFileRepository(db)
	fileRepo := database.NewFileRepository(db)
	repos := database.NewRepositories(db)

	file1, file2 := createChunkFileTestFiles(t, fileRepo)
	mustCreateChunks(t, repos, chunk1Hash)

	// Test Create
	cf1 := &database.ChunkFile{
		ChunkHash:  types.ChunkHash(chunk1Hash),
		FileID:     file1.ID,
		FileOffset: 0,
		Length:     1024,
	}

	err := repo.Create(ctx, nil, cf1)
	if err != nil {
		t.Fatalf("failed to create chunk file: %v", err)
	}

	// Add same chunk in different file (deduplication scenario)
	cf2 := &database.ChunkFile{
		ChunkHash:  types.ChunkHash(chunk1Hash),
		FileID:     file2.ID,
		FileOffset: 2048,
		Length:     1024,
	}

	err = repo.Create(ctx, nil, cf2)
	if err != nil {
		t.Fatalf("failed to create second chunk file: %v", err)
	}

	// Test GetByChunkHash
	chunkFiles, err := repo.GetByChunkHash(ctx, chunk1Hash)
	if err != nil {
		t.Fatalf("failed to get chunk files: %v", err)
	}

	if len(chunkFiles) != 2 {
		t.Errorf("expected 2 files for chunk, got %d", len(chunkFiles))
	}

	// Verify both files are returned
	verifyChunkFilePair(t, chunkFiles, file1.ID, file2.ID)

	// Test GetByFileID
	chunkFiles, err = repo.GetByFileID(ctx, file1.ID)
	if err != nil {
		t.Fatalf("failed to get chunks by file ID: %v", err)
	}

	if len(chunkFiles) != 1 {
		t.Errorf("expected 1 chunk for file, got %d", len(chunkFiles))
	}

	if chunkFiles[0].ChunkHash != types.ChunkHash(chunk1Hash) {
		t.Errorf("wrong chunk hash: expected chunk1, got %s", chunkFiles[0].ChunkHash)
	}

	// Test duplicate insert (should be idempotent)
	err = repo.Create(ctx, nil, cf1)
	if err != nil {
		t.Fatalf("failed to create duplicate chunk file: %v", err)
	}
}

func TestChunkFileRepositoryComplexDeduplication(t *testing.T) {
	t.Parallel()

	db, cleanup := setupTestDB(t)
	defer cleanup()

	ctx := context.Background()
	repo := database.NewChunkFileRepository(db)
	fileRepo := database.NewFileRepository(db)
	repos := database.NewRepositories(db)

	// Create test files
	testTime := time.Now().Truncate(time.Second)
	file1 := &database.File{
		Path: testFilePath1, MTime: testTime, Size: 3072,
		Mode: 0644, UID: 1000, GID: 1000,
	}
	file2 := &database.File{
		Path: testFilePath2, MTime: testTime, Size: 3072,
		Mode: 0644, UID: 1000, GID: 1000,
	}
	file3 := &database.File{
		Path: "/file3.txt", MTime: testTime, Size: 2048,
		Mode: 0644, UID: 1000, GID: 1000,
	}

	mustCreateFile(t, fileRepo, file1)
	mustCreateFile(t, fileRepo, file2)
	mustCreateFile(t, fileRepo, file3)
	mustCreateChunks(t, repos, chunk1Hash, chunk2Hash, chunk3Hash, chunk4Hash)

	// Simulate a scenario where multiple files share chunks
	// File1: chunk1, chunk2, chunk3
	// File2: chunk2, chunk3, chunk4
	// File3: chunk1, chunk4

	chunkFiles := []database.ChunkFile{
		// File1
		{ChunkHash: chunk1Hash, FileID: file1.ID, FileOffset: 0, Length: 1024},
		{ChunkHash: chunk2Hash, FileID: file1.ID, FileOffset: 1024, Length: 1024},
		{ChunkHash: chunk3Hash, FileID: file1.ID, FileOffset: 2048, Length: 1024},
		// File2
		{ChunkHash: chunk2Hash, FileID: file2.ID, FileOffset: 0, Length: 1024},
		{ChunkHash: chunk3Hash, FileID: file2.ID, FileOffset: 1024, Length: 1024},
		{ChunkHash: chunk4Hash, FileID: file2.ID, FileOffset: 2048, Length: 1024},
		// File3
		{ChunkHash: chunk1Hash, FileID: file3.ID, FileOffset: 0, Length: 1024},
		{ChunkHash: chunk4Hash, FileID: file3.ID, FileOffset: 1024, Length: 1024},
	}

	for _, cf := range chunkFiles {
		err := repo.Create(ctx, nil, &cf)
		if err != nil {
			t.Fatalf("failed to create chunk file: %v", err)
		}
	}

	// Test chunk1 (used by file1 and file3)
	files, err := repo.GetByChunkHash(ctx, chunk1Hash)
	if err != nil {
		t.Fatalf("failed to get files for chunk1: %v", err)
	}

	if len(files) != 2 {
		t.Errorf("expected 2 files for chunk1, got %d", len(files))
	}

	// Test chunk2 (used by file1 and file2)
	files, err = repo.GetByChunkHash(ctx, chunk2Hash)
	if err != nil {
		t.Fatalf("failed to get files for chunk2: %v", err)
	}

	if len(files) != 2 {
		t.Errorf("expected 2 files for chunk2, got %d", len(files))
	}

	// Test file2 chunks
	file2Chunks, err := repo.GetByFileID(ctx, file2.ID)
	if err != nil {
		t.Fatalf("failed to get chunks for file2: %v", err)
	}

	if len(file2Chunks) != 3 {
		t.Errorf("expected 3 chunks for file2, got %d", len(file2Chunks))
	}
}