using Microsoft.EntityFrameworkCore;
using Prefab.Data.Entities;

using Prefab.Domain.Common;

namespace Prefab.Data.Queries;

/// <summary>
/// Provides extension methods for the <see cref="GenericAttribute"/> entity.
/// </summary>
public static class GenericAttributeQueries
{
    /// <summary>
    /// Query for records where the <see cref="GenericAttribute.EntityId"/> field matches the given entity.
    /// </summary>
    public static IQueryable<GenericAttribute> ForEntity(this IQueryable<GenericAttribute> query, IEntity<Guid> entity)
    {
        ArgumentNullException.ThrowIfNull(entity);

        return query.Where(x => x.EntityId == entity.Id && x.KeyGroup == entity.GetType().FullName);
    }

    /// <summary>
    /// Query for records in a module-specific view where the EntityId matches the given entity.
    /// </summary>
    public static IQueryable<TView> ForEntity<TView>(this IQueryable<TView> query, IEntity<Guid> entity, string keyGroup)
        where TView : class
    {
        return GenericAttributeViewQueries.ForEntity(query, entity, keyGroup);
    }

    /// <summary>
    /// Query for records where the <see cref="GenericAttribute.Value"/> field contains characters from the given string value.
    /// </summary>
    public static IQueryable<GenericAttribute> WhereTheValueContains(this IQueryable<GenericAttribute> query, string value)
    {
        return query.Where(x => x.Value.Contains(value));
    }

    /// <summary>
    /// Filter by key (exact match).
    /// </summary>
    private static IQueryable<GenericAttribute> WhereKey(
        this IQueryable<GenericAttribute> q, string key) =>
        q.Where(x => x.Key == key);

    /// <summary>
    /// Filter by key-group (exact match).
    /// </summary>
    public static IQueryable<GenericAttribute> WhereGroup(
        this IQueryable<GenericAttribute> q, string keyGroup) =>
        q.Where(x => x.KeyGroup == keyGroup);

    /// <summary>
    /// Filter by type (exact match).
    /// </summary>
    public static IQueryable<GenericAttribute> WhereType(
        this IQueryable<GenericAttribute> q, string type) =>
        q.Where(x => x.Type == type);

    /// <summary>
    /// Filter by any of the given keys.
    /// </summary>
    public static IQueryable<GenericAttribute> WhereKeys(
        this IQueryable<GenericAttribute> q, params string[] keys) =>
        q.Where(x => keys.Contains(x.Key));

    /// <summary>
    /// Case-insensitive substring search on Value using EF.Functions.Like.
    /// </summary>
    public static IQueryable<GenericAttribute> WhereValueLike(
        this IQueryable<GenericAttribute> q, string pattern) =>
        q.Where(x => EF.Functions.Like(x.Value, pattern));

    /// <summary>
    /// Project into a key→value dictionary.
    /// </summary>
    public static async Task<Dictionary<string, string>> ToDictionaryAsync(
        this IQueryable<GenericAttribute> q,
        CancellationToken ct = default)
    {
        return await q
            .Select(x => new { x.Key, x.Value })
            .ToDictionaryAsync(x => x.Key, x => x.Value, ct)
            .ConfigureAwait(false);
    }

    /// <summary>
    /// Shortcut to fetch a single attribute value (or null).
    /// </summary>
    public static async Task<string?> GetValueAsync(
        this IQueryable<GenericAttribute> q, string key, CancellationToken ct = default)
    {
        return await q
            .WhereKey(key)
            .Select(x => x.Value)
            .FirstOrDefaultAsync(ct)
            .ConfigureAwait(false);
    }

    /// <summary>
    /// Apply AsNoTracking for read-only queries.
    /// </summary>
    public static IQueryable<GenericAttribute> AsReadOnly(
        this IQueryable<GenericAttribute> q) =>
        q.AsNoTracking();
}