"""
Hysteria 2 protocol manager — teddysun/hysteria Docker image.

Installs Hysteria with Let's Encrypt TLS for an admin-provided domain
(certbot standalone on port 80), then runs the UDP QUIC server.
Clients use userpass auth; share links are hysteria2:// URIs.
"""

from __future__ import annotations

import json
import logging
import re
import secrets
import shlex
import string
from urllib.parse import quote

logger = logging.getLogger(__name__)


def _q(value):
    return shlex.quote(str(value))


def _rand_token(length=16):
    alphabet = string.ascii_lowercase + string.digits
    return ''.join(secrets.choice(alphabet) for _ in range(length))


class HysteriaManager:
    PROTOCOL = 'hysteria'
    CONTAINER_NAME = 'amnezia-hysteria'
    IMAGE_NAME = 'teddysun/hysteria:latest'
    CERTBOT_IMAGE = 'certbot/certbot:latest'
    BASE_DIR = '/opt/amnezia/hysteria'
    DEFAULT_PORT = 8998

    def __init__(self, ssh, protocol='hysteria'):
        self.ssh = ssh
        self.protocol = protocol or self.PROTOCOL
        self.instance = self._instance_index(self.protocol)
        self.container_name = self._container_name(self.protocol)
        self.base_dir = self._base_dir(self.protocol)
        self.config_path = f'{self.base_dir}/server.yaml'
        self.clients_path = f'{self.base_dir}/clients.json'
        self.meta_path = f'{self.base_dir}/metadata.json'
        self.cert_path = f'{self.base_dir}/cert.crt'
        self.key_path = f'{self.base_dir}/private.key'
        self.letsencrypt_dir = f'{self.base_dir}/letsencrypt'

    def _instance_index(self, protocol=None):
        parts = str(protocol or self.protocol or '').split('__', 1)
        if len(parts) == 2:
            try:
                return max(1, int(parts[1]))
            except ValueError:
                return 1
        return 1

    def _container_name(self, protocol=None):
        idx = self._instance_index(protocol or self.protocol)
        return self.CONTAINER_NAME if idx <= 1 else f'{self.CONTAINER_NAME}-{idx}'

    def _base_dir(self, protocol=None):
        idx = self._instance_index(protocol or self.protocol)
        return self.BASE_DIR if idx <= 1 else f'{self.BASE_DIR}-{idx}'

    # ===================== STATUS =====================

    def check_docker_installed(self):
        out, _, code = self.ssh.run_command("docker --version 2>/dev/null")
        if code != 0:
            return False
        out2, _, _ = self.ssh.run_command(
            "systemctl is-active docker 2>/dev/null || service docker status 2>/dev/null"
        )
        return 'active' in out2 or 'running' in out2.lower()

    def check_protocol_installed(self, protocol_type=None):
        name = self._container_name(protocol_type or self.protocol)
        out, _, _ = self.ssh.run_sudo_command(
            f"docker ps -a --filter name=^{name}$ --format '{{{{.Names}}}}'"
        )
        return name in out.strip().split('\n')

    def check_container_running(self, protocol_type=None):
        name = self._container_name(protocol_type or self.protocol)
        out, _, _ = self.ssh.run_sudo_command(
            f"docker ps --filter name=^{name}$ --format '{{{{.Status}}}}'"
        )
        return 'Up' in out

    def get_server_status(self, protocol_type=None):
        protocol_type = protocol_type or self.protocol
        exists = self.check_protocol_installed(protocol_type)
        running = self.check_container_running(protocol_type)
        meta = self._read_metadata() if exists else {}
        clients = self._read_clients() if exists else []
        return {
            'container_exists': exists,
            'container_running': running,
            'port': int(meta.get('port') or self.DEFAULT_PORT),
            'domain': meta.get('domain'),
            'email': meta.get('email'),
            'clients_count': len(clients),
            'protocol': protocol_type,
            'base_protocol': self.PROTOCOL,
            'instance': self._instance_index(protocol_type),
            'container_name': self._container_name(protocol_type),
        }

    # ===================== HELPERS =====================

    def _validate_domain(self, domain):
        domain = (domain or '').strip().lower()
        if not domain or len(domain) > 253:
            raise ValueError('Domain is required for Hysteria SSL')
        if not re.match(r'^(?!-)[a-z0-9.-]+(?<!-)$', domain) or '.' not in domain:
            raise ValueError('Invalid domain name')
        return domain

    def _validate_email(self, email):
        email = (email or '').strip()
        if not email or '@' not in email:
            raise ValueError("Valid Let's Encrypt email is required")
        return email

    def _read_file(self, path):
        out, _, code = self.ssh.run_sudo_command(f"cat {_q(path)} 2>/dev/null")
        return out if code == 0 else ''

    def _write_file(self, path, content):
        parent = path.rsplit('/', 1)[0]
        self.ssh.run_sudo_command(f"mkdir -p {_q(parent)}")
        self.ssh.upload_file_sudo(content, path)

