using Microsoft.EntityFrameworkCore;
using System.ComponentModel.DataAnnotations.Schema;

namespace MeetingAssistant.Speakers;

public sealed class SpeakerIdentity
{
    public int Id { get; set; }

    public string? CanonicalName { get; set; }

    public DateTimeOffset CreatedAt { get; set; }

    public DateTimeOffset UpdatedAt { get; set; }

    public int TranscriptionCount { get; set; }

    public List<SpeakerCandidateName> CandidateNames { get; set; } = [];

    public List<SpeakerAlias> Aliases { get; set; } = [];

    public List<SpeakerSnippet> Snippets { get; set; } = [];

    public List<SpeakerIdentityReference> References { get; set; } = [];

    [NotMapped]
    public int ReferenceCount => References.Count;

    public string? GetDisplayName()
    {
        if (!string.IsNullOrWhiteSpace(CanonicalName))
        {
            return CanonicalName;
        }

        return Aliases
            .Select(alias => alias.Name)
            .Where(alias => !string.IsNullOrWhiteSpace(alias))
            .Order(StringComparer.OrdinalIgnoreCase)
            .FirstOrDefault();
    }
}

public sealed class SpeakerIdentityReference
{
    public int Id { get; set; }

    public int SpeakerIdentityId { get; set; }

    public SpeakerIdentity? SpeakerIdentity { get; set; }

    public string MeetingNotePath { get; set; } = "";

    public string TranscriptPath { get; set; } = "";

    public DateTimeOffset CreatedAt { get; set; }
}

public static class SpeakerIdentityReferences
{
    public static SpeakerIdentityReference Create(
        string meetingNotePath,
        string transcriptPath,
        DateTimeOffset createdAt)
    {
        return new SpeakerIdentityReference
        {
            MeetingNotePath = meetingNotePath,
            TranscriptPath = transcriptPath,
            CreatedAt = createdAt
        };
    }

    public static void AddIfMissing(
        SpeakerIdentity identity,
        SpeakerIdentityReference reference,
        DateTimeOffset? createdAt = null)
    {
        if (IsEmpty(reference) || identity.References.Any(existing => IsSame(existing, reference)))
        {
            return;
        }

        identity.References.Add(Create(
            reference.MeetingNotePath,
            reference.TranscriptPath,
            createdAt ?? reference.CreatedAt));
    }

    private static bool IsEmpty(SpeakerIdentityReference reference)
    {
        return string.IsNullOrWhiteSpace(reference.MeetingNotePath) &&
            string.IsNullOrWhiteSpace(reference.TranscriptPath);
    }

    private static bool IsSame(SpeakerIdentityReference first, SpeakerIdentityReference second)
    {
        return string.Equals(first.MeetingNotePath, second.MeetingNotePath, StringComparison.OrdinalIgnoreCase) &&
            string.Equals(first.TranscriptPath, second.TranscriptPath, StringComparison.OrdinalIgnoreCase);
    }
}

public sealed class SpeakerCandidateName
{
    public int Id { get; set; }

    public int SpeakerIdentityId { get; set; }

    public SpeakerIdentity? SpeakerIdentity { get; set; }

    public string Name { get; set; } = "";
}

public sealed class SpeakerSnippet
{
    public int Id { get; set; }

    public int SpeakerIdentityId { get; set; }

    public SpeakerIdentity? SpeakerIdentity { get; set; }

    public byte[] WavBytes { get; set; } = [];

    public DateTimeOffset CreatedAt { get; set; }
}

public sealed class SpeakerAlias
{
    public int Id { get; set; }

    public int SpeakerIdentityId { get; set; }

    public SpeakerIdentity? SpeakerIdentity { get; set; }

    public string Name { get; set; } = "";
}

public sealed class SpeakerIdentityDbContext : DbContext
{
    public SpeakerIdentityDbContext(DbContextOptions<SpeakerIdentityDbContext> options)
        : base(options)
    {
    }

    public DbSet<SpeakerIdentity> SpeakerIdentities => Set<SpeakerIdentity>();

    public DbSet<SpeakerCandidateName> SpeakerCandidateNames => Set<SpeakerCandidateName>();

    public DbSet<SpeakerAlias> SpeakerAliases => Set<SpeakerAlias>();

    public DbSet<SpeakerSnippet> SpeakerSnippets => Set<SpeakerSnippet>();

    public DbSet<SpeakerIdentityReference> SpeakerIdentityReferences => Set<SpeakerIdentityReference>();

    protected override void OnModelCreating(ModelBuilder modelBuilder)
    {
        modelBuilder.Entity<SpeakerIdentity>(entity =>
        {
            entity.Property(identity => identity.TranscriptionCount)
                .IsRequired()
                .ValueGeneratedNever();

            entity.HasMany(identity => identity.CandidateNames)
                .WithOne(candidate => candidate.SpeakerIdentity)
                .HasForeignKey(candidate => candidate.SpeakerIdentityId)
                .OnDelete(DeleteBehavior.Cascade);

            entity.HasMany(identity => identity.Aliases)
                .WithOne(alias => alias.SpeakerIdentity)
                .HasForeignKey(alias => alias.SpeakerIdentityId)
                .OnDelete(DeleteBehavior.Cascade);

            entity.HasMany(identity => identity.Snippets)
                .WithOne(snippet => snippet.SpeakerIdentity)
                .HasForeignKey(snippet => snippet.SpeakerIdentityId)
                .OnDelete(DeleteBehavior.Cascade);

            entity.HasMany(identity => identity.References)
                .WithOne(reference => reference.SpeakerIdentity)
                .HasForeignKey(reference => reference.SpeakerIdentityId)
                .OnDelete(DeleteBehavior.Cascade);
        });

        modelBuilder.Entity<SpeakerCandidateName>()
            .HasIndex(candidate => new { candidate.SpeakerIdentityId, candidate.Name })
            .IsUnique();

        modelBuilder.Entity<SpeakerAlias>()
            .HasIndex(alias => new { alias.SpeakerIdentityId, alias.Name })
            .IsUnique();

        modelBuilder.Entity<SpeakerIdentityReference>()
            .HasIndex(reference => new { reference.SpeakerIdentityId, reference.MeetingNotePath, reference.TranscriptPath })
            .IsUnique();
    }
}