defmodule Foundation.Test.ClusterManager do
  @moduledoc """
  Manages test clusters for integration testing with configurable node topologies.
  """
  
  @type cluster_config :: %{
    node_count: pos_integer(),
    topology: :ring | :star | :mesh | :custom,
    partition_tolerance: boolean(),
    node_specs: [node_spec()],
    network_latency: latency_config()
  }
  
  @type node_spec :: %{
    name: atom(),
    applications: [atom()],
    config_overrides: keyword(),
    resource_limits: resource_config()
  }
  
  @spec start_test_cluster(cluster_config()) :: 
    {:ok, cluster_state()} | {:error, term()}
  def start_test_cluster(%{node_count: count} = config) when count > 1 do
    with {:ok, nodes} <- start_cluster_nodes(config),
         :ok <- establish_node_connections(nodes, config.topology),
         :ok <- deploy_applications_to_nodes(nodes, config),
         :ok <- verify_cluster_health(nodes) do
      
      cluster_state = %{
        nodes: nodes,
        config: config,
        started_at: DateTime.utc_now(),
        status: :healthy
      }
      
      {:ok, cluster_state}
    else
      {:error, reason} -> 
        cleanup_partial_cluster()
        {:error, reason}
    end
  end
  
  @spec simulate_network_partition(cluster_state(), partition_spec()) :: 
    {:ok, partition_result()} | {:error, term()}
  def simulate_network_partition(cluster_state, partition_spec) do
    with :ok <- validate_partition_spec(partition_spec),
         {:ok, partition_groups} <- create_partition_groups(cluster_state.nodes, partition_spec),
         :ok <- apply_network_partition(partition_groups),
         :ok <- monitor_partition_effects(partition_groups) do
      
      {:ok, %{
        partition_groups: partition_groups,
        applied_at: DateTime.utc_now(),
        status: :active
      }}
    end
  end
  
  # Node lifecycle management
  defp start_cluster_nodes(config) do
    node_tasks = Enum.map(config.node_specs, fn node_spec ->
      Task.async(fn -> start_test_node(node_spec, config) end)
    end)
    
    case Task.await_many(node_tasks, 30_000) do
      results when length(results) == length(config.node_specs) ->
        case Enum.all?(results, &match?({:ok, _}, &1)) do
          true -> {:ok, Enum.map(results, fn {:ok, node} -> node end)}
          false -> {:error, {:node_start_failures, results}}
        end
      _ ->
        {:error, :timeout_starting_nodes}
    end
  end
  
  defp start_test_node(node_spec, cluster_config) do
    # Start node with specific configuration
    node_args = [
      name: node_spec.name,
      cookie: :test_cluster_cookie,
      erl: build_erl_args(node_spec, cluster_config)
    ]
    
    case Node.start(node_spec.name, :longnames) do
      {:ok, node} ->
        configure_test_node(node, node_spec)
        {:ok, node}
      {:error, reason} ->
        {:error, {:failed_to_start_node, node_spec.name, reason}}
    end
  end
end

defmodule Foundation.Test.DistributedApplicationTest do
  @moduledoc """
  Tests for distributed application behavior across multiple nodes.
  """
  
  use ExUnit.Case
  alias Foundation.Test.ClusterManager
  
  @cluster_config %{
    node_count: 3,
    topology: :ring,
    partition_tolerance: true,
    node_specs: [
      %{name: :foundation_node_1, applications: [:foundation], config_overrides: []},
      %{name: :mabeam_node_1, applications: [:mabeam], config_overrides: []},
      %{name: :integration_node_1, applications: [:foundation, :mabeam], config_overrides: []}
    ],
    network_latency: %{min: 10, max: 100, unit: :millisecond}
  }
  
  setup_all do
    {:ok, cluster_state} = ClusterManager.start_test_cluster(@cluster_config)
    
    on_exit(fn ->
      ClusterManager.stop_test_cluster(cluster_state)
    end)
    
