/**
 * Client-Side Fingerprinting for Fraud Detection
 * 
 * This script collects browser fingerprint and behavior data to enhance
 * fraud detection. Users can add this script to their landing pages.
 * 
 * Usage:
 *   <script src="https://tracker.cybkit.com/assets/js/fingerprint.js"></script>
 * 
 * Or with custom configuration:
 *   <script>
 *     window.TrackerFPConfig = {
 *       endpoint: 'https://tracker.cybkit.com/fingerprint_endpoint.php',
 *       sendDelay: 3000,
 *       sendOnLeave: true
 *     };
 *   </script>
 *   <script src="https://tracker.cybkit.com/assets/js/fingerprint.js"></script>
 */

(function() {
    'use strict';
    
    // Configuration with defaults
    var config = window.TrackerFPConfig || {};
    var endpoint = config.endpoint || (window.location.protocol + '//' + (config.trackerDomain || 'tracker.cybkit.com') + '/fingerprint_endpoint.php');
    var sendDelay = config.sendDelay || 3000;
    var sendOnLeave = config.sendOnLeave !== false;
    
    // State
    var dataSent = false;
    var pageLoadTime = Date.now();
    
    // Behavior tracking counters
    var behavior = {
        mousemove: 0,
        click: 0,
        keydown: 0,
        scroll: 0,
        touchstart: 0,
        timeOnPage: 0
    };
    
    /**
     * Get click_id from URL parameters
     */
    function getClickId() {
        var params = new URLSearchParams(window.location.search);
        return params.get('click_id') || params.get('clickid') || params.get('cid') || null;
    }
    
    /**
     * Collect screen information
     */
    function getScreenInfo() {
        return {
            screen: screen.width + 'x' + screen.height,
            colorDepth: screen.colorDepth,
            pixelRatio: window.devicePixelRatio || 1
        };
    }
    
    /**
     * Collect timezone information
     */
    function getTimezoneInfo() {
        var timezone = '';
        try {
            timezone = Intl.DateTimeFormat().resolvedOptions().timeZone;
        } catch (e) {
            timezone = 'unknown';
        }
        return {
            timezone: timezone,
            timezoneOffset: new Date().getTimezoneOffset()
        };
    }
    
    /**
     * Collect browser properties
     */
    function getBrowserInfo() {
        var nav = navigator;
        return {
            language: nav.language || '',
            languages: (nav.languages || []).join(','),
            cookieEnabled: nav.cookieEnabled,
            doNotTrack: nav.doNotTrack || 'unspecified'
        };
    }
    
    /**
     * Collect hardware indicators
     */
    function getHardwareInfo() {
        var nav = navigator;
        return {
            hardwareConcurrency: nav.hardwareConcurrency || 0,
            deviceMemory: nav.deviceMemory || 0,
            maxTouchPoints: nav.maxTouchPoints || 0
        };
    }
    
    /**
     * Collect bot detection signals
     */
    function getBotSignals() {
        var nav = navigator;
        return {
            webdriver: nav.webdriver || false,
            plugins: nav.plugins ? nav.plugins.length : 0
        };
    }
    
    /**
     * Generate canvas fingerprint
     */
    function getCanvasFingerprint() {
        try {
            var canvas = document.createElement('canvas');
            canvas.width = 200;
            canvas.height = 50;
            var ctx = canvas.getContext('2d');
            
            if (!ctx) {
                return 'no_context';
            }
            
            // Draw text with various styles
            ctx.textBaseline = 'top';
            ctx.font = '14px Arial';
            ctx.fillStyle = '#f60';
            ctx.fillRect(10, 10, 100, 30);
            ctx.fillStyle = '#069';
            ctx.fillText('Fingerprint', 15, 15);
            ctx.fillStyle = 'rgba(102, 204, 0, 0.7)';
            ctx.fillText('Canvas', 50, 25);
            
            // Get data URL and return last 50 characters as hash
            var dataUrl = canvas.toDataURL();
            return dataUrl.slice(-50);
        } catch (e) {
            return 'error';
        }
    }
    
    /**
     * Get WebGL fingerprint
     */
    function getWebGLFingerprint() {
        try {
            var canvas = document.createElement('canvas');
            var gl = canvas.getContext('webgl') || canvas.getContext('experimental-webgl');
            
            if (!gl) {
                return { vendor: '', renderer: '' };
            }
            
            var debugInfo = gl.getExtension('WEBGL_debug_renderer_info');
            if (!debugInfo) {
                return { vendor: 'unknown', renderer: 'unknown' };
            }
            
            return {
                vendor: gl.getParameter(debugInfo.UNMASKED_VENDOR_WEBGL) || '',
                renderer: gl.getParameter(debugInfo.UNMASKED_RENDERER_WEBGL) || ''
            };
        } catch (e) {
            return { vendor: 'error', renderer: 'error' };
        }
    }
    
