import httpx
from typing import Dict, Any, Optional
from app.providers.base import BaseProvider
from app.core.config import settings

class WhatsAppCloudProvider(BaseProvider):
    """WhatsApp Cloud API provider (Meta)"""
    
    def __init__(self):
        self.access_token = settings.WHATSAPP_CLOUD_ACCESS_TOKEN
        self.phone_number_id = settings.WHATSAPP_CLOUD_PHONE_NUMBER_ID
        self.base_url = "https://graph.facebook.com/v18.0"
    
    def send_message(
        self,
        to: str,
        template_name: Optional[str],
        template_body: str,
        variables: Dict[str, str],
        language: str = "en"
    ) -> str:
        """
        Send message via WhatsApp Cloud API.
        
        If template_name is provided, sends a template message.
        Otherwise, sends a text message.
        """
        url = f"{self.base_url}/{self.phone_number_id}/messages"
        headers = {
            "Authorization": f"Bearer {self.access_token}",
            "Content-Type": "application/json"
        }
        
        if template_name:
            # Send template message
            # Build template parameters
            components = []
            if variables:
                parameters = [
                    {"type": "text", "text": value}
                    for value in variables.values()
                ]
                components.append({
                    "type": "body",
                    "parameters": parameters
                })
            
            payload = {
                "messaging_product": "whatsapp",
                "to": to.replace("+", ""),
                "type": "template",
                "template": {
                    "name": template_name,
                    "language": {
                        "code": language
                    },
                    "components": components
                }
            }
        else:
            # Send text message (only for contacts with conversation window)
            # Substitute variables in body
            message_text = template_body
            for key, value in variables.items():
                message_text = message_text.replace(f"{{{{{key}}}}}", value)
            
            payload = {
                "messaging_product": "whatsapp",
                "to": to.replace("+", ""),
                "type": "text",
                "text": {
                    "body": message_text
                }
            }
        
        try:
            with httpx.Client(timeout=30.0) as client:
                response = client.post(url, headers=headers, json=payload)
                response.raise_for_status()
                
                data = response.json()
                message_id = data.get("messages", [{}])[0].get("id")
                
                if not message_id:
                    raise Exception("No message ID in response")
                
                return message_id
        
        except httpx.HTTPStatusError as e:
            raise Exception(f"WhatsApp API error: {e.response.status_code} - {e.response.text}")
        except Exception as e:
            raise Exception(f"Send error: {str(e)}")
    
    def get_provider_name(self) -> str:
        return "whatsapp_cloud"