    %{cluster: cluster_state}
  end
  
  describe "distributed Foundation services" do
    test "ProcessRegistry synchronizes across nodes", %{cluster: cluster} do
      [node1, node2, node3] = cluster.nodes
      
      # Register process on node1
      process_name = :test_distributed_process
      {:ok, pid1} = Node.spawn_link(node1, fn -> 
        Foundation.ProcessRegistry.register(process_name, self())
        receive do
          :stop -> :ok
        end
      end)
      
      # Verify registration visible on other nodes
      assert {:ok, ^pid1} = 
        :rpc.call(node2, Foundation.ProcessRegistry, :lookup, [process_name])
      assert {:ok, ^pid1} = 
        :rpc.call(node3, Foundation.ProcessRegistry, :lookup, [process_name])
      
      # Cleanup
      send(pid1, :stop)
    end
    
    test "Events propagate across node boundaries", %{cluster: cluster} do
      [node1, node2, node3] = cluster.nodes
      
      # Subscribe to events on node2
      subscriber_pid = Node.spawn(node2, fn ->
        Foundation.Events.subscribe(self(), "test.distributed.event")
        receive do
          {:event, "test.distributed.event", data} ->
            send(:test_process, {:received_event, data})
        after
          5_000 -> send(:test_process, :timeout)
        end
      end)
      
      # Register test process
      Process.register(self(), :test_process)
      
      # Publish event from node1
      :rpc.call(node1, Foundation.Events, :publish, [
        "test.distributed.event", 
        %{message: "distributed test", from_node: node1}
      ])
      
      # Verify event received on node2
      assert_receive {:received_event, %{message: "distributed test"}}, 2_000
    end
  end
  
  describe "distributed MABEAM coordination" do
    test "Agent coordination works across nodes", %{cluster: cluster} do
      [node1, node2, node3] = cluster.nodes
      
      # Start agents on different nodes
      agent1_pid = start_test_agent_on_node(node1, :agent_1)
      agent2_pid = start_test_agent_on_node(node2, :agent_2)
      agent3_pid = start_test_agent_on_node(node3, :agent_3)
      
      # Initiate cross-node coordination
      agent_group = %MABEAM.Coordination.AgentGroup{
        agents: [
          %{id: :agent_1, pid: agent1_pid, node: node1},
          %{id: :agent_2, pid: agent2_pid, node: node2},
          %{id: :agent_3, pid: agent3_pid, node: node3}
        ]
      }
      
      {:ok, coordination_id} = 
        :rpc.call(node1, MABEAM.Coordination.AgentCoordinator, :coordinate_agent_group, [agent_group])
      
      # Verify coordination completes successfully
      assert_coordination_completion(coordination_id, 10_000)
    end
    
    test "Economic transactions work across distributed agents", %{cluster: cluster} do
      [node1, node2, _node3] = cluster.nodes
      
      # Create auction on node1
      auction_spec = build_distributed_auction_spec()
      {:ok, auction_id} = 
        :rpc.call(node1, MABEAM.Economics.AuctionManager, :create_auction, [auction_spec])
      
      # Place bid from agent on node2
      bid = build_test_bid(auction_id)
      :ok = :rpc.call(node2, MABEAM.Economics.AuctionManager, :place_bid_async, [auction_id, bid])
      
      # Verify bid processing across nodes
      eventually(fn ->
        {:ok, auction_status} = 
          :rpc.call(node1, MABEAM.Economics.AuctionManager, :get_auction_status, [auction_id])
        
        assert length(auction_status.bids) > 0
      end, 5_000)
    end
  end
end

defmodule Foundation.Test.NetworkPartitionTest do
  @moduledoc """
  Tests system behavior under network partitions and connectivity issues.
  """
  
  use ExUnit.Case
  alias Foundation.Test.ClusterManager
  
  describe "network partition tolerance" do
    test "Foundation services handle node isolation gracefully" do
      cluster_config = %{
        node_count: 5,
        topology: :mesh,
        partition_tolerance: true,
        node_specs: build_foundation_node_specs(5)
      }
      
