using LCU.Library.Internal.MemberPreferencesApiModels.Entities;
using LCU.Library.Internal.MemberPreferencesApiModels.Enums;
using LCU.Library.Internal.MemberPreferencesApiModels.Models;
using Microsoft.EntityFrameworkCore;
using System.Reflection;

namespace LCU.API.Internal.MemberPreferencesApiLib.Persistence;

public class ApplicationDbContext : DbContext, IApplicationDbContext
{
    private readonly IDictionary<Auditable, string> _systemModifiedAuditables = new Dictionary<Auditable, string>();

    public ApplicationDbContext(DbContextOptions options) : base(options)
    {
    }

    public DbSet<MemberPreference> MemberPreferences { get; set; }
    public DbSet<MemberOptInSettings> MemberOptInSettings { get; set; }
    public DbSet<DnaAuditProcess> DnaAuditProcesses { get; set; }
    public DbSet<XdiBatchItem> XdiBatchItems { get; set; }

    public override Task<int> SaveChangesAsync(CancellationToken cancellationToken = new CancellationToken())
    {
        foreach (var entry in ChangeTracker.Entries<Auditable>())
        {
            var auditableUser = _systemModifiedAuditables.TryGetValue(entry.Entity, out var systemUser);
            var applicationUser = new ApplicationUser
            {
                UserName = systemUser,
                UserType = UserType.System
            };

            var otherUser = new ApplicationUser
            {
                UserName = "Unknown",
                UserType = UserType.System,
            };

            var currentUser = auditableUser ? applicationUser : otherUser;
            switch (entry.State)
            {
                case EntityState.Added:
                    entry.Entity.CreatedByType = currentUser.UserType;
                    entry.Entity.CreatedBy = currentUser.UserName;
                    entry.Entity.Created = DateTime.Now;
                    entry.Entity.LastUpdatedByType = currentUser.UserType;
                    entry.Entity.LastUpdatedBy = currentUser.UserName;
                    entry.Entity.LastUpdated = DateTime.Now;
                    break;
                case EntityState.Modified:
                    entry.Entity.LastUpdatedByType = currentUser.UserType;
                    entry.Entity.LastUpdatedBy = currentUser.UserName;
                    entry.Entity.LastUpdated = DateTime.Now;
                    break;
            }
        }

        return base.SaveChangesAsync(cancellationToken);
    }

    public Task<int> SaveChangesWithOperatorAsync(string operatorId, DateTime dateAdded, UserType userType, CancellationToken cancellationToken = new CancellationToken())
    {
        foreach (var entry in ChangeTracker.Entries<Auditable>())
        {
            switch (entry.State)
            {
                case EntityState.Added:
                    entry.Entity.CreatedByType = userType;
                    entry.Entity.CreatedBy = operatorId;
                    entry.Entity.Created = dateAdded;
                    entry.Entity.LastUpdatedByType = userType;
                    entry.Entity.LastUpdatedBy = operatorId;
                    entry.Entity.LastUpdated = dateAdded;
                    break;
                case EntityState.Modified:
                    entry.Entity.LastUpdatedByType = userType;
                    entry.Entity.LastUpdatedBy = operatorId;
                    entry.Entity.LastUpdated = dateAdded;
                    break;
            }
        }

        return base.SaveChangesAsync(cancellationToken);
    }

    public void SystemModified(Auditable entity, string modifiedBy) => _systemModifiedAuditables[entity] = modifiedBy;

    protected override void OnModelCreating(ModelBuilder builder)
    {
        builder.ApplyConfigurationsFromAssembly(Assembly.GetExecutingAssembly());
        base.OnModelCreating(builder);

        builder.Entity<MemberPreference>().ToTable("MemberPreference");
        builder.Entity<MemberPreference>().HasKey(p => p.Id);

        builder.Entity<XdiBatchItem>().ToTable("XdiBatchItems");
        builder.Entity<XdiBatchItem>().HasKey(p => new { p.UserId, p.BatchState });

        builder.Entity<MemberOptInSettings>().ToTable("MemberOptInSettings");
        builder.Entity<MemberOptInSettings>().HasKey(p => p.Id);
        builder.Entity<MemberOptInSettings>().HasIndex(p => new { p.UserId })
            .IsUnique(true);

        builder.Entity<DnaAuditProcess>().ToTable("DnaAuditProcess");
        builder.Entity<DnaAuditProcess>().HasKey(p => p.ProcessId);
    }
}