// ============================================================================
// KPI CALCULATION Function
// Purpose: Calculate OEE, Availability, Performance, Quality metrics
// Triggered by: Timer (every 5 seconds) or on cycle updates
// ============================================================================

// Get current global variables
const activeOrder = global.get("activeWorkOrder");
const cycleCount = global.get("cycleCount") || 0;
const trackingEnabled = global.get("trackingEnabled") || false;
const operatingTime = global.get("operatingTime") || 0; // seconds
const downtime = global.get("downtime") || 0; // seconds
const productionStartTime = global.get("productionStartTime");

// If no active order or not tracking, send zeros
if (!activeOrder || !activeOrder.id || !trackingEnabled || !productionStartTime) {
    msg.payload = {
        oee: 0,
        availability: 0,
        performance: 0,
        quality: 0
    };
    return msg;
}

// Extract work order data
const targetQty = Number(activeOrder.target) || 0;
const goodParts = Number(activeOrder.good) || 0;
const scrapParts = Number(activeOrder.scrap) || 0;
const totalProduced = goodParts + scrapParts;
const theoreticalCycleTime = Number(activeOrder.cycleTime || activeOrder.theoreticalCycleTime || 0);

// ============================================================================
// AVAILABILITY = Operating Time / (Operating Time + Downtime)
// ============================================================================
let availability = 0;
const totalTime = operatingTime + downtime;

if (totalTime > 0) {
    availability = (operatingTime / totalTime) * 100;
}

// ============================================================================
// PERFORMANCE = (Actual Production / Theoretical Production) * 100
// Theoretical Production = Operating Time / Theoretical Cycle Time
// ============================================================================
let performance = 0;

if (theoreticalCycleTime > 0 && operatingTime > 0) {
    const theoreticalProduction = operatingTime / theoreticalCycleTime;
    if (theoreticalProduction > 0) {
        performance = (cycleCount / theoreticalProduction) * 100;
    }
}

// Cap performance at 100% (can't exceed theoretical max)
performance = Math.min(performance, 100);

// ============================================================================
// QUALITY = Good Parts / Total Parts Produced
// ============================================================================
let quality = 0;

if (totalProduced > 0) {
    quality = (goodParts / totalProduced) * 100;
}

// ============================================================================
// OEE = Availability × Performance × Quality (as decimals)
// ============================================================================
const oee = (availability / 100) * (performance / 100) * (quality / 100) * 100;

// ============================================================================
// OUTPUT: Send KPIs to Home template
// ============================================================================
msg.topic = "kpiUpdate";
msg.payload = {
    oee: Math.round(oee),
    availability: Math.round(availability),
    performance: Math.round(performance),
    quality: Math.round(quality)
};

return msg;