from __future__ import annotations

import copy
import glob
import os
import threading
from collections import OrderedDict
from pathlib import Path
from typing import Any, Mapping, Optional
from urllib.parse import urlparse

import yaml

from plugins.filter.merge_with_defaults import merge_with_defaults
from plugins.lookup.application_gid import LookupModule as ApplicationGidLookup
from utils.templating import _templar_render_best_effort

try:
    from ansible.parsing.vault import EncryptedString as _AnsibleEncryptedString
except Exception:
    _AnsibleEncryptedString = None


def _decrypt_ansible_encrypted_strings(value: Any) -> Any:
    """Recursively convert Ansible EncryptedString values to plaintext str.

    Ansible 2.19+ refuses to store EncryptedString as an intermediate variable
    during task arg finalization, so decrypt at the lookup boundary.
    """
    if _AnsibleEncryptedString is not None and isinstance(
        value, _AnsibleEncryptedString
    ):
        try:
            return str(value)
        except Exception:
            return value
    if isinstance(value, Mapping):
        return {k: _decrypt_ansible_encrypted_strings(v) for k, v in value.items()}
    if isinstance(value, list):
        return [_decrypt_ansible_encrypted_strings(v) for v in value]
    if isinstance(value, tuple):
        return tuple(_decrypt_ansible_encrypted_strings(v) for v in value)
    return value


PROJECT_ROOT = Path(__file__).resolve().parents[1]
ROLES_DIR = PROJECT_ROOT / "roles"
DEFAULT_TOKENS_FILE = Path("/var/lib/infinito/secrets/tokens.yml")

_APPLICATIONS_DEFAULTS_CACHE: dict[str, dict[str, Any]] = {}
_USERS_DEFAULTS_CACHE: dict[str, dict[str, Any]] = {}

# Single-slot rendered caches. lookup('config'), lookup('applications') and
# lookup('users') are called many times per play (sanity checks, env.j2, etc.).
# With Ansible 2.19+ trust-tagging actually firing templar rendering, rebuilding
# the merged+rendered payload each call dominates runtime. We cache the
# rendered result keyed on (roles_dir_str, _stable_variables_signature(...)).
# The signature uses id() of applications/users sub-dicts (stable across tasks
# unless a set_fact replaces them) plus DOMAIN_PRIMARY/SYSTEM_EMAIL_DOMAIN
# string values. templar is NOT in the key: rendering is a pure function of
# input+variables; the templar instance is churned per-task by Ansible.
_MERGED_APPLICATIONS_CACHE: dict[tuple, dict[str, Any]] = {}
_MERGED_USERS_CACHE: dict[tuple, dict[str, Any]] = {}
_MERGED_DOMAINS_CACHE: dict[tuple, dict[str, Any]] = {}

# Re-entry guards. Cross-lookups ({{ lookup('users', ...) }} inside applications
# and vice versa) can otherwise drive unbounded recursion once strings are
# trust-tagged and actually rendered (Ansible 2.19+). When a re-entrant call is
# detected, callers return the pre-render (still-templated) payload, which the
# caller's own templar will resolve lazily at use-site.
_RENDER_GUARD = threading.local()


def _cache_key(roles_dir: Path) -> str:
    return str(roles_dir.resolve())


_FINGERPRINT_BY_ID: "dict[int, str]" = {}


def _fingerprint_mapping(obj: Any) -> str:
    """Cheap-ish content fingerprint for cache keying.

    Ansible 2.19+ composes a fresh `variables` mapping per task via
    VariableManager.get_vars() and — empirically — often reconstructs the
    inventory-level `applications`/`users` dicts too, so keying on `id(obj)`
    misses the cache across tasks. A content fingerprint hits across tasks
    whenever the inventory payload is unchanged.

    Fast path: id()-keyed memo (within a single task the same dict instance is
    typically reused for multiple lookups, so we avoid re-hashing).
    Slow path: repr-based MD5. Non-mapping values collapse to an "id:..." tag
    so we don't accidentally collide across unrelated types.
    """
    if obj is None:
        return "0"
    obj_id = id(obj)
    cached = _FINGERPRINT_BY_ID.get(obj_id)
    if cached is not None:
        return cached
    try:
        import hashlib

        data = repr(sorted(obj.items())) if isinstance(obj, Mapping) else repr(obj)
        digest = hashlib.md5(data.encode("utf-8", errors="replace")).hexdigest()
    except Exception:
        digest = f"id:{obj_id}"
    _FINGERPRINT_BY_ID[obj_id] = digest
    return digest


def _stable_variables_signature(variables: Optional[Mapping[str, Any]]) -> tuple:
    """Build a content-based cache signature from the subset of `variables`
    that influences the merged applications/users payload.

