"""Tests for multi-agent accelerations: parallel execution, pool, delegation."""

import pytest

from fusionagi.planning import ready_steps
from fusionagi.schemas.plan import Plan, PlanStep
from fusionagi.multi_agent import (
    execute_steps_parallel,
    ParallelStepResult,
    AgentPool,
    PooledExecutorRouter,
    delegate_sub_tasks,
    DelegationConfig,
    SubTask,
)
from fusionagi.core import EventBus, StateManager, Orchestrator
from fusionagi.agents import ExecutorAgent, PlannerAgent
from fusionagi.tools import ToolRegistry
from fusionagi.adapters import StubAdapter


class TestReadySteps:
    """Test ready_steps for parallel dispatch."""

    def test_parallel_ready_steps(self):
        """Steps with same deps are ready together."""
        plan = Plan(
            steps=[
                PlanStep(id="s1", description="First"),
                PlanStep(id="s2", description="Second", dependencies=["s1"]),
                PlanStep(id="s3", description="Third", dependencies=["s1"]),
                PlanStep(id="s4", description="Fourth", dependencies=["s2", "s3"]),
            ]
        )
        assert ready_steps(plan, set()) == ["s1"]
        assert set(ready_steps(plan, {"s1"})) == {"s2", "s3"}
        assert ready_steps(plan, {"s1", "s2", "s3"}) == ["s4"]
        assert ready_steps(plan, {"s1", "s2", "s3", "s4"}) == []


class TestAgentPool:
    """Test AgentPool and PooledExecutorRouter."""

    def test_pool_round_robin(self):
        """Round-robin selection rotates through agents."""
        pool = AgentPool(strategy="round_robin")
        calls = []

        class FakeAgent:
            def __init__(self, aid):
                self.identity = aid

            def handle_message(self, env):
                calls.append(self.identity)
                return None

        pool.add("a1", FakeAgent("a1"))
        pool.add("a2", FakeAgent("a2"))
        pool.add("a3", FakeAgent("a3"))

        from fusionagi.schemas.messages import AgentMessage, AgentMessageEnvelope

        env = AgentMessageEnvelope(
            message=AgentMessage(sender="x", recipient="pool", intent="execute_step", payload={}),
            task_id="t1",
        )
        for _ in range(6):
            pool.dispatch(env)

        assert calls == ["a1", "a2", "a3", "a1", "a2", "a3"]

    def test_pool_least_busy(self):
        """Least-busy prefers agent with fewest in-flight."""
        pool = AgentPool(strategy="least_busy")

        class SlowAgent:
            def __init__(self, aid):
                self.identity = aid

            def handle_message(self, env):
                import time
                time.sleep(0.05)
                return None

        pool.add("slow1", SlowAgent("slow1"))
        pool.add("slow2", SlowAgent("slow2"))

        from fusionagi.schemas.messages import AgentMessage, AgentMessageEnvelope

        env = AgentMessageEnvelope(
            message=AgentMessage(sender="x", recipient="pool", intent="test", payload={}),
        )
        # Sequential dispatch - both should get used
        pool.dispatch(env)
        pool.dispatch(env)
        stats = pool.stats()
        assert stats["size"] == 2
        assert sum(a["total_dispatched"] for a in stats["agents"]) == 2

    def test_pooled_executor_router(self):
        """PooledExecutorRouter routes to pool."""
        registry = ToolRegistry()
        state = StateManager()
        exec1 = ExecutorAgent(identity="exec1", registry=registry, state_manager=state)
        exec2 = ExecutorAgent(identity="exec2", registry=registry, state_manager=state)

        router = PooledExecutorRouter(identity="executor_pool")
        router.add_executor("exec1", exec1)
        router.add_executor("exec2", exec2)

        assert router.stats()["size"] == 2


class TestDelegation:
    """Test sub-task delegation."""

    def test_delegate_sub_tasks_parallel(self):
        """Delegation runs sub-tasks in parallel."""
        results_received = []

        def delegate_fn(st: SubTask) -> dict:
            results_received.append(st.sub_task_id)
            return dict(
                sub_task_id=st.sub_task_id,
                success=True,
                result=f"done-{st.sub_task_id}",
                agent_id="agent1",
            )

        # Wrap to return SubTaskResult
        def wrapped(st):
            r = delegate_fn(st)
            from fusionagi.multi_agent.delegation import SubTaskResult
            return SubTaskResult(
                sub_task_id=r["sub_task_id"],
                success=r["success"],
                result=r["result"],
                agent_id=r.get("agent_id"),
            )

        tasks = [
            SubTask("t1", "Goal 1"),
            SubTask("t2", "Goal 2"),
            SubTask("t3", "Goal 3"),
        ]
        config = DelegationConfig(max_parallel=3)
        results = delegate_sub_tasks(tasks, wrapped, config)

        assert len(results) == 3
        assert all(r.success for r in results)
        assert set(r.sub_task_id for r in results) == {"t1", "t2", "t3"}


class TestParallelExecution:
    """Test parallel step execution."""

    def test_execute_steps_parallel(self):
        """Parallel execution runs ready steps concurrently."""
        completed = []

        def execute_fn(task_id, step_id, plan, sender):
            completed.append(step_id)
            from fusionagi.schemas.messages import AgentMessage, AgentMessageEnvelope
            return AgentMessageEnvelope(
                message=AgentMessage(
                    sender="executor",
                    recipient=sender,
                    intent="step_done",
                    payload={"step_id": step_id, "result": f"ok-{step_id}"},
                ),
                task_id=task_id,
            )

        plan = Plan(
            steps=[
                PlanStep(id="s1", description="First"),
                PlanStep(id="s2", description="Second", dependencies=["s1"]),
                PlanStep(id="s3", description="Third", dependencies=["s1"]),
            ]
        )
        # s2 and s3 are ready when s1 is done
        results = execute_steps_parallel(
            execute_fn, "task1", plan, completed_step_ids={"s1"}, max_workers=4
        )

        assert len(results) == 2
        assert set(r.step_id for r in results) == {"s2", "s3"}
        assert all(r.success for r in results)


class TestOrchestratorBatchRouting:
    """Test orchestrator batch routing."""

    def test_route_messages_batch(self):
        """Batch routing returns responses in order."""
        from fusionagi.schemas.messages import AgentMessage, AgentMessageEnvelope

        class EchoAgent:
            identity = "echo"

            def handle_message(self, env):
                return AgentMessageEnvelope(
                    message=AgentMessage(
                        sender="echo",
                        recipient=env.message.sender,
                        intent="echo_reply",
                        payload={"orig": env.message.payload.get("n")},
                    ),
                )

        bus = EventBus()
        state = StateManager()
        orch = Orchestrator(bus, state)
        orch.register_agent("echo", EchoAgent())

        envelopes = [
            AgentMessageEnvelope(
                message=AgentMessage(sender="c", recipient="echo", intent="test", payload={"n": i}),
            )
            for i in range(5)
        ]
        responses = orch.route_messages_batch(envelopes)

        assert len(responses) == 5
        for i, r in enumerate(responses):
            assert r is not None
            assert r.message.payload["orig"] == i