import pytest
import tornado

from ddtrace.context import Context
from ddtrace.contrib.tornado import TracerStackContext

from .utils import TornadoTestCase
from .web.compat import sleep


class TestStackContext(TornadoTestCase):
    @pytest.mark.skipif(tornado.version_info >= (5, 0),
                        reason='tornado.stack_context deprecated in Tornado 5.0 and removed in Tornado 6.0')
    def test_without_stack_context(self):
        # without a TracerStackContext, propagation is not available
        ctx = self.tracer.context_provider.active()
        assert ctx is None

    def test_stack_context(self):
        # a TracerStackContext should automatically propagate a tracing context
        with TracerStackContext():
            ctx = self.tracer.context_provider.active()

        assert ctx is not None

    def test_propagation_with_new_context(self):
        # inside a TracerStackContext it should be possible to set
        # a new Context for distributed tracing
        with TracerStackContext():
            ctx = Context(trace_id=100, span_id=101)
            self.tracer.context_provider.activate(ctx)
            with self.tracer.trace('tornado'):
                sleep(0.01)

        traces = self.tracer.writer.pop_traces()
        assert len(traces) == 1
        assert len(traces[0]) == 1
        assert traces[0][0].trace_id == 100
        assert traces[0][0].parent_id == 101

    @pytest.mark.skipif(tornado.version_info >= (5, 0),
                        reason='tornado.stack_context deprecated in Tornado 5.0 and removed in Tornado 6.0')
    def test_propagation_without_stack_context(self):
        # a Context is discarded if not set inside a TracerStackContext
        ctx = Context(trace_id=100, span_id=101)
        self.tracer.context_provider.activate(ctx)
        with self.tracer.trace('tornado'):
            sleep(0.01)

        traces = self.tracer.writer.pop_traces()
        assert len(traces) == 1
        assert len(traces[0]) == 1
        assert traces[0][0].trace_id != 100
        assert traces[0][0].parent_id != 101