Cleanuparr/code/backend/Cleanuparr.Infrastructure/Helpers/FileReader.cs

using Cleanuparr.Shared.Helpers;

namespace Cleanuparr.Infrastructure.Helpers;

public class FileReader
{
    private readonly HttpClient _httpClient;
    
    public FileReader(IHttpClientFactory httpClientFactory)
    {
        _httpClient = httpClientFactory.CreateClient(Constants.HttpClientWithRetryName);
    }
    
    /// <summary>
    /// Whether a configured path points at a remote URL rather than a file on disk.
    /// An absolute local path parses as a file:// URI, so the scheme has to be checked.
    /// </summary>
    public static bool IsRemote(string? path) =>
        Uri.TryCreate(path, UriKind.Absolute, out Uri? uri)
        && (uri.Scheme == Uri.UriSchemeHttp || uri.Scheme == Uri.UriSchemeHttps);

    /// <summary>
    /// Resolves a configured path to something the file system understands, unwrapping a file:// URI to the path it points at.
    /// </summary>
    public static string ToLocalPath(string path) =>
        Uri.TryCreate(path, UriKind.Absolute, out Uri? uri) && uri.Scheme == Uri.UriSchemeFile
            ? uri.LocalPath
            : path;

    /// <summary>
    /// Reads content from either a local file or HTTP(S) URL
    /// Extracted from BlocklistProvider.ReadContentAsync for reuse
    /// </summary>
    /// <param name="path">File path or URL</param>
    /// <returns>Array of lines from the content</returns>
    public async Task<string[]> ReadContentAsync(string path)
    {
        if (IsRemote(path))
        {
            return await ReadFromUrlAsync(path);
        }

        string localPath = ToLocalPath(path);

        if (File.Exists(localPath))
        {
            return await File.ReadAllLinesAsync(localPath);
        }

        throw new ArgumentException($"File not found: {path}");
    }

    private async Task<string[]> ReadFromUrlAsync(string url)
    {
        using HttpResponseMessage response = await _httpClient.GetAsync(url);
        response.EnsureSuccessStatusCode();
        
        return (await response.Content.ReadAsStringAsync())
            .Split(['\r','\n'], StringSplitOptions.RemoveEmptyEntries);
    }
}