/**
 * Shopify Checkout Redirect
 *
 * Redirects to Shopify checkout with session_id attached as a line item property.
 * After payment, Shopify fires an orders/paid webhook → backend generates the PDF.
 *
 * SETUP:
 * 1. Create products in Shopify with variant IDs
 * 2. Set the variant IDs below
 * 3. Set your Shopify store domain
 */

const SHOPIFY_CONFIG = {
    storeDomain: 'avvaleconsulting.myshopify.com',

    variantIds: {
        'business-plan': '57824589709696',   // AI Business Plan Generator — £0 (testing) → £29
        'pitch-deck': '57824615760256',       // AI Pitch Deck Generator — £0 (testing) → £39
        'marketing-plan': '57824628113792',   // AI Marketing Plan Generator — £0 (testing) → £49
    },

    // Set to true to enable Shopify checkout flow
    enabled: true,
};


/**
 * Redirect to Shopify checkout with session_id attached.
 * Falls back to direct generation if Shopify is not configured.
 */
async function redirectToShopifyCheckout(sessionId, toolType) {
    if (!SHOPIFY_CONFIG.enabled) {
        console.log('[Shopify] Not configured — using direct generation');
        return false;
    }

    const variantId = SHOPIFY_CONFIG.variantIds[toolType];
    if (!variantId || variantId === 'REPLACE_WITH_VARIANT_ID') {
        console.warn(`[Shopify] No variant ID for ${toolType} — using direct generation`);
        return false;
    }

    // Build tool-specific return path for Shopify's "Continue shopping" link
    const toolNames = {
        'business-plan': 'business-plan-generator',
        'pitch-deck': 'pitch-deck-generator',
        'marketing-plan': 'marketing-plan-generator',
    };
    const returnPath = `/tools/${toolNames[toolType] || toolType}?session_id=${sessionId}`;

    // Build Shopify checkout URL with session_id as line item property
    const checkoutUrl = `https://${SHOPIFY_CONFIG.storeDomain}/cart/${variantId}:1`
        + `?attributes[session_id]=${encodeURIComponent(sessionId)}`
        + `&note=${encodeURIComponent('AI Tool: ' + toolType + ' | Session: ' + sessionId)}`
        + `&return_to=${encodeURIComponent(returnPath)}`;

    // Store session_id in localStorage — cleared only after download is clicked
    localStorage.setItem('avvale_session_id', sessionId);
    localStorage.setItem('avvale_tool_type', toolType);

    window.location.href = checkoutUrl;
    return true;
}


/**
 * Check if returning from Shopify checkout.
 * Checks URL query params first, then localStorage.
 * Does NOT clear localStorage — that happens when user clicks download.
 */
function checkPostCheckoutReturn() {
    // 1. Check URL query param (most reliable — survives browser navigation)
    const urlParams = new URLSearchParams(window.location.search);
    const urlSessionId = urlParams.get('session_id');
    if (urlSessionId) {
        // Clean URL without reloading
        const cleanUrl = window.location.pathname;
        window.history.replaceState({}, '', cleanUrl);
        return urlSessionId;
    }

    // 2. Check localStorage (fallback — user pressed back from Shopify)
    const storedSessionId = localStorage.getItem('avvale_session_id');
    if (storedSessionId) {
        return storedSessionId;
    }

    return null;
}


/**
 * Clear session from localStorage. Call after download is clicked.
 */
function clearSessionStorage() {
    localStorage.removeItem('avvale_session_id');
    localStorage.removeItem('avvale_tool_type');
}