    See `_fingerprint_mapping` for why id()-only keys don't work reliably.
    """
    if not variables:
        return ("0", "0", "", "")
    return (
        _fingerprint_mapping(variables.get("applications")),
        _fingerprint_mapping(variables.get("users")),
        str(variables.get("DOMAIN_PRIMARY") or ""),
        str(variables.get("SYSTEM_EMAIL_DOMAIN") or ""),
    )


def _tokens_file_signature(path: Path) -> tuple:
    """Return a cheap stat-based signature for the tokens file.

    The merged-users cache must invalidate whenever sys-token-store persists a
    new token — otherwise downstream `lookup('users', ...)` returns stale tokens
    within the same play. stat() is cheap and captures in-place writes.
    """
    try:
        st = path.stat()
    except (FileNotFoundError, OSError):
        return (str(path), 0, 0)
    return (str(path), st.st_mtime_ns, st.st_size)


def _load_yaml_mapping(path: Path) -> dict[str, Any]:
    if not path.exists():
        return {}

    data = yaml.safe_load(path.read_text(encoding="utf-8")) or {}
    if not isinstance(data, dict):
        raise ValueError(f"{path} must contain a YAML mapping")
    return data


def _deep_merge(base: Any, override: Any) -> Any:
    if isinstance(base, Mapping) and isinstance(override, Mapping):
        merged = {k: copy.deepcopy(v) for k, v in base.items()}
        for key, value in override.items():
            merged[key] = _deep_merge(merged.get(key), value)
        return merged
    return copy.deepcopy(override)


def _merge_users(
    defaults: Mapping[str, Any],
    overrides: Optional[Mapping[str, Any]],
) -> dict[str, Any]:
    merged = {key: copy.deepcopy(value) for key, value in defaults.items()}
    for key, value in (overrides or {}).items():
        merged[key] = _deep_merge(merged.get(key, {}), value)
    return merged


def _resolve_roles_dir(*, roles_dir: Optional[str | os.PathLike[str]] = None) -> Path:
    return Path(roles_dir).resolve() if roles_dir else ROLES_DIR.resolve()


def _compute_reserved_usernames(roles_dir: Path) -> list[str]:
    reserved: set[str] = set()
    for role_dir in roles_dir.iterdir():
        if not role_dir.is_dir():
            continue
        candidate = role_dir.name.rsplit("-", 1)[-1]
        if candidate.isalnum() and candidate.islower():
            reserved.add(candidate)
    return sorted(reserved)


def _load_user_defs(roles_dir: Path) -> OrderedDict[str, dict[str, Any]]:
    pattern = os.path.join(str(roles_dir), "*/users/main.yml")
    files = sorted(glob.glob(pattern))
    merged: OrderedDict[str, dict[str, Any]] = OrderedDict()

    for filepath in files:
        data = _load_yaml_mapping(Path(filepath))
        users = data.get("users", {})
        if not isinstance(users, dict):
            continue

        for key, overrides in users.items():
            if not isinstance(overrides, dict):
                raise ValueError(f"Invalid definition for user '{key}' in {filepath}")

            if key not in merged:
                merged[key] = copy.deepcopy(overrides)
                continue

            existing = merged[key]
            for field, value in overrides.items():
                if field in existing and existing[field] != value:
                    raise ValueError(
                        f"Conflict for user '{key}': field '{field}' has existing value "
                        f"'{existing[field]}', tried to set '{value}' in {filepath}"
                    )
            existing.update(copy.deepcopy(overrides))

    return merged


def _build_users(
    defs: OrderedDict[str, dict[str, Any]],
    primary_domain: str,
    start_id: int,
    become_pwd: str,
) -> OrderedDict[str, dict[str, Any]]:
    users: OrderedDict[str, dict[str, Any]] = OrderedDict()
    used_uids = set()

    for key, overrides in defs.items():
        if "uid" in overrides:
            uid = overrides["uid"]
            if uid in used_uids:
                raise ValueError(f"Duplicate uid {uid} for user '{key}'")
            used_uids.add(uid)

    next_uid = start_id

    def allocate_uid() -> int:
        nonlocal next_uid
        while next_uid in used_uids:
            next_uid += 1
        free_uid = next_uid
        used_uids.add(free_uid)
        next_uid += 1
        return free_uid

