import smtplib
from email.mime.text import MIMEText
from email.mime.multipart import MIMEMultipart
import os
from fastapi import FastAPI, HTTPException
from pydantic import BaseModel, EmailStr

# --- Configuration ---
class SMTPSettings:
    # Use os.getenv for all settings, with default values for non-sensitive ones
    SMTP_HOST: str = os.getenv('SMTP_HOST', 'smtp.gmail.com')
    SMTP_PORT: int = int(os.getenv('SMTP_PORT', 587))
    SMTP_USER: str = os.getenv('SMTP_USER')
    SMTP_PASS: str = os.getenv('SMTP_PASS')
    RECIPIENT_EMAIL: str = os.getenv('RECIPIENT_EMAIL')
    SENDER_NAME: str = os.getenv('SENDER_NAME', 'FastAPI Mailer')
    SENDER_EMAIL: str = os.getenv('SENDER_EMAIL')

    # Basic validation to ensure required fields are set
    if not all([SMTP_USER, SMTP_PASS, RECIPIENT_EMAIL, SENDER_EMAIL]):
        raise EnvironmentError("Missing one or more required environment variables: SMTP_USER, SMTP_PASS, RECIPIENT_EMAIL, SENDER_EMAIL")

settings = SMTPSettings()

# --- Pydantic Models ---
class EmailRequest(BaseModel):
    subject: str
    body: str
    recipient_email: EmailStr = settings.RECIPIENT_EMAIL # Default to the configured recipient

# --- Email Utility Function ---
def send_email(subject: str, body: str, recipient_email: str):
    try:
        # Create a multipart message and set headers
        message = MIMEMultipart()
        message['From'] = f"{settings.SENDER_NAME} <{settings.SENDER_EMAIL}>"
        message['To'] = recipient_email
        message['Subject'] = subject

        # Add body to email
        message.attach(MIMEText(body, 'plain'))

        # Connect to the SMTP server
        with smtplib.SMTP(settings.SMTP_HOST, settings.SMTP_PORT) as server:
            server.starttls()  # Secure the connection
            server.login(settings.SMTP_USER, settings.SMTP_PASS)
            server.sendmail(settings.SENDER_EMAIL, recipient_email, message.as_string())
        
        return {"message": "Email sent successfully"}

    except Exception as e:
        print(f"Error sending email: {e}")
        raise HTTPException(status_code=500, detail=f"Failed to send email: {e}")

# --- FastAPI Application ---
app = FastAPI(title="FastAPI SMTP Server")

@app.get("/")
def read_root():
    return {"message": "FastAPI SMTP Server is running."}

@app.post("/send-test-email")
def send_test_email_endpoint():
    subject = "FastAPI SMTP Test Email"
    body = "This is a test email sent from the FastAPI server using the configured SMTP settings."
    try:
        send_email(subject, body, settings.RECIPIENT_EMAIL)
        return {"status": "success", "message": f"Test email sent to {settings.RECIPIENT_EMAIL}"}
    except HTTPException as e:
        raise e

@app.post("/send-email")
def send_email_endpoint(email_request: EmailRequest):
    try:
        send_email(email_request.subject, email_request.body, email_request.recipient_email)
        return {"status": "success", "message": f"Email sent to {email_request.recipient_email}"}
    except HTTPException as e:
        raise e

if __name__ == "__main__":
    import uvicorn
    uvicorn.run(app, host="0.0.0.0", port=8000)