      {:ok, cluster} = ClusterManager.start_test_cluster(cluster_config)
      
      # Create partition: isolate 2 nodes from the other 3
      partition_spec = %{
        groups: [
          %{nodes: Enum.take(cluster.nodes, 3), name: :majority},
          %{nodes: Enum.drop(cluster.nodes, 3), name: :minority}
        ],
        duration: 30_000  # 30 seconds
      }
      
      {:ok, partition_result} = ClusterManager.simulate_network_partition(cluster, partition_spec)
      
      # Test that majority partition continues to function
      [majority_node | _] = partition_spec.groups |> Enum.find(&(&1.name == :majority)) |> Map.get(:nodes)
      
      # Test ProcessRegistry operations during partition
      test_name = :partition_test_process
      {:ok, test_pid} = :rpc.call(majority_node, fn ->
        Foundation.ProcessRegistry.register(test_name, spawn(fn -> :timer.sleep(60_000) end))
      end)
      
      # Verify registration works within majority partition
      {:ok, ^test_pid} = :rpc.call(majority_node, Foundation.ProcessRegistry, :lookup, [test_name])
      
      # Heal partition
      :ok = ClusterManager.heal_network_partition(cluster, partition_result)
      
      # Verify system recovers and synchronizes
      eventually(fn ->
        # All nodes should see the registration
        Enum.each(cluster.nodes, fn node ->
          assert {:ok, ^test_pid} = :rpc.call(node, Foundation.ProcessRegistry, :lookup, [test_name])
        end)
      end, 10_000)
    end
    
    test "MABEAM coordination handles split-brain scenarios" do
      cluster_config = build_mabeam_cluster_config(4)
      {:ok, cluster} = ClusterManager.start_test_cluster(cluster_config)
      
      # Start coordination process before partition
      coordination_spec = build_test_coordination_spec()
      {:ok, coordination_id} = start_distributed_coordination(cluster.nodes, coordination_spec)
      
      # Create symmetric partition (2 nodes each side)
      partition_spec = %{
        groups: [
          %{nodes: Enum.take(cluster.nodes, 2), name: :group_a},
          %{nodes: Enum.drop(cluster.nodes, 2), name: :group_b}
        ],
        duration: 20_000
      }
      
      {:ok, _partition_result} = ClusterManager.simulate_network_partition(cluster, partition_spec)
      
      # Verify both groups handle coordination appropriately
      # Should detect split-brain and enter safe mode
      eventually(fn ->
        Enum.each(cluster.nodes, fn node ->
          coordination_status = :rpc.call(node, MABEAM.Coordination, :get_status, [coordination_id])
          assert coordination_status.mode in [:safe_mode, :partition_detected]
        end)
      end, 15_000)
    end
  end
  
  describe "cascading failure scenarios" do
    test "system handles progressive node failures" do
      cluster_config = build_fault_tolerance_cluster_config(6)
      {:ok, cluster} = ClusterManager.start_test_cluster(cluster_config)
      
      # Start system-wide processes
      system_processes = start_distributed_system_processes(cluster.nodes)
      
      # Progressively fail nodes (1 every 5 seconds)
      failure_schedule = [
        {5_000, Enum.at(cluster.nodes, 0)},
        {10_000, Enum.at(cluster.nodes, 1)},
        {15_000, Enum.at(cluster.nodes, 2)}
      ]
      
      Enum.each(failure_schedule, fn {delay, node} ->
        Process.sleep(delay)
        ClusterManager.simulate_node_failure(cluster, node, :crash)
      end)
      
      # Verify remaining nodes adapt and maintain functionality
      remaining_nodes = Enum.drop(cluster.nodes, 3)
      
      eventually(fn ->
        # System should still be functional on remaining nodes
        Enum.each(remaining_nodes, fn node ->
          assert :ok = verify_node_functionality(node, system_processes)
        end)
      end, 30_000)
    end
  end
end

defmodule Foundation.Test.ChaosEngineering do
  @moduledoc """
  Chaos engineering tests for system resilience validation.
  """
  
