"""Headless application service for the isolated user-engine MVP."""

from __future__ import annotations

from dataclasses import dataclass, replace
from typing import Any, Mapping

from user_engine.adapters.local import InMemoryUserEngineStore
from user_engine.domain import (
    Account,
    AccountStatus,
    Actor,
    Application,
    ApplicationBinding,
    AttributeDefinition,
    AuditRecord,
    AuthorizationRequest,
    Catalog,
    CatalogLifecycle,
    ExternalIdentity,
    Mutability,
    OutboxEvent,
    ProfileScope,
    ProfileValue,
    ProjectionType,
    Sensitivity,
    User,
    Visibility,
    new_id,
)
from user_engine.errors import (
    AuthorizationDenied,
    ConflictError,
    NotFoundError,
    ValidationError,
)
from user_engine.ports import AuthorizationCheckPort, IdentityClaimsAdapter

REDACTED = "<redacted>"


@dataclass(frozen=True)
class HealthReport:
    status: str
    schema_version: str | None


@dataclass(frozen=True)
class ReadinessReport:
    ready: bool
    checks: Mapping[str, bool]


@dataclass(frozen=True)
class UserSession:
    actor: Actor
    user: User
    account: Account
    identities: tuple[ExternalIdentity, ...]


@dataclass(frozen=True)
class EffectiveProfile:
    user_id: str
    application_id: str | None
    values: Mapping[str, Any]
    source_layers: Mapping[str, str]
    trace: Mapping[str, tuple[str, ...]]


@dataclass(frozen=True)
class Projection:
    user_id: str
    projection_type: ProjectionType
    application_id: str | None
    values: Mapping[str, Any]
    redactions: Mapping[str, str]


class UserEngineService:
    """Headless service API for isolated user and profile management."""

    def __init__(
        self,
        *,
        store: InMemoryUserEngineStore,
        identity_adapter: IdentityClaimsAdapter,
        authorization: AuthorizationCheckPort,
    ) -> None:
        self.store = store
        self.identity_adapter = identity_adapter
        self.authorization = authorization
        if not self.store.ready:
            self.store.migrate()

    def health(self) -> HealthReport:
        return HealthReport(status="ok", schema_version=self.store.schema_version)

    def readiness(self) -> ReadinessReport:
        return ReadinessReport(
            ready=self.store.ready,
            checks={
                "store_schema": self.store.ready,
                "identity_adapter": self.identity_adapter is not None,
                "authorization_port": self.authorization is not None,
            },
        )

    def me(
        self,
        claims: Mapping[str, Any],
        *,
        correlation_id: str | None = None,
    ) -> UserSession:
        actor = self.identity_adapter.normalize(claims)
        correlation_id = correlation_id or new_id("corr")
        decision = self._authorize(
            actor,
            action="me.read",
            resource_type="user-engine:me",
            resource_id=actor.subject,
            tenant=actor.tenant,
            correlation_id=correlation_id,
        )
        identity = self.store.find_identity(*actor.identity_key)
        if identity is not None:
            user = self._require_user(identity.user_id)
            account = self._require_account(user.user_id)
            return self._session(actor, user, account)

        user = User(
            display_name=actor.preferred_username,
            primary_email=_optional_claim(actor, "email"),
        )
        account = Account(
            account_id=new_id("acct"),
            user_id=user.user_id,
            status=AccountStatus.ACTIVE,
        )
        identity = ExternalIdentity(
            identity_id=new_id("idn"),
            user_id=user.user_id,
            issuer=actor.issuer,
            subject=actor.subject,
            provider=actor.authorized_party,
        )
        self.store.save_user(user)
        self.store.save_account(account)
        self.store.save_identity(identity)
        self._record_mutation(
            actor,
            action="user.create_from_identity",
            subject=user.user_id,
            tenant=actor.tenant,
            correlation_id=correlation_id,
            decision_id=decision.decision_id,
            event_type="user.created",
            aggregate_id=user.user_id,
            payload={
                "user_id": user.user_id,
                "account_id": account.account_id,
                "identity": {"issuer": actor.issuer, "subject": actor.subject},
            },
        )
        return self._session(actor, user, account)

