/**
 * MapGeo Safety System
 * Prevents MapGeo and third-party map plugins from crashing the page
 * Works in all browsers including Safari and Chrome
 * 
 * @package HVAC_Community_Events
 * @since 2.0.0
 */

(function() {
    'use strict';
    
    // Safety configuration
    const config = window.HVAC_MapGeo_Config || {
        maxRetries: 3,
        retryDelay: 2000,
        timeout: 10000,
        fallbackEnabled: true,
        debugMode: false
    };
    
    const log = config.debugMode ? console.log.bind(console) : () => {};
    const error = config.debugMode ? console.error.bind(console) : () => {};
    
    log('[MapGeo Safety] Initializing protection system');
    
    /**
     * Resource Load Monitor
     * Tracks and manages external script loading
     */
    class ResourceLoadMonitor {
        constructor() {
            this.resources = new Map();
            this.criticalResources = [
                'amcharts',
                'mapgeo',
                'interactive-geo-maps',
                'map-widget'
            ];
            this.setupMonitoring();
        }
        
        setupMonitoring() {
            // Monitor script loading
            const originalAppendChild = Element.prototype.appendChild;
            const self = this;
            
            Element.prototype.appendChild = function(element) {
                if (element.tagName === 'SCRIPT' && element.src) {
                    self.monitorScript(element);
                }
                return originalAppendChild.call(this, element);
            };
            
            // Monitor existing scripts
            document.querySelectorAll('script[src]').forEach(script => {
                this.monitorScript(script);
            });
        }
        
        monitorScript(script) {
            const src = script.src;
            const isCritical = this.criticalResources.some(resource => 
                src.toLowerCase().includes(resource)
            );
            
            if (isCritical) {
                log('[MapGeo Safety] Monitoring critical resource:', src);
                
                const timeoutId = setTimeout(() => {
                    error('[MapGeo Safety] Resource timeout:', src);
                    this.handleResourceFailure(src);
                }, config.timeout);
                
                script.addEventListener('load', () => {
                    clearTimeout(timeoutId);
                    log('[MapGeo Safety] Resource loaded:', src);
                    this.resources.set(src, 'loaded');
                });
                
                script.addEventListener('error', () => {
                    clearTimeout(timeoutId);
                    error('[MapGeo Safety] Resource failed:', src);
                    this.handleResourceFailure(src);
                });
            }
        }
        
        handleResourceFailure(src) {
            this.resources.set(src, 'failed');
            
            // Check if this is a MapGeo CDN resource
            if (src.includes('cdn') || src.includes('amcharts')) {
                log('[MapGeo Safety] CDN resource failed, activating fallback');
                this.activateFallback();
            }
        }
        
        activateFallback() {
            // Hide map container
            const mapContainers = document.querySelectorAll(
                '.igm-map-container, [class*="mapgeo"], [id*="map-"], .map-widget-container'
            );
            
            mapContainers.forEach(container => {
                container.style.display = 'none';
            });
            
            // Show fallback content
            const fallback = document.getElementById('hvac-map-fallback');
            if (fallback) {
                fallback.style.display = 'block';
            }
            
            // Dispatch custom event
            window.dispatchEvent(new CustomEvent('hvac:mapgeo:fallback', {
                detail: { reason: 'resource_failure' }
            }));
        }
    }
    
    /**
     * MapGeo API Wrapper
     * Safely wraps MapGeo API calls
     */
    class MapGeoAPIWrapper {
        constructor() {
            this.wrapAPIs();
        }
        
        wrapAPIs() {
            // Wrap potential MapGeo global functions
            const mapGeoAPIs = [
                'MapGeoWidget',
                'InteractiveGeoMaps',
                'IGM',
                'mapWidget'
            ];
            
            mapGeoAPIs.forEach(api => {
                if (typeof window[api] !== 'undefined') {
                    this.wrapAPI(api);
                }
                
