feat: extract files from message logs

internal/isphere/files.go

@@ -0,0 +1,142 @@
+package isphere
+
+import (
+	"path/filepath"
+	"regexp"
+	"sort"
+	"strings"
+)
+
+type File struct {
+	FileID         string
+	MessageID      string
+	ConversationID string
+	FileName       string
+	SizeBytes      *int64
+	MimeType       string
+	CreatedAt      string
+	DownloadRef    string
+	SavedPath      string
+	SHA256         string
+	Source         string
+	RawRef         string
+}
+
+type ListFilesQuery struct {
+	ConversationID string
+	MessageID      string
+	FileID         string
+	NameContains   string
+	Limit          int
+}
+
+type ListFilesResult struct {
+	Files []File
+}
+
+var fileNamePattern = regexp.MustCompile(`(?i)[^\s<>:"|?*]+\.(?:docx?|xlsx?|pptx?|pdf|zip|rar|png|jpe?g|txt|csv)\b`)
+
+func ListFilesFromMessages(messages []Message, query ListFilesQuery) ListFilesResult {
+	files := make([]File, 0)
+	for _, message := range messages {
+		if !messageLooksFileBacked(message) {
+			continue
+		}
+		fileName := extractMessageFileName(message.Text)
+		if fileName == "" {
+			continue
+		}
+		file := File{
+			FileID:         fileID(message.ID, fileName),
+			MessageID:      message.ID,
+			ConversationID: message.ConversationID,
+			FileName:       fileName,
+			MimeType:       mimeTypeForFileName(fileName),
+			CreatedAt:      message.Timestamp,
+			Source:         "local_readonly",
+			RawRef:         "packetlog_file_transfer",
+		}
+		if fileMatchesQuery(file, query) {
+			files = append(files, file)
+		}
+	}
+
+	sort.Slice(files, func(i, j int) bool {
+		if files[i].FileID == files[j].FileID {
+			return files[i].MessageID < files[j].MessageID
+		}
+		return files[i].FileID < files[j].FileID
+	})
+
+	limit := query.Limit
+	if limit <= 0 || limit > len(files) {
+		limit = len(files)
+	}
+	return ListFilesResult{Files: files[:limit]}
+}
+
+func messageLooksFileBacked(message Message) bool {
+	return strings.Contains(strings.ToUpper(message.Subject), "FILE_TRANSFER") || extractMessageFileName(message.Text) != ""
+}
+
+func extractMessageFileName(text string) string {
+	match := fileNamePattern.FindString(strings.TrimSpace(text))
+	return strings.Trim(match, " .,;，。；")
+}
+
+func fileID(messageID string, fileName string) string {
+	if messageID == "" {
+		return fileName
+	}
+	return messageID + ":" + fileName
+}
+
+func fileMatchesQuery(file File, query ListFilesQuery) bool {
+	if query.ConversationID != "" && file.ConversationID != query.ConversationID {
+		return false
+	}
+	if query.MessageID != "" && file.MessageID != query.MessageID {
+		return false
+	}
+	if query.FileID != "" && file.FileID != query.FileID {
+		return false
+	}
+	nameQuery := strings.ToLower(strings.TrimSpace(query.NameContains))
+	if nameQuery != "" && !strings.Contains(strings.ToLower(file.FileName), nameQuery) {
+		return false
+	}
+	return true
+}
+
+func mimeTypeForFileName(name string) string {
+	switch strings.ToLower(filepath.Ext(name)) {
+	case ".doc":
+		return "application/msword"
+	case ".docx":
+		return "application/vnd.openxmlformats-officedocument.wordprocessingml.document"
+	case ".xls":
+		return "application/vnd.ms-excel"
+	case ".xlsx":
+		return "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet"
+	case ".ppt":
+		return "application/vnd.ms-powerpoint"
+	case ".pptx":
+		return "application/vnd.openxmlformats-officedocument.presentationml.presentation"
+	case ".pdf":
+		return "application/pdf"
+	case ".zip":
+		return "application/zip"
+	case ".rar":
+		return "application/vnd.rar"
+	case ".png":
+		return "image/png"
+	case ".jpg", ".jpeg":
+		return "image/jpeg"
+	case ".txt":
+		return "text/plain"
+	case ".csv":
+		return "text/csv"
+	default:
+		return ""
+	}
+}

internal/isphere/files_test.go

@@ -0,0 +1,31 @@
+package isphere
+
+import (
+	"reflect"
+	"testing"
+)
+
+func TestListFilesFromMessagesExtractsFileTransferCandidates(t *testing.T) {
+	messages := []Message{
+		{ID: "msg-1", ConversationID: "alice@imopenfire1-lanzhou|bob@imopenfire1-lanzhou", Text: "redacted-report.docx", Timestamp: "1783423807000", Subject: "FILE_TRANSFER_CANCEL"},
+		{ID: "msg-2", ConversationID: "alice@imopenfire1-lanzhou|bob@imopenfire1-lanzhou", Text: "plain chat", Timestamp: "1783423808000"},
+		{ID: "msg-3", ConversationID: "room@conference.imopenfire1-lanzhou", Text: "redacted-screenshot.png", Timestamp: "1783423809000"},
+	}
+
+	got := ListFilesFromMessages(messages, ListFilesQuery{NameContains: "report", Limit: 10})
+	want := ListFilesResult{Files: []File{
+		{
+			FileID:         "msg-1:redacted-report.docx",
+			MessageID:      "msg-1",
+			ConversationID: "alice@imopenfire1-lanzhou|bob@imopenfire1-lanzhou",
+			FileName:       "redacted-report.docx",
+			MimeType:       "application/vnd.openxmlformats-officedocument.wordprocessingml.document",
+			CreatedAt:      "1783423807000",
+			Source:         "local_readonly",
+			RawRef:         "packetlog_file_transfer",
+		},
+	}}
+	if !reflect.DeepEqual(got, want) {
+		t.Fatalf("ListFilesFromMessages() = %#v, want %#v", got, want)
+	}
+}