#!/bin/bash

# Colors for output
RED='\033[0;31m'
GREEN='\033[0;32m'
YELLOW='\033[1;33m'
NC='\033[0m' # No Color

# Function to print section headers
print_header() {
    echo -e "\n${YELLOW}=== $1 ===${NC}\n"
}

# Function to check if a command exists
command_exists() {
    command -v "$1" >/dev/null 2>&1
}

# Check required tools
check_requirements() {
    local missing_tools=()

    for tool in dig curl openssl whois; do
        if ! command_exists "$tool"; then
            missing_tools+=("$tool")
        fi
    done

    if [ ${#missing_tools[@]} -ne 0 ]; then
        echo -e "${RED}Error: The following required tools are missing:${NC}"
        printf '%s\n' "${missing_tools[@]}"
        exit 1
    fi
}

# Function to check DNS records
check_dns() {
    local domain=$1
    print_header "DNS Information for $domain"

    echo "A Record:"
    dig +short A "$domain"

    echo -e "\nCNAME Record:"
    dig +short CNAME "$domain"

    echo -e "\nNS Records:"
    dig +short NS "$domain"

    echo -e "\nDNS Resolution from different locations:"
    echo "Google DNS (8.8.8.8):"
    dig @8.8.8.8 +short "$domain"

    echo -e "\nCloudflare DNS (1.1.1.1):"
    dig @1.1.1.1 +short "$domain"
}

# Function to check SSL certificate
check_ssl() {
    local domain=$1
    print_header "SSL Certificate Information for $domain"

    echo "Attempting to retrieve SSL certificate info..."
    openssl s_client -connect "${domain}:443" -servername "$domain" </dev/null 2>/dev/null | openssl x509 -noout -text | grep -A 2 "Issuer:" -A 2 "Validity"

    echo -e "\nSSL Certificate Expiry:"
    echo | openssl s_client -servername "$domain" -connect "${domain}:443" 2>/dev/null | openssl x509 -noout -dates

    echo -e "\nComplete Certificate Chain:"
    openssl s_client -showcerts -connect "${domain}:443" -servername "$domain" </dev/null 2>/dev/null | grep -A 1 "issuer="
}

# Function to check HTTP response
check_http() {
    local domain=$1
    print_header "HTTP Response Information for $domain"

    echo "HTTP Response (http):"
    curl -IL "http://${domain}" 2>/dev/null | grep -E "HTTP|Location|Server"

    echo -e "\nHTTP Response (https):"
    curl -IL "https://${domain}" 2>/dev/null | grep -E "HTTP|Location|Server"
}

# Function to check website availability
check_availability() {
    local domain=$1
    print_header "Website Availability Check for $domain"

    local urls=("http://${domain}" "https://${domain}" "http://www.${domain}" "https://www.${domain}")

    for url in "${urls[@]}"; do
        echo -n "Testing $url: "
        http_code=$(curl -o /dev/null -s -w "%{http_code}" "$url")
        if [ "$http_code" -eq 200 ]; then
            echo -e "${GREEN}Available (HTTP $http_code)${NC}"
        else
            echo -e "${RED}Not available (HTTP $http_code)${NC}"
        fi
    done
}

# Main function
main() {
    if [ -z "$1" ]; then
        echo "Usage: $0 domain.com"
        exit 1
    fi

    local domain=$1

    # Remove protocol if included
    domain=${domain#http://}
    domain=${domain#https://}
    domain=${domain%/}

    # Check for required tools
    check_requirements

    # Run all checks
    check_dns "$domain"
    check_ssl "$domain"
    check_http "$domain"
    check_availability "$domain"
}

# Run the script
main "$@"

=== DNS Information for shaharia.com ===

A Record:
172.66.46.247
172.66.45.9

CNAME Record:

NS Records:
ernest.ns.cloudflare.com.
noor.ns.cloudflare.com.

DNS Resolution from different locations:
Google DNS (8.8.8.8):
172.66.45.9
172.66.46.247

Cloudflare DNS (1.1.1.1):
172.66.46.247
172.66.45.9

=== SSL Certificate Information for shaharia.com ===

Attempting to retrieve SSL certificate info...
grep: Validity: No such file or directory

SSL Certificate Expiry:
notBefore=Nov 27 11:53:45 2024 GMT
notAfter=Feb 25 12:53:44 2025 GMT

Complete Certificate Chain:
issuer=C = US, O = Google Trust Services, CN = WE1
---

=== HTTP Response Information for shaharia.com ===

HTTP Response (http):
HTTP/1.1 301 Moved Permanently
Location: https://shaharia.com/
Server: cloudflare
HTTP/2 200 

HTTP Response (https):
HTTP/2 200 

=== Website Availability Check for shaharia.com ===

Testing http://shaharia.com: Not available (HTTP 301)
Testing https://shaharia.com: Available (HTTP 200)
Testing http://www.shaharia.com: Not available (HTTP 301)
Testing https://www.shaharia.com: Available (HTTP 200)