    def create_user(
        self,
        actor: Actor,
        *,
        display_name: str | None,
        primary_email: str | None,
        correlation_id: str | None = None,
    ) -> User:
        correlation_id = correlation_id or new_id("corr")
        decision = self._authorize(
            actor,
            action="user.create",
            resource_type="user-engine:user",
            resource_id="new",
            tenant=actor.tenant,
            correlation_id=correlation_id,
        )
        user = User(display_name=display_name, primary_email=primary_email)
        account = Account(account_id=new_id("acct"), user_id=user.user_id)
        self.store.save_user(user)
        self.store.save_account(account)
        self._record_mutation(
            actor,
            action="user.create",
            subject=user.user_id,
            tenant=actor.tenant,
            correlation_id=correlation_id,
            decision_id=decision.decision_id,
            event_type="user.created",
            aggregate_id=user.user_id,
            payload={"user_id": user.user_id, "account_id": account.account_id},
        )
        return user

    def set_account_status(
        self,
        actor: Actor,
        user_id: str,
        status: AccountStatus,
        *,
        correlation_id: str | None = None,
    ) -> Account:
        account = self._require_account(user_id)
        correlation_id = correlation_id or new_id("corr")
        decision = self._authorize(
            actor,
            action="account.update",
            resource_type="user-engine:account",
            resource_id=account.account_id,
            tenant=actor.tenant,
            correlation_id=correlation_id,
            target_user_id=user_id,
        )
        updated = replace(account, status=status)
        self.store.save_account(updated)
        self._record_mutation(
            actor,
            action="account.update",
            subject=user_id,
            tenant=actor.tenant,
            correlation_id=correlation_id,
            decision_id=decision.decision_id,
            event_type="account.status_changed",
            aggregate_id=account.account_id,
            payload={"user_id": user_id, "status": status},
        )
        return updated

    def link_identity(
        self,
        actor: Actor,
        user_id: str,
        *,
        issuer: str,
        subject: str,
        provider: str | None = None,
        correlation_id: str | None = None,
    ) -> ExternalIdentity:
        self._require_user(user_id)
        existing = self.store.find_identity(issuer, subject)
        if existing is not None and existing.user_id != user_id:
            raise ConflictError("external identity is already linked")
        if existing is not None:
            return existing

        correlation_id = correlation_id or new_id("corr")
        decision = self._authorize(
            actor,
            action="identity.link",
            resource_type="user-engine:identity",
            resource_id=f"{issuer}:{subject}",
            tenant=actor.tenant,
            correlation_id=correlation_id,
            target_user_id=user_id,
        )
        identity = ExternalIdentity(
            identity_id=new_id("idn"),
            user_id=user_id,
            issuer=issuer,
            subject=subject,
            provider=provider,
        )
        self.store.save_identity(identity)
        self._record_mutation(
            actor,
            action="identity.link",
            subject=user_id,
            tenant=actor.tenant,
            correlation_id=correlation_id,
            decision_id=decision.decision_id,
            event_type="identity.linked",
            aggregate_id=user_id,
            payload={"issuer": issuer, "subject": subject, "user_id": user_id},
        )
        return identity

    def register_application(
        self,
        actor: Actor,
        application: Application,
        *,
        binding: ApplicationBinding | None = None,
        correlation_id: str | None = None,
    ) -> Application:
        if application.application_id in self.store.applications:
            raise ConflictError("application already exists")
        correlation_id = correlation_id or new_id("corr")
        decision = self._authorize(
            actor,
            action="application.register",
            resource_type="user-engine:application",
            resource_id=application.application_id,
            tenant=actor.tenant,
            correlation_id=correlation_id,
            application_id=application.application_id,
        )
        self.store.save_application(application)
        if binding is not None:
            if binding.application_id != application.application_id:
                raise ValidationError("binding application id must match application")
            self.store.save_binding(binding)
        self._record_mutation(
            actor,
            action="application.register",
            subject=application.application_id,
            tenant=actor.tenant,
            correlation_id=correlation_id,
            decision_id=decision.decision_id,
            event_type="application.registered",
            aggregate_id=application.application_id,
            payload={"application_id": application.application_id},
            application_id=application.application_id,
        )
        return application

