import typing

from .metric_base import MetricBase, MetricGroupBase, MetricGroupDefinition, MetricMutableValue, Now, NOW
from .registry import Path, GLOBAL_REGISTRY

__all__ = [
    'Counter',
    'Gauge',
    'Summary',
]


class Counter(MetricBase):
    metric_type: typing.ClassVar[str] = 'counter'

    def __init__(self, value: float = 0, path: typing.Optional[Path] = None, help: typing.Optional[str] = None):
        super().__init__(value=value, help=help)
        if not path is None:
            GLOBAL_REGISTRY.register(path, self)


class Gauge(MetricBase):
    metric_type: typing.ClassVar[str] = 'gauge'

    def __init__(self, value: float = float('nan'), path: typing.Optional[Path] = None, help: typing.Optional[str] = None):
        super().__init__(value=value, help=help)
        if not path is None:
            GLOBAL_REGISTRY.register(path, self)


class Summary(MetricGroupBase):
    metric_type: typing.ClassVar[str] = 'summary'
    group_definition: typing.ClassVar[MetricGroupDefinition] = MetricGroupDefinition(
        frozenset(['_sum', '_count']),
        frozenset(['quantile']),
    )

    def __init__(self, path: typing.Optional[Path] = None, help: typing.Optional[str] = None):
        super().__init__(help=help)
        self._lock = MetricMutableValue.DEFAULT_LOCK
        self._sum = MetricMutableValue(0, None, self._lock)
        self._count = MetricMutableValue(0, None, self._lock)
        if not path is None:
            GLOBAL_REGISTRY.register(path, self)

    def metrics(self) -> typing.Iterator[typing.Tuple[(Path, MetricMutableValue)]]:
        return [
            (Path('_sum'), self._sum),
            (Path('_count'), self._count),
        ]

    def observe(self, value: float, timestamp: typing.Union[int, None, Now] = NOW):
        if isinstance(timestamp, Now):
            timestamp = timestamp.time()
        with self._lock:
            self._count.inc_no_lock(1, timestamp)
            self._sum.inc_no_lock(value, timestamp)