    for key, overrides in defs.items():
        username = overrides.get("username", key)
        firstname = overrides.get("firstname", f"{username}")
        lastname = overrides.get("lastname", f"{primary_domain}")
        email = overrides.get("email", f"{username}@{primary_domain}")
        description = overrides.get(
            "description", f"Created by Infinito.Nexus Ansible for {primary_domain}"
        )
        roles = overrides.get("roles", [])
        password = overrides.get("password", become_pwd)
        reserved = overrides.get("reserved", False)
        tokens = overrides.get("tokens", {})
        authorized_keys = overrides.get("authorized_keys", [])

        uid = overrides["uid"] if "uid" in overrides else allocate_uid()
        gid = overrides.get("gid", uid)

        users[key] = {
            "username": username,
            "firstname": firstname,
            "lastname": lastname,
            "email": email,
            "password": password,
            "uid": uid,
            "gid": gid,
            "roles": roles,
            "tokens": tokens,
            "authorized_keys": authorized_keys,
            "reserved": reserved,
            "description": description,
        }

    seen_usernames: set[str] = set()
    seen_emails: set[str] = set()
    for key, entry in users.items():
        username = entry["username"]
        email = entry["email"]
        if username in seen_usernames:
            raise ValueError(f"Duplicate username '{username}' in merged users")
        if email in seen_emails:
            raise ValueError(f"Duplicate email '{email}' in merged users")
        seen_usernames.add(username)
        seen_emails.add(email)

    return users


def _load_store_users(file_tokens: Optional[str | os.PathLike[str]]) -> dict[str, Any]:
    if not file_tokens:
        return {}

    path = Path(file_tokens)
    if not path.exists():
        return {}

    data = yaml.safe_load(path.read_text(encoding="utf-8")) or {}
    if not isinstance(data, dict):
        return {}

    users = data.get("users", {})
    return users if isinstance(users, dict) else {}


def _resolve_tokens_file(variables: Optional[Mapping[str, Any]]) -> Path:
    candidates: list[Path] = []

    def _add_candidate(value: Any) -> None:
        if value is None:
            return
        text = str(value).strip()
        if text:
            candidates.append(Path(text))

    variables = variables or {}
    _add_candidate(variables.get("FILE_TOKENS"))

    dir_secrets = variables.get("DIR_SECRETS")
    if dir_secrets:
        _add_candidate(Path(str(dir_secrets)) / "tokens.yml")

    dir_var_lib = variables.get("DIR_VAR_LIB")
    if dir_var_lib:
        _add_candidate(Path(str(dir_var_lib)) / "secrets" / "tokens.yml")

    _add_candidate(os.environ.get("FILE_TOKENS"))

    env_dir_secrets = os.environ.get("DIR_SECRETS")
    if env_dir_secrets:
        _add_candidate(Path(env_dir_secrets) / "tokens.yml")

    env_dir_var_lib = os.environ.get("DIR_VAR_LIB")
    if env_dir_var_lib:
        _add_candidate(Path(env_dir_var_lib) / "secrets" / "tokens.yml")

    candidates.append(DEFAULT_TOKENS_FILE)

    seen: set[Path] = set()
    for candidate in candidates:
        if candidate in seen:
            continue
        seen.add(candidate)
        if candidate.exists():
            return candidate

    return candidates[0]


def _hydrate_users_tokens(
    users: Optional[Mapping[str, Any]],
    store_users: Optional[Mapping[str, Any]],
) -> dict[str, Any]:
    def _as_stripped(value: Any) -> Optional[str]:
        if value is None:
            return None
        return str(value).strip()

    def _is_effectively_empty(value: Any) -> bool:
        stripped = _as_stripped(value)
        return stripped is None or stripped == ""

    out: dict[str, Any] = copy.deepcopy(dict(users or {}))
    if not store_users:
        return out

    for user_key, user_data in store_users.items():
        if not isinstance(user_data, Mapping):
            continue
        store_tokens = user_data.get("tokens", {})
        if not isinstance(store_tokens, Mapping):
            continue

        out_user = copy.deepcopy(dict(out.get(user_key, {}) or {}))
        out_tokens = copy.deepcopy(dict(out_user.get("tokens", {}) or {}))

        for app_id, store_token in store_tokens.items():
            token = _as_stripped(store_token)
            if token is None or token == "":
                continue
            if _is_effectively_empty(out_tokens.get(app_id)):
                out_tokens[app_id] = token

