refactor: dry - extract file ID resolution helper in Drive package

[aliwatters]

Summary

Every Drive testable function repeats a 6-line block to resolve the service, extract file_id, validate it's non-empty, and call ExtractGoogleResourceID. This block appears 8 times. Additionally, TestableDriveDownload is 99 lines with an inline readLimited closure and complex MIME type branching that should be decomposed.

Location

• File: internal/drive/drive_tools_testable.go
• Repeated block: L57-66, L78-87, L334-343, L378-387, L419-428, L448-457, L475-484, L522-531 (8 instances)
• Long function: TestableDriveDownload L77-175 (99 lines)
• Inline closure: readLimited L102-112
• Google Workspace MIME mapping: L118-151 (inline magic strings)

Category

Type: DRY Violation / Long Function

Severity: High

Evidence

Repeated 6-line block (8x):

srv, errResult, ok := ResolveDriveServiceOrError(ctx, request, deps)
if !ok { return errResult, nil }
fileID := common.ParseStringArg(request.Params.Arguments, "file_id", "")
if fileID == "" { return mcp.NewToolResultError("file_id parameter is required"), nil }
fileID = common.ExtractGoogleResourceID(fileID)

Magic MIME strings (inline):

"application/vnd.google-apps.document"
"application/vnd.google-apps.spreadsheet"
"application/vnd.google-apps.presentation"
"application/vnd.google-apps.folder"

Suggested Refactoring

1. Extract resolveFileID(ctx, request, deps) (DriveService, string, *mcp.CallToolResult, bool) helper
2. Extract readLimited as a package-level or common/ function
3. Extract Google Workspace MIME-to-export mapping as a constant map
4. Split TestableDriveDownload into separate export and download paths

Effort Estimate

• Size: Medium (1-4 hours)
• Risk: Low (internal refactoring only)
• Tests Required: Yes (existing tests must pass)

Acceptance Criteria

• resolveFileID helper eliminates 8 repeated blocks (~40 lines saved)
• readLimited extracted to reusable function
• MIME type mapping extracted to named constant
• TestableDriveDownload decomposed to <50 lines
• All existing tests pass

[aliwatters]

{
  "relevance": 8,
  "complexity": "medium",
  "estimate_hours": 5.5,
  "category": "new-feature",
  "summary": "refactor: dry - extract file ID resolution helper in Drive package",
  "analyzed_at": "2026-02-13T20:20:45Z",
  "content_hash": "sha256:ebcc799daacebab5f832d7c532012d58c5f1b9eac63e8c2736d75f25b101903a"
}

[aliwatters]

Claimed by AI Agent

Workspace: gsuite-mcp
Claimed at: 2026-02-13T12:20:56-08:00

This issue is now being worked on by an AI agent in workspace gsuite-mcp.