using Microsoft.AspNetCore.Mvc;
using w4c_workflows.Filters;
using w4c_workflows.Models.Nodes;
using w4c_workflows.Services.Nodes.Binary;

namespace w4c_workflows.Controllers;

/// <summary>
/// Streams binary payloads referenced by run items. Items carry only an opaque,
/// content-addressed <c>assetId</c>; the bytes live in <see cref="IBinaryStore"/>.
/// The node catalog's HTTP/binary nodes write assets here, and the run panel's
/// item preview reads them back (inline preview with <c>?download=false</c>, or
/// a named download with <c>?download=true</c>).
/// </summary>
[ApiController]
[Route("api/binary")]
public class BinaryController : ControllerBase
{
    private readonly IBinaryStore _store;

    public BinaryController(IBinaryStore store)
    {
        _store = store;
    }

    /// <summary>Streams one stored asset. 404 when the id is unknown/malformed.</summary>
    [HttpGet("{assetId}")]
    [RequireScope("read")]
    public async Task<IActionResult> Get(string assetId, [FromQuery] bool download = false, CancellationToken ct = default)
    {
        var meta = await _store.DescribeAsync(assetId, ct);
        var stream = await _store.OpenAsync(assetId, ct);
        if (stream == null)
            return NotFound(new { error = "Asset not found." });

        var contentType = meta?.MimeType ?? "application/octet-stream";
        var fileName = SafeFileName(meta?.FileName) ?? "asset";

        return download
            ? File(stream, contentType, fileName)
            : File(stream, contentType);
    }

    /// <summary>Asset metadata only — used to label binary chips without downloading.</summary>
    [HttpGet("{assetId}/meta")]
    [RequireScope("read")]
    public async Task<IActionResult> Meta(string assetId, CancellationToken ct)
    {
        var meta = await _store.DescribeAsync(assetId, ct);
        if (meta == null)
            return NotFound(new { error = "Asset not found." });
        return Ok(meta);
    }

    private static string? SafeFileName(string? name)
    {
        if (string.IsNullOrWhiteSpace(name))
            return null;
        var trimmed = name.Replace('\\', '/');
        var slash = trimmed.LastIndexOf('/');
        return slash >= 0 ? trimmed[(slash + 1)..] : trimmed;
    }
}