using Microsoft.AspNetCore.Authorization;
using Microsoft.AspNetCore.Mvc;
using PowderCoating.Application.Interfaces;
using PowderCoating.Shared.Constants;

namespace PowderCoating.Web.Controllers;

/// <summary>
/// SuperAdmin-only tool for migrating locally stored media files from the on-disk
/// <c>media/</c> folder to Azure Blob Storage via
/// <see cref="IStorageMigrationService"/>.  Intended to be run once (or a small number
/// of times) during a storage-backend transition — it is not a routine operation.
/// </summary>
[Authorize(Policy = AppConstants.Policies.SuperAdminOnly)]
public class StorageMigrationController : Controller
{
    private readonly IStorageMigrationService _migrationService;
    private readonly IWebHostEnvironment _environment;

    public StorageMigrationController(
        IStorageMigrationService migrationService,
        IWebHostEnvironment environment)
    {
        _migrationService = migrationService;
        _environment = environment;
    }

    /// <summary>
    /// Renders the migration status page showing the local <c>media/</c> path, whether
    /// the directory exists, and how many files it currently contains.  This information
    /// lets operators confirm there is work to migrate before triggering the potentially
    /// long-running <see cref="Migrate"/> action.
    /// </summary>
    public IActionResult Index()
    {
        var mediaPath = Path.Combine(_environment.ContentRootPath, "media");
        ViewBag.MediaPath = mediaPath;
        ViewBag.MediaExists = Directory.Exists(mediaPath);

        if (Directory.Exists(mediaPath))
        {
            var fileCount = Directory.EnumerateFiles(mediaPath, "*.*", SearchOption.AllDirectories).Count();
            ViewBag.LocalFileCount = fileCount;
        }
        else
        {
            ViewBag.LocalFileCount = 0;
        }

        return View();
    }

    /// <summary>
    /// Executes the migration of all local <c>media/</c> files to Azure Blob Storage
    /// and renders a Results view with the outcome.
    /// <para>
    /// The <paramref name="deleteAfterMigration"/> flag controls whether source files
    /// are removed from disk after successful upload.  It defaults to <c>false</c> so
    /// that operators can verify the migration result before committing to deletion.
    /// The actual upload logic is encapsulated in <see cref="IStorageMigrationService"/>
    /// so it can be tested independently of the HTTP layer.
    /// </para>
    /// </summary>
    [HttpPost]
    [ValidateAntiForgeryToken]
    public async Task<IActionResult> Migrate(bool deleteAfterMigration = false)
    {
        var mediaPath = Path.Combine(_environment.ContentRootPath, "media");
        var result = await _migrationService.MigrateFilesystemToAzureAsync(mediaPath, deleteAfterMigration);

        return View("Results", result);
    }
}