using GozareshgirProgramManager.Application._Common.Interfaces;
using GozareshgirProgramManager.Application._Common.Models;
using GozareshgirProgramManager.Application.Modules.TaskChat.DTOs;
using GozareshgirProgramManager.Application.Services.FileManagement;
using GozareshgirProgramManager.Domain._Common.Exceptions;
using GozareshgirProgramManager.Domain.TaskChatAgg.Entities;
using GozareshgirProgramManager.Domain.TaskChatAgg.Repositories;
using GozareshgirProgramManager.Domain.TaskChatAgg.Enums;
using GozareshgirProgramManager.Domain.FileManagementAgg.Entities;
using GozareshgirProgramManager.Domain.FileManagementAgg.Repositories;
using GozareshgirProgramManager.Domain.FileManagementAgg.Enums;
using GozareshgirProgramManager.Domain.ProjectAgg.Repositories;
using MediatR;
using Microsoft.AspNetCore.Http;

namespace GozareshgirProgramManager.Application.Modules.TaskChat.Commands.SendMessage;

public record SendMessageCommand(
    Guid TaskId,
    MessageType MessageType,
    string? TextContent,
    IFormFile? File,
    Guid? ReplyToMessageId
) : IBaseCommand<MessageDto>;

public class SendMessageCommandHandler : IBaseCommandHandler<SendMessageCommand, MessageDto>
{
    private readonly ITaskChatMessageRepository _messageRepository;
    private readonly IUploadedFileRepository _fileRepository;
    private readonly IProjectTaskRepository _taskRepository;
    private readonly IFileStorageService _fileStorageService;
    private readonly IThumbnailGeneratorService _thumbnailService;
    private readonly IAuthHelper _authHelper;

    public SendMessageCommandHandler(
        ITaskChatMessageRepository messageRepository,
        IUploadedFileRepository fileRepository,
        IProjectTaskRepository taskRepository,
        IFileStorageService fileStorageService,
        IThumbnailGeneratorService thumbnailService, IAuthHelper authHelper)
    {
        _messageRepository = messageRepository;
        _fileRepository = fileRepository;
        _taskRepository = taskRepository;
        _fileStorageService = fileStorageService;
        _thumbnailService = thumbnailService;
        _authHelper = authHelper;
    }

    public async Task<OperationResult<MessageDto>> Handle(SendMessageCommand request, CancellationToken cancellationToken)
    {
        var currentUserId = _authHelper.GetCurrentUserId()
                            ?? throw new UnAuthorizedException("کاربر احراز هویت نشده است");

        var task = await _taskRepository.GetByIdAsync(request.TaskId, cancellationToken);
        if (task == null)
        {
            return OperationResult<MessageDto>.NotFound("تسک یافت نشد");
        }
        
        Guid? uploadedFileId = null;
        if (request.File != null)
        {
            if (request.File.Length == 0)
            {
                return OperationResult<MessageDto>.ValidationError("فایل خالی است");
            }

            const long maxFileSize = 100 * 1024 * 1024;
            if (request.File.Length > maxFileSize)
            {
                return OperationResult<MessageDto>.ValidationError("حجم فایل بیش از حد مجاز است (حداکثر 100MB)");
            }

            var fileType = DetectFileType(request.File.ContentType, Path.GetExtension(request.File.FileName));

            var uploadedFile = new UploadedFile(
                originalFileName: request.File.FileName,
                fileSizeBytes: request.File.Length,
                mimeType: request.File.ContentType,
                fileType: fileType,
                category: FileCategory.TaskChatMessage,
                uploadedByUserId: currentUserId,
                storageProvider: StorageProvider.LocalFileSystem
            );

            await _fileRepository.AddAsync(uploadedFile);
            await _fileRepository.SaveChangesAsync();

            try
            {
                using var stream = request.File.OpenReadStream();
                var uploadResult = await _fileStorageService.UploadAsync(
                    stream,
                    uploadedFile.UniqueFileName,
                    "TaskChatMessage"
                );