    /**
     * Collect all fingerprint data
     */
    function collectFingerprint() {
        var screen = getScreenInfo();
        var timezone = getTimezoneInfo();
        var browser = getBrowserInfo();
        var hardware = getHardwareInfo();
        var botSignals = getBotSignals();
        var webgl = getWebGLFingerprint();
        
        return {
            screen: screen.screen,
            colorDepth: screen.colorDepth,
            pixelRatio: screen.pixelRatio,
            timezone: timezone.timezone,
            timezoneOffset: timezone.timezoneOffset,
            language: browser.language,
            languages: browser.languages,
            cookieEnabled: browser.cookieEnabled,
            doNotTrack: browser.doNotTrack,
            hardwareConcurrency: hardware.hardwareConcurrency,
            deviceMemory: hardware.deviceMemory,
            maxTouchPoints: hardware.maxTouchPoints,
            webdriver: botSignals.webdriver,
            plugins: botSignals.plugins,
            canvas: getCanvasFingerprint(),
            webgl_vendor: webgl.vendor,
            webgl_renderer: webgl.renderer
        };
    }
    
    /**
     * Send data to tracker endpoint
     */
    function sendData() {
        if (dataSent) {
            return;
        }
        
        var clickId = getClickId();
        if (!clickId) {
            // No click_id, don't send anything
            return;
        }
        
        dataSent = true;
        
        // Calculate time on page
        behavior.timeOnPage = Date.now() - pageLoadTime;
        
        var payload = {
            click_id: clickId,
            fingerprint: collectFingerprint(),
            behavior: behavior
        };
        
        var jsonData = JSON.stringify(payload);
        
        // Try sendBeacon first (most reliable for page unload)
        if (navigator.sendBeacon) {
            try {
                var blob = new Blob([jsonData], { type: 'application/json' });
                navigator.sendBeacon(endpoint, blob);
                return;
            } catch (e) {
                // Fall through to fetch
            }
        }
        
        // Fallback to fetch with keepalive
        try {
            fetch(endpoint, {
                method: 'POST',
                headers: {
                    'Content-Type': 'application/json'
                },
                body: jsonData,
                keepalive: true,
                mode: 'cors',
                credentials: 'omit' // Don't send cookies to avoid CORS issues
            }).catch(function() {
                // Silently fail
            });
        } catch (e) {
            // Silently fail
        }
    }
    
    /**
     * Set up behavior tracking
     */
    function setupBehaviorTracking() {
        // Throttle function to limit event frequency
        function throttle(callback, limit) {
            var waiting = false;
            return function() {
                if (!waiting) {
                    callback.apply(this, arguments);
                    waiting = true;
                    setTimeout(function() {
                        waiting = false;
                    }, limit);
                }
            };
        }
        
        // Mouse move tracking (throttled)
        document.addEventListener('mousemove', throttle(function() {
            behavior.mousemove++;
        }, 100), { passive: true });
        
        // Click tracking
        document.addEventListener('click', function() {
            behavior.click++;
        }, { passive: true });
        
        // Keyboard tracking
        document.addEventListener('keydown', function() {
            behavior.keydown++;
        }, { passive: true });
        
        // Scroll tracking (throttled)
        document.addEventListener('scroll', throttle(function() {
            behavior.scroll++;
        }, 100), { passive: true });
        
        // Touch tracking
        document.addEventListener('touchstart', function() {
            behavior.touchstart++;
        }, { passive: true });
    }
    
    /**
     * Set up send triggers
     */
    function setupSendTriggers() {
        // Send after delay
        setTimeout(sendData, sendDelay);
        
        if (sendOnLeave) {
            // Send when page visibility changes (user switches tab)
            document.addEventListener('visibilitychange', function() {
                if (document.visibilityState === 'hidden') {
                    sendData();
                }
            });
            
            // Send before page unload
            window.addEventListener('beforeunload', sendData);
            
            // Also try pagehide for mobile browsers
            window.addEventListener('pagehide', sendData);
        }
    }
    
    /**
     * Initialize fingerprinting
     */
    function init() {
        // Don't run if no click_id in URL
        if (!getClickId()) {
            return;
        }
        
        setupBehaviorTracking();
        setupSendTriggers();
    }
    
    // Initialize when DOM is ready
    if (document.readyState === 'loading') {
        document.addEventListener('DOMContentLoaded', init);
    } else {
        init();
    }
    
})();