BridgeMail is a high-performance email translation engine built for Google Workspace. It automates the monitoring, translation, and re-dispatching of international communications. Unlike simple scripts, BridgeMail follows Enterprise Design Patterns, utilizing an optimized $O(1)$ search strategy for audit logs and an intelligent HTML-safe chunking mechanism.

Log sheet with processing metrics and status tracking.

Dynamic settings sheet.

• 📄 Original Email (Japanese): The source payload.
• 📄 Translated Result: The final multi-language delivery.

• HTML-Safe Chunking: Slices large email bodies into translatable fragments without breaking HTML tags, ensuring the visual integrity of the original layout.
• Resilience via Exponential Backoff: Automatic retry logic with increasing delays ($delay = base \times 2^{n}$) to handle Google Service rate limits.
• High-Performance Deduplication: Uses a Set-based cache for $O(1)$ lookup complexity, preventing duplicate translations even in massive inboxes.
• Smart Merge Setup: One-click infrastructure deployment that preserves existing user data while updating system headers and protections.
• Multi-Language Orchestration: Support for multiple target languages in a single execution, generating a unified multi-lingual response.
• Execution Time Guard: Self-monitoring system that breaks processing loops before hitting Google's 6-minute script execution limit.

graph TD
    Trigger[Time-Based Trigger] --> Engine[Translation Engine]
    Engine -->|Loads| Config[Config Manager]
    Engine -->|Queries| Gmail[Gmail API]
    Gmail -->|Fetched Threads| Engine
    Engine -->|Checks| Audit[Audit Manager]
    Audit -->|Set Cache Lookup| Engine
    Engine -->|Delegates| Service[Translation Service]
    Service -->|Backoff & Chunking| LangApp[Google LanguageApp]
    Engine -->|Logs Result| Audit
    Engine -->|Dispatches| SMTP[Gmail App Send]

BridgeMail/
├── translator.gs              # Main Engine: Orchestration, Translation & Audit
├── send_test.gs               # Test Tool: Generates a Japanese HTML e-mail
├── docs/
│   ├── images/                # Screenshots of the Sheets interface
│   └── email_examples/        # PDF examples (Original vs Translated)

• A Google account.

You can set up BridgeMail in two ways. The recommended method saves time and ensures all formatting, data validation, and cell protections are correctly applied.

1. Access the Template: Open the BridgeMail Master Spreadsheet.
2. Duplicate the File: Go to File > Make a copy. This creates your own private instance of the engine.
3. Configure Parameters: Access the Settings tab and fill in the required values (emails, language codes, etc.).
4. Install Automation: From the top menu, click BridgeMail > Refresh Trigger Automation. This activates the background monitoring.

1. Create Spreadsheet: Open a new Google Sheet.
2. Access Apps Script: Go to Extensions > Apps Script.
3. Paste the Code: Create translator.gs and send_test.gs files and paste the respective contents.
4. Initialize System: Refresh the spreadsheet page and go to the BridgeMail menu > Setup System.
5. Settings: Fill in the Settings sheet generated by the setup process.
6. Activate Trigger: Go to the menu BridgeMail > Refresh Trigger Automation.

When you run BridgeMail for the first time, Google will request permissions to access your Gmail, Sheets, and Translation services.

Note: You might see a "Google hasn't verified this app" screen. This is normal for private scripts. Click Advanced > Go to BridgeMail (unsafe) to proceed. The script runs entirely within your account; no data is shared with third parties except for the Google Translation API.

This project is licensed under the Creative Commons Attribution-NonCommercial 4.0 International License.

• Attribution: You must give appropriate credit to the author.
• NonCommercial: You may NOT use the material for commercial purposes.
• Adaptation: You can remix and build upon the material.

Rubens Braz