                // Set up getter to wrap when loaded
                Object.defineProperty(window, `_original_${api}`, {
                    value: window[api],
                    writable: true
                });
                
                Object.defineProperty(window, api, {
                    get() {
                        return window[`_wrapped_${api}`] || window[`_original_${api}`];
                    },
                    set(value) {
                        window[`_original_${api}`] = value;
                        window[`_wrapped_${api}`] = new Proxy(value, {
                            construct(target, args) {
                                try {
                                    return new target(...args);
                                } catch (e) {
                                    error('[MapGeo Safety] Construction error:', e);
                                    return {};
                                }
                            },
                            apply(target, thisArg, args) {
                                try {
                                    return target.apply(thisArg, args);
                                } catch (e) {
                                    error('[MapGeo Safety] Execution error:', e);
                                    return null;
                                }
                            }
                        });
                    }
                });
            });
        }
        
        wrapAPI(apiName) {
            const original = window[apiName];
            
            window[apiName] = new Proxy(original, {
                construct(target, args) {
                    try {
                        log(`[MapGeo Safety] Creating ${apiName} instance`);
                        return new target(...args);
                    } catch (e) {
                        error(`[MapGeo Safety] Failed to create ${apiName}:`, e);
                        return {};
                    }
                },
                apply(target, thisArg, args) {
                    try {
                        log(`[MapGeo Safety] Calling ${apiName}`);
                        return target.apply(thisArg, args);
                    } catch (e) {
                        error(`[MapGeo Safety] Failed to call ${apiName}:`, e);
                        return null;
                    }
                }
            });
        }
    }
    
    /**
     * DOM Ready Safety
     * Ensures MapGeo only runs when DOM is safe
     */
    class DOMReadySafety {
        constructor() {
            this.setupSafety();
        }
        
        setupSafety() {
            // Intercept jQuery ready calls that might contain MapGeo code
            if (typeof jQuery !== 'undefined') {
                const originalReady = jQuery.fn.ready;
                
                jQuery.fn.ready = function(callback) {
                    const wrappedCallback = function() {
                        try {
                            // Check if MapGeo elements exist before running
                            const hasMapElements = document.querySelector(
                                '.igm-map-container, [class*="mapgeo"], [id*="map-"]'
                            );
                            
                            if (hasMapElements || !callback.toString().includes('map')) {
                                return callback.apply(this, arguments);
                            } else {
                                log('[MapGeo Safety] Skipping map-related ready callback - no map elements found');
                            }
                        } catch (e) {
                            error('[MapGeo Safety] Error in ready callback:', e);
                        }
                    };
                    
                    return originalReady.call(this, wrappedCallback);
                };
            }
        }
    }
    
    /**
     * CDN Health Checker
     * Proactively checks AmCharts CDN availability before MapGeo initialization
     */
    class CDNHealthChecker {
        constructor() {
            this.criticalCDNs = [
                'https://cdn.amcharts.com/lib/version/4.10.29/core.js',
                'https://cdn.amcharts.com/lib/version/4.10.29/maps.js',
                'https://cdn.amcharts.com/lib/4/geodata/usaLow.js'
            ];
            this.timeout = 5000; // 5 second timeout
            this.cacheKey = 'hvac_cdn_health';
            this.cacheExpiry = 10 * 60 * 1000; // 10 minutes
        }
        
        async checkCDNHealth() {
            log('[MapGeo Safety] Checking AmCharts CDN health...');
            
            // Check cached result first
            const cached = this.getCachedResult();
            if (cached !== null) {
                log('[MapGeo Safety] Using cached CDN status:', cached);
                return cached;
            }
            
            // Test primary CDN endpoints
            const results = await Promise.allSettled(
                this.criticalCDNs.map(url => this.testCDNEndpoint(url))
            );
            
