📧 Build an AI Email Subject Generator with Gemini

Prompt Gemini to write subject lines in five distinct tones.

def generate_subjects(email_body):
    prompt = f"""You are an email marketing expert.
Read the email body below and generate exactly 5 subject lines — one for each of these tones:
1. Professional / Formal
2. Friendly / Conversational
3. Urgent / Time-sensitive
4. Curiosity-driven / Intriguing
5. Direct / Clear benefit

Format your response EXACTLY like this:
1. [Professional]: subject here
2. [Friendly]: subject here
3. [Urgent]: subject here
4. [Curiosity]: subject here
5. [Direct]: subject here

Email body:
{email_body}"""

    response = model.generate_content(prompt)
    return response.text

email = """
Hi team,

I wanted to let you know that we have redesigned our onboarding process.
New users can now complete setup in under 5 minutes instead of 30.
The new flow includes video guides, tooltips, and a progress checklist.
Please review the attached document and share your feedback by Friday.

Thanks,
Sarah
"""

print(generate_subjects(email))

1. [Professional]: New Onboarding Process: Review Required by Friday
2. [Friendly]: We've made onboarding way easier — check it out!
3. [Urgent]: Action Required: Onboarding Review Due This Friday
4. [Curiosity]: What if new users could be fully set up in 5 minutes?
5. [Direct]: New 5-Minute Onboarding Flow — Your Feedback Needed

def main():
    print("AI Email Subject Generator (powered by Gemini)")
    print("Paste your email body below. Type DONE on a new line when finished.\n")

    while True:
        lines = []
        while True:
            line = input()
            if line.strip() == 'DONE': break
            lines.append(line)

        body = '\n'.join(lines).strip()
        if not body:
            print("No email content — exiting."); break

        print("\nGenerating subject lines...\n")
        result = generate_subjects(body)
        print(result)
        print("\n" + "="*50)
        print("Generate for another email? (paste it, or press Ctrl+C to exit)\n")

main()