  @type chaos_scenario :: %{
    name: String.t(),
    duration: pos_integer(),
    conditions: [chaos_condition()],
    success_criteria: [success_criterion()]
  }
  
  @type chaos_condition :: 
    {:node_failure, node_failure_spec()} |
    {:network_latency, latency_spec()} |
    {:resource_exhaustion, resource_spec()} |
    {:message_loss, loss_spec()}
  
  @spec run_chaos_scenario(cluster_state(), chaos_scenario()) :: 
    {:ok, chaos_result()} | {:error, term()}
  def run_chaos_scenario(cluster_state, scenario) do
    Logger.info("Starting chaos scenario", scenario: scenario.name)
    
    # Setup monitoring
    monitoring_pid = start_chaos_monitoring(cluster_state, scenario)
    
    # Apply chaos conditions
    chaos_pids = Enum.map(scenario.conditions, fn condition ->
      apply_chaos_condition(cluster_state, condition, scenario.duration)
    end)
    
    # Wait for scenario completion
    Process.sleep(scenario.duration)
    
    # Cleanup chaos conditions
    Enum.each(chaos_pids, &GenServer.stop/1)
    
    # Collect results
    results = collect_chaos_results(monitoring_pid, scenario)
    GenServer.stop(monitoring_pid)
    
    # Evaluate success criteria
    case evaluate_success_criteria(results, scenario.success_criteria) do
      :success -> {:ok, results}
      {:failure, reasons} -> {:error, {:chaos_scenario_failed, reasons, results}}
    end
  end
  
  # Chaos condition implementations
  defp apply_chaos_condition(cluster_state, {:node_failure, failure_spec}, duration) do
    GenServer.start_link(__MODULE__.NodeFailureAgent, {cluster_state, failure_spec, duration})
  end
  
  defp apply_chaos_condition(cluster_state, {:network_latency, latency_spec}, duration) do
    GenServer.start_link(__MODULE__.NetworkLatencyAgent, {cluster_state, latency_spec, duration})
  end
  
  defp apply_chaos_condition(cluster_state, {:resource_exhaustion, resource_spec}, duration) do
    GenServer.start_link(__MODULE__.ResourceExhaustionAgent, {cluster_state, resource_spec, duration})
  end
  
  # Example chaos scenarios
  @chaos_scenarios [
    %{
      name: "Progressive Node Failures",
      duration: 60_000,
      conditions: [
        {:node_failure, %{type: :random, interval: 10_000, count: 2}},
        {:network_latency, %{min: 100, max: 1000, affected_percentage: 30}}
      ],
      success_criteria: [
        {:system_availability, 0.8},
        {:data_consistency, 1.0},
        {:recovery_time, 30_000}
      ]
    },
    %{
      name: "Memory Pressure with Partitions",
      duration: 45_000,
      conditions: [
        {:resource_exhaustion, %{type: :memory, target_percentage: 90}},
        {:network_latency, %{min: 500, max: 2000, affected_percentage: 50}}
      ],
      success_criteria: [
        {:system_availability, 0.7},
        {:error_rate, 0.05},
        {:gc_pressure, 0.8}
      ]
    }
  ]
  
  def run_all_chaos_scenarios(cluster_state) do
    Enum.map(@chaos_scenarios, fn scenario ->
      {scenario.name, run_chaos_scenario(cluster_state, scenario)}
    end)
  end
end

defmodule Foundation.Test.EndToEndWorkflows do
  @moduledoc """
  End-to-end workflow testing across Foundation and MABEAM services.
  """
  
  use ExUnit.Case
  
  describe "complete economic workflow" do
    test "auction creation through settlement workflow" do
      # Step 1: Create auction (Economics.AuctionManager)
      auction_spec = build_comprehensive_auction_spec()
      {:ok, auction_id} = MABEAM.Economics.AuctionManager.create_auction(auction_spec)
      
