from __future__ import annotations
from abc import ABC
from collections.abc import Mapping
from typing import TYPE_CHECKING, ClassVar
from app.simulation.core.catalog import ComponentDisplaySpec
from app.simulation.core.equations import EquationDefinition
from app.simulation.core.metadata import ParameterDefinition, ResultVariableDefinition, ResultVariableMetadata, THERMODYNAMIC_VOLUME_RESULT_VARIABLES
from app.simulation.core.ports import PortDefinition, PortState
if TYPE_CHECKING:
    from app.simulation.core.medium import GasMedium

class Component(ABC):
    MODEL_TYPE: ClassVar[str | None] = None
    MODEL_VERSION: ClassVar[str | None] = None
    PORTS: ClassVar[tuple[PortDefinition, ...]] = ()
    PARAMETERS: ClassVar[tuple[ParameterDefinition, ...]] = ()
    RESULT_VARIABLES: ClassVar[tuple[ResultVariableDefinition, ...]] = ()
    DISPLAY: ClassVar[ComponentDisplaySpec | None] = None

    def __init__(self, name: str) -> None:
        self.name = name
        self.model_type = self.MODEL_TYPE or self.__class__.__name__.lower()
        self._ports: dict[str, PortState] = {}
        self._parameter_values: dict[str, float] = {}

    @property
    def ports(self) -> dict[str, PortState]:
        return dict(self._ports)

    @property
    def port_definitions(self) -> tuple[PortDefinition, ...]:
        return tuple((port.definition for port in self._ports.values() if port.definition is not None))

    @classmethod
    def active_port_definitions_for_parameters(cls, parameters: Mapping[str, float]) -> tuple[PortDefinition, ...]:
        """Declared ports enabled by one normalized parameter set."""
        return cls.PORTS

    @property
    def active_port_definitions(self) -> tuple[PortDefinition, ...]:
        """Instance ports that participate in execution and result reporting."""
        return self.port_definitions

    @property
    def required_connection_ports(self) -> tuple[str, ...]:
        """Physical ports that must have an external connection before simulation."""
        return tuple((definition.name for definition in self.active_port_definitions if definition.kind == 'physical'))

    def register_port(self, port: PortState) -> PortState:
        definition = port.definition
        if definition is None:
            raise ValueError(f'Component {self.name} cannot register an undefined port.')
        if definition.name in self._ports:
            raise ValueError(f'Duplicate port {self.name}.{definition.name}.')
        self._ports[definition.name] = port
        return port

    def register_declared_port(self, name: str) -> PortState:
        try:
            definition = next((item for item in self.PORTS if item.name == name))
        except StopIteration as exc:
            raise ValueError(f'Component model {self.model_type} does not declare port {name}.') from exc
        return self.register_port(PortState(definition=definition))

    def set_parameter_values(self, values: Mapping[str, float]) -> None:
        definitions = {definition.name: definition for definition in self.PARAMETERS}
        unknown = sorted(set(values) - set(definitions))
        if unknown:
            raise ValueError(f'Component {self.name} contains unsupported parameters: ' + ', '.join(unknown) + '.')
        missing = sorted(set(definitions) - set(values))
        if missing:
            raise ValueError(f'Component {self.name} is missing parameters: ' + ', '.join(missing) + '.')
        resolved: dict[str, float] = {}
        for name, definition in definitions.items():
            value = float(values[name])
            message = definition.validation_message(value)
            if message is not None:
                raise ValueError(f"Parameter '{name}' on component '{self.name}' {message}.")
            resolved[name] = value
        self._parameter_values = resolved

    @property
    def parameter_values(self) -> dict[str, float]:
        return dict(self._parameter_values)

    def get_port(self, name: str) -> PortState:
        try:
            return self._ports[name]
        except KeyError as exc:
            raise ValueError(f'Component {self.name} has no port named {name}.') from exc

    def result_variable_metadata(self) -> tuple[ResultVariableMetadata, ...]:
        metadata = [ResultVariableMetadata(key=f'{self.name}.{definition.name}', component_id=self.name, component_type=self.model_type, scope='component', name=definition.name, label=definition.label, quantity=definition.quantity, unit=definition.unit, category=definition.category, order=definition.order) for definition in self.RESULT_VARIABLES if definition.visible]
        for port_definition in self.active_port_definitions:
            for variable in port_definition.variables:
                if not variable.result_visible:
                    continue
                metadata.append(ResultVariableMetadata(key=f'{self.name}.{port_definition.name}.{variable.name}', component_id=self.name, component_type=self.model_type, scope='port', port_name=port_definition.name, name=variable.name, label=variable.label or variable.name, quantity=variable.quantity or variable.name, unit=variable.unit, category=variable.role, order=variable.order))
        return tuple(metadata)

    def parameter_interface_dicts(self) -> list[dict[str, object]]:
        return [definition.as_interface_dict(value=self._parameter_values.get(definition.name)) for definition in self.PARAMETERS]

    @classmethod
    def create(cls, *, name: str, medium: GasMedium, parameters: Mapping[str, float]) -> Component:
        """Create a catalog model from normalized SI parameters."""
        raise NotImplementedError(f'Component model {cls.__name__} must implement create().')
    EQUATIONS = ()

    def equation_definitions(self):

        def bind(value):
            if isinstance(value, str):
                return value.replace('__MODEL__', self.name)
            return tuple((bind(v) for v in value))
        return tuple((EquationDefinition(id=bind(e['id']), owner=e['owner'], owner_id=self.name, relation=e['relation'], variables=bind(e['variables']), role=e['role']) for e in self.EQUATIONS))

class DynamicComponent(Component):
    state_size = 2

class ThermodynamicVolumeComponent(DynamicComponent):
    """Two-state gas volume exposing the shared thermodynamic result contract."""
    RESULT_VARIABLES = THERMODYNAMIC_VOLUME_RESULT_VARIABLES

class AlgebraicComponent(Component):
    """Stateless element described by algebraic constraints only."""