                uploadedFile.CompleteUpload(uploadResult.StoragePath, uploadResult.StorageUrl);

                if (fileType == FileType.Image)
                {
                    var dimensions = await _thumbnailService.GetImageDimensionsAsync(uploadResult.StoragePath);
                    if (dimensions.HasValue)
                    {
                        uploadedFile.SetImageDimensions(dimensions.Value.Width, dimensions.Value.Height);
                    }

                    var thumbnail = await _thumbnailService
                        .GenerateImageThumbnailAsync(uploadResult.StoragePath, category: "TaskChatMessage");
                    if (thumbnail.HasValue)
                    {
                        uploadedFile.SetThumbnail(thumbnail.Value.ThumbnailUrl);
                    }
                }

                await _fileRepository.UpdateAsync(uploadedFile);
                await _fileRepository.SaveChangesAsync();

                uploadedFileId = uploadedFile.Id;
            }
            catch (Exception ex)
            {
                await _fileRepository.DeleteAsync(uploadedFile);
                await _fileRepository.SaveChangesAsync();

                return OperationResult<MessageDto>.ValidationError($"خطا در آپلود فایل: {ex.Message}");
            }
        }

        var message = new TaskChatMessage(
            taskId: request.TaskId,
            senderUserId: currentUserId,
            messageType: request.MessageType,
            textContent: request.TextContent,
            uploadedFileId
        );

        if (request.ReplyToMessageId.HasValue)
        {
            message.SetReplyTo(request.ReplyToMessageId.Value);
        }

        await _messageRepository.AddAsync(message);
        await _messageRepository.SaveChangesAsync();

        if (uploadedFileId.HasValue)
        {
            var file = await _fileRepository.GetByIdAsync(uploadedFileId.Value);
            if (file != null)
            {
                file.SetReference("TaskChatMessage", message.Id.ToString());
                await _fileRepository.UpdateAsync(file);
                await _fileRepository.SaveChangesAsync();
            }
        }

        var dto = new MessageDto
        {
            Id = message.Id,
            TaskId = message.TaskId,
            SenderUserId = message.SenderUserId,
            SenderName = "کاربر",
            MessageType = message.MessageType.ToString(),
            TextContent = message.TextContent,
            ReplyToMessageId = message.ReplyToMessageId,
            IsEdited = message.IsEdited,
            IsPinned = message.IsPinned,
            CreationDate = message.CreationDate,
            IsMine = true
        };

        if (uploadedFileId.HasValue)
        {
            var file = await _fileRepository.GetByIdAsync(uploadedFileId.Value);
            if (file != null)
            {
                dto.File = new MessageFileDto
                {
                    Id = file.Id,
                    FileName = file.OriginalFileName,
                    FileUrl = file.StorageUrl ?? "",
                    FileSizeBytes = file.FileSizeBytes,
                    FileType = file.FileType.ToString(),
                    ThumbnailUrl = file.ThumbnailUrl,
                    ImageWidth = file.ImageWidth,
                    ImageHeight = file.ImageHeight,
                    DurationSeconds = file.DurationSeconds
                };
            }
        }

        return OperationResult<MessageDto>.Success(dto);
    }

    private FileType DetectFileType(string mimeType, string extension)
    {
        if (mimeType.StartsWith("image/", StringComparison.OrdinalIgnoreCase))
            return FileType.Image;

        if (mimeType.StartsWith("video/", StringComparison.OrdinalIgnoreCase))
            return FileType.Video;

        if (mimeType.StartsWith("audio/", StringComparison.OrdinalIgnoreCase))
            return FileType.Audio;

        if (new[] { ".zip", ".rar", ".7z", ".tar", ".gz" }.Contains(extension.ToLower()))
            return FileType.Archive;

        return FileType.Document;
    }
}