        out_user["tokens"] = out_tokens
        out[user_key] = out_user

    return out


def _materialize_builtin_user_aliases(
    users: Optional[Mapping[str, Any]],
    variables: Optional[Mapping[str, Any]],
    templar: Any = None,
) -> dict[str, Any]:
    def _normalize_domain_candidate(value: Any) -> str:
        text = str(value or "").strip()
        if not text:
            return ""
        if ("{{" in text or "{%" in text) and variables:
            text = str(
                _templar_render_best_effort(templar, text, dict(variables))
            ).strip()
        if "://" in text:
            parsed = urlparse(text)
            text = parsed.hostname or text
        text = text.split("/", 1)[0].split(":", 1)[0].strip()
        return text

    def _to_primary_domain(value: Any) -> str:
        text = _normalize_domain_candidate(value)
        if not text:
            return ""
        labels = [label for label in text.split(".") if label]
        if len(labels) >= 2:
            return ".".join(labels[-2:])
        return text

    out: dict[str, Any] = copy.deepcopy(dict(users or {}))
    variables = variables or {}

    primary_domain = ""
    for candidate_key, extractor in (
        ("DOMAIN_PRIMARY", _normalize_domain_candidate),
        ("SYSTEM_EMAIL_DOMAIN", _normalize_domain_candidate),
        ("KEYCLOAK_DOMAIN", _to_primary_domain),
        ("domain", _to_primary_domain),
    ):
        primary_domain = extractor(variables.get(candidate_key))
        if primary_domain:
            break
    if not primary_domain:
        return out

    labels = [label for label in primary_domain.split(".") if label]
    alias_values = {
        "sld": labels[0] if labels else primary_domain,
        "tld": (labels[1] if len(labels) > 1 else (primary_domain + "_tld ")),
    }

    for alias_key, alias_value in alias_values.items():
        raw_user = out.get(alias_key)
        if not isinstance(raw_user, Mapping):
            continue

        raw_username = str(raw_user.get("username", ""))
        if "DOMAIN_PRIMARY.split" not in raw_username:
            continue

        updated_user = copy.deepcopy(dict(raw_user))
        updated_user["username"] = alias_value
        out[alias_key] = updated_user

    return out


def _resolve_override_mapping(
    variables: Optional[Mapping[str, Any]],
    key: str,
    templar: Any = None,
) -> dict[str, Any]:
    """Return runtime override mappings defensively.

    Nested `lookup('template', ...)` renders sometimes expose top-level lookup
    inputs like `applications`/`users` as non-mapping placeholder values instead
    of the original inventory overrides. Try to coerce via templar before
    falling back to aggregated defaults.
    """

    variables = variables or {}
    value = variables.get(key, {})
    if value is None:
        value = {}
    if not isinstance(value, Mapping) and templar is not None:
        try:
            rendered = templar.template(value, fail_on_undefined=False)
        except TypeError:
            try:
                rendered = templar.template(value)
            except Exception:
                rendered = value
        except Exception:
            rendered = value
        if isinstance(rendered, Mapping):
            value = rendered
    if not isinstance(value, Mapping):
        raw_key = {
            "applications": "_INFINITO_APPLICATIONS_RAW",
            "users": "_INFINITO_USERS_RAW",
        }.get(key)
        if raw_key:
            raw = variables.get(raw_key)
            if isinstance(raw, Mapping):
                value = raw
    if isinstance(value, Mapping):
        return dict(value)
    return {}


def _render_with_templar(
    value: Any,
    *,
    templar: Any,
    variables: Optional[dict[str, Any]],
    raw_applications: Optional[dict[str, Any]] = None,
    raw_users: Optional[dict[str, Any]] = None,
    max_rounds: int = 4,
) -> Any:
    if templar is None:
        return value

    # Start from whatever the templar already had available so that
    # ansible_facts/hostvars stay accessible during nested renders. Overlay the
    # caller-supplied variables on top, then inject our raw.*_RAW helpers.
    prev_templar_avail = getattr(templar, "available_variables", None)
    base_variables: dict[str, Any] = (
        dict(prev_templar_avail) if prev_templar_avail else {}
    )
    if variables:
        base_variables.update(variables)
    if raw_applications is not None:
        base_variables["_INFINITO_APPLICATIONS_RAW"] = raw_applications
    if raw_users is not None:
        base_variables["_INFINITO_USERS_RAW"] = raw_users