    def publish_catalog(
        self,
        actor: Actor,
        catalog: Catalog,
        *,
        correlation_id: str | None = None,
    ) -> Catalog:
        self._validate_catalog(catalog)
        correlation_id = correlation_id or new_id("corr")
        decision = self._authorize(
            actor,
            action="catalog.publish",
            resource_type="user-engine:catalog",
            resource_id=catalog.catalog_id,
            tenant=actor.tenant,
            correlation_id=correlation_id,
            application_id=catalog.owning_application_id,
        )
        self.store.save_catalog(catalog)
        self._record_mutation(
            actor,
            action="catalog.publish",
            subject=catalog.catalog_id,
            tenant=actor.tenant,
            correlation_id=correlation_id,
            decision_id=decision.decision_id,
            event_type="catalog.published",
            aggregate_id=catalog.catalog_id,
            payload={
                "catalog_id": catalog.catalog_id,
                "namespace": catalog.namespace,
                "version": catalog.version,
            },
            application_id=catalog.owning_application_id,
        )
        return catalog

    def set_profile_value(
        self,
        actor: Actor,
        user_id: str,
        attribute_key: str,
        value: Any,
        *,
        scope: ProfileScope = ProfileScope.GLOBAL,
        scope_id: str | None = None,
        application_id: str | None = None,
        correlation_id: str | None = None,
    ) -> ProfileValue:
        self._require_user(user_id)
        definition = self._require_attribute(attribute_key)
        self._validate_profile_scope(definition, scope, scope_id)
        self._validate_value(definition, value)
        correlation_id = correlation_id or new_id("corr")
        decision = self._authorize(
            actor,
            action="profile.write",
            resource_type="user-engine:profile",
            resource_id=f"{user_id}:{attribute_key}",
            tenant=actor.tenant,
            correlation_id=correlation_id,
            application_id=application_id,
            target_user_id=user_id,
            context={"scope": scope, "scope_id": scope_id},
        )
        profile_value = ProfileValue(
            user_id=user_id,
            attribute_key=attribute_key,
            value=value,
            scope=scope,
            scope_id=scope_id,
            source=f"{actor.issuer}:{actor.subject}",
        )
        self.store.save_profile_value(profile_value)
        self._record_mutation(
            actor,
            action="profile.write",
            subject=user_id,
            tenant=actor.tenant,
            correlation_id=correlation_id,
            decision_id=decision.decision_id,
            event_type="profile.value_set",
            aggregate_id=user_id,
            payload={
                "user_id": user_id,
                "attribute_key": attribute_key,
                "scope": scope,
                "scope_id": scope_id,
            },
            application_id=application_id,
        )
        return profile_value

    def effective_profile(
        self,
        actor: Actor,
        user_id: str,
        *,
        application_id: str | None = None,
        correlation_id: str | None = None,
    ) -> EffectiveProfile:
        correlation_id = correlation_id or new_id("corr")
        self._authorize(
            actor,
            action="profile.read",
            resource_type="user-engine:profile",
            resource_id=user_id,
            tenant=actor.tenant,
            correlation_id=correlation_id,
            application_id=application_id,
            target_user_id=user_id,
        )
        return self._resolve_effective_profile(user_id, application_id)

    def projection(
        self,
        actor: Actor,
        user_id: str,
        projection_type: ProjectionType,
        *,
        application_id: str | None = None,
        correlation_id: str | None = None,
    ) -> Projection:
        correlation_id = correlation_id or new_id("corr")
        self._authorize(
            actor,
            action="projection.read",
            resource_type="user-engine:projection",
            resource_id=user_id,
            tenant=actor.tenant,
            correlation_id=correlation_id,
            application_id=application_id,
            target_user_id=user_id,
            context={"projection_type": projection_type},
        )
        effective = self._resolve_effective_profile(user_id, application_id)
        values: dict[str, Any] = {}
        redactions: dict[str, str] = {}
        for key, definition in self._active_attribute_definitions().items():
            if key not in effective.values:
                continue
            if not _visible_in_projection(definition, projection_type):
                continue
            if _must_redact(definition, projection_type):
                values[key] = REDACTED
                redactions[key] = "sensitivity"
            else:
                values[key] = effective.values[key]
        return Projection(
            user_id=user_id,
            projection_type=projection_type,
            application_id=application_id,
            values=values,
            redactions=redactions,
        )

    def audit_records(self) -> tuple[AuditRecord, ...]:
        return tuple(self.store.audit_records)

    def outbox_events(self) -> tuple[OutboxEvent, ...]:
        return tuple(self.store.outbox_events)

    def _session(self, actor: Actor, user: User, account: Account) -> UserSession:
        identities = tuple(
            identity
            for identity in self.store.identities.values()
            if identity.user_id == user.user_id
        )
        return UserSession(actor=actor, user=user, account=account, identities=identities)

