"""Nginx daemon handler."""

import logging
import os
from copy import deepcopy
from pathlib import Path
from typing import Any

from jinja2 import Environment, FileSystemLoader

from daemon.iface import (
    DELETE_NGINX_DOMAINS_REMOVE,
    GET_NGINX_CONFIG,
    GET_NGINX_DOMAINS,
    PATCH_NGINX_CONFIG,
    POST_NGINX_APPLY,
    POST_NGINX_CONFIG,
    POST_NGINX_DOMAINS_ADD,
    POST_NGINX_DOMAINS_UPDATE,
    POST_NGINX_RELOAD,
    POST_NGINX_SSL_APPLY,
    POST_NGINX_TEST,
)
from daemon.server import NotFoundError, refresh_state, registry
from lib.acme import find_cert_dir
from lib.common import ensure_dirs, load_json, run, run_proc, save_json

logger = logging.getLogger(__name__)

PROJECT_DIR = Path(__file__).resolve().parent.parent.parent
CONFIG_DIR = PROJECT_DIR / "config" / "nginx"
DATA_DIR = PROJECT_DIR / "data" / "nginx"
SITES_DIR = DATA_DIR / "sites-enabled"
CONFIG_FILE = CONFIG_DIR / "config.json"
INCLUDE_FILE = Path("/etc/nginx/conf.d/vacuum-wall.conf")
SSL_SNIPPET = Path("/etc/nginx/snippets/vacuum-wall-ssl.conf")
HTPASSWD_FILE = DATA_DIR / ".htpasswd"

ENV = Environment(
    loader=FileSystemLoader(str(PROJECT_DIR / "system")),
    autoescape=False,
    lstrip_blocks=True,
    trim_blocks=True,
)

DEFAULT_SSL: dict[str, Any] = {
    "protocols": "TLSv1.2 TLSv1.3",
    "ciphers": (
        "ECDHE-ECDSA-AES128-GCM-SHA256:"
        "ECDHE-RSA-AES128-GCM-SHA256:"
        "ECDHE-ECDSA-AES256-GCM-SHA384:"
        "ECDHE-RSA-AES256-GCM-SHA384:"
        "ECDHE-ECDSA-CHACHA20-POLY1305:"
        "ECDHE-RSA-CHACHA20-POLY1305"
    ),
    "prefer_server_ciphers": False,
}

DEFAULT_CONFIG: dict[str, Any] = {
    "domains": {},
    "ssl": {**DEFAULT_SSL},
}


def _migrate_config(raw: dict[str, Any]) -> dict[str, Any]:
    """Migrate legacy config formats to the new paths-based model."""
    if "management" in raw and raw["management"] is not None:
        mgmt = raw["management"]
        mgmt_domain = mgmt.get("domain", "")
        if mgmt_domain:
            domains = raw.setdefault("domains", {})
            if mgmt_domain not in domains:
                domains[mgmt_domain] = {
                    "force_ssl": True,
                    "paths": {},
                }
            dom = domains[mgmt_domain]
            paths = dom.setdefault("paths", {})
            if "/" not in paths:
                paths["/"] = {
                    "backend": {
                        "host": mgmt.get("backend", {}).get("host", "127.0.0.1"),
                        "port": mgmt.get("backend", {}).get("port", 9090),
                        "proto": "http",
                    },
                    "is_management": True,
                }
                if mgmt.get("auth"):
                    paths["/"]["auth"] = mgmt["auth"]
            if "/ws" not in paths:
                paths["/ws"] = {
                    "backend": {"host": "127.0.0.1", "port": 9091, "proto": "http"},
                    "is_websocket": True,
                }
        del raw["management"]

    for dom in raw.get("domains", {}).values():
        if "paths" not in dom and "backend" in dom:
            dom["paths"] = {
                "/": {
                    "backend": dom.pop("backend"),
                    "headers": dom.pop("headers", {}),
                }
            }
    return raw


