Tp_blazor/BlazorTp1/Services/DataLocalService.cs

using Blazored.LocalStorage;
using BlazorTp1.Factories;
using BlazorTp1.Models;
using Microsoft.AspNetCore.Components;

public class DataLocalService : IDataService
{
    private readonly HttpClient _http;
    private readonly ILocalStorageService _localStorage;
    private readonly NavigationManager _navigationManager;
    private readonly IWebHostEnvironment _webHostEnvironment;

    public DataLocalService(
        ILocalStorageService localStorage,
        HttpClient http,
        IWebHostEnvironment webHostEnvironment,
        NavigationManager navigationManager)
    {
        _localStorage = localStorage;
        _http = http;
        _webHostEnvironment = webHostEnvironment;
        _navigationManager = navigationManager;
    }

    public async Task Add(ItemModel model)
    {
        // Get the current data
        var currentData = await _localStorage.GetItemAsync<List<Item>>("data");

        // Simulate the Id
        model.Id = currentData.Max(s => s.Id) + 1;

        // Add the item to the current data
        currentData.Add(ItemFactory.Create(model));

        // Save the image
        var imagePathInfo = new DirectoryInfo($"{_webHostEnvironment.WebRootPath}/images");

        // Check if the folder "images" exist
        if (!imagePathInfo.Exists)
        {
            imagePathInfo.Create();
        }

        // Determine the image name
        var fileName = new FileInfo($"{imagePathInfo}/{model.Name}.png");

        // Write the file content
        await File.WriteAllBytesAsync(fileName.FullName, model.ImageContent);

        // Save the data
        await _localStorage.SetItemAsync("data", currentData);
    }

    public async Task<int> Count()
    {
        return (await _localStorage.GetItemAsync<Item[]>("data")).Length;
    }

    public async Task<List<Item>> List(int currentPage, int pageSize)
    {
        // Load data from the local storage
        var currentData = await _localStorage.GetItemAsync<Item[]>("data");

        // Check if data exist in the local storage
        if (currentData == null)
        {
            // this code add in the local storage the fake data
            var originalData = await _http.GetFromJsonAsync<Item[]>($"{_navigationManager.BaseUri}fake-data.json");
            await _localStorage.SetItemAsync("data", originalData);
        }

        return (await _localStorage.GetItemAsync<Item[]>("data")).Skip((currentPage - 1) * pageSize).Take(pageSize).ToList();
    }
    
    //new methods

    public async Task<Item> GetById(int id)
    {
        // Get the current data
        var currentData = await _localStorage.GetItemAsync<List<Item>>("data");

        // Get the item int the list
        var item = currentData.FirstOrDefault(w => w.Id == id);

        // Check if item exist
        if (item == null)
        {
            throw new Exception($"Unable to found the item with ID: {id}");
        }

        return item;
    }

    public async Task Update(int id, ItemModel model)
    {
        // Get the current data
        var currentData = await _localStorage.GetItemAsync<List<Item>>("data");

        // Get the item int the list
        var item = currentData.FirstOrDefault(w => w.Id == id);

        // Check if item exist
        if (item == null)
        {
            throw new Exception($"Unable to found the item with ID: {id}");
        }

        // Save the image
        var imagePathInfo = new DirectoryInfo($"{_webHostEnvironment.WebRootPath}/images");

        // Check if the folder "images" exist
        if (!imagePathInfo.Exists)
        {
            imagePathInfo.Create();
        }

        // Delete the previous image
        if (item.Name != model.Name)
        {
            var oldFileName = new FileInfo($"{imagePathInfo}/{item.Name}.png");

            if (oldFileName.Exists)
            {
                File.Delete(oldFileName.FullName);
            }
        }

        // Determine the image name
        var fileName = new FileInfo($"{imagePathInfo}/{model.Name}.png");

        // Write the file content
        await File.WriteAllBytesAsync(fileName.FullName, model.ImageContent);

        // Modify the content of the item
        ItemFactory.Update(item, model);

        // Save the data
        await _localStorage.SetItemAsync("data", currentData);
    }

    public async Task Delete(int id)
    {
        // Get the current data
        var currentData = await _localStorage.GetItemAsync<List<Item>>("data");

        // Get the item int the list
        var item = currentData.FirstOrDefault(w => w.Id == id);

        // Delete item in
        currentData.Remove(item);

        // Delete the image
        var imagePathInfo = new DirectoryInfo($"{_webHostEnvironment.WebRootPath}/images");
        var fileName = new FileInfo($"{imagePathInfo}/{item.Name}.png");

        if (fileName.Exists)
        {
            File.Delete(fileName.FullName);
        }

        // Save the data
        await _localStorage.SetItemAsync("data", currentData);
    }
}