package geodb

import (
	"net"
	"net/http"
	"strings"
)

// Utilities function
func GetRequesterIP(r *http.Request) string {
	ip := r.Header.Get("X-Forwarded-For")
	if ip == "" {
		ip = r.Header.Get("X-Real-IP")
		if ip == "" {
			ip = strings.Split(r.RemoteAddr, ":")[0]
		}
	}
	return ip
}

// Match the IP address with a wildcard string
func MatchIpWildcard(ipAddress, wildcard string) bool {
	// Split IP address and wildcard into octets
	ipOctets := strings.Split(ipAddress, ".")
	wildcardOctets := strings.Split(wildcard, ".")

	// Check that both have 4 octets
	if len(ipOctets) != 4 || len(wildcardOctets) != 4 {
		return false
	}

	// Check each octet to see if it matches the wildcard or is an exact match
	for i := 0; i < 4; i++ {
		if wildcardOctets[i] == "*" {
			continue
		}
		if ipOctets[i] != wildcardOctets[i] {
			return false
		}
	}

	return true
}

// Match ip address with CIDR
func MatchIpCIDR(ip string, cidr string) bool {
	// parse the CIDR string
	_, cidrnet, err := net.ParseCIDR(cidr)
	if err != nil {
		return false
	}

	// parse the IP address
	ipAddr := net.ParseIP(ip)

	// check if the IP address is within the CIDR range
	return cidrnet.Contains(ipAddr)
}

// Check if a ip is private IP range
func IsPrivateIP(ipStr string) bool {
	ip := net.ParseIP(ipStr)
	if ip == nil {
		return false
	}

	// Check for IPv4 private address ranges
	if ip.To4() != nil {
		privateIPv4Ranges := []string{
			"10.0.0.0/8",     // 10.0.0.0 - 10.255.255.255
			"172.16.0.0/12",  // 172.16.0.0 - 172.31.255.255
			"192.168.0.0/16", // 192.168.0.0 - 192.168.255.255
			"169.254.0.0/16", // 169.254.0.0 - 169.254.255.255 (link-local addresses)
		}

		for _, network := range privateIPv4Ranges {
			_, privateNet, _ := net.ParseCIDR(network)
			if privateNet.Contains(ip) {
				return true
			}
		}
	} else {
		// Check for IPv6 private address ranges
		privateIPv6Ranges := []string{
			"fc00::/7",  // Unique local addresses
			"fe80::/10", // Link-local addresses
		}

		for _, network := range privateIPv6Ranges {
			_, privateNet, _ := net.ParseCIDR(network)
			if privateNet.Contains(ip) {
				return true
			}
		}
	}

	return false
}