import typing as t

import attr

import ddtrace
from ddtrace._trace.span import Span
from ddtrace.constants import ORIGIN_KEY
from ddtrace.debugging._expressions import DDExpressionEvaluationError
from ddtrace.debugging._probe.model import Probe
from ddtrace.debugging._probe.model import ProbeEvaluateTimingForMethod
from ddtrace.debugging._probe.model import SpanDecorationFunctionProbe
from ddtrace.debugging._probe.model import SpanDecorationLineProbe
from ddtrace.debugging._probe.model import SpanDecorationMixin
from ddtrace.debugging._probe.model import SpanDecorationTargetSpan
from ddtrace.debugging._probe.model import SpanFunctionProbe
from ddtrace.debugging._signal.model import EvaluationError
from ddtrace.debugging._signal.model import LogSignal
from ddtrace.debugging._signal.model import Signal
from ddtrace.debugging._signal.model import SignalState
from ddtrace.debugging._signal.utils import serialize
from ddtrace.internal.compat import ExcInfoType
from ddtrace.internal.logger import get_logger
from ddtrace.internal.safety import _isinstance


log = get_logger(__name__)

SPAN_NAME = "dd.dynamic.span"
PROBE_ID_TAG_NAME = "debugger.probeid"


@attr.s
class DynamicSpan(Signal):
    """Dynamically created span"""

    _span_cm = attr.ib(type=t.Optional[t.ContextManager[Span]], init=False)

    def __attrs_post_init__(self) -> None:
        self._span_cm = None

    def enter(self) -> None:
        probe = self.probe
        if not isinstance(probe, SpanFunctionProbe):
            log.debug("Dynamic span entered with non-span probe: %s", self.probe)
            return

        if not self._eval_condition(dict(self.args) if self.args else {}):
            return

        self._span_cm = ddtrace.tracer.trace(
            SPAN_NAME,
            service=None,  # Currently unused
            resource=probe.func_qname,
            span_type=None,  # Currently unused
        )
        span = self._span_cm.__enter__()

        span.set_tags(probe.tags)
        span.set_tag_str(PROBE_ID_TAG_NAME, probe.probe_id)
        span.set_tag_str(ORIGIN_KEY, "di")

        self.state = SignalState.DONE

    def exit(self, retval: t.Any, exc_info: ExcInfoType, duration: float) -> None:
        if not isinstance(self.probe, SpanFunctionProbe):
            log.debug("Dynamic span exited with non-span probe: %s", self.probe)
            return

        if self._span_cm is not None:
            # Condition evaluated to true so we created a span. Finish it.
            self._span_cm.__exit__(*exc_info)

    def line(self):
        raise NotImplementedError("Dynamic line spans are not supported in Python")


@attr.s
class SpanDecoration(LogSignal):
    """Decorate a span."""

    def _decorate_span(self, _locals: t.Dict[str, t.Any]) -> None:
        probe = t.cast(SpanDecorationMixin, self.probe)

        if probe.target_span == SpanDecorationTargetSpan.ACTIVE:
            span = ddtrace.tracer.current_span()
        elif probe.target_span == SpanDecorationTargetSpan.ROOT:
            span = ddtrace.tracer.current_root_span()
        else:
            log.error("Invalid target span for span decoration: %s", probe.target_span)
            return

        if span is not None:
            log.debug("Decorating span %r according to span decoration probe %r", span, probe)
            for d in probe.decorations:
                try:
                    if not (d.when is None or d.when(_locals)):
                        continue
                except DDExpressionEvaluationError as e:
                    self.errors.append(
                        EvaluationError(expr=e.dsl, message="Failed to evaluate condition: %s" % e.error)
                    )
                    continue
                for tag in d.tags:
                    try:
                        tag_value = tag.value.render(_locals, serialize)
                    except DDExpressionEvaluationError as e:
                        span.set_tag_str(
                            "_dd.di.%s.evaluation_error" % tag.name, ", ".join([serialize(v) for v in e.args])
                        )
                    else:
                        span.set_tag_str(tag.name, tag_value if _isinstance(tag_value, str) else serialize(tag_value))
                        span.set_tag_str("_dd.di.%s.probe_id" % tag.name, t.cast(Probe, probe).probe_id)

    def enter(self) -> None:
        probe = self.probe
        if not isinstance(probe, SpanDecorationFunctionProbe):
            log.debug("Span decoration entered with non-span decoration probe: %s", self.probe)
            return

        if probe.evaluate_at == ProbeEvaluateTimingForMethod.ENTER:
            self._decorate_span(dict(self.args) if self.args else {})
            self.state = SignalState.DONE

    def exit(self, retval: t.Any, exc_info: ExcInfoType, duration: float) -> None:
        probe = self.probe

        if not isinstance(probe, SpanDecorationFunctionProbe):
            log.debug("Span decoration exited with non-span decoration probe: %s", self.probe)
            return

        if probe.evaluate_at == ProbeEvaluateTimingForMethod.EXIT:
            self._decorate_span(self._enrich_args(retval, exc_info, duration))
            self.state = SignalState.DONE

    def line(self):
        probe = self.probe
        if not isinstance(probe, SpanDecorationLineProbe):
            log.debug("Span decoration on line with non-span decoration probe: %s", self.probe)
            return

        self._decorate_span(self.frame.f_locals)

        self.state = SignalState.DONE

    @property
    def message(self):
        return ("Condition evaluation errors for probe %s" % self.probe.probe_id) if self.errors else None

    def has_message(self):
        # type () -> bool
        return bool(self.errors)