using Govor.Application.Interfaces;
using Govor.Core.Models;
using Govor.Core.Repositories.Groups; // Assuming IGroupsRepository will be used
using Microsoft.Extensions.Logging;
using System;
using System.Collections.Generic;
using System.Threading.Tasks;

namespace Govor.Application.Services;

public class GroupService : IGroupService
{
    private readonly IGroupsRepository _groupsRepository;
    private readonly ILogger<GroupService> _logger;

    public GroupService(IGroupsRepository groupsRepository, ILogger<GroupService> logger)
    {
        _groupsRepository = groupsRepository;
        _logger = logger;
    }

    public Task<ChatGroup?> GetGroupByIdAsync(Guid groupId)
    {
        _logger.LogInformation("GetGroupByIdAsync called for {GroupId}", groupId);
        // Implementation Note: Use _groupsRepository.GetByIdAsync(groupId);
        throw new NotImplementedException();
    }

    public Task<ChatGroup> CreateGroupAsync(string name, Guid creatorId, IEnumerable<Guid> initialMemberIds)
    {
        _logger.LogInformation("CreateGroupAsync called by {CreatorId} with name {Name}", creatorId, name);
        // Implementation Note:
        // 1. Create ChatGroup entity.
        // 2. Create GroupMembership entities for creator and initial members.
        // 3. Save to repository.
        throw new NotImplementedException();
    }

    public Task<Result> AddUserToGroupAsync(Guid groupId, Guid userId, Guid addedByUserId)
    {
        _logger.LogInformation("AddUserToGroupAsync: User {UserId} to Group {GroupId} by {AddedByUserId}", userId, groupId, addedByUserId);
        // Implementation Note:
        // 1. Verify group exists.
        // 2. Verify addedByUserId has permission (e.g., is admin or member, depending on rules).
        // 3. Verify userId is not already a member.
        // 4. Create GroupMembership entity.
        // 5. Save to repository.
        throw new NotImplementedException();
    }

    public Task<Result> RemoveUserFromGroupAsync(Guid groupId, Guid userId, Guid removedByUserId)
    {
        _logger.LogInformation("RemoveUserFromGroupAsync: User {UserId} from Group {GroupId} by {RemovedByUserId}", userId, groupId, removedByUserId);
        // Implementation Note:
        // 1. Verify group exists.
        // 2. Verify removedByUserId has permission.
        // 3. Verify userId is a member.
        // 4. Remove GroupMembership entity.
        // 5. Save to repository.
        // 6. Consider what happens if the last admin/member is removed.
        throw new NotImplementedException();
    }

    public Task<Result> DeleteGroupAsync(Guid groupId, Guid userId)
    {
        _logger.LogInformation("DeleteGroupAsync: Group {GroupId} by User {UserId}", groupId, userId);
        // Implementation Note:
        // 1. Verify group exists.
        // 2. Verify userId has permission (e.g., is owner or admin).
        // 3. Delete group and its memberships.
        // 4. Save to repository.
        throw new NotImplementedException();
    }

    public Task<List<User>> GetGroupMembersAsync(Guid groupId)
    {
        _logger.LogInformation("GetGroupMembersAsync for Group {GroupId}", groupId);
        // Implementation Note: Use _groupsRepository to fetch members.
        throw new NotImplementedException();
    }

    public Task<List<ChatGroup>> GetUserGroupsAsync(Guid userId)
    {
        _logger.LogInformation("GetUserGroupsAsync for User {UserId}", userId);
        // Implementation Note: Use _groupsRepository to fetch groups for the user.
        // This is important for ChatsHub.OnConnectedAsync to subscribe user to their group channels.
        throw new NotImplementedException();
    }

    public ChatGroup? GetGroupByInviteCode(string code)
    {
        _logger.LogInformation("GetGroupByInviteCode called with code {Code}", code);
        // Implementation Note:
        // 1. Find group by invite code (may require a specific table/field for invite codes).
        throw new NotImplementedException();
    }
}