"""Add domain servers to nginx.conf executable script."""
import argparse
from dataclasses import dataclass, field
import json
import sys

REDIRECT_TEMPLATE = "\n".join(
    (
        "\tlocation / {{",
        "\t\tresolver 127.0.0.11 valid=30s;",
        "\t\tset $host_{i} {redirection_host};",
        "\t\tproxy_pass $host_{i}/;",
        "\t\tinclude proxy_common.conf;",
        "\t}}",
    )
)

SERVER_HTTPS_TEMPLATE = "\n".join(
    (
        "server {{",
        "\tinclude server_common.conf;",
        "\tlisten              443 ssl;",
        "\t",
        "\tserver_name         {server_name};",
        "\tssl_certificate     {certificates_path}/{certificate}/fullchain.pem;",
        "\tssl_certificate_key {certificates_path}/{certificate}/privkey.pem;",
        "\t",
        "{options}",
        "{redirection}",
        "}}",
    )
)

SERVER_HTTP_TEMPLATE = "\n".join(
    (
        "server {{",
        "\tinclude server_common.conf;",
        "\t",
        "\tserver_name         {server_name};",
        "{options}",
        "{redirection}",
        "}}",
    )
)


@dataclass
class Server:
    """Server entry for nginx.conf file."""

    server_name: str
    redirect: str | None = None
    certificate: str | None = None
    options: list[str] = field(default_factory=list)

    certificates_path: str = "/etc/letsencrypt/live"

    def __post_init__(self) -> None:
        if self.options is None:
            self.options = []

    def format(self, i: int, indent: str = "    ", base_indent: int = 1) -> str:
        """Format server to place inside nginx.conf"""
        res = (indent * base_indent) + (
            SERVER_HTTPS_TEMPLATE if self.certificate is not None else SERVER_HTTP_TEMPLATE
        ).replace("\n", "\n" + indent * base_indent).replace("\t", indent).format(
            server_name=self.server_name,
            certificate=self.certificate,
            redirection=(
                REDIRECT_TEMPLATE.replace("\n", "\n" + indent * base_indent)
                .replace("\t", indent)
                .format(i=i, redirection_host=self.redirect)
                if self.redirect is not None
                else ""
            ),
            options=(
                ("\n" + indent * (base_indent + 1))
                + ("\n" + indent * (base_indent + 1)).join(
                    ("\n" + indent * (base_indent + 1)).join(option.split("\n")) for option in self.options
                )
            ),
            certificates_path=self.certificates_path,
        )
        res = "\n".join(line for line in res.split("\n") if line.strip() != "")
        return res


@dataclass
class CLIParams:
    """add_servers CLI parameters"""

    nginx: str
    domains_list_txt: str
    servers_config_json: str
    certificates_path: str
    http_only: bool
    dry_run: bool


def main() -> None:
    """Parse arguments and add domains to nginx.conf"""
    parser = argparse.ArgumentParser("add-servers", description="Add domain servers to a given nginx.conf file")
    parser.add_argument("--nginx", "-f", required=True, help="Path to nginx.conf file to edit inplace")
    parser.add_argument(
        "--domains_list_txt",
        "-d",
        required=True,
        help="Path to domains list with ssl certificates ",
    )
    parser.add_argument(
        "--servers_config_json",
        "-s",
        required=False,
        default=None,
        help='Path to domains json {"domain": {"redirect": "redirection_path", "options": []}};',
    )
    parser.add_argument(
        "--certificates_path",
        "-c",
        required=False,
        default="/etc/letsencrypt/live",
        help="Path to a directory containing certificates",
    )
    parser.add_argument(
        "--http-only",
        action="store_true",
        help="Remove certificates usage from servers section",
    )
    parser.add_argument(
        "--dry-run",
        action="store_true",
        help="Print servers section and quit withot making changes",
    )

    args: CLIParams = parser.parse_args()

    replacement_substring = "# <place_for_servers>"

    with open(args.nginx, "r", encoding="utf-8") as file:
        nginx_config = file.read()
    if nginx_config.count(replacement_substring) != 1:
        print(
            f"Error. File must contain exactly one '{replacement_substring}' substring to replace with servers. Exiting"
        )
        sys.exit(1)

    if args.domains_list_txt is not None:
        with open(args.domains_list_txt, "r", encoding="utf-8") as file:
            domains_certs_list = [
                domain.strip() for domain in file.readlines() if domain.strip() != "" and not domain.startswith("#")
            ]
    else:
        domains_certs_list = []

    nginx_servers: list[Server] = []
    if args.servers_config_json is not None:
        with open(args.servers_config_json, "r", encoding="utf-8") as file:
            for server_name, params in json.load(file).items():
                server_name: str
                params: dict[str, str]
                nginx_servers.append(
                    Server(
                        (server_name if "*" not in server_name else f"{server_name} {server_name.replace('*.', '')}"),
                        params.get("redirect"),
                        (
                            None
                            if args.http_only
                            else server_name.replace("*.", "")
                            if server_name in domains_certs_list
                            else server_name[server_name.find(".") + 1 :]
                            if "." in server_name
                            and f"*.{server_name[server_name.find('.') + 1:]}" in domains_certs_list
                            else None
                        ),
                        params.get("options"),
                        args.certificates_path,
                    )
                )
    for domain in domains_certs_list:
        if not any(
            (
                domain == server.server_name
                or (
                    domain == f"*.{server.server_name[server.server_name.find('.') + 1:]}"
                    if "." in server.server_name
                    else False
                )
            )
            for server in nginx_servers
        ):
            nginx_servers.append(
                Server(domain, None, domain if not args.http_only else None, certificates_path=args.certificates_path)
            )

    nginx_servers_part = "\n\n".join(server.format(i) for i, server in enumerate(nginx_servers))

    print(f"Using following servers part for nginx.conf:\n\n{nginx_servers_part}")

    if not args.dry_run:
        config_backup_filename = f"{args.nginx}.bak"
        print(f"Backing up old nginx config {args.nginx} as {config_backup_filename}")

        with open(config_backup_filename, "w", encoding="utf-8") as file:
            file.write(nginx_config)

        with open(args.nginx, "w", encoding="utf-8") as file:
            file.write(nginx_config.replace(replacement_substring, nginx_servers_part.lstrip()))


if __name__ == "__main__":
    main()