event_state_tracker.py

import os
import json
import logging
from datetime import datetime
from main import send_email_message

logger = logging.getLogger(__name__)

STATE_FILE = "event_state.json"

def load_state():
    """Loads the previous state of events from the JSON file."""
    if not os.path.exists(STATE_FILE):
        return {}
    
    try:
        with open(STATE_FILE, "r", encoding="utf-8") as f:
            return json.load(f)
    except Exception as e:
        logger.warning(f"Failed to load {STATE_FILE}, starting fresh. Error: {e}")
        return {}

def save_state(state):
    """Saves the current state of events to the JSON file."""
    try:
        with open(STATE_FILE, "w", encoding="utf-8") as f:
            json.dump(state, f, indent=4)
    except Exception as e:
        logger.error(f"Failed to save {STATE_FILE}. Error: {e}")

def extract_tracked_fields(event):
    """Extracts only the fields we care about tracking."""
    return {
        "status": str(event.get("status", "Unknown")).strip(),
        "maximum_count": event.get("maximum_count", 0),
        "event_code": event.get("event_code", "-"),
        "event_name": event.get("event_name", "-")
    }

def send_change_alert(event, changed_field, old_value, new_value):
    """Sends an HTML email alert when a tracked field changes."""
    recipient = os.getenv("STATUS_EVENT_EMAIL_RECIPIENT", "")
    if not recipient:
        logger.warning("No STATUS_EVENT_EMAIL_RECIPIENT configured. Skipping change alert.")
        return

    subject = f"🚨 Event {changed_field} Changed: {event.get('event_code', '-')} → {new_value}"
    
    def format_date(date_str):
        try:
            dt = datetime.strptime(date_str, "%Y-%m-%d")
            return dt.strftime('%d-%m-%Y')
        except:
            return date_str

    start = format_date(event.get("start_date", "")) if event.get("start_date") else ""
    end = format_date(event.get("end_date", "")) if event.get("end_date") else ""
    date_str = f"{start} to {end}" if start and end else (start or end or "-")

    try:
        max_count = int(event.get("maximum_count", 0))
    except (ValueError, TypeError):
        max_count = 0
        
    try:
        applied = int(event.get("applied_count", 0))
    except (ValueError, TypeError):
        applied = 0
        
    try:
        balance = int(event.get("ComputedField", 0))
    except (ValueError, TypeError):
        balance = 0

    body = f"""
    <div style="font-family: Arial, sans-serif; background-color: #f4f6f9; padding: 20px;">
        <div style="max-width: 600px; margin: 0 auto; background: #ffffff; border-radius: 8px; 
                    box-shadow: 0 4px 6px rgba(0,0,0,0.1); overflow: hidden;">
            
            <div style="background-color: #0056b3; color: #ffffff; padding: 15px 20px; 
                        font-size: 18px; font-weight: bold; text-align: center;">
                🚨 Event {changed_field} Changed
            </div>

            <div style="padding: 20px;">
                <div style="background-color: #f0fdf4; padding: 15px; border-radius: 6px; margin-bottom: 20px; text-align: center; border: 1px solid #bbf7d0;">
                    <span style="font-weight: bold; color: #166534;">{changed_field} Update:</span><br>
                    <span style="font-size: 16px;">{old_value} &rarr; <b style="color: #15803d;">{new_value}</b></span>
                </div>

