MilkyShots/Lactose/Jobs/IntegrityCheckJob.cs

using Butter.Settings;
using Lactose.Context;
using Lactose.Models;
using Lactose.Utils;

namespace Lactose.Jobs;

/// <summary>
/// Performs a comprehensive integrity check of the system — database, assets, albums, people, thumbnails, and previews.
/// </summary>
public class IntegrityCheckJob (ILogger<IntegrityCheckJob> logger, IServiceProvider serviceProvider): Job{
    const float totalSteps = 7;

    /// <inheritdoc />
    public override string Name => "Integrity Check Job";

    void IncrementProgress(float f) => JobStatus.UpdateProgress(f/totalSteps, "Database connection successful.");

    /// <inheritdoc />
    protected override async Task TaskJob(CancellationToken token) {
        try {

            float progress = 0;
            logger.LogInformation("Starting integrity check job...");
            using var scope     = serviceProvider.CreateScope();
            var         dbContext = scope.ServiceProvider.GetRequiredService<LactoseDbContext>();

            //Step 1
            // Check database connection
            if (!dbContext.Database.CanConnect()) {
                logger.LogError("Cannot connect to the database.");
                JobStatus.Fail("Cannot connect to the database.");
                return;
            }
            IncrementProgress(++progress);

            token.ThrowIfCancellationRequested();

            // Step 2
            // Check for pending migrations
            var pendingMigrations = dbContext.Database.GetPendingMigrations().ToList();

            if (pendingMigrations.Any()) {
                logger.LogWarning("There are pending migrations:");

                foreach (var migration in pendingMigrations) logger.LogWarning($"- {migration}");

                // Apply migrations
                try {
                    dbContext.Database.Migrate();
                    logger.LogInformation("Applied pending migrations successfully.");
                } catch (Exception ex) {
                    logger.LogError(ex, "Error applying migrations.");
                    JobStatus.Fail("Error applying migrations.");
                    return;
                }
            }
            IncrementProgress(++progress);

            token.ThrowIfCancellationRequested();

            // A bit of context: Load() will load all entities from the table into the DbContext.
            // Essentially it will ask the DB for all rows in the table and create entities for them in the DbContext.
            // This will basically warm up the cache of the DbContext so that when we later access all the rows in the table,
            // it won't lazy load them one by one, one call at the time.
            // This is important because lazy loading one by one would be a huge performance hit,
            // especially if there are many rows in the table.
            // While for folders it might not be a big deal, this is just for consistency with all the other steps,
            // especially the asset one.

            // Step 3
            // Check for folders existence
            dbContext.Folders.Load();
            foreach (Folder folder in dbContext.Folders.ToList()) {
                token.ThrowIfCancellationRequested();
                if (!Directory.Exists(folder.BasePath)) {
                    logger.LogWarning($"Folder {folder.Id} does not exist. Deactivating.");
                    folder.Active = false;
                    dbContext.Folders.Update(folder);

                    var affectedAssets = dbContext.Assets.Where(a => a.FolderId == folder.Id && a.DeletedAt == null)
                        .ToList();
                    foreach (var asset in affectedAssets) {
                        asset.DeletedAt = DateTime.UtcNow;
                        dbContext.Assets.Update(asset);
                    }
                    dbContext.SaveChanges();
                    logger.LogWarning("Soft-deleted {Count} assets associated with missing folder {FolderId}.", affectedAssets.Count, folder.Id);
                }
            }
            IncrementProgress(++progress);

            token.ThrowIfCancellationRequested();

            // Step 4
            // Check for assets existence
            dbContext.Assets.Load();
            foreach (Asset asset in dbContext.Assets.Where(a => a.DeletedAt == null)) {
                token.ThrowIfCancellationRequested();
                if (File.Exists(asset.OriginalPath)) continue;
                asset.DeletedAt = DateTime.UtcNow;
                dbContext.Assets.Update(asset);
                logger.LogWarning($"Asset {asset.Id} does not exist. Soft-deleting.");
            }

            int changes = dbContext.SaveChanges();
            logger.LogInformation("Soft-deleted {Changes} non-existent assets.", changes);
            IncrementProgress(++progress);

            token.ThrowIfCancellationRequested();

