"""
Contact and Newsletter API endpoints.

Endpoints:
- POST /contact - Submit contact form
- POST /newsletter/subscribe - Subscribe to newsletter
- POST /newsletter/unsubscribe - Unsubscribe from newsletter

Rate Limits:
- Contact form: 5 requests per hour per IP
- Newsletter: 10 requests per hour per IP
"""
import logging
import os
from datetime import datetime
from typing import Optional

from fastapi import APIRouter, HTTPException, status, BackgroundTasks, Request
from fastapi.responses import HTMLResponse
from pydantic import BaseModel, EmailStr, Field
from sqlalchemy import select, delete
from slowapi import Limiter
from slowapi.util import get_remote_address
from urllib.parse import urlencode

from app.api.deps import Database
from app.services.email_service import email_service
from app.models.newsletter import NewsletterSubscriber

logger = logging.getLogger(__name__)

router = APIRouter()

# Rate limiter for contact endpoints
limiter = Limiter(key_func=get_remote_address)

def _build_unsubscribe_url(email: str, token: str) -> str:
    base = os.getenv("SITE_URL", "https://pounce.ch").rstrip("/")
    query = urlencode({"email": email, "token": token})
    return f"{base}/api/v1/contact/newsletter/unsubscribe?{query}"


# ============== Schemas ==============

class ContactRequest(BaseModel):
    """Contact form submission."""
    name: str = Field(..., min_length=2, max_length=100)
    email: EmailStr
    subject: str = Field(..., min_length=5, max_length=200)
    message: str = Field(..., min_length=20, max_length=5000)


class NewsletterSubscribeRequest(BaseModel):
    """Newsletter subscription request."""
    email: EmailStr


class NewsletterUnsubscribeRequest(BaseModel):
    """Newsletter unsubscription request."""
    email: EmailStr
    token: Optional[str] = None  # For one-click unsubscribe


class MessageResponse(BaseModel):
    """Simple message response."""
    message: str
    success: bool = True


# ============== Contact Endpoints ==============

@router.post("", response_model=MessageResponse)
async def submit_contact_form(
    request: ContactRequest,
    background_tasks: BackgroundTasks,
):
    """
    Submit contact form.
    
    - Sends email to support team
    - Sends confirmation to user
    - Rate limited to prevent abuse
    """
    try:
        # Send emails in background
        background_tasks.add_task(
            email_service.send_contact_form,
            name=request.name,
            email=request.email,
            subject=request.subject,
            message=request.message,
        )
        
        logger.info(f"Contact form submitted: {request.email} - {request.subject}")
        
        return MessageResponse(
            message="Thank you for your message! We'll get back to you soon.",
            success=True,
        )
        
    except Exception as e:
        logger.error(f"Failed to process contact form: {e}")
        raise HTTPException(
            status_code=status.HTTP_500_INTERNAL_SERVER_ERROR,
            detail="Failed to submit contact form. Please try again later.",
        )


# ============== Newsletter Endpoints ==============

@router.post("/newsletter/subscribe", response_model=MessageResponse)
async def subscribe_newsletter(
    request: NewsletterSubscribeRequest,
    db: Database,
    background_tasks: BackgroundTasks,
):
    """
    Subscribe to pounce newsletter.
    
    - Stores email in database
    - Sends welcome email
    - Idempotent (subscribing twice is OK)
    """
    email_lower = request.email.lower()
    
    # Check if already subscribed
    result = await db.execute(
        select(NewsletterSubscriber).where(
            NewsletterSubscriber.email == email_lower
        )
    )
    existing = result.scalar_one_or_none()
    
    if existing:
        if existing.is_active:
            return MessageResponse(
                message="You're already subscribed to our newsletter!",
                success=True,
            )
        else:
            # Reactivate subscription
            existing.is_active = True
            existing.subscribed_at = datetime.utcnow()
            await db.commit()
            
            background_tasks.add_task(
                email_service.send_newsletter_welcome,
                to_email=email_lower,
                unsubscribe_url=_build_unsubscribe_url(email_lower, existing.unsubscribe_token),
            )
            
            return MessageResponse(
                message="Welcome back! You've been re-subscribed to our newsletter.",
                success=True,
            )
    