def _get_state() -> dict[str, Any] | None:
    """Retrieve cached nginx state from the state store."""
    from lib.state import state as state_store

    return state_store.get("nginx")


def _get_config() -> dict[str, Any]:
    """Load the nginx config JSON, applying defaults and migrations."""
    ensure_dirs(CONFIG_DIR, SITES_DIR)
    raw = load_json(CONFIG_FILE)
    if not raw:
        raw = deepcopy(DEFAULT_CONFIG)
    if "ssl" not in raw:
        raw["ssl"] = deepcopy(DEFAULT_SSL)
    raw = _migrate_config(raw)
    _save_config(raw)
    return raw


def _save_config(cfg: dict[str, Any]) -> None:
    """Persist the nginx config dict to disk."""
    save_json(CONFIG_FILE, cfg)


def _generate_server_conf(domain_cfg: dict[str, Any]) -> str:
    """Render an nginx server block config from a domain entry via Jinja."""
    tmpl = ENV.get_template("nginx/server_block.conf")
    acme_home_path = PROJECT_DIR / "data" / "acme"
    acme_cert_dir = str(find_cert_dir(domain_cfg["domain"], acme_home_path))
    paths = domain_cfg.get("paths", {})
    has_management = any(p.get("is_management") for p in paths.values())
    # Resolve custom cert paths for cert=="file"
    cert_cfg = domain_cfg.get("cert")
    if isinstance(cert_cfg, dict):
        cert_path = cert_cfg.get("cert_path", "")
        cert_key_path = cert_cfg.get("cert_key_path", "")
    else:
        cert_path = domain_cfg.get("cert_path", "")
        cert_key_path = domain_cfg.get("cert_key_path", "")
    return tmpl.render(
        domain=domain_cfg["domain"],
        paths=paths,
        force_ssl=domain_cfg.get("force_ssl", True),
        cert=domain_cfg.get("cert"),
        cert_path=cert_path,
        cert_key_path=cert_key_path,
        domain_auth=domain_cfg.get("auth"),
        has_management=has_management,
        acme_cert_dir=acme_cert_dir,
        certs_dir=str(PROJECT_DIR / "data" / "certs"),
        acme_webroot=str(PROJECT_DIR / "data" / "acme" / "www"),
    )


def _write_site(domain: str, conf_text: str) -> None:
    """Atomically write a single site config file into sites-enabled."""
    ensure_dirs(SITES_DIR)
    path = SITES_DIR / f"{domain}.conf"
    tmp = path.with_suffix(".tmp")
    with open(tmp, "w") as f:
        f.write(conf_text)
        f.write("\n")
    os.chmod(tmp, 0o644)
    os.replace(tmp, path)


def _write_include_file() -> None:
    """Write the system include file that references all per-site configs."""
    tmpl = ENV.get_template("nginx/include.conf")
    content = tmpl.render(sites_glob=str(SITES_DIR / "*.conf"))
    tmp = Path("/tmp") / "vacuum-wall-include.tmp"
    with open(tmp, "w") as f:
        f.write(content)
    os.chmod(tmp, 0o644)
    run(["cp", str(tmp), str(INCLUDE_FILE)], sudo=True)
    run(["chown", "root:root", str(INCLUDE_FILE)], sudo=True)
    tmp.unlink(missing_ok=True)


def _write_ssl_snippet() -> None:
    """Render and install the shared SSL snippet to /etc/nginx/snippets/."""
    cfg = _get_config()
    ssl_cfg = cfg.get("ssl", {})
    ssl_cfg.setdefault("prefer_server_ciphers", DEFAULT_SSL["prefer_server_ciphers"])
    ssl_cfg.setdefault("protocols", DEFAULT_SSL["protocols"])
    ssl_cfg.setdefault("ciphers", DEFAULT_SSL["ciphers"])
    tmpl = ENV.get_template("nginx/ssl_snippet.conf")
    content = tmpl.render(ssl=ssl_cfg)
    tmp = Path("/tmp") / "vacuum-wall-ssl-snippet.tmp"
    with open(tmp, "w") as f:
        f.write(content)
    os.chmod(tmp, 0o644)
    run(["cp", str(tmp), str(SSL_SNIPPET)], sudo=True)
    run(["chown", "root:root", str(SSL_SNIPPET)], sudo=True)
    tmp.unlink(missing_ok=True)