      # Step 2: Verify market data updated (Economics.MarketDataService)
      eventually(fn ->
        market_state = MABEAM.Economics.MarketDataService.get_current_market_state()
        assert Map.has_key?(market_state.active_auctions, auction_id)
      end, 5_000)
      
      # Step 3: Coordinate bidding agents (Coordination.AgentCoordinator)
      bidding_agents = create_bidding_agent_group(auction_id)
      {:ok, coordination_id} = 
        MABEAM.Coordination.AgentCoordinator.coordinate_agent_group(bidding_agents)
      
      # Step 4: Agents place bids (via agent coordination)
      wait_for_coordination_completion(coordination_id, 10_000)
      
      # Step 5: Verify bids placed (Economics.AuctionManager)
      eventually(fn ->
        {:ok, auction_status} = MABEAM.Economics.AuctionManager.get_auction_status(auction_id)
        assert length(auction_status.bids) >= 3
      end, 5_000)
      
      # Step 6: Close auction (Economics.AuctionManager)
      {:ok, auction_result} = MABEAM.Economics.AuctionManager.close_auction(auction_id)
      
      # Step 7: Process payment (Economics.TransactionProcessor)
      {:ok, transaction_id} = 
        MABEAM.Economics.TransactionProcessor.process_transaction(auction_result.winning_transaction)
      
      # Step 8: Verify transaction completion
      eventually(fn ->
        assert_receive {:event, "economics.transaction.completed", %{transaction_id: ^transaction_id}}, 1_000
      end, 10_000)
      
      # Step 9: Verify analytics updated (Economics.AnalyticsService)
      eventually(fn ->
        {:ok, metrics} = MABEAM.Economics.AnalyticsService.get_cached_report(:recent_auctions, :last_hour)
        assert Enum.any?(metrics.completed_auctions, &(&1.auction_id == auction_id))
      end, 5_000)
      
      # Step 10: Verify performance metrics recorded (Foundation.Telemetry)
      telemetry_events = collect_telemetry_events_for_workflow(auction_id)
      assert length(telemetry_events) >= 8  # One for each major step
    end
    
    test "multi-agent coordination with resource allocation" do
      # Step 1: Create resource pool
      resource_pool = create_test_resource_pool()
      
      # Step 2: Start multiple agents requiring resources
      agents = Enum.map(1..10, fn i ->
        start_resource_requiring_agent("agent_#{i}", resource_pool.id)
      end)
      
      # Step 3: Initiate resource allocation coordination
      allocation_spec = %{
        resource_pool_id: resource_pool.id,
        agents: agents,
        allocation_strategy: :fair_share
      }
      
      {:ok, allocation_id} = 
        MABEAM.Coordination.ResourceAllocator.allocate_resources(allocation_spec)
      
      # Step 4: Wait for allocation completion
      wait_for_resource_allocation(allocation_id, 15_000)
      
      # Step 5: Verify all agents received resources
      Enum.each(agents, fn agent ->
        agent_resources = MABEAM.Coordination.ResourceAllocator.get_agent_resources(agent.id)
        assert agent_resources.allocated_resources |> Map.values() |> Enum.sum() > 0
      end)
      
      # Step 6: Simulate resource usage and monitoring
      simulate_resource_usage(agents, 10_000)
      
      # Step 7: Verify resource monitoring and reallocation
      eventually(fn ->
        reallocation_events = get_reallocation_events(allocation_id)
        assert length(reallocation_events) >= 2  # Some reallocation should occur
      end, 20_000)
    end
  end
  
  describe "fault tolerance workflow" do
    test "system recovery after coordinated agent failure" do
      # Step 1: Start coordination with 5 agents
      agents = start_coordination_agent_group(5)
      {:ok, coordination_id} = start_long_running_coordination(agents)
      
      # Step 2: Verify coordination is running
      assert_coordination_active(coordination_id)
      
      # Step 3: Simulate failure of 2 agents
      [agent1, agent2 | remaining_agents] = agents
      simulate_agent_crash(agent1)
      simulate_agent_crash(agent2)
      