    def _authorize(
        self,
        actor: Actor,
        *,
        action: str,
        resource_type: str,
        resource_id: str,
        tenant: str,
        correlation_id: str,
        application_id: str | None = None,
        target_user_id: str | None = None,
        context: Mapping[str, Any] | None = None,
    ):
        request = AuthorizationRequest(
            actor=actor,
            resource_type=resource_type,
            resource_id=resource_id,
            action=action,
            tenant=tenant,
            correlation_id=correlation_id,
            application_id=application_id,
            target_user_id=target_user_id,
            context=context or {},
        )
        decision = self.authorization.check(request)
        if not decision.allowed:
            self.store.append_audit(
                AuditRecord(
                    audit_id=new_id("aud"),
                    actor=actor,
                    action=action,
                    subject=resource_id,
                    tenant=tenant,
                    correlation_id=correlation_id,
                    decision_id=decision.decision_id,
                    application_id=application_id,
                    summary="authorization denied",
                )
            )
            raise AuthorizationDenied(decision.reason or "authorization denied")
        return decision

    def _record_mutation(
        self,
        actor: Actor,
        *,
        action: str,
        subject: str,
        tenant: str,
        correlation_id: str,
        decision_id: str | None,
        event_type: str,
        aggregate_id: str,
        payload: Mapping[str, Any],
        application_id: str | None = None,
    ) -> None:
        self.store.append_audit(
            AuditRecord(
                audit_id=new_id("aud"),
                actor=actor,
                action=action,
                subject=subject,
                tenant=tenant,
                correlation_id=correlation_id,
                decision_id=decision_id,
                application_id=application_id,
                summary=event_type,
            )
        )
        self.store.append_outbox(
            OutboxEvent(
                event_id=new_id("evt"),
                event_type=event_type,
                aggregate_id=aggregate_id,
                payload=dict(payload),
                tenant=tenant,
                correlation_id=correlation_id,
            )
        )

    def _resolve_effective_profile(
        self, user_id: str, application_id: str | None
    ) -> EffectiveProfile:
        self._require_user(user_id)
        values: dict[str, Any] = {}
        source_layers: dict[str, str] = {}
        trace: dict[str, list[str]] = {}
        definitions = self._active_attribute_definitions()
        for key, definition in definitions.items():
            if definition.default is not None:
                values[key] = definition.default
                source_layers[key] = "catalog_default"
                trace[key] = ["catalog_default"]

        profile_values = self.store.values_for_user(user_id)
        for profile_value in profile_values:
            if profile_value.attribute_key not in definitions:
                continue
            if profile_value.scope != ProfileScope.GLOBAL:
                continue
            values[profile_value.attribute_key] = profile_value.value
            source_layers[profile_value.attribute_key] = "global"
            trace.setdefault(profile_value.attribute_key, []).append("global")

        for profile_value in profile_values:
            if profile_value.attribute_key not in definitions:
                continue
            if profile_value.scope != ProfileScope.APPLICATION:
                continue
            if profile_value.scope_id != application_id:
                continue
            values[profile_value.attribute_key] = profile_value.value
            layer = f"application:{application_id}"
            source_layers[profile_value.attribute_key] = layer
            trace.setdefault(profile_value.attribute_key, []).append(layer)

        return EffectiveProfile(
            user_id=user_id,
            application_id=application_id,
            values=values,
            source_layers=source_layers,
            trace={key: tuple(layers) for key, layers in trace.items()},
        )

    def _validate_catalog(self, catalog: Catalog) -> None:
        if catalog.owning_application_id not in self.store.applications:
            raise ValidationError("catalog owning application is not registered")
        if catalog.lifecycle != CatalogLifecycle.ACTIVE:
            raise ValidationError("only active catalogs can be published")
        if not catalog.attributes:
            raise ValidationError("catalog must define at least one attribute")
        keys = [attribute.key for attribute in catalog.attributes]
        if len(keys) != len(set(keys)):
            raise ValidationError("catalog attribute keys must be unique")
        binding = self.store.bindings.get(catalog.owning_application_id)
        if binding and catalog.namespace not in binding.catalog_namespaces:
            raise ValidationError("catalog namespace is not bound to application")