            // Consider CDN healthy if at least 2 out of 3 endpoints work
            const successCount = results.filter(r => r.status === 'fulfilled' && r.value).length;
            const isHealthy = successCount >= 2;
            
            log(`[MapGeo Safety] CDN health check: ${successCount}/${this.criticalCDNs.length} endpoints available`);
            
            // Cache result
            this.setCachedResult(isHealthy);
            
            return isHealthy;
        }
        
        async testCDNEndpoint(url) {
            try {
                const controller = new AbortController();
                const timeoutId = setTimeout(() => controller.abort(), this.timeout);
                
                const response = await fetch(url, {
                    method: 'HEAD',
                    mode: 'no-cors', // Allow cross-origin requests
                    signal: controller.signal
                });
                
                clearTimeout(timeoutId);
                return true; // If we get here, endpoint is reachable
            } catch (e) {
                log(`[MapGeo Safety] CDN endpoint failed: ${url} - ${e.message}`);
                return false;
            }
        }
        
        getCachedResult() {
            try {
                const cached = sessionStorage.getItem(this.cacheKey);
                if (cached) {
                    const data = JSON.parse(cached);
                    if (Date.now() - data.timestamp < this.cacheExpiry) {
                        return data.healthy;
                    }
                }
            } catch (e) {
                log('[MapGeo Safety] Error reading CDN cache:', e.message);
            }
            return null;
        }
        
        setCachedResult(healthy) {
            try {
                const data = {
                    healthy: healthy,
                    timestamp: Date.now()
                };
                sessionStorage.setItem(this.cacheKey, JSON.stringify(data));
            } catch (e) {
                log('[MapGeo Safety] Error caching CDN status:', e.message);
            }
        }
    }
    
    /**
     * Initialize all safety systems with proactive CDN checking
     */
    async function initializeSafetySystems() {
        // Only initialize on pages with potential maps
        if (!document.querySelector('[class*="map"], [id*="map"]')) {
            log('[MapGeo Safety] No map elements detected, skipping initialization');
            return;
        }
        
        // CRITICAL: Check CDN health before allowing MapGeo to initialize
        const cdnChecker = new CDNHealthChecker();
        const cdnHealthy = await cdnChecker.checkCDNHealth();
        
        if (!cdnHealthy) {
            error('[MapGeo Safety] AmCharts CDN unavailable - activating immediate fallback');
            
            // Show fallback state
            UIManager.showFallbackState();
            
            // Dispatch event to notify other systems
            window.dispatchEvent(new CustomEvent('hvac:mapgeo:cdn_unavailable', {
                detail: { reason: 'amcharts_cdn_timeout' }
            }));
            
            log('[MapGeo Safety] Immediate fallback activated due to CDN unavailability');
            return;
        }
        
        log('[MapGeo Safety] AmCharts CDN healthy - proceeding with MapGeo initialization');
        
        // Show map state since CDN is healthy
        UIManager.showMapState();
        
        // Initialize monitors
        new ResourceLoadMonitor();
        new MapGeoAPIWrapper();
        new DOMReadySafety();
        
        // Set up periodic health check with shorter timeout now that we pre-checked CDN
        let healthCheckCount = 0;
        const healthCheckInterval = setInterval(() => {
            healthCheckCount++;
            
            // Check if map loaded successfully
            const mapLoaded = document.querySelector('.igm-map-loaded, .mapgeo-loaded, .map-initialized');
            
            if (mapLoaded) {
                log('[MapGeo Safety] Map loaded successfully');
                clearInterval(healthCheckInterval);
            } else if (healthCheckCount >= 6) {
                // Reduced to 6 seconds since we already verified CDN
                error('[MapGeo Safety] Map failed to load after 6 seconds (CDN was healthy)');
                clearInterval(healthCheckInterval);
                
