from fastapi import FastAPI, Request, HTTPException
import requests
import json
import uuid
from datetime import datetime, timezone
import os  # Import the 'os' module

app = FastAPI()

# --- CONFIGURATION ---
# Use Hugging Face Secrets for sensitive data
CLIENT_ID = "amzn1.application-oa2-client.bc4475f5b85148fa8c1329e4bb6da5e9"  # Your *NEW* ALEXA Client ID (from Custom Skill)
CLIENT_SECRET = os.environ.get("CLIENT_SECRET")  # Get *ALEXA* Client Secret from environment variable
ALEXA_EVENT_GATEWAY = "https://api.amazonalexa.com/v3/events"

# --- DEVICE MAPPING ---
TRIGGERS = {
    "Trigger1": {"endpointId": "device-001", "description": "Webhook Trigger 1", "state": "NOT_DETECTED"},
    "Trigger2": {"endpointId": "device-002", "description": "Webhook Trigger 2", "state": "NOT_DETECTED"},
    "Trigger3": {"endpointId": "device-003", "description": "Webhook Trigger 3", "state": "NOT_DETECTED"},
    "Trigger4": {"endpointId": "device-004", "description": "Webhook Trigger 4", "state": "NOT_DETECTED"},
    "Trigger5": {"endpointId": "device-005", "description": "Webhook Trigger 5", "state": "NOT_DETECTED"},
    "Trigger6": {"endpointId": "device-006", "description": "Webhook Trigger 6", "state": "NOT_DETECTED"},
    "Trigger7": {"endpointId": "device-007", "description": "Webhook Trigger 7", "state": "NOT_DETECTED"},
    "Trigger8": {"endpointId": "device-008", "description": "Webhook Trigger 8", "state": "NOT_DETECTED"},
    "Trigger9": {"endpointId": "device-009", "description": "Webhook Trigger 9", "state": "NOT_DETECTED"},
    "Trigger10": {"endpointId": "device-010", "description": "Webhook Trigger 10", "state": "NOT_DETECTED"},
}

# --- TOKEN MANAGEMENT (Simple - In-Memory for Now) ---
TOKEN_DATA = {
    "access_token": None,
    "expires_at": None,  # Timestamp when the token expires
}

# --- HELPER FUNCTION: Get LWA Access Token ---
async def get_lwa_access_token():
    """Fetches or refreshes the LWA access token."""
    global TOKEN_DATA

    # Check if we have a token and if it's still valid
    if TOKEN_DATA["access_token"] and TOKEN_DATA["expires_at"] and datetime.now(timezone.utc).timestamp() < TOKEN_DATA["expires_at"]:
        return TOKEN_DATA["access_token"]

    # Get a new token
    token_url = "https://api.amazon.com/auth/o2/token"
    data = {
        "grant_type": "client_credentials",
        "client_id": CLIENT_ID,
        "client_secret": CLIENT_SECRET,
        "scope": "alexa::proactive_events",
    }

    # --- DEBUGGING LOGS ---
    print("----- LWA Token Request Data -----")
    print(data)
    print("---------------------------------")
    print(f"----- CLIENT_SECRET Value: {CLIENT_SECRET} -----")
    # --- END OF DEBUGGING LOGS ---

    try:
        response = requests.post(token_url, data=data)
        response.raise_for_status()  # Raise HTTPError for bad responses (4xx or 5xx)
        token_response = response.json()
        TOKEN_DATA["access_token"] = token_response["access_token"]
        # Calculate expiry time (subtract a small buffer to be safe)
        TOKEN_DATA["expires_at"] = datetime.now(timezone.utc).timestamp() + token_response["expires_in"] - 60
        return TOKEN_DATA["access_token"]
    except requests.exceptions.RequestException as e:
        print(f"Error getting LWA token: {e}")
        raise HTTPException(status_code=500, detail="Failed to get LWA access token")


# --- HELPER FUNCTION: Send ChangeReport to Alexa ---
async def send_change_report(endpoint_id, property_name, property_value):
    """Sends a ChangeReport event to Alexa."""
    try:
        access_token = await get_lwa_access_token()
    except HTTPException: # Re-raise exception from get_lwa_access_token
        raise

    headers = {
        "Authorization": f"Bearer {access_token}",
        "Content-Type": "application/json",
    }

    change_report = {
        "event": {
            "header": {
                "namespace": "Alexa",
                "name": "ChangeReport",
                "messageId": str(uuid.uuid4()),
                "payloadVersion": "3",
            },
            "endpoint": {
                "endpointId": endpoint_id,
            },
            "payload": {
                "change": {
                    "cause": {"type": "PHYSICAL_INTERACTION"},
                    "properties": [
                        {
                            "namespace": "Alexa.ContactSensor",
                            "name": property_name,
                            "value": property_value,
                            "timeOfSample": datetime.now(timezone.utc).isoformat(),
                            "uncertaintyInMilliseconds": 0,
                        }
                    ],
                }
            },
        }
    }

    try:
        response = requests.post(
            ALEXA_EVENT_GATEWAY, headers=headers, data=json.dumps(change_report)
        )
        response.raise_for_status()
        print(f"ChangeReport sent for {endpoint_id}. Response: {response.status_code} - {response.text}") # Log full response
    except requests.exceptions.RequestException as e:
        print(f"Error sending ChangeReport: {e}")
        raise HTTPException(status_code=500, detail=f"Failed to send ChangeReport: {e}")


# --- WEBHOOK ENDPOINT ---
@app.post("/{trigger_name}")
async def alexa_webhook(trigger_name: str, request: Request):
    data = await request.json()
    print(f"Received request for {trigger_name}: {data}")

    if trigger_name in TRIGGERS:
        endpoint_id = TRIGGERS[trigger_name]["endpointId"]

        # Toggle the state
        current_state = TRIGGERS[trigger_name]["state"]
        new_state = "NOT_DETECTED" if current_state == "DETECTED" else "DETECTED"
        TRIGGERS[trigger_name]["state"] = new_state

        try:
            await send_change_report(endpoint_id, "detectionState", new_state)
        except HTTPException as e:
            return e  # Return the HTTPException directly

        return {
            "event": {
                "header": {
                    "namespace": "Alexa",
                    "name": "Response",
                    "payloadVersion": "3",
                    "messageId": str(uuid.uuid4())
                },
                "payload": {"message": f"{trigger_name} activated! New state: {new_state}"}
            }
        }

    else:
        raise HTTPException(status_code=404, detail=f"Unknown trigger: {trigger_name}")