using System;
using System.Collections.Generic;
using System.Linq.Expressions;
using System.Threading;
using System.Threading.Tasks;

namespace ECMJobRunner.Domain.Interfaces
{
    /// <summary>
    /// Generic repository interface for data access operations
    /// </summary>
    /// <typeparam name="TEntity">Entity type</typeparam>
    public interface IRepository<TEntity> where TEntity : class
    {
        /// <summary>
        /// Get entity by ID asynchronously
        /// </summary>
        Task<TEntity?> GetByIdAsync(long id, CancellationToken cancellationToken = default);

        /// <summary>
        /// Get all entities asynchronously
        /// </summary>
        Task<IEnumerable<TEntity>> GetAllAsync(CancellationToken cancellationToken = default);

        /// <summary>
        /// Find entities by predicate asynchronously
        /// </summary>
        Task<IEnumerable<TEntity>> FindAsync(Expression<Func<TEntity, bool>> predicate, CancellationToken cancellationToken = default);

        /// <summary>
        /// Get single entity by predicate asynchronously
        /// </summary>
        Task<TEntity?> SingleOrDefaultAsync(Expression<Func<TEntity, bool>> predicate, CancellationToken cancellationToken = default);

        /// <summary>
        /// Add new entity from DTO asynchronously
        /// Maps DTO to entity and adds it
        /// </summary>
        /// <typeparam name="TDto">DTO type</typeparam>
        /// <param name="dto">DTO containing values for new entity</param>
        /// <param name="cancellationToken">Cancellation token</param>
        /// <returns>Created entity</returns>
        Task<TEntity> AddAsync<TDto>(TDto dto, CancellationToken cancellationToken = default) where TDto : class;

        /// <summary>
        /// Add multiple entities from DTOs asynchronously
        /// Maps DTOs to entities and adds them
        /// </summary>
        /// <typeparam name="TDto">DTO type</typeparam>
        /// <param name="dtos">DTOs containing values for new entities</param>
        /// <param name="cancellationToken">Cancellation token</param>
        /// <returns>Number of entities added</returns>
        Task<int> AddRangeAsync<TDto>(IEnumerable<TDto> dtos, CancellationToken cancellationToken = default) where TDto : class;

        /// <summary>
        /// Update entities matching predicate with DTO values asynchronously
        /// Maps DTO properties onto matching entities
        /// </summary>
        /// <typeparam name="TDto">DTO type</typeparam>
        /// <param name="predicate">Predicate to find entities</param>
        /// <param name="dto">DTO containing values to update</param>
        /// <param name="cancellationToken">Cancellation token</param>
        /// <returns>Number of entities updated</returns>
        Task<int> UpdateAsync<TDto>(Expression<Func<TEntity, bool>> predicate, TDto dto, CancellationToken cancellationToken = default) where TDto : class;

        /// <summary>
        /// Update single entity matching predicate with DTO values asynchronously
        /// Throws exception if multiple entities match
        /// </summary>
        /// <typeparam name="TDto">DTO type</typeparam>
        /// <param name="predicate">Predicate to find entity</param>
        /// <param name="dto">DTO containing values to update</param>
        /// <param name="cancellationToken">Cancellation token</param>
        /// <returns>True if entity was found and updated, false otherwise</returns>
        Task<bool> UpdateSingleAsync<TDto>(Expression<Func<TEntity, bool>> predicate, TDto dto, CancellationToken cancellationToken = default) where TDto : class;

        /// <summary>
        /// Delete entities matching predicate asynchronously (hard delete)
        /// </summary>
        /// <param name="predicate">Predicate to find entities to delete</param>
        /// <param name="cancellationToken">Cancellation token</param>
        /// <returns>Number of entities deleted</returns>
        Task<int> DeleteAsync(Expression<Func<TEntity, bool>> predicate, CancellationToken cancellationToken = default);

        /// <summary>
        /// Delete single entity matching predicate asynchronously (hard delete)
        /// Throws exception if multiple entities match
        /// </summary>
        /// <param name="predicate">Predicate to find entity to delete</param>
        /// <param name="cancellationToken">Cancellation token</param>
        /// <returns>True if entity was found and deleted, false otherwise</returns>
        Task<bool> DeleteSingleAsync(Expression<Func<TEntity, bool>> predicate, CancellationToken cancellationToken = default);
    }
}