def _test_config() -> tuple[bool, str]:
    """Run `nginx -t` to validate the current config."""
    result = run_proc(["nginx", "-t"], sudo=True, check=False)
    ok = result.returncode == 0
    output = (result.stderr or result.stdout or "").strip()
    if not output and ok:
        output = "nginx configuration test passed"
    return ok, output


def _reload_nginx() -> None:
    """Send SIGHUP to nginx to reload its configuration."""
    result = run_proc(["nginx", "-s", "reload"], sudo=True, check=False)
    if result.returncode != 0:
        logger.error("nginx reload failed: %s", result.stderr.strip())
    else:
        logger.info("nginx configuration applied and reloaded")


def _write_all_sites() -> None:
    """Regenerate all site configs and ACME challenge site."""
    ensure_dirs(SITES_DIR)
    cfg = _get_config()
    existing = set(SITES_DIR.iterdir()) if SITES_DIR.exists() else set()
    written: set[str] = set()
    for name, dom in cfg.get("domains", {}).items():
        dom_copy = dict(dom, domain=name)
        conf = _generate_server_conf(dom_copy)
        _write_site(name, conf)
        written.add(f"{name}.conf")

    old_mgmt = SITES_DIR / "management.conf"
    if old_mgmt.exists() and old_mgmt.name not in written:
        old_mgmt.unlink()

    for old in existing:
        if old.suffix == ".conf" and old.name not in written:
            old.unlink()
    tmpl = ENV.get_template("nginx/acme-challenge.conf")
    acme_content = tmpl.render(acme_webroot=str(PROJECT_DIR / "data" / "acme" / "www"))
    site = SITES_DIR / "_acme-challenge.conf"
    tmp = site.with_suffix(".tmp")
    with open(tmp, "w") as f:
        f.write(acme_content)
        f.write("\n")
    os.chmod(tmp, 0o644)
    os.replace(tmp, site)


def _hash_password(password: str) -> str:
    """Hash *password* using SHA-256 crypt via passlib."""
    from passlib.hash import sha256_crypt

    return sha256_crypt.hash(password)


def _write_htpasswd(user: str, password: str) -> None:
    """Add or update a user entry in the .htpasswd file using SHA-256 hashing."""
    ensure_dirs(DATA_DIR)
    hashed = _hash_password(password)
    existing: dict[str, str] = {}
    if HTPASSWD_FILE.exists():
        with open(HTPASSWD_FILE) as f:
            for line in f:
                line = line.strip()
                if not line or line.startswith("#"):
                    continue
                parts = line.split(":", 1)
                if len(parts) == 2:
                    existing[parts[0]] = line
    existing[user] = f"{user}:{hashed}"
    tmp = HTPASSWD_FILE.with_suffix(".tmp")
    with open(tmp, "w") as f:
        for _uname, entry in existing.items():
            f.write(entry + "\n")
    os.chmod(tmp, 0o640)
    os.replace(tmp, HTPASSWD_FILE)


def _get_nginx_state() -> dict[str, Any]:
    """Return a shallow copy of the cached nginx state, or empty dict if unset."""
    ng = _get_state()
    if ng is None:
        return {}
    return ng


# ---------------------------------------------------------------------------
# Routes


@registry.register(GET_NGINX_CONFIG)
def get_config(_request: Any, _body: Any) -> dict[str, Any]:
    """GET /nginx/config — return current nginx config."""
    ng = _get_nginx_state()
    if ng:
        return ng.get("config", {})
    return _get_config()