    def _render_scalar(raw: Any) -> Any:
        if isinstance(raw, str) and "{{" not in raw and "{%" not in raw:
            return raw
        data = copy.deepcopy(raw)
        if isinstance(data, str):
            for _ in range(max_rounds):
                try:
                    rendered = _templar_render_best_effort(
                        templar, data, base_variables
                    )
                except Exception:
                    return data
                if rendered == data:
                    break
                data = rendered
            return data

        for _ in range(max_rounds):
            try:
                rendered = templar.template(data, fail_on_undefined=False)
            except TypeError:
                rendered = templar.template(data)
            except Exception:
                return data
            if rendered == data:
                break
            data = rendered
        return data

    def _render_deep(raw: Any) -> Any:
        if isinstance(raw, Mapping):
            return {key: _render_deep(item) for key, item in raw.items()}
        if isinstance(raw, list):
            return [_render_deep(item) for item in raw]
        if isinstance(raw, tuple):
            return tuple(_render_deep(item) for item in raw)
        return _render_scalar(raw)

    try:
        if hasattr(templar, "available_variables"):
            templar.available_variables = base_variables
        data = _render_deep(value)
    finally:
        if hasattr(templar, "available_variables"):
            templar.available_variables = prev_templar_avail

    return _decrypt_ansible_encrypted_strings(data)


def _build_application_defaults(roles_dir: Path) -> dict[str, Any]:
    gid_lookup = ApplicationGidLookup()
    applications: dict[str, Any] = {}

    for config_file in sorted(roles_dir.glob("*/config/main.yml")):
        role_dir = config_file.parents[1]
        application_id = role_dir.name
        config_data = _load_yaml_mapping(config_file)

        if config_data:
            group_id = gid_lookup.run([application_id], roles_dir=str(roles_dir))[0]
            config_data["group_id"] = group_id

            users_meta = _load_yaml_mapping(role_dir / "users" / "main.yml")
            users_data = users_meta.get("users", {})
            if isinstance(users_data, dict) and users_data:
                config_data["users"] = {
                    user_key: "{{ lookup('users', " + repr(user_key) + ") }}"
                    for user_key in users_data
                }

        applications[application_id] = config_data

    return {key: applications[key] for key in sorted(applications)}


def get_application_defaults(
    *, roles_dir: Optional[str | os.PathLike[str]] = None
) -> dict[str, Any]:
    resolved_roles_dir = _resolve_roles_dir(roles_dir=roles_dir)
    key = _cache_key(resolved_roles_dir)
    cached = _APPLICATIONS_DEFAULTS_CACHE.get(key)
    if cached is None:
        cached = _build_application_defaults(resolved_roles_dir)
        _APPLICATIONS_DEFAULTS_CACHE[key] = cached
    return copy.deepcopy(cached)


def get_user_defaults(
    *, roles_dir: Optional[str | os.PathLike[str]] = None
) -> dict[str, Any]:
    resolved_roles_dir = _resolve_roles_dir(roles_dir=roles_dir)
    key = _cache_key(resolved_roles_dir)
    cached = _USERS_DEFAULTS_CACHE.get(key)
    if cached is None:
        definitions = _load_user_defs(resolved_roles_dir)
        for reserved_username in _compute_reserved_usernames(resolved_roles_dir):
            if reserved_username not in definitions:
                definitions[reserved_username] = {"reserved": True}
        built = _build_users(
            definitions,
            primary_domain="{{ DOMAIN_PRIMARY }}",
            start_id=1001,
            become_pwd="{{ 42 | strong_password }}",
        )
        cached = {key: built[key] for key in sorted(built)}
        _USERS_DEFAULTS_CACHE[key] = cached
    return copy.deepcopy(cached)


def get_merged_applications(
    *,
    variables: Optional[dict[str, Any]] = None,
    roles_dir: Optional[str | os.PathLike[str]] = None,
    templar: Any = None,
) -> dict[str, Any]:
    variables = variables or {}
    resolved_roles_dir = _resolve_roles_dir(roles_dir=roles_dir)
    cache_key = (
        _cache_key(resolved_roles_dir),
        _stable_variables_signature(variables),
    )
    cached = _MERGED_APPLICATIONS_CACHE.get(cache_key)
    if cached is not None:
        return cached

    defaults = get_application_defaults(roles_dir=roles_dir)
    overrides = _resolve_override_mapping(variables, "applications", templar=templar)

    merged = merge_with_defaults(defaults, overrides)

    if getattr(_RENDER_GUARD, "applications", False):
        # Re-entry via cross-lookup: return unrendered merged payload; the
        # outer templar will resolve remaining Jinja at use-site.
        return merged