                // Activate fallback if configured
                if (config.fallbackEnabled) {
                    const monitor = new ResourceLoadMonitor();
                    monitor.activateFallback();
                }
            }
        }, 1000);
        
        log('[MapGeo Safety] All safety systems initialized with CDN pre-check');
    }
    
    /**
     * Enhanced UI Management for CDN fallbacks
     */
    class UIManager {
        static showLoadingState() {
            const loading = document.getElementById('hvac-map-loading');
            const fallback = document.getElementById('hvac-map-fallback');
            const mapWrapper = document.querySelector('.hvac-mapgeo-wrapper');
            
            if (loading) loading.style.display = 'block';
            if (fallback) fallback.style.display = 'none';
            if (mapWrapper) mapWrapper.style.display = 'none';
            
            log('[MapGeo Safety] Loading state activated');
        }
        
        static showFallbackState() {
            const loading = document.getElementById('hvac-map-loading');
            const fallback = document.getElementById('hvac-map-fallback');
            const mapWrapper = document.querySelector('.hvac-mapgeo-wrapper');
            
            if (loading) loading.style.display = 'none';
            if (fallback) fallback.style.display = 'block';
            if (mapWrapper) mapWrapper.style.display = 'none';
            
            log('[MapGeo Safety] Fallback state activated');
        }
        
        static showMapState() {
            const loading = document.getElementById('hvac-map-loading');
            const fallback = document.getElementById('hvac-map-fallback');
            const mapWrapper = document.querySelector('.hvac-mapgeo-wrapper');
            
            if (loading) loading.style.display = 'none';
            if (fallback) fallback.style.display = 'none';
            if (mapWrapper) mapWrapper.style.display = 'block';
            
            log('[MapGeo Safety] Map state activated');
        }
        
        static setupRetryButton() {
            const retryButton = document.querySelector('.hvac-retry-map');
            if (retryButton) {
                retryButton.addEventListener('click', async () => {
                    retryButton.disabled = true;
                    retryButton.textContent = 'Checking...';
                    
                    try {
                        UIManager.showLoadingState();
                        
                        // Clear CDN health cache
                        const cdnChecker = new CDNHealthChecker();
                        sessionStorage.removeItem(cdnChecker.cacheKey);
                        
                        // Re-check CDN health
                        const isHealthy = await cdnChecker.checkCDNHealth();
                        
                        if (isHealthy) {
                            log('[MapGeo Safety] CDN healthy on retry - reloading page');
                            window.location.reload();
                        } else {
                            UIManager.showFallbackState();
                            retryButton.textContent = 'Still Unavailable';
                            setTimeout(() => {
                                retryButton.textContent = 'Try Loading Map Again';
                                retryButton.disabled = false;
                            }, 3000);
                        }
                    } catch (e) {
                        error('[MapGeo Safety] Error during retry:', e.message);
                        UIManager.showFallbackState();
                        retryButton.textContent = 'Error - Try Again';
                        retryButton.disabled = false;
                    }
                });
            }
        }
    }
    
    // Initialize when DOM is ready
    if (document.readyState === 'loading') {
        document.addEventListener('DOMContentLoaded', () => {
            UIManager.showLoadingState();
            UIManager.setupRetryButton();
            initializeSafetySystems();
        });
    } else {
        // DOM already loaded
        UIManager.showLoadingState();
        UIManager.setupRetryButton();
        initializeSafetySystems();
    }
    
    // Enhanced safety API for debugging and manual control
    window.HVACMapGeoSafety = {
        config: config,
        reinitialize: initializeSafetySystems,
        activateFallback: () => {
            const monitor = new ResourceLoadMonitor();
            monitor.activateFallback();
        },
        ui: UIManager,
        checkCDN: async () => {
            const checker = new CDNHealthChecker();
            return await checker.checkCDNHealth();
        },
        clearCDNCache: () => {
            const checker = new CDNHealthChecker();
            sessionStorage.removeItem(checker.cacheKey);
            log('[MapGeo Safety] CDN cache cleared');
        }
    };
    
})();