using System.Collections.Generic;
using System.Threading;
using System.Threading.Tasks;
using GermanApp.Domain.Entities;

namespace GermanApp.Domain.Interfaces;

/// <summary>
/// Repository interface for managing StorySegment entities.
/// This is part of the Domain layer.
/// </summary>
public interface IStoryRepository
{
    /// <summary>
    /// Gets a story segment by its ID.
    /// </summary>
    /// <param name="id">The segment ID</param>
    /// <param name="cancellationToken">Cancellation token</param>
    /// <returns>The story segment or null if not found</returns>
    Task<StorySegment?> GetByIdAsync(int id, CancellationToken cancellationToken = default);

    /// <summary>
    /// Gets all story segments for a specific level.
    /// </summary>
    /// <param name="levelId">The level ID</param>
    /// <param name="includeInactive">Whether to include inactive segments</param>
    /// <param name="cancellationToken">Cancellation token</param>
    /// <returns>List of story segments ordered by Order</returns>
    Task<IReadOnlyList<StorySegment>> GetByLevelAsync(
        int levelId,
        bool includeInactive = false,
        CancellationToken cancellationToken = default);

    /// <summary>
    /// Gets all story segments for a specific lesson.
    /// </summary>
    /// <param name="lessonId">The lesson ID</param>
    /// <param name="cancellationToken">Cancellation token</param>
    /// <returns>List of story segments associated with the lesson</returns>
    Task<IReadOnlyList<StorySegment>> GetByLessonAsync(
        int lessonId,
        CancellationToken cancellationToken = default);

    /// <summary>
    /// Gets the next segment to unlock for a user after completing a lesson.
    /// </summary>
    /// <param name="levelId">The level ID</param>
    /// <param name="completedLessonOrder">The order of the completed lesson</param>
    /// <param name="cancellationToken">Cancellation token</param>
    /// <returns>The next story segment to unlock, or null if none</returns>
    Task<StorySegment?> GetNextSegmentToUnlockAsync(
        int levelId,
        int completedLessonOrder,
        CancellationToken cancellationToken = default);

    /// <summary>
    /// Gets story segments by their order range.
    /// </summary>
    /// <param name="levelId">The level ID</param>
    /// <param name="startOrder">Starting order (inclusive)</param>
    /// <param name="endOrder">Ending order (inclusive)</param>
    /// <param name="cancellationToken">Cancellation token</param>
    /// <returns>List of story segments in the specified order range</returns>
    Task<IReadOnlyList<StorySegment>> GetByOrderRangeAsync(
        int levelId,
        int startOrder,
        int endOrder,
        CancellationToken cancellationToken = default);

    /// <summary>
    /// Adds a new story segment.
    /// </summary>
    /// <param name="segment">The story segment to add</param>
    /// <param name="cancellationToken">Cancellation token</param>
    /// <returns>The added segment with generated ID</returns>
    Task<StorySegment> AddAsync(StorySegment segment, CancellationToken cancellationToken = default);

    /// <summary>
    /// Updates an existing story segment.
    /// </summary>
    /// <param name="segment">The story segment to update</param>
    /// <param name="cancellationToken">Cancellation token</param>
    Task UpdateAsync(StorySegment segment, CancellationToken cancellationToken = default);

    /// <summary>
    /// Deletes a story segment by its ID.
    /// </summary>
    /// <param name="id">The segment ID</param>
    /// <param name="cancellationToken">Cancellation token</param>
    Task DeleteAsync(int id, CancellationToken cancellationToken = default);

    /// <summary>
    /// Gets the highest order value for segments in a level.
    /// </summary>
    /// <param name="levelId">The level ID</param>
    /// <param name="cancellationToken">Cancellation token</param>
    /// <returns>The highest order value, or 0 if no segments exist</returns>
    Task<int> GetMaxOrderAsync(int levelId, CancellationToken cancellationToken = default);

    /// <summary>
    /// Checks if a story segment exists for the given ID.
    /// </summary>
    /// <param name="id">The segment ID</param>
    /// <param name="cancellationToken">Cancellation token</param>
    /// <returns>True if the segment exists</returns>
    Task<bool> ExistsAsync(int id, CancellationToken cancellationToken = default);

    /// <summary>
    /// Gets all story segments that need audio generation.
    /// </summary>
    /// <param name="cancellationToken">Cancellation token</param>
    /// <returns>List of segments with null or empty AudioUrl</returns>
    Task<IReadOnlyList<StorySegment>> GetSegmentsNeedingAudioAsync(
        CancellationToken cancellationToken = default);
}