"""Tests for CRDT flow dampening."""

import numpy as np
from src.crdt.flow_dampening import (
    CRDTFlowSystem,
    merge_flow_states,
    peer_penalty,
    simulate_drain_attack,
    update_peer_flow,
)


class TestPeerFlowTracking:
    def test_new_peer_no_penalty(self):
        system = CRDTFlowSystem(default_total_value_ref=1000.0)
        assert peer_penalty(system, "alice") == 1.0

    def test_update_records_flow(self):
        system = CRDTFlowSystem(default_total_value_ref=1000.0)
        system = update_peer_flow(system, "alice", 50.0, 0.0)
        assert "alice" in system.peers
        assert system.peers["alice"].tracker.current_flow == 50.0

    def test_multiple_peers_independent(self):
        system = CRDTFlowSystem(default_total_value_ref=1000.0)
        system = update_peer_flow(system, "alice", 50.0, 0.0)
        system = update_peer_flow(system, "bob", 200.0, 0.0)
        assert system.peers["alice"].tracker.current_flow == 50.0
        assert system.peers["bob"].tracker.current_flow == 200.0

    def test_high_flow_triggers_penalty(self):
        system = CRDTFlowSystem(
            default_total_value_ref=1000.0, default_threshold=0.1,
        )
        system = update_peer_flow(system, "alice", 200.0, 0.0)
        penalty = peer_penalty(system, "alice")
        assert penalty < 1.0

    def test_pure_functional_no_mutation(self):
        system = CRDTFlowSystem(default_total_value_ref=1000.0)
        updated = update_peer_flow(system, "alice", 50.0, 0.0)
        assert "alice" not in system.peers
        assert "alice" in updated.peers


class TestFlowMerge:
    def test_merge_commutativity(self):
        a = CRDTFlowSystem(default_total_value_ref=1000.0)
        a = update_peer_flow(a, "alice", 100.0, 0.0)
        b = CRDTFlowSystem(default_total_value_ref=1000.0)
        b = update_peer_flow(b, "alice", 50.0, 1.0)

        ab = merge_flow_states(a, b)
        ba = merge_flow_states(b, a)
        assert ab.peers["alice"].tracker.current_flow == ba.peers["alice"].tracker.current_flow
        assert ab.peers["alice"].tracker.last_update_time == ba.peers["alice"].tracker.last_update_time

    def test_merge_idempotency(self):
        a = CRDTFlowSystem(default_total_value_ref=1000.0)
        a = update_peer_flow(a, "alice", 100.0, 0.0)
        aa = merge_flow_states(a, a)
        assert aa.peers["alice"].tracker.current_flow == a.peers["alice"].tracker.current_flow

    def test_merge_takes_max_flow(self):
        a = CRDTFlowSystem(default_total_value_ref=1000.0)
        a = update_peer_flow(a, "alice", 100.0, 0.0)
        b = CRDTFlowSystem(default_total_value_ref=1000.0)
        b = update_peer_flow(b, "alice", 200.0, 0.0)

        merged = merge_flow_states(a, b)
        assert merged.peers["alice"].tracker.current_flow == 200.0

    def test_merge_disjoint_peers(self):
        a = CRDTFlowSystem(default_total_value_ref=1000.0)
        a = update_peer_flow(a, "alice", 100.0, 0.0)
        b = CRDTFlowSystem(default_total_value_ref=1000.0)
        b = update_peer_flow(b, "bob", 50.0, 0.0)

        merged = merge_flow_states(a, b)
        assert "alice" in merged.peers
        assert "bob" in merged.peers


class TestDrainSimulation:
    def test_simulation_returns_arrays(self):
        system = CRDTFlowSystem(
            default_total_value_ref=10000.0, default_threshold=0.1,
        )
        result = simulate_drain_attack(
            system, "attacker",
            amounts=[100.0] * 10,
            times=[float(i) for i in range(10)],
        )
        assert len(result["times"]) == 10
        assert len(result["flows"]) == 10
        assert len(result["penalties"]) == 10

    def test_penalty_increases_with_drain(self):
        system = CRDTFlowSystem(
            default_total_value_ref=1000.0, default_threshold=0.1,
        )
        result = simulate_drain_attack(
            system, "attacker",
            amounts=[200.0] * 5,
            times=[0.0, 0.1, 0.2, 0.3, 0.4],
        )
        # Penalties should decrease (get worse) as flow accumulates
        assert result["penalties"][-1] <= result["penalties"][0]