import subprocess
import re
import tempfile
import os
import sys
import argparse
import pathlib

SCRIPT_PATH = pathlib.Path(__file__).parent / "worker.py"


def execute_script(provider, location, server_type):
    command = [
        os.path.realpath(sys.executable),
        SCRIPT_PATH,
        "--provider",
        provider,
        "--location",
        location,
        "--server_type",
        server_type,
    ]
    result = subprocess.run(command, capture_output=True, text=True)
    if result.returncode != 0:
        raise Exception(f"Error executing script: {result.stderr}")
    return result.stdout.strip()


def replace_peer_section(config_content, new_peer_section):
    # Regular expression to match the [Peer] section
    peer_section_pattern = re.compile(r"\[Peer\](?:\n(?!\[)[^\n]*)*")

    # Find the existing [Peer] section
    match = peer_section_pattern.search(config_content)

    if match:
        # Replace the existing [Peer] section with the new one
        updated_content = (
            config_content[: match.start()]
            + new_peer_section
            + config_content[match.end() :]
        )
    else:
        # If no [Peer] section exists, append the new one
        updated_content = config_content + "\n" + new_peer_section

    return updated_content


def main():
    parser = argparse.ArgumentParser(
        description="Update local Wireguard configuration with a new peer."
    )
    parser.add_argument(
        "--provider",
        type=str,
        choices=["hetzner", "aws", "digitalocean", "azure"],
        required=True,
        help="Cloud provider",
    )
    parser.add_argument("--location", type=str, required=True, help="Server location")
    parser.add_argument("--server_type", type=str, required=True, help="Server type")
    parser.add_argument(
        "--interface", type=str, required=True, help="Wireguard interface (e.g., wg0)"
    )
    parser.add_argument(
        "--config_path", type=str, help="Path to the Wireguard configuration file"
    )

    args = parser.parse_args()

    provider = args.provider
    location = args.location
    server_type = args.server_type
    interface = args.interface
    config_path = args.config_path or f"/etc/wireguard/{interface}.conf"

    # Step 1: Execute the existing script to set up the remote VPN server
    new_peer_section = execute_script(provider, location, server_type)

    # Step 2: Read the local Wireguard configuration file
    with open(config_path, "r") as file:
        config_content = file.read()

    # Step 3: Replace the existing [Peer] section with the new one
    updated_content = replace_peer_section(config_content, new_peer_section)

    # Step 4: Save the updated configuration file
    with tempfile.TemporaryDirectory() as tempdir:
        temp_file = pathlib.Path(tempdir) / f"{interface}.conf"
        temp_file_path = str(temp_file)

        with open(temp_file_path, "w") as file:
            file.write(updated_content)

        # Step 5: Apply the updated Wireguard configuration
        subprocess.run(["wg-quick", "down", interface], stderr=subprocess.DEVNULL)
        subprocess.run(["wg-quick", "up", temp_file_path])

        # Overwrite the original config file with the updated content
        os.replace(temp_file_path, config_path)

    print(
        f"Local Wireguard configuration for {interface} updated and applied successfully."
    )


if __name__ == "__main__":
    main()