            // Step 5
            // Check for empty albums
            dbContext.Albums.Load();
            dbContext.Albums.Include(a => a.Assets)
                .Where(a => a.Assets!.Count == 0)
                .ToList().ForEach(a => {
                    logger.LogWarning($"Album {a.Id} is empty. Removing from database.");
                    dbContext.Albums.Remove(a);
                });
            changes = dbContext.SaveChanges();
            logger.LogInformation("Removed {Changes} empty albums from the database.", changes);
            IncrementProgress(++progress);

            token.ThrowIfCancellationRequested();

            // Step 6
            // Check for orphaned thumbnails
            dbContext.Settings.Load();
            dbContext.Assets.Load();
            var thumbnailPath = dbContext.Settings.First(s => s.Name == Settings.ThumbnailPath.AsString()).Value;

            if (!Directory.Exists(thumbnailPath)) {
                logger.LogWarning("Thumbnail path does not exist. Creating...");

                try {
                    if (thumbnailPath != null)
                        Directory.CreateDirectory(thumbnailPath);
                } catch (Exception e) {
                    logger.LogError(e, "Could not create thumbnail directory.");
                }

                logger.LogWarning("Marking all assets as missing thumbnails.");
                dbContext.Assets.ForEach(a => a.ThumbnailPath = "");
                changes = dbContext.SaveChanges();
                logger.LogInformation("Marked {Changes} assets as missing thumbnails.", changes);
            } else {
                dbContext.Assets.Where(a => !String.IsNullOrEmpty(a.ThumbnailPath)).AsEnumerable()
                    .Where(a => !File.Exists(a.ThumbnailPath)).AsEnumerable()
                    .ForEach(a => {
                        logger.LogWarning($"Asset {a.Id} has a missing thumbnail. Marking as missing.");
                        a.ThumbnailPath = "";
                        dbContext.Assets.Update(a);
                    });
                changes = dbContext.SaveChanges();
                logger.LogInformation("Marked {Changes} assets as missing thumbnails.", changes);
            }

            IncrementProgress(++progress);

            token.ThrowIfCancellationRequested();

            // Step 7
            // Check for orphaned previews

            var previewPath = dbContext.Settings.First(s => s.Name == Settings.PreviewPath.AsString()).Value;
            if (!Directory.Exists(previewPath)) {
                logger.LogWarning("Preview path does not exist. Creating...");

                try {
                    if (previewPath != null)
                        Directory.CreateDirectory(previewPath);
                } catch (Exception e) {
                    logger.LogError(e, "Could not create preview directory.");
                }

                logger.LogWarning("Marking all assets as missing previews.");
                dbContext.Assets.ForEach(a => a.PreviewPath = "");
                changes = dbContext.SaveChanges();
                logger.LogInformation("Marked {Changes} assets as missing previews.", changes);
            } else {
                dbContext.Assets.Where(a => !String.IsNullOrEmpty(a.PreviewPath)).AsEnumerable()
                    .Where(a => !File.Exists(a.PreviewPath)).AsEnumerable()
                    .ForEach(a => {
                        logger.LogWarning($"Asset {a.Id} has a missing preview. Marking as missing.");
                        a.PreviewPath = "";
                        dbContext.Assets.Update(a);
                    });
            }
            changes = dbContext.SaveChanges();
            logger.LogInformation("Marked {Changes} assets as missing previews.", changes);

            IncrementProgress(++progress);

            // Complete
            logger.LogInformation("Integrity check completed successfully.");
            JobStatus.Complete("Integrity check completed successfully.");
        } catch (OperationCanceledException) {
            JobStatus.Cancel();
        }
    }
}