    def _read_metadata(self):
        raw = self._read_file(self.meta_path)
        if not raw.strip():
            return {}
        try:
            return json.loads(raw)
        except Exception:
            return {}

    def _write_metadata(self, meta):
        self._write_file(self.meta_path, json.dumps(meta, indent=2, ensure_ascii=False))

    def _read_clients(self):
        raw = self._read_file(self.clients_path)
        if not raw.strip():
            return []
        try:
            data = json.loads(raw)
            return data if isinstance(data, list) else []
        except Exception:
            return []

    def _write_clients(self, clients):
        self._write_file(self.clients_path, json.dumps(clients, indent=2, ensure_ascii=False))

    def _build_server_yaml(self, port, clients):
        lines = [
            f'listen: :{int(port)}',
            '',
            'tls:',
            '  cert: /etc/hysteria/cert.crt',
            '  key: /etc/hysteria/private.key',
            '',
            'auth:',
            '  type: userpass',
            '  userpass:',
        ]
        if clients:
            for c in clients:
                user = str(c.get('username') or '').strip()
                pwd = str(c.get('password') or '').strip()
                if user and pwd:
                    # YAML double-quote to allow special chars
                    lines.append(f'    "{user}": "{pwd}"')
        else:
            # Placeholder so Hysteria starts; first real client replaces this
            lines.append(f'    "__bootstrap__": "{_rand_token(24)}"')
        lines.extend([
            '',
            'masquerade:',
            '  type: proxy',
            '  proxy:',
            '    url: https://www.bing.com',
            '    rewriteHost: true',
            '',
        ])
        return '\n'.join(lines)

    def _write_config_from_clients(self, port=None):
        meta = self._read_metadata()
        port = int(port or meta.get('port') or self.DEFAULT_PORT)
        clients = self._read_clients()
        self._write_file(self.config_path, self._build_server_yaml(port, clients))
        return port

    def _reload_container(self):
        name = self.container_name
        if self.check_container_running(self.protocol):
            self.ssh.run_sudo_command(f"docker restart {name}", timeout=60)

    def _issue_certificate(self, domain, email):
        """Issue Let's Encrypt cert via certbot standalone (needs free TCP 80)."""
        self.ssh.run_sudo_command(f"mkdir -p {_q(self.letsencrypt_dir)}")
        self.ssh.run_sudo_command(f"docker pull {self.CERTBOT_IMAGE}", timeout=180)

        # Stop anything briefly occupying 80 if it's our leftover certbot
        self.ssh.run_sudo_command(
            "docker rm -fv amnezia-hysteria-certbot 2>/dev/null || true"
        )

        cmd = (
            f"docker run --rm --name amnezia-hysteria-certbot "
            f"-p 80:80 "
            f"-v {_q(self.letsencrypt_dir)}:/etc/letsencrypt "
            f"{self.CERTBOT_IMAGE} certonly --standalone "
            f"--non-interactive --agree-tos --no-eff-email "
            f"--email {_q(email)} -d {_q(domain)}"
        )
        out, err, code = self.ssh.run_sudo_command(cmd, timeout=300)
        if code != 0:
            raise RuntimeError(
                f"Let's Encrypt failed for {domain}. "
                f"Point A-record to this server and free TCP port 80. {err or out}"
            )

        # Copy live certs into paths expected by teddysun image
        copy_script = f"""
set -e
LIVE={_q(self.letsencrypt_dir)}/live/{_q(domain)}
test -s "$LIVE/fullchain.pem"
test -s "$LIVE/privkey.pem"
cp -f "$LIVE/fullchain.pem" {_q(self.cert_path)}
cp -f "$LIVE/privkey.pem" {_q(self.key_path)}
chmod 644 {_q(self.cert_path)}
chmod 600 {_q(self.key_path)}
"""
        out, err, code = self.ssh.run_sudo_command(f"sh -c {_q(copy_script)}", timeout=30)
        if code != 0:
            raise RuntimeError(f'Failed to install certificate files: {err or out}')

    def _build_share_uri(self, host, port, domain, username, password, name):
        userinfo = f"{quote(username, safe='')}:{quote(password, safe='')}"
        fragment = quote(name or username, safe='')
        sni = domain or host
        conn_host = domain or host
        return (
            f"hysteria2://{userinfo}@{conn_host}:{int(port)}/"
            f"?sni={quote(sni, safe='')}&insecure=0#{fragment}"
        )