        active_definitions = self._active_attribute_definitions(
            excluding_catalog_id=catalog.catalog_id
        )
        for attribute in catalog.attributes:
            if not attribute.key.startswith(f"{catalog.namespace}."):
                raise ValidationError("attribute keys must use the catalog namespace")
            if attribute.key in active_definitions:
                raise ConflictError("active catalog already owns attribute key")
            if not attribute.visibility:
                raise ValidationError("attribute must declare visibility")
            if not attribute.mutability:
                raise ValidationError("attribute must declare mutability")
            if Mutability.READ_ONLY in attribute.mutability and len(attribute.mutability) > 1:
                raise ValidationError("read-only mutability cannot be combined")
            if attribute.default is not None:
                self._validate_value(attribute, attribute.default)

    def _validate_profile_scope(
        self,
        definition: AttributeDefinition,
        scope: ProfileScope,
        scope_id: str | None,
    ) -> None:
        allowed_scopes = {ProfileScope.GLOBAL, ProfileScope.APPLICATION, definition.scope}
        if scope not in allowed_scopes:
            raise ValidationError("profile value scope is not allowed for attribute")
        if scope == ProfileScope.APPLICATION:
            if scope_id is None:
                raise ValidationError("application profile values require scope_id")
            if scope_id not in self.store.applications:
                raise ValidationError("application profile scope_id is not registered")
        elif scope_id is not None:
            raise ValidationError("only application scoped values may set scope_id")

    def _validate_value(self, definition: AttributeDefinition, value: Any) -> None:
        if value is None:
            return
        validators = {
            "string": lambda item: isinstance(item, str),
            "integer": lambda item: isinstance(item, int) and not isinstance(item, bool),
            "number": lambda item: isinstance(item, (int, float))
            and not isinstance(item, bool),
            "boolean": lambda item: isinstance(item, bool),
            "object": lambda item: isinstance(item, Mapping),
            "array": lambda item: isinstance(item, (list, tuple)),
        }
        validator = validators.get(definition.value_type)
        if validator is None:
            raise ValidationError(f"unsupported attribute value_type: {definition.value_type}")
        if not validator(value):
            raise ValidationError(f"{definition.key} must be {definition.value_type}")
        enum_values = definition.validation.get("enum")
        if enum_values is not None and value not in enum_values:
            raise ValidationError(f"{definition.key} is not an allowed value")

    def _require_user(self, user_id: str) -> User:
        user = self.store.users.get(user_id)
        if user is None:
            raise NotFoundError("user not found")
        return user

    def _require_account(self, user_id: str) -> Account:
        account = self.store.user_account(user_id)
        if account is None:
            raise NotFoundError("account not found")
        return account

    def _require_attribute(self, attribute_key: str) -> AttributeDefinition:
        definition = self._active_attribute_definitions().get(attribute_key)
        if definition is None:
            raise NotFoundError("active attribute definition not found")
        return definition

    def _active_attribute_definitions(
        self, *, excluding_catalog_id: str | None = None
    ) -> dict[str, AttributeDefinition]:
        definitions: dict[str, AttributeDefinition] = {}
        for catalog in self.store.catalogs.values():
            if catalog.catalog_id == excluding_catalog_id:
                continue
            if catalog.lifecycle != CatalogLifecycle.ACTIVE:
                continue
            for attribute in catalog.attributes:
                definitions[attribute.key] = attribute
        return dict(sorted(definitions.items()))


def _optional_claim(actor: Actor, key: str) -> str | None:
    value = actor.claims.get(key)
    if value is None:
        return None
    return str(value)


def _visible_in_projection(
    definition: AttributeDefinition, projection_type: ProjectionType
) -> bool:
    if projection_type == ProjectionType.AUDIT:
        return True
    visibility = {
        ProjectionType.SELF_SERVICE: Visibility.USER,
        ProjectionType.ADMIN: Visibility.ADMIN,
        ProjectionType.APPLICATION_RUNTIME: Visibility.APPLICATION,
        ProjectionType.AGENT_CONTEXT: Visibility.APPLICATION,
        ProjectionType.CLAIMS_ENRICHMENT: Visibility.APPLICATION,
    }.get(projection_type)
    if visibility is None:
        return False
    return visibility in definition.visibility


def _must_redact(
    definition: AttributeDefinition, projection_type: ProjectionType
) -> bool:
    if projection_type in {
        ProjectionType.ADMIN,
        ProjectionType.AUDIT,
        ProjectionType.SELF_SERVICE,
    }:
        return False
    return definition.sensitivity in {Sensitivity.SENSITIVE, Sensitivity.SECRET}