using Microsoft.EntityFrameworkCore;
using ComiServ.Entities;

namespace ComiServ;

public class ComicsContext : DbContext
{
    //TODO is this the best place for this to live?
    public const int HANDLE_LENGTH = 12;
    //relies on low probability of repeat handles in a short period of time
    //duplicate handles could be created before either of them are commited
    public string CreateHandle()
    {
        char ToChar(int i)
        {
            if (i < 10)
                return (char)('0' + i);
            if (i - 10 + 'A' < 'O')
                return (char)('A' + i - 10);
            else
                //skip 'O'
                return (char)('A' + i - 9);
        }
        string handle = "";
        do
        {
            handle = string.Join("", Enumerable.Repeat(0, HANDLE_LENGTH)
            .Select(_ => ToChar(Random.Shared.Next(0, 35))));
        } while (Comics.Any(c => c.Handle == handle));
        return handle;
    }
    public DbSet<Comic> Comics { get; set; }
    public DbSet<ComicTag> ComicTags { get; set; }
    public DbSet<Tag> Tags { get; set; }
    public DbSet<ComicAuthor> ComicAuthors { get; set; }
    public DbSet<Author> Authors { get; set; }
    public DbSet<Cover> Covers { get; set; }
    public DbSet<User> Users { get; set; }
    public DbSet<UserType> UserTypes { get; set; }
    public DbSet<ComicRead> ComicsRead { get; set; }
    public ComicsContext(DbContextOptions<ComicsContext> options)
        : base(options)
    {

    }
    protected override void OnModelCreating(ModelBuilder modelBuilder)
    {
        modelBuilder.Entity<Comic>().ToTable("Comics");
        modelBuilder.Entity<ComicTag>().ToTable("ComicTags");
        modelBuilder.Entity<Tag>().ToTable("Tags");
        modelBuilder.Entity<ComicAuthor>().ToTable("ComicAuthors");
        modelBuilder.Entity<Author>().ToTable("Authors");
        modelBuilder.Entity<Cover>().ToTable("Covers");
        modelBuilder.Entity<User>().ToTable("Users");
        modelBuilder.Entity<UserType>().ToTable("UserTypes")
            .HasData(
                Enum.GetValues(typeof(UserTypeEnum))
                    .Cast<UserTypeEnum>()
                    .Select(e => new UserType()
                    {
                        Id = e,
                        Name = e.ToString()
                    })
            );
    }
    /// <summary>
    /// puts a user-provided handle into the proper form
    /// </summary>
    /// <param name="handle"></param>
    /// <returns>formatted handle or null if invalid</returns>
    public static string? CleanValidateHandle(string? handle)
    {
        if (handle is null)
            return null;
        handle = handle.Trim();
        if (handle.Length != HANDLE_LENGTH)
            return null;
        return handle.ToUpper();
    }
}