    # Create new subscription
    import secrets
    subscriber = NewsletterSubscriber(
        email=email_lower,
        is_active=True,
        unsubscribe_token=secrets.token_urlsafe(32),
    )
    db.add(subscriber)
    await db.commit()
    
    # Send welcome email
    background_tasks.add_task(
        email_service.send_newsletter_welcome,
        to_email=email_lower,
        unsubscribe_url=_build_unsubscribe_url(email_lower, subscriber.unsubscribe_token),
    )
    
    logger.info(f"Newsletter subscription: {email_lower}")
    
    return MessageResponse(
        message="Thanks for subscribing! Check your inbox for a welcome email.",
        success=True,
    )


@router.post("/newsletter/unsubscribe", response_model=MessageResponse)
async def unsubscribe_newsletter(
    request: NewsletterUnsubscribeRequest,
    db: Database,
):
    """
    Unsubscribe from pounce newsletter.
    
    - Marks subscription as inactive
    - Can use token for one-click unsubscribe
    """
    email_lower = request.email.lower()
    
    # Find subscription
    query = select(NewsletterSubscriber).where(
        NewsletterSubscriber.email == email_lower
    )
    
    # If token provided, verify it
    if request.token:
        query = query.where(
            NewsletterSubscriber.unsubscribe_token == request.token
        )
    
    result = await db.execute(query)
    subscriber = result.scalar_one_or_none()
    
    if not subscriber:
        # Always return success (don't reveal if email exists)
        return MessageResponse(
            message="If you were subscribed, you have been unsubscribed.",
            success=True,
        )
    
    subscriber.is_active = False
    subscriber.unsubscribed_at = datetime.utcnow()
    await db.commit()
    
    logger.info(f"Newsletter unsubscription: {email_lower}")
    
    return MessageResponse(
        message="You have been unsubscribed from our newsletter.",
        success=True,
    )


@router.get("/newsletter/unsubscribe")
async def unsubscribe_newsletter_one_click(
    email: EmailStr,
    token: str,
    db: Database,
):
    """
    One-click unsubscribe endpoint (for List-Unsubscribe header).
    Always returns 200 with a human-readable HTML response.
    """
    email_lower = email.lower()
    result = await db.execute(
        select(NewsletterSubscriber).where(
            NewsletterSubscriber.email == email_lower,
            NewsletterSubscriber.unsubscribe_token == token,
        )
    )
    subscriber = result.scalar_one_or_none()
    if subscriber and subscriber.is_active:
        subscriber.is_active = False
        subscriber.unsubscribed_at = datetime.utcnow()
        await db.commit()

    return HTMLResponse(
        content="""
<!doctype html>
<html lang="en">
  <head>
    <meta charset="utf-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1" />
    <title>Unsubscribed</title>
  </head>
  <body style="font-family: system-ui, -apple-system, Segoe UI, Roboto, Helvetica, Arial, sans-serif; padding: 32px;">
    <h1 style="margin: 0 0 12px 0;">You are unsubscribed.</h1>
    <p style="margin: 0; color: #555;">
      If you were subscribed, you will no longer receive pounce insights emails.
    </p>
  </body>
</html>
""".strip(),
        status_code=200,
    )


@router.get("/newsletter/status")
async def check_newsletter_status(
    email: EmailStr,
    db: Database,
):
    """Check if an email is subscribed to the newsletter."""
    result = await db.execute(
        select(NewsletterSubscriber).where(
            NewsletterSubscriber.email == email.lower()
        )
    )
    subscriber = result.scalar_one_or_none()
    
    return {
        "email": email,
        "subscribed": subscriber is not None and subscriber.is_active,
    }