                <table style="width: 100%; border-collapse: collapse; margin-bottom: 25px; font-size: 15px; color: #333333; text-align: left;">
                    <tr>
                        <td style="padding: 8px 0; font-weight: bold; width: 35%;">Code</td>
                        <td style="padding: 8px 0; width: 5%;">:</td>
                        <td style="padding: 8px 0; width: 60%; font-weight: bold;">{event.get('event_code', '-')}</td>
                    </tr>
                    <tr>
                        <td style="padding: 8px 0; font-weight: bold;">Name</td>
                        <td style="padding: 8px 0;">:</td>
                        <td style="padding: 8px 0;">{event.get('event_name', '-')}</td>
                    </tr>
                    <tr>
                        <td style="padding: 8px 0; font-weight: bold;">Organizer</td>
                        <td style="padding: 8px 0;">:</td>
                        <td style="padding: 8px 0;">{event.get('organizer', '-')}</td>
                    </tr>
                    <tr>
                        <td style="padding: 8px 0; font-weight: bold;">Date</td>
                        <td style="padding: 8px 0;">:</td>
                        <td style="padding: 8px 0;">{date_str}</td>
                    </tr>
                    <tr>
                        <td style="padding: 8px 0; font-weight: bold;">Category</td>
                        <td style="padding: 8px 0;">:</td>
                        <td style="padding: 8px 0;">{event.get('event_category', '-')}</td>
                    </tr>
                    <tr>
                        <td style="padding: 8px 0; font-weight: bold;">Location</td>
                        <td style="padding: 8px 0;">:</td>
                        <td style="padding: 8px 0;">{event.get('location', '-')}</td>
                    </tr>
                    <tr>
                        <td style="padding: 8px 0; font-weight: bold;">Status</td>
                        <td style="padding: 8px 0;">:</td>
                        <td style="padding: 8px 0;">{event.get('status', '-')}</td>
                    </tr>
                    <tr>
                        <td style="padding: 8px 0; font-weight: bold;">Apply by student</td>
                        <td style="padding: 8px 0;">:</td>
                        <td style="padding: 8px 0;">{event.get('apply_by_student', '-')}</td>
                    </tr>
                    <tr>
                        <td style="padding: 8px 0; font-weight: bold;">Logger URL</td>
                        <td style="padding: 8px 0;">:</td>
                        <td style="padding: 8px 0;">
                            <a href="https://bip.bitsathy.ac.in/nova/resources/student-achievement-loggers/new"
                            style="color: #0056b3; text-decoration: none;">Link</a>
                        </td>
                    </tr>
                    <tr>
                        <td style="padding: 8px 0; font-weight: bold;">View Link</td>
                        <td style="padding: 8px 0;">:</td>
                        <td style="padding: 8px 0;">
                            <a href="{event.get('web_url', '#')}"
                            style="color: #0056b3; text-decoration: none;">View Event Here</a>
                        </td>
                    </tr>
                    <tr>
                        <td style="padding: 12px 0; font-weight: bold;">Count</td>
                        <td style="padding: 12px 0;">:</td>
                        <td style="padding: 12px 0;">
                            Max: <b>{max_count}</b> | Balance: <b>{balance}</b> | Applied: <b>{applied}</b>
                        </td>
                    </tr>
                </table>
            </div>
            <div style="background-color: #f8f9fa; padding: 15px 20px; text-align: center; font-size: 12px; color: #777777; border-top: 1px solid #e0e0e0;">
                Automated Notification from BIP Tracker
            </div>
        </div>
    </div>
    """
    
    logger.info(f"🚨 STATUS TRACKER: Sending {changed_field} alert for {event.get('event_code', '-')}")
    send_email_message(subject, body, is_html=True, recipient=recipient)

def track_event_changes(events):
    """
    Analyzes a list of events fetched from the API, compares them to the 
    previous state, and triggers alerts for any that just became 'Active'.
    """
    if not events:
        return
        
    state = load_state()
    state_changed = False
    
    for event in events:
        event_id = str(event.get("id"))
        if not event_id:
            continue
            
        current_data = extract_tracked_fields(event)
        
        # Hugging Face Restart Protection:
        # If the event ID doesn't exist in our state file at all, this might 
        # be the first run, or the container just restarted and lost its file.
        # We record it, but we DO NOT trigger an alert to prevent false positives.
        if event_id not in state:
            state[event_id] = current_data
            state_changed = True
            logger.debug(f"Tracking new state for event {event_id} (No alert)")
            continue
            
        previous_data = state[event_id]
        
        # Detect if status changed
        old_status = str(previous_data.get("status", "")).strip()
        new_status = str(current_data.get("status", "")).strip()
        
        if old_status != new_status:
            # Only trigger alert if status changes to 'active'
            if old_status and new_status.lower() == "active":
                logger.info(f"Event {event_id} ({current_data.get('event_code', '-')}) changed status to {new_status}!")
                send_change_alert(event, "Status", old_status, new_status)
            
        # Detect if maximum_count increased
        try:
            old_max = int(previous_data.get("maximum_count", 0))
        except (ValueError, TypeError):
            old_max = 0
            
        try:
            new_max = int(current_data.get("maximum_count", 0))
        except (ValueError, TypeError):
            new_max = 0

        if new_max > old_max:
            logger.info(f"Event {event_id} ({current_data.get('event_code', '-')}) increased max count from {old_max} to {new_max}!")
            send_change_alert(event, "Capacity", str(old_max), str(new_max))

        # Update state if anything changed
        if current_data != previous_data:
            state[event_id] = current_data
            state_changed = True

    if state_changed:
        save_state(state)