@registry.register(POST_NGINX_CONFIG)
def save_config_handler(_request: Any, body: dict[str, Any] | None) -> dict[str, Any]:
    """POST /nginx/config — replace the entire nginx config and refresh state."""
    if not body:
        raise ValueError("Request body required")
    _save_config(body)
    refresh_state(["nginx"])
    return {"config_saved": True}


@registry.register(PATCH_NGINX_CONFIG)
def patch_config(_request: Any, body: dict[str, Any] | None) -> dict[str, Any]:
    """PATCH /nginx/config — deep-merge partial updates into current config."""
    if not body:
        raise ValueError("Request body required")
    from lib.common import deep_merge

    current = _get_config()
    merged = deep_merge(current, body)
    _save_config(merged)
    refresh_state(["nginx"])
    return {"config_saved": True}


@registry.register(GET_NGINX_DOMAINS)
def get_domains(_request: Any, _body: Any) -> list[dict[str, Any]]:
    """GET /nginx/domains — return the list of configured proxy domains."""
    ng = _get_nginx_state()
    if ng:
        return ng.get("domains", [])
    return []


@registry.register(POST_NGINX_DOMAINS_ADD)
def add_domain(_request: Any, body: dict[str, Any] | None) -> dict[str, Any]:
    """POST /nginx/domains/add — add a new reverse-proxy domain entry.

    Accepts either legacy backend_* fields or a ``paths`` map.
    """
    if not body:
        raise ValueError("Request body required")
    domain = body.get("domain", "").strip()
    if not domain:
        raise ValueError("'domain' is required")
    cfg = _get_config()
    if domain in cfg["domains"]:
        raise ValueError(f"Domain {domain!r} already configured")

    paths = body.get("paths")
    cert = body.get("cert")
    force_ssl = body.get("force_ssl", True)

    if paths is not None:
        entry: dict[str, Any] = {
            "paths": paths,
            "force_ssl": force_ssl,
        }
        if cert is not None:
            entry["cert"] = cert
    else:
        backend_host = body.get("backend_host", "").strip()
        backend_port = body.get("backend_port")
        backend_proto = body.get("backend_proto", "http").strip() or "http"
        extra_headers = body.get("extra_headers")
        if not backend_host:
            raise ValueError("'backend_host' is required")
        if backend_port is None:
            raise ValueError("'backend_port' is required")
        entry = {
            "paths": {
                "/": {
                    "backend": {
                        "host": backend_host,
                        "port": int(backend_port),
                        "proto": backend_proto,
                    },
                    "headers": extra_headers or {},
                }
            },
            "force_ssl": force_ssl,
        }
        if cert is not None:
            entry["cert"] = cert

    # Handle auth credentials for management domain
    auth_user = body.get("auth_user", "").strip()
    auth_pass = body.get("auth_pass", "")
    if auth_user and auth_pass:
        _write_htpasswd(auth_user, auth_pass)
        auth_dict = {"user": auth_user, "htpasswd": str(HTPASSWD_FILE)}
        paths_entry = entry.get("paths", {})
        for _ppath, pcfg in paths_entry.items():
            if pcfg.get("is_management"):
                pcfg["auth"] = auth_dict
                break
        entry["auth"] = auth_dict

    # Handle auth credentials for management paths
    auth_user = body.get("auth_user", "").strip()
    auth_pass = body.get("auth_pass", "").strip()
    if auth_user and auth_pass:
        _write_htpasswd(auth_user, auth_pass)
        auth_entry = {
            "user": auth_user,
            "htpasswd": str(HTPASSWD_FILE),
        }
        # Store auth on root path if it exists
        root_path = entry.get("paths", {}).get("/")
        if root_path:
            root_path["auth"] = auth_entry
        # Also store at domain level for template
        entry["auth"] = auth_entry

    cfg["domains"][domain] = entry
    _save_config(cfg)
    refresh_state(["nginx"])
    return {"domain": domain}


