using Butter;
using Butter.Settings;
using Butter.Types;
using Lactose.Context;
using Lactose.Models;
using Microsoft.AspNetCore.Identity;
using System.Diagnostics.CodeAnalysis;
using System.Text.Json.Serialization;

namespace Lactose.Services;

/// <summary>
/// Defines the contract for database initialization.
/// </summary>
interface IDbInitializer {
    /// <summary>
    /// Applies pending migrations and seeds default data.
    /// </summary>
    void Initialize();
}

/// <summary>
/// Initializes the database — applies migrations and seeds default users, settings, and folders.
/// </summary>
internal class DbInitializer(LactoseDbContext dbContext, IPasswordHasher<User> passwordHasher) : IDbInitializer {
    /// <inheritdoc />
    public void Initialize() {
        ArgumentNullException.ThrowIfNull(dbContext, nameof(dbContext));

        var task = dbContext.Database.GetPendingMigrationsAsync();

        task.ContinueWith((r) => {
                    if (r.Result.Any()) dbContext.Database.Migrate();
                }
            )
            .Wait();

        // if(dbContext.Database.GetPendingMigrations().Any()) // Timeoout

    #region Users

        if (!dbContext.Users.Any()) {
            var user = new User {
                Username    = "admin",
                Email       = "admin@admin.com",
                AccessLevel = EAccessLevel.Admin,
                CreatedAt   = DateTime.Now,
                UpdatedAt   = DateTime.Now
            };

            user.Password = passwordHasher.HashPassword(user, "admin");
            dbContext.Users.Add(user);
            dbContext.SaveChanges();
        }

    #endregion

    #region Settings

        var settings = System.Text.Json.JsonSerializer.Deserialize<List<Setting>>(File.ReadAllText("DefaultSettings.json"));

        if (settings is not null) {
            //remove all settings that are not in the default settings file
            var existingSettings = dbContext.Settings.ToList();

            foreach (Setting existingSetting in existingSettings.Where(existingSetting
                    => settings.All(s => s.Name != existingSetting.Name)
                )) dbContext.Settings.Remove(existingSetting);

            settings.First(s => s.Name == Settings.ThumbnailPath.AsString()).Value
                = Path.Combine(Environment.CurrentDirectory, "thumbnails");

            settings.First(s => s.Name == Settings.PreviewPath.AsString()).Value
                = Path.Combine(Environment.CurrentDirectory, "previews");

            // set max concurrent jobs to number of processors - 2, at least one. (who the fuck is using a single core cpu?)
            settings.First(s => s.Name == Settings.MaxConcurrentJobs.AsString()).Value
                = (Math.Max(Environment.ProcessorCount - 2, 1)).ToString();

            // add or update settings from the default settings file leaving value unchanged
            foreach (var setting in settings) {
                if (!dbContext.Settings.Any(s => s.Name == setting.Name)) { dbContext.Settings.Add(setting); } else {
                    var dbSetting = dbContext.Settings.First(s => s.Name == setting.Name);
                    dbSetting.Description = setting.Description;
                    dbSetting.Type        = setting.Type;
                    dbSetting.DisplayType = setting.DisplayType;
                    dbSetting.Options     = setting.Options;
                    dbContext.Settings.Update(dbSetting);
                }
            }

            dbContext.SaveChanges();
        } //else, we are a bit fucked.

    #endregion

    #region Folders

        if (!dbContext.Folders.Any()) {
            dbContext.Folders.Add(
                new Folder() {
                    BasePath = "/diary",
                    Active   = false
                }
            );
        }

        dbContext.SaveChanges();

    #endregion

    }
}