    # ===================== INSTALL / REMOVE =====================

    def install_protocol(self, protocol_type=None, port=None, domain=None, email=None):
        protocol_type = protocol_type or self.protocol
        if not self.check_docker_installed():
            return {'status': 'error', 'message': 'Docker not installed'}

        domain = self._validate_domain(domain)
        email = self._validate_email(email)
        port = int(port or self.DEFAULT_PORT)
        if port == 80:
            return {'status': 'error', 'message': 'Port 80 is reserved for Let\'s Encrypt validation'}

        log = []
        self.ssh.run_sudo_command(f"docker pull {self.IMAGE_NAME}", timeout=180)
        log.append(f'Pulled {self.IMAGE_NAME}')

        if self.check_protocol_installed(protocol_type):
            self.remove_container(protocol_type)
            log.append('Removed previous container')

        self.ssh.run_sudo_command(f"mkdir -p {_q(self.base_dir)}")
        self._write_clients([])
        self._write_metadata({
            'domain': domain,
            'email': email,
            'port': port,
        })
        self._write_config_from_clients(port)
        log.append('Prepared config directory')

        try:
            self._issue_certificate(domain, email)
            log.append(f"Issued Let's Encrypt certificate for {domain}")
        except Exception as e:
            return {'status': 'error', 'message': str(e), 'log': log}

        # Map host dir to /etc/hysteria as required by teddysun image
        run_cmd = (
            f"docker run -d --restart always "
            f"--name {self.container_name} "
            f"--cap-add=NET_ADMIN "
            f"-p {port}:{port}/udp "
            f"-v {_q(self.base_dir)}:/etc/hysteria "
            f"{self.IMAGE_NAME}"
        )
        _, err, code = self.ssh.run_sudo_command(run_cmd, timeout=60)
        if code != 0:
            return {'status': 'error', 'message': f'Failed to start Hysteria: {err}', 'log': log}

        log.append(f'Started {self.container_name} on UDP {port}')
        return {
            'status': 'success',
            'message': 'Hysteria installed',
            'log': log,
            'port': str(port),
            'domain': domain,
            'email': email,
        }

    def remove_container(self, protocol_type=None):
        protocol_type = protocol_type or self.protocol
        name = self._container_name(protocol_type)
        base = self._base_dir(protocol_type)
        self.ssh.run_sudo_command(f"docker rm -fv {name} 2>/dev/null || true")
        self.ssh.run_sudo_command(f"rm -rf {_q(base)}")
        return True

    def get_server_config(self, protocol_type=None):
        return self._read_file(self.config_path)

    def save_server_config(self, protocol_type=None, config_text=''):
        self._write_file(self.config_path, config_text or '')
        self._reload_container()
        return True

    # ===================== CLIENTS =====================

    def get_clients(self, protocol_type=None):
        clients = self._read_clients()
        result = []
        for c in clients:
            result.append({
                'clientId': c.get('id'),
                'client_id': c.get('id'),
                'id': c.get('id'),
                'name': c.get('name') or c.get('username'),
                'email': c.get('username'),
                'userData': {'clientName': c.get('name') or c.get('username')},
            })
        return result

    def add_client(self, protocol_type, name, host, port=None):
        meta = self._read_metadata()
        domain = meta.get('domain') or host
        port = int(port or meta.get('port') or self.DEFAULT_PORT)
        client_id = secrets.token_hex(8)
        username = f"u_{client_id}"
        password = _rand_token(20)
        clients = self._read_clients()
        clients.append({
            'id': client_id,
            'name': name or username,
            'username': username,
            'password': password,
            'enabled': True,
        })
        self._write_clients(clients)
        self._write_config_from_clients(port)
        self._reload_container()
        config = self._build_share_uri(host, port, domain, username, password, name or username)
        return {'client_id': client_id, 'config': config}

    def get_client_config(self, protocol_type, client_id, host, port=None):
        meta = self._read_metadata()
        domain = meta.get('domain') or host
        port = int(port or meta.get('port') or self.DEFAULT_PORT)
        clients = self._read_clients()
        client = next((c for c in clients if c.get('id') == client_id), None)
        if not client:
            raise RuntimeError('Client not found')
        return self._build_share_uri(
            host, port, domain,
            client.get('username'), client.get('password'),
            client.get('name') or client.get('username'),
        )

    def remove_client(self, protocol_type, client_id):
        clients = [c for c in self._read_clients() if c.get('id') != client_id]
        self._write_clients(clients)
        self._write_config_from_clients()
        self._reload_container()
        return True

    def toggle_client(self, protocol_type, client_id, enable=True):
        # Soft-disable: remove from yaml but keep in table with enabled=false
        clients = self._read_clients()
        found = False
        for c in clients:
            if c.get('id') == client_id:
                c['enabled'] = bool(enable)
                found = True
                break
        if not found:
            raise RuntimeError('Client not found')
        self._write_clients(clients)
        # Rebuild yaml with only enabled clients
        active = [c for c in clients if c.get('enabled', True)]
        meta = self._read_metadata()
        port = int(meta.get('port') or self.DEFAULT_PORT)
        self._write_file(self.config_path, self._build_server_yaml(port, active))
        self._reload_container()
        return True