    _RENDER_GUARD.applications = True
    try:
        raw_users = get_merged_users(
            variables=variables,
            roles_dir=roles_dir,
            templar=None,
        )
        rendered = _render_with_templar(
            merged,
            templar=templar,
            variables=variables,
            raw_applications=merged,
            raw_users=raw_users,
        )
    finally:
        _RENDER_GUARD.applications = False

    _MERGED_APPLICATIONS_CACHE[cache_key] = rendered
    return rendered


def get_merged_users(
    *,
    variables: Optional[dict[str, Any]] = None,
    roles_dir: Optional[str | os.PathLike[str]] = None,
    templar: Any = None,
) -> dict[str, Any]:
    source_variables = variables
    variables = dict(variables or {})
    if not variables.get("DOMAIN_PRIMARY") and variables.get("SYSTEM_EMAIL_DOMAIN"):
        variables["DOMAIN_PRIMARY"] = variables["SYSTEM_EMAIL_DOMAIN"]

    resolved_roles_dir = _resolve_roles_dir(roles_dir=roles_dir)
    tokens_file = _resolve_tokens_file(variables)
    cache_key = (
        _cache_key(resolved_roles_dir),
        _stable_variables_signature(source_variables),
        _tokens_file_signature(tokens_file),
    )
    cached = _MERGED_USERS_CACHE.get(cache_key)
    if cached is not None:
        return cached

    defaults = get_user_defaults(roles_dir=roles_dir)
    overrides = _resolve_override_mapping(variables, "users", templar=templar)

    merged = _merge_users(defaults, overrides)
    hydrated = _hydrate_users_tokens(
        merged,
        _load_store_users(tokens_file),
    )

    if getattr(_RENDER_GUARD, "users", False):
        # Re-entry via cross-lookup: skip the heavy materialize+render pass.
        return hydrated

    _RENDER_GUARD.users = True
    try:
        materialized = _materialize_builtin_user_aliases(
            hydrated,
            variables,
            templar=templar,
        )
        rendered = _render_with_templar(
            materialized,
            templar=templar,
            variables=variables,
            raw_users=materialized,
        )
    finally:
        _RENDER_GUARD.users = False

    _MERGED_USERS_CACHE[cache_key] = rendered
    return rendered


def get_merged_domains(
    *,
    variables: Optional[dict[str, Any]] = None,
    roles_dir: Optional[str | os.PathLike[str]] = None,
    templar: Any = None,
) -> dict[str, Any]:
    """Build the canonical-domain map lazily from the merged applications view.

    The result is canonical_domains_map(applications, DOMAIN_PRIMARY).
    Per-app domain overrides belong in `applications.<app>.server.domains`
    (canonical/aliases) — they flow through the regular applications-merge
    pipeline rather than a parallel top-level `domains` escape hatch.

    Cached keyed on (roles_dir, variables_signature).
    """
    from plugins.filter.canonical_domains_map import (
        FilterModule as _CanonicalDomainsFilter,
    )

    variables = variables or {}
    resolved_roles_dir = _resolve_roles_dir(roles_dir=roles_dir)

    cache_key = (
        _cache_key(resolved_roles_dir),
        _stable_variables_signature(variables),
    )
    cached = _MERGED_DOMAINS_CACHE.get(cache_key)
    if cached is not None:
        return cached

    primary_domain = (
        variables.get("DOMAIN_PRIMARY") or variables.get("SYSTEM_EMAIL_DOMAIN") or ""
    )
    if not primary_domain:
        raise ValueError(
            "get_merged_domains: DOMAIN_PRIMARY (or SYSTEM_EMAIL_DOMAIN fallback) "
            "must be set in variables."
        )

    apps = get_merged_applications(
        variables=variables,
        roles_dir=roles_dir,
        templar=templar,
    )

    filter_instance = _CanonicalDomainsFilter()
    merged = filter_instance.canonical_domains_map(apps, primary_domain)

    _MERGED_DOMAINS_CACHE[cache_key] = merged
    return merged


def _reset_cache_for_tests() -> None:
    _APPLICATIONS_DEFAULTS_CACHE.clear()
    _USERS_DEFAULTS_CACHE.clear()
    _MERGED_APPLICATIONS_CACHE.clear()
    _MERGED_USERS_CACHE.clear()
    _MERGED_DOMAINS_CACHE.clear()
    _FINGERPRINT_BY_ID.clear()