prepare_download.go RawHistoryFolder

1package usecase
2
3import (
4	"context"
5	"path/filepath"
6
7	"github.com/bnema/dumber/internal/application/port"
8	"github.com/bnema/dumber/internal/domain/download"
9	"github.com/bnema/dumber/internal/logging"
10)
11
12// PrepareDownloadInput is an alias for port.DownloadPrepareInput.
13type PrepareDownloadInput = port.DownloadPrepareInput
14
15// PrepareDownloadOutput is an alias for port.DownloadPrepareOutput.
16type PrepareDownloadOutput = port.DownloadPrepareOutput
17
18// Compile-time check: PrepareDownloadUseCase must satisfy port.DownloadPreparer.
19var _ port.DownloadPreparer = (*PrepareDownloadUseCase)(nil)
20
21// PrepareDownloadUseCase orchestrates filename resolution for downloads.
22// It combines multiple sources (suggested name, response headers, URI) to
23// determine the best filename, then sanitizes it to prevent path traversal.
24type PrepareDownloadUseCase struct {
25	fs port.FileSystem
26}
27
28// NewPrepareDownloadUseCase creates a new PrepareDownloadUseCase.
29// If fs is nil, filename deduplication is disabled.
30func NewPrepareDownloadUseCase(fs port.FileSystem) *PrepareDownloadUseCase {
31	return &PrepareDownloadUseCase{fs: fs}
32}
33
34// Execute resolves the download filename and destination path.
35func (u *PrepareDownloadUseCase) Execute(ctx context.Context, input PrepareDownloadInput) *PrepareDownloadOutput {
36	log := logging.FromContext(ctx)
37
38	// Resolve filename from multiple sources (priority: suggested > response suggested > URI)
39	resolvedName := u.resolveSuggestedFilename(input.SuggestedFilename, input.Response)
40
41	// Get MIME type for extension inference
42	mimeType := ""
43	if input.Response != nil {
44		mimeType = input.Response.GetMimeType()
45	}
46
47	// Sanitize filename and add extension if needed
48	safeName := download.SanitizeFilenameWithExtension(resolvedName, mimeType)
49
50	// Make filename unique if file already exists
51	if u.fs != nil {
52		safeName = download.MakeUniqueFilename(input.DownloadDir, safeName, func(path string) bool {
53			exists, err := u.fs.Exists(ctx, path)
54			if err != nil {
55				log.Warn().Err(err).Str("path", path).
56					Msg("failed to check file existence; assuming exists")
57				return true // Conservative: assume exists to avoid overwrite
58			}
59			return exists
60		})
61	}
62
63	destPath := filepath.Join(input.DownloadDir, safeName)
64
65	log.Debug().
66		Str("suggested", input.SuggestedFilename).
67		Str("resolved", resolvedName).
68		Str("sanitized", safeName).
69		Str("destPath", destPath).
70		Msg("prepared download destination")
71
72	return &PrepareDownloadOutput{
73		Filename:        safeName,
74		DestinationPath: destPath,
75	}
76}
77
78// resolveSuggestedFilename determines the best filename from available sources.
79func (*PrepareDownloadUseCase) resolveSuggestedFilename(name string, response port.DownloadResponse) string {
80	// Priority 1: Use provided suggested filename
81	if name != "" {
82		return name
83	}
84
85	if response == nil {
86		return name
87	}
88
89	// Priority 2: Use response's suggested filename (from Content-Disposition)
90	if suggested := response.GetSuggestedFilename(); suggested != "" {
91		return suggested
92	}
93
94	// Priority 3: Extract from URI path
95	uri := response.GetUri()
96	if uri == "" {
97		return name
98	}
99
100	return download.ExtractFilenameFromURI(uri)
101}