"""
Email Service - SendGrid integration for verification and password reset emails.
"""
import os
import secrets
from datetime import datetime, timedelta
from typing import Optional
import httpx

SENDGRID_API_KEY = os.getenv("SENDGRID_API_KEY", "")
EMAIL_FROM = os.getenv("EMAIL_FROM", "noreply@elmeg.xyz")
FRONTEND_URL = os.getenv("FRONTEND_URL", "https://elmeg.runfoo.run")

async def send_email(to: str, subject: str, html_content: str) -> bool:
    """Send email via SendGrid API"""
    if not SENDGRID_API_KEY:
        print(f"[EMAIL DEV MODE] To: {to}, Subject: {subject}")
        print(f"[EMAIL DEV MODE] Content: {html_content[:200]}...")
        return True
    
    async with httpx.AsyncClient() as client:
        response = await client.post(
            "https://api.sendgrid.com/v3/mail/send",
            headers={
                "Authorization": f"Bearer {SENDGRID_API_KEY}",
                "Content-Type": "application/json"
            },
            json={
                "personalizations": [{"to": [{"email": to}]}],
                "from": {"email": EMAIL_FROM, "name": "Elmeg"},
                "subject": subject,
                "content": [{"type": "text/html", "value": html_content}]
            }
        )
        return response.status_code in (200, 202)

def generate_token() -> str:
    """Generate a secure random token"""
    return secrets.token_urlsafe(32)

async def send_verification_email(email: str, token: str) -> bool:
    """Send email verification link"""
    verify_url = f"{FRONTEND_URL}/verify-email?token={token}"
    
    html = f"""
    <div style="font-family: sans-serif; max-width: 600px; margin: 0 auto;">
        <h1 style="color: #333;">Welcome to Elmeg!</h1>
        <p>Please verify your email address by clicking the button below:</p>
        <a href="{verify_url}" 
           style="display: inline-block; background: #4F46E5; color: white; 
                  padding: 12px 24px; text-decoration: none; border-radius: 6px;
                  margin: 16px 0;">
            Verify Email
        </a>
        <p style="color: #666; font-size: 14px;">
            Or copy this link: {verify_url}
        </p>
        <p style="color: #999; font-size: 12px;">
            This link expires in 48 hours.
        </p>
    </div>
    """
    
    return await send_email(email, "Verify your Elmeg account", html)

async def send_password_reset_email(email: str, token: str) -> bool:
    """Send password reset link"""
    reset_url = f"{FRONTEND_URL}/reset-password?token={token}"
    
    html = f"""
    <div style="font-family: sans-serif; max-width: 600px; margin: 0 auto;">
        <h1 style="color: #333;">Password Reset</h1>
        <p>You requested a password reset. Click below to set a new password:</p>
        <a href="{reset_url}" 
           style="display: inline-block; background: #4F46E5; color: white; 
                  padding: 12px 24px; text-decoration: none; border-radius: 6px;
                  margin: 16px 0;">
            Reset Password
        </a>
        <p style="color: #666; font-size: 14px;">
            Or copy this link: {reset_url}
        </p>
        <p style="color: #999; font-size: 12px;">
            This link expires in 1 hour. If you didn't request this, ignore this email.
        </p>
    </div>
    """
    
    return await send_email(email, "Reset your Elmeg password", html)

# Token expiration helpers
def get_verification_expiry() -> datetime:
    """48 hour expiry for email verification"""
    return datetime.utcnow() + timedelta(hours=48)

def get_reset_expiry() -> datetime:
    """1 hour expiry for password reset"""
    return datetime.utcnow() + timedelta(hours=1)