@registry.register(DELETE_NGINX_DOMAINS_REMOVE)
def remove_domain(_request: Any, body: dict[str, Any] | None) -> dict[str, Any]:
    """DELETE /nginx/domains/remove — remove a domain from the proxy config."""
    if not body:
        raise ValueError("Request body required")
    domain = body.get("domain", "").strip()
    if not domain:
        raise ValueError("'domain' is required")
    cfg = _get_config()
    if domain not in cfg["domains"]:
        raise NotFoundError(f"Domain {domain!r} not found")
    del cfg["domains"][domain]
    _save_config(cfg)
    site = SITES_DIR / f"{domain}.conf"
    if site.exists():
        site.unlink()
    refresh_state(["nginx"])
    return {"domain": domain}


@registry.register(POST_NGINX_DOMAINS_UPDATE)
def update_domain(_request: Any, body: dict[str, Any] | None) -> dict[str, Any]:
    """POST /nginx/domains/update — patch fields of an existing domain entry."""
    if not body:
        raise ValueError("Request body required")
    domain = body.get("domain", "").strip()
    if not domain:
        raise ValueError("'domain' is required")
    cfg = _get_config()
    if domain not in cfg["domains"]:
        raise NotFoundError(f"Domain {domain!r} not configured")
    entry = cfg["domains"][domain]

    # Path removal: if body has `path` key (string) but no `paths`/`backend`/`headers`
    path_to_remove = body.get("path")
    if (
        path_to_remove is not None
        and "paths" not in body
        and "backend" not in body
        and "headers" not in body
    ):
        paths = entry.get("paths", {})
        if path_to_remove in paths:
            del paths[path_to_remove]
            if not paths:
                entry.pop("paths", None)
        _save_config(cfg)
        refresh_state(["nginx"])
        return {"domain": domain, "path_removed": path_to_remove}

    updates = {k: v for k, v in body.items() if k not in ("domain", "path")}

    if "paths" in updates:
        entry["paths"] = updates["paths"]
    else:
        paths = entry.setdefault("paths", {})
        if "backend" in updates:
            root = paths.setdefault("/", {"backend": {}, "headers": {}})
            root["backend"] = updates["backend"]
        if "headers" in updates:
            root = paths.setdefault("/", {"backend": {}, "headers": {}})
            root["headers"] = updates["headers"]

    for key, val in updates.items():
        if key in ("backend", "headers", "paths"):
            continue
        if isinstance(val, dict) and key in entry:
            entry[key].update(val)
        else:
            entry[key] = val
    _save_config(cfg)
    refresh_state(["nginx"])
    return {"domain": domain}


@registry.register(POST_NGINX_APPLY)
def apply(_request: Any, _body: Any) -> dict[str, Any]:
    """POST /nginx/apply — render all configs, test, and reload nginx."""
    _write_ssl_snippet()
    _write_all_sites()
    _write_include_file()
    ok, msg = _test_config()
    if not ok:
        raise RuntimeError(f"nginx config test failed: {msg}")
    _reload_nginx()
    refresh_state(["nginx"])
    return {"applied": True}


@registry.register(POST_NGINX_TEST)
def test(_request: Any, _body: Any) -> dict[str, Any]:
    """POST /nginx/test — dry-run validate the live nginx config without applying."""
    valid, output = _test_config()
    return {"valid": valid, "output": output}


@registry.register(POST_NGINX_SSL_APPLY)
def ssl_apply(_request: Any, _body: Any) -> dict[str, Any]:
    """POST /nginx/ssl-apply — re-render and install only the SSL snippet."""
    _write_ssl_snippet()
    refresh_state(["nginx"])
    return {"applied": True}


@registry.register(POST_NGINX_RELOAD)
def reload_nginx(_request: Any, _body: Any) -> dict[str, Any]:
    """POST /nginx/reload — trigger an nginx reload (SIGHUP)."""
    _reload_nginx()
    return {"reloaded": True}