import pytest
from models import Ticket
from dag_engine import TrackDAG, ExecutionEngine

def test_cascade_blocks_simple() -> None:
 """Test that a blocked dependency blocks its immediate dependent."""
 t1 = Ticket(id="T1", description="T1", status="blocked", assigned_to="worker")
 t2 = Ticket(id="T2", description="T2", status="todo", assigned_to="worker", depends_on=["T1"])
 dag = TrackDAG([t1, t2])
 dag.cascade_blocks()
 assert t2.status == "blocked"

def test_cascade_blocks_multi_hop() -> None:
 """Test that blocking cascades through multiple levels: A(blocked) -> B -> C."""
 t1 = Ticket(id="T1", description="T1", status="blocked", assigned_to="worker")
 t2 = Ticket(id="T2", description="T2", status="todo", assigned_to="worker", depends_on=["T1"])
 t3 = Ticket(id="T3", description="T3", status="todo", assigned_to="worker", depends_on=["T2"])
 dag = TrackDAG([t1, t2, t3])
 dag.cascade_blocks()
 assert t2.status == "blocked"
 assert t3.status == "blocked"

def test_cascade_blocks_no_cascade_to_completed() -> None:
 """Test that completed tasks are not changed even if a dependency is blocked (though this shouldn't normally happen)."""
 t1 = Ticket(id="T1", description="T1", status="blocked", assigned_to="worker")
 t2 = Ticket(id="T2", description="T2", status="completed", assigned_to="worker", depends_on=["T1"])
 dag = TrackDAG([t1, t2])
 dag.cascade_blocks()
 assert t2.status == "completed"

def test_cascade_blocks_partial_dependencies() -> None:
 """Test that if one dependency is blocked, the dependent is blocked even if others are completed."""
 t1 = Ticket(id="T1", description="T1", status="blocked", assigned_to="worker")
 t2 = Ticket(id="T2", description="T2", status="completed", assigned_to="worker")
 t3 = Ticket(id="T3", description="T3", status="todo", assigned_to="worker", depends_on=["T1", "T2"])
 dag = TrackDAG([t1, t2, t3])
 dag.cascade_blocks()
 assert t3.status == "blocked"

def test_cascade_blocks_already_in_progress() -> None:
 """Test that in_progress tasks are not blocked automatically (only todo)."""
 t1 = Ticket(id="T1", description="T1", status="blocked", assigned_to="worker")
 t2 = Ticket(id="T2", description="T2", status="in_progress", assigned_to="worker", depends_on=["T1"])
 dag = TrackDAG([t1, t2])
 dag.cascade_blocks()
 assert t2.status == "in_progress"

def test_execution_engine_tick_cascades_blocks() -> None:
 """Test that ExecutionEngine.tick() triggers the cascading blocks."""
 t1 = Ticket(id="T1", description="T1", status="blocked", assigned_to="worker")
 t2 = Ticket(id="T2", description="T2", status="todo", assigned_to="worker", depends_on=["T1"])
 dag = TrackDAG([t1, t2])
 engine = ExecutionEngine(dag)
 
 # Before tick, T2 is todo
 assert t2.status == "todo"
 
 # After tick, T2 should be blocked
 engine.tick()
 assert t2.status == "blocked"