using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Threading;
using System.Threading.Tasks;
using AsbCloudApp.Data.Manuals;
using AsbCloudApp.Exceptions;
using AsbCloudApp.Repositories;
using AsbCloudApp.Services;
using AsbCloudDb.Model;
using Microsoft.Extensions.Configuration;

namespace AsbCloudInfrastructure.Services;

public class ManualCatalogService : IManualCatalogService
{
	private readonly IEnumerable<string> validExtensions = new[]
	{
		".pdf",
		".mp4"
	};

	private readonly string directoryFiles;
	private readonly IFileStorageRepository fileStorageRepository;
	private readonly IManualFolderRepository manualFolderRepository;
	private readonly IManualRepository manualRepository;
	private readonly IFileCategoryRepository fileCategoryRepository;

	public ManualCatalogService(IFileStorageRepository fileStorageRepository,
		IManualFolderRepository manualFolderRepository,
		IManualRepository manualRepository,
		IFileCategoryRepository fileCategoryRepository,
		IConfiguration configuration)
	{
		this.fileStorageRepository = fileStorageRepository;
		this.manualFolderRepository = manualFolderRepository;
		this.manualRepository = manualRepository;
		this.fileCategoryRepository = fileCategoryRepository;
		directoryFiles = configuration.GetValue<string>("DirectoryManualFiles");

		if (string.IsNullOrWhiteSpace(directoryFiles))
			directoryFiles = "manuals";
	}

	public async Task<int> SaveFileAsync(int? idCategory, int? idFolder, string name, Stream stream,
		CancellationToken cancellationToken)
	{
		var extension = Path.GetExtension(name);

		if (!validExtensions.Contains(extension))
			throw new ArgumentInvalidException(
				$"Невозможно загрузить файл с расширением '{extension}'. Допустимые форматы файлов: {string.Join(", ", validExtensions)}",
				extension);

		var path = await BuildFilePathAsync(idCategory, idFolder, name, cancellationToken);

		await fileStorageRepository.SaveFileAsync(path,
			stream,
			cancellationToken);

		var manual = new ManualDto
		{
			Name = name,
			DateDownload = DateTime.UtcNow,
			IdFolder = idFolder,
			IdCategory = idCategory
		};

		return await manualRepository.InsertAsync(manual, cancellationToken);
	}

	public async Task<int> AddFolderAsync(string name, int? idParent, int idCategory,
		CancellationToken cancellationToken)
	{
		if (idParent.HasValue)
		{
			var parent = await manualFolderRepository.GetOrDefaultAsync(idParent.Value, cancellationToken)
						?? throw new ArgumentInvalidException("Родительской папки не существует", nameof(idParent));

			if (parent.IdCategory != idCategory)
				throw new ArgumentInvalidException("Категория родительской папки не соответствует текущей категории",
					nameof(idCategory));
		}

		var manualFolder = new ManualFolderDto
		{
			Name = name,
			IdParent = idParent,
			IdCategory = idCategory,
		};

		if (await IsExistFolderAsync(manualFolder, cancellationToken))
			throw new ArgumentInvalidException("Папка с таким названием уже существует", name);

		return await manualFolderRepository.InsertAsync(manualFolder, cancellationToken);
	}

	public async Task UpdateFolderAsync(int id, string name, CancellationToken cancellationToken)
	{
		var folder = await manualFolderRepository.GetOrDefaultAsync(id, cancellationToken)
					?? throw new ArgumentInvalidException($"Папки с Id: {id} не сущесвует", nameof(id));

		folder.Name = name;

		if (await IsExistFolderAsync(folder, cancellationToken))
			throw new ArgumentInvalidException("Папка с таким названием уже существует", name);

		await manualFolderRepository.UpdateAsync(folder, cancellationToken);
	}


	public async Task<int> DeleteFolderAsync(int id, CancellationToken cancellationToken)
	{
		var folder = await manualFolderRepository.GetOrDefaultAsync(id, cancellationToken);

		if (folder is null)
			return 0;

		var path = Path.Combine(directoryFiles, folder.IdCategory.ToString(), folder.Id.ToString());
		fileStorageRepository.DeleteDirectory(path);

		return await manualFolderRepository.DeleteAsync(folder.Id, cancellationToken);
	}

	public async Task<int> DeleteFileAsync(int id, CancellationToken cancellationToken)
	{
		var manual = await manualRepository.GetOrDefaultAsync(id, cancellationToken);

		if (manual is null)
			return 0;

		var filePath = await BuildFilePathAsync(manual.IdCategory, manual.IdFolder, manual.Name,
			cancellationToken);

		fileStorageRepository.DeleteFile(filePath);

		return await manualRepository.DeleteAsync(manual.Id, cancellationToken);
	}

	public async Task<(Stream stream, string fileName)?> GetFileAsync(int id, CancellationToken cancellationToken)
	{
		var manual = await manualRepository.GetOrDefaultAsync(id, cancellationToken);

		if (manual is null)
			return null;

		var path = await BuildFilePathAsync(manual.IdCategory, manual.IdFolder, manual.Name, cancellationToken);

		var fileStream = new FileStream(Path.GetFullPath(path), FileMode.Open);

		return (fileStream, manual.Name);
	}

	public async Task<IEnumerable<CatalogItemManualDto>> GetCatalogAsync(CancellationToken cancellationToken)
	{
		var catalogItems = new List<CatalogItemManualDto>();
		
		var categories = await fileCategoryRepository.GetAllAsync(FileCategory.IdFileCategoryTypeManuals,
			cancellationToken);

		foreach (var category in categories)
		{
			catalogItems.Add(new CatalogItemManualDto()
			{
				Category = category,
				ManualsWithoutFolder = await manualRepository.GetManualsWithoutFolderAsync(category.Id, cancellationToken),
				Folders = await manualFolderRepository.GetTreeAsync(category.Id, cancellationToken)
			});
		}

		return catalogItems;
	}

	private async Task<bool> IsExistFolderAsync(ManualFolderDto folder, CancellationToken cancellationToken)
	{
		var existingFolder = await manualFolderRepository.GetOrDefaultAsync(folder.Name, folder.IdParent,
			folder.IdCategory,
			cancellationToken);

		return existingFolder is not null && folder.Id != existingFolder.Id;
	}

	private async Task<string> BuildFilePathAsync(int? idCategory, int? idFolder, string name,
		CancellationToken cancellationToken)
	{
		if (idFolder.HasValue)
		{
			var folder = await manualFolderRepository.GetOrDefaultAsync(idFolder.Value, cancellationToken)
						?? throw new ArgumentInvalidException($"Папки с Id: {idFolder} не сущесвует", nameof(idFolder));

			return fileStorageRepository.MakeFilePath(directoryFiles, Path.Combine(folder.IdCategory.ToString(),
				folder.IdParent.ToString() ?? string.Empty,
				folder.Id.ToString()), name);
		}

		if (!idCategory.HasValue)
			throw new ArgumentInvalidException("Не указан идентификатор категории", nameof(idCategory));

		return fileStorageRepository.MakeFilePath(directoryFiles, idCategory.Value.ToString(), name);
	}
}