      # Step 4: Verify fault detection
      eventually(fn ->
        coordination_status = get_coordination_status(coordination_id)
        assert coordination_status.failed_agents == [agent1.id, agent2.id]
      end, 5_000)
      
      # Step 5: Verify automatic recovery initiation
      eventually(fn ->
        recovery_status = get_recovery_status(coordination_id)
        assert recovery_status.recovery_initiated == true
      end, 10_000)
      
      # Step 6: Start replacement agents
      replacement_agents = start_replacement_agents(2)
      
      # Step 7: Verify coordination adapts to new topology
      eventually(fn ->
        coordination_status = get_coordination_status(coordination_id)
        active_agent_count = length(coordination_status.active_agents)
        assert active_agent_count == 5  # Original count restored
      end, 15_000)
      
      # Step 8: Verify coordination completes successfully
      wait_for_coordination_completion(coordination_id, 30_000)
    end
  end
end

defmodule Foundation.Test.ServiceContractValidation do
  @moduledoc """
  Validates service contracts and API compatibility across service boundaries.
  """
  
  use ExUnit.Case
  
  # Contract specification for Foundation.ProcessRegistry
  @process_registry_contract %{
    register: %{
      input: {:name, :pid, :opts},
      output: [:ok, {:error, :term}],
      side_effects: [:process_monitored, :registration_event_published]
    },
    lookup: %{
      input: {:name},
      output: [{:ok, :pid}, {:error, :not_found}],
      side_effects: []
    },
    unregister: %{
      input: {:name},
      output: [:ok, {:error, :not_found}],
      side_effects: [:process_unmonitored, :unregistration_event_published]
    }
  }
  
  describe "Foundation service contracts" do
    test "ProcessRegistry adheres to defined contract" do
      contract = @process_registry_contract
      
      # Test register/3 contract
      test_pid = spawn(fn -> :timer.sleep(1_000) end)
      
      # Verify successful registration follows contract
      assert :ok = Foundation.ProcessRegistry.register(:test_process, test_pid, [])
      
      # Verify lookup follows contract
      assert {:ok, ^test_pid} = Foundation.ProcessRegistry.lookup(:test_process)
      
      # Verify unregistration follows contract  
      assert :ok = Foundation.ProcessRegistry.unregister(:test_process)
      assert {:error, :not_found} = Foundation.ProcessRegistry.lookup(:test_process)
      
      # Verify error conditions follow contract
      assert {:error, :already_registered} = 
        Foundation.ProcessRegistry.register(:test_process, test_pid, [])
    end
    
    test "Events service maintains event contract integrity" do
      event_contract = %{
        publish: %{
          input: {:topic, :data},
          output: [:ok],
          side_effects: [:event_delivered_to_subscribers]
        },
        subscribe: %{
          input: {:subscriber_pid, :topic_pattern},
          output: [:ok, {:error, :term}],
          side_effects: [:subscription_registered]
        }
      }
      
      # Test event publishing contract
      test_topic = "test.contract.validation"
      test_data = %{message: "contract test", timestamp: DateTime.utc_now()}
      
      # Subscribe first to verify delivery
      Foundation.Events.subscribe(self(), test_topic)
      
      # Publish event
      assert :ok = Foundation.Events.publish(test_topic, test_data)
      
      # Verify contract side effect (event delivery)
      assert_receive {:event, ^test_topic, ^test_data}, 1_000
    end
  end
  
  describe "MABEAM service contracts" do
    test "Economics services maintain transactional integrity" do
      # Test auction creation contract
      auction_spec = build_valid_auction_spec()
      
      assert {:ok, auction_id} = 
        MABEAM.Economics.AuctionManager.create_auction(auction_spec)
      assert is_binary(auction_id)
      
      # Verify auction appears in market data (contract side effect)
      eventually(fn ->
        market_state = MABEAM.Economics.MarketDataService.get_current_market_state()
        assert Map.has_key?(market_state.active_auctions, auction_id)
      end, 5_000)
      
      # Test bidding contract
      bid = build_valid_bid(auction_id)
      assert :ok = MABEAM.Economics.AuctionManager.place_bid_async(auction_id, bid)
      
      # Verify bid recorded (contract side effect)
      eventually(fn ->
        {:ok, auction_status} = MABEAM.Economics.AuctionManager.get_auction_status(auction_id)
        assert length(auction_status.bids) > 0
      end, 3_000)
    end
    
    test "Coordination services maintain consistency guarantees" do
      # Test agent coordination contract
      agent_group = build_test_agent_group()
      
      assert {:ok, coordination_id} = 
        MABEAM.Coordination.AgentCoordinator.coordinate_agent_group(agent_group)
      assert is_binary(coordination_id)
      
      # Verify coordination status accessible (contract guarantee)
      assert {:ok, _status} = 
        MABEAM.Coordination.AgentCoordinator.get_coordination_status(coordination_id)
      
      # Test consensus protocol contract
      proposal = build_test_proposal()
      
      assert {:ok, consensus_id} = 
        MABEAM.Coordination.ConsensusProtocol.initiate_consensus(proposal)
      
      # Vote casting should follow contract
      agent_ids = Enum.map(agent_group.agents, & &1.id)
      Enum.each(agent_ids, fn agent_id ->
        vote = build_test_vote(:approve)
        assert :ok = MABEAM.Coordination.ConsensusProtocol.cast_vote(consensus_id, agent_id, vote)
      end)
      
      # Verify consensus completion (contract guarantee)
      eventually(fn ->
        assert_receive {:event, "coordination.consensus.completed", %{consensus_id: ^consensus_id}}, 1_000
      end, 10_000)
    end
  end
end

defmodule Foundation.Test.DistributedLoadTest do
  @moduledoc """
  Distributed load testing framework for validating system performance under load.
  """
  
  @type load_test_spec :: %{
    name: String.t(),
    duration: pos_integer(),
    concurrent_users: pos_integer(),
    operations_per_second: pos_integer(),
    test_scenarios: [test_scenario()],
    success_criteria: [performance_criterion()]
  }
  
  @type test_scenario :: %{
    name: String.t(),
    weight: float(),
    operation: operation_spec()
  }
  
  @spec run_distributed_load_test(cluster_state(), load_test_spec()) :: 
    {:ok, load_test_result()} | {:error, term()}
  def run_distributed_load_test(cluster_state, test_spec) do
    Logger.info("Starting distributed load test", test: test_spec.name)
    
    # Distribute load generators across cluster nodes
    load_generators = distribute_load_generators(cluster_state, test_spec)
    
    # Start coordinated load generation
    coordinator_pid = start_load_test_coordinator(test_spec, load_generators)
    
    # Monitor system performance during test
    monitoring_pid = start_performance_monitoring(cluster_state, test_spec)
    
    # Wait for test completion
    receive do
      {:load_test_complete, results} -> 
        stop_monitoring(monitoring_pid)
        {:ok, results}
      {:load_test_failed, reason} -> 
        cleanup_load_test(load_generators, monitoring_pid)
        {:error, reason}
    after
      test_spec.duration + 30_000 -> 
        cleanup_load_test(load_generators, monitoring_pid)
        {:error, :test_timeout}
    end
  end
  
  # Load generator distribution
  defp distribute_load_generators(cluster_state, test_spec) do
    generators_per_node = div(test_spec.concurrent_users, length(cluster_state.nodes))
    
    Enum.map(cluster_state.nodes, fn node ->
      generator_spec = %{
        node: node,
        concurrent_users: generators_per_node,
        operations_per_second: test_spec.operations_per_second,
        scenarios: test_spec.test_scenarios
      }
      
      {:ok, generator_pid} = 
        :rpc.call(node, Foundation.Test.LoadGenerator, :start_link, [generator_spec])
      
      %{node: node, pid: generator_pid, spec: generator_spec}
    end)
  end
  
  # Performance monitoring during load test
  defp start_performance_monitoring(cluster_state, test_spec) do
    spawn_link(fn ->
      monitor_performance_metrics(cluster_state, test_spec)
    end)
  end
  
  defp monitor_performance_metrics(cluster_state, test_spec) do
    start_time = System.monotonic_time(:millisecond)
    end_time = start_time + test_spec.duration
    
    metrics_collection_loop(cluster_state, start_time, end_time, [])
  end
  
  defp metrics_collection_loop(cluster_state, start_time, end_time, accumulated_metrics) do
    current_time = System.monotonic_time(:millisecond)
    
    if current_time >= end_time do
      # Send final metrics
      send(self(), {:performance_metrics_complete, accumulated_metrics})
    else
      # Collect current metrics from all nodes
      current_metrics = collect_cluster_metrics(cluster_state, current_time - start_time)
      
      # Wait 1 second before next collection
      Process.sleep(1_000)
      
      metrics_collection_loop(cluster_state, start_time, end_time, [current_metrics | accumulated_metrics])
    end
  end
  
  defp collect_cluster_metrics(cluster_state, elapsed_time) do
    node_metrics = Enum.map(cluster_state.nodes, fn node ->
      metrics = :rpc.call(node, Foundation.Telemetry, :get_current_metrics, [])
      {node, metrics}
    end)
    
    %{
      timestamp: elapsed_time,
      node_metrics: node_metrics,
      cluster_metrics: aggregate_cluster_metrics(node_metrics)
    }
  end
end

defmodule Foundation.Test.WorkloadSimulator do
  @moduledoc """
  Simulates realistic workloads for comprehensive system testing.
  """
  
  # Realistic economics workload patterns
  @economics_workload_patterns [
    %{
      name: "High Frequency Trading",
      operations: [
        %{type: :create_auction, frequency: 100, weight: 0.3},
        %{type: :place_bid, frequency: 500, weight: 0.5},
        %{type: :check_market_data, frequency: 1000, weight: 0.2}
      ],
      duration: 300_000,  # 5 minutes
      concurrent_users: 200
    },
    %{
      name: "Normal Business Operations",
      operations: [
        %{type: :create_auction, frequency: 10, weight: 0.4},
        %{type: :place_bid, frequency: 50, weight: 0.4},
        %{type: :generate_reports, frequency: 1, weight: 0.2}
      ],
      duration: 600_000,  # 10 minutes
      concurrent_users: 50
    }
  ]
  
  # Realistic coordination workload patterns
  @coordination_workload_patterns [
    %{
      name: "Multi-Agent Coordination Burst",
      operations: [
        %{type: :coordinate_agents, frequency: 20, weight: 0.4},
        %{type: :consensus_voting, frequency: 10, weight: 0.3},
        %{type: :resource_allocation, frequency: 5, weight: 0.3}
      ],
      duration: 180_000,  # 3 minutes
      concurrent_users: 100
    },
    %{
      name: "Steady State Coordination",
      operations: [
        %{type: :coordinate_agents, frequency: 5, weight: 0.5},
        %{type: :monitor_performance, frequency: 1, weight: 0.3},
        %{type: :fault_detection, frequency: 0.1, weight: 0.2}
      ],
      duration: 900_000,  # 15 minutes
      concurrent_users: 25
    }
  ]
  
  @spec simulate_realistic_workload(workload_pattern()) :: {:ok, workload_result()}
  def simulate_realistic_workload(workload_pattern) do
    # Start workload generators for each operation type
    operation_generators = Enum.map(workload_pattern.operations, fn operation ->
      start_operation_generator(operation, workload_pattern)
    end)
    
    # Monitor workload execution
    workload_monitor = start_workload_monitor(workload_pattern)
    
    # Wait for workload completion
    Process.sleep(workload_pattern.duration)
    
    # Stop generators and collect results
    results = collect_workload_results(operation_generators, workload_monitor)
    cleanup_workload_generators(operation