"""
Utility for generating OpenVPN client configuration files.
"""

import os
import subprocess

def generate_client_config(username: str):
    """
    Generates a .ovpn file for a given user.

    Args:
        username: The username for which to generate the config.
    """
    easyrsa_dir = "/home/arthur/openvpn-ca/"
    ca_path = "/home/arthur/openvpn-ca/pki/ca.crt"
    ta_path = "/home/arthur/openvpn-ca/ta.key"
    client_crt_path = f"/home/arthur/openvpn-ca/pki/issued/{username}.crt"
    client_key_path = f"/home/arthur/openvpn-ca/pki/private/{username}.key"
    output_path = f"/etc/openvpn/client/{username}.ovpn"

    # Step 1: Generate the client certificate
    print(f"Generating certificate for user: {username}...")
    try:
        command = ["./easyrsa", "build-client-full", username, "nopass"]
        process = subprocess.run(
            command,
            cwd=easyrsa_dir,
            check=True,
            capture_output=True,
            text=True
        )
        print(process.stdout)
        print("Certificate generated successfully.")
    except FileNotFoundError:
        print(f"Error: 'easyrsa' script not found in {easyrsa_dir}. Please check the path.")
        return
    except subprocess.CalledProcessError as e:
        print(f"Error generating certificate for user: {username}")
        print(f"Return code: {e.returncode}")
        print(f"Stderr: {e.stderr}")
        return

    # Step 2: Verify that all required files exist
    for f in [ca_path, ta_path, client_crt_path, client_key_path]:
        if not os.path.isfile(f):
            print(f"Error: Cannot read file '{f}'. File not found after generation.")
            return

    # Step 3: Read the content of the files
    try:
        with open(ca_path, 'r') as f:
            ca_content = f.read()
        with open(client_crt_path, 'r') as f:
            client_crt_content = f.read()
        with open(client_key_path, 'r') as f:
            client_key_content = f.read()
        with open(ta_path, 'r') as f:
            ta_content = f.read()
    except IOError as e:
        print(f"Error reading files: {e}")
        return

    # Step 4: Assemble the .ovpn configuration
    ovpn_config = f"""
client
dev tun
proto udp
remote 14.241.240.102 1194 # use FTP IP address 
resolv-retry infinite
nobind
persist-key
persist-tun
remote-cert-tls server
cipher AES-256-GCM
# push mac address info 
push-peer-info
verb 3

<ca>
{ca_content}
</ca>

<cert>
{client_crt_content}
</cert>

<key>
{client_key_content}
</key>

<tls-auth>
{ta_content}
</tls-auth>
key-direction 1
"""

    # Step 5: Write the configuration to the output file
    try:
        output_dir = os.path.dirname(output_path)
        # Check if dir exists and if we have write permission
        if not os.path.isdir(output_dir) or not os.access(output_dir, os.W_OK):
            print(f"Error: Output directory '{output_dir}' does not exist or is not writable.")
            print("Please ensure you have the correct permissions to write to this directory.")
            # As a fallback, save to a local directory
            local_output_dir = "generated-clients"
            if not os.path.exists(local_output_dir):
                os.makedirs(local_output_dir)
            local_output_path = os.path.join(local_output_dir, f"{username}.ovpn")
            with open(local_output_path, 'w') as f:
                f.write(ovpn_config)
            print(f"Could not write to server path. Saved config locally to: {local_output_path}")
            return

        with open(output_path, 'w') as f:
            f.write(ovpn_config)
        print(f"Successfully generated client config: {output_path}")
    except IOError as e:
        print(f"Error writing to file: {e}")