using Microsoft.Extensions.Options;

namespace foodmarket.Api.Storage;

/// <summary>Файловое хранилище в <c>{ContentRoot}/uploads/</c>. По умолчанию.
/// Содержимое раздаётся nginx'ом как статика (см. deploy/nginx.conf, location
/// /uploads/). Используется когда MinIO не настроен или fallback после
/// ошибки MinIO connect на старте.</summary>
public sealed class LocalObjectStorage : IObjectStorage
{
    private readonly IWebHostEnvironment _env;
    private readonly StorageOptions _opts;

    public LocalObjectStorage(IWebHostEnvironment env, IOptions<StorageOptions> opts)
    {
        _env = env;
        _opts = opts.Value;
    }

    public string Kind => "local";

    private string Root => Path.Combine(_env.ContentRootPath, _opts.LocalRoot.TrimStart('/'));

    private string PathOf(string key) => Path.Combine(Root, key.Replace('/', Path.DirectorySeparatorChar));

    public async Task<string> SaveAsync(string key, Stream content, string contentType, CancellationToken ct = default)
    {
        var path = PathOf(key);
        var dir = Path.GetDirectoryName(path);
        if (dir is not null) Directory.CreateDirectory(dir);
        await using var fs = File.Create(path);
        await content.CopyToAsync(fs, ct);
        return key;
    }

    public Task<(Stream Stream, string ContentType)?> OpenAsync(string key, CancellationToken ct = default)
    {
        var path = PathOf(key);
        if (!File.Exists(path)) return Task.FromResult<(Stream, string)?>(null);
        Stream s = File.OpenRead(path);
        return Task.FromResult<(Stream, string)?>((s, GuessContentType(path)));
    }

    public Task DeleteAsync(string key, CancellationToken ct = default)
    {
        var path = PathOf(key);
        try { if (File.Exists(path)) File.Delete(path); }
        catch { /* idempotent */ }
        return Task.CompletedTask;
    }

    private static string GuessContentType(string path) => Path.GetExtension(path).ToLowerInvariant() switch
    {
        ".jpg" or ".jpeg" => "image/jpeg",
        ".png" => "image/png",
        ".gif" => "image/gif",
        ".webp" => "image/webp",
        ".csv" => "text/csv",
        _ => "application/octet-stream",
    };
}