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 contains the inputs for preparing a download destination.
13type PrepareDownloadInput struct {
14	// SuggestedFilename is the filename suggested by WebKit (from Content-Disposition or other sources).
15	SuggestedFilename string
16	// Response provides additional metadata (MIME type, URI) for filename resolution.
17	// May be nil if not available.
18	Response port.DownloadResponse
19	// DownloadDir is the directory where downloads should be saved.
20	DownloadDir string
21}
22
23// PrepareDownloadOutput contains the resolved download destination.
24type PrepareDownloadOutput struct {
25	// Filename is the sanitized, safe filename to use.
26	Filename string
27	// DestinationPath is the full path where the download should be saved.
28	DestinationPath string
29}
30
31// PrepareDownloadUseCase orchestrates filename resolution for downloads.
32// It combines multiple sources (suggested name, response headers, URI) to
33// determine the best filename, then sanitizes it to prevent path traversal.
34type PrepareDownloadUseCase struct {
35	fs port.FileSystem
36}
37
38// NewPrepareDownloadUseCase creates a new PrepareDownloadUseCase.
39// If fs is nil, filename deduplication is disabled.
40func NewPrepareDownloadUseCase(fs port.FileSystem) *PrepareDownloadUseCase {
41	return &PrepareDownloadUseCase{fs: fs}
42}
43
44// Execute resolves the download filename and destination path.
45func (u *PrepareDownloadUseCase) Execute(ctx context.Context, input PrepareDownloadInput) *PrepareDownloadOutput {
46	log := logging.FromContext(ctx)
47
48	// Resolve filename from multiple sources (priority: suggested > response suggested > URI)
49	resolvedName := u.resolveSuggestedFilename(input.SuggestedFilename, input.Response)
50
51	// Get MIME type for extension inference
52	mimeType := ""
53	if input.Response != nil {
54		mimeType = input.Response.GetMimeType()
55	}
56
57	// Sanitize filename and add extension if needed
58	safeName := download.SanitizeFilenameWithExtension(resolvedName, mimeType)
59
60	// Make filename unique if file already exists
61	if u.fs != nil {
62		safeName = download.MakeUniqueFilename(input.DownloadDir, safeName, func(path string) bool {
63			exists, err := u.fs.Exists(ctx, path)
64			if err != nil {
65				log.Warn().Err(err).Str("path", path).
66					Msg("failed to check file existence; assuming exists")
67				return true // Conservative: assume exists to avoid overwrite
68			}
69			return exists
70		})
71	}
72
73	destPath := filepath.Join(input.DownloadDir, safeName)
74
75	log.Debug().
76		Str("suggested", input.SuggestedFilename).
77		Str("resolved", resolvedName).
78		Str("sanitized", safeName).
79		Str("destPath", destPath).
80		Msg("prepared download destination")
81
82	return &PrepareDownloadOutput{
83		Filename:        safeName,
84		DestinationPath: destPath,
85	}
86}
87
88// resolveSuggestedFilename determines the best filename from available sources.
89func (*PrepareDownloadUseCase) resolveSuggestedFilename(name string, response port.DownloadResponse) string {
90	// Priority 1: Use provided suggested filename
91	if name != "" {
92		return name
93	}
94
95	if response == nil {
96		return name
97	}
98
99	// Priority 2: Use response's suggested filename (from Content-Disposition)
100	if suggested := response.GetSuggestedFilename(); suggested != "" {
101		return suggested
102	}
103
104	// Priority 3: Extract from URI path
105	uri := response.GetUri()
106	if uri == "" {
107		return name
108	}
109
110	return download.ExtractFilenameFromURI(uri)
111}