package rules

import (
	"net/url"
)

// trackingParameters is a set of query parameter names that should be removed from URLs
var trackingParameters = map[string]struct{}{
	"utm_source":   {}, // UTM parameter - marketing campaign source
	"utm_medium":   {}, // UTM parameter - marketing campaign medium
	"utm_campaign": {}, // UTM parameter - marketing campaign name
	"utm_term":     {}, // UTM parameter - marketing campaign term
	"utm_content":  {}, // UTM parameter - marketing campaign content
	"fbclid":       {}, // Facebook click ID
	"gclid":        {}, // Google click ID
	"ref_src":      {}, // Twitter/X referrer source
	"ref_url":      {}, // Twitter/X referrer URL
}

// CleanURL removes tracking and social network parameters from a URL.
// Other query parameters are preserved. If the URL cannot be parsed, it returns the original URL.
func CleanURL(urlStr string) string {
	parsedURL, err := url.Parse(urlStr)
	if err != nil {
		// If URL cannot be parsed, return original
		return urlStr
	}

	// If there are no query parameters, return original URL
	if parsedURL.RawQuery == "" {
		return urlStr
	}

	// Parse query parameters
	query := parsedURL.Query()

	// Remove tracking parameters
	for param := range trackingParameters {
		query.Del(param)
	}

	// Reconstruct URL with cleaned query parameters
	parsedURL.RawQuery = query.Encode()

	// If all query parameters were removed, clear the query string
	if parsedURL.RawQuery == "" {
		parsedURL.RawQuery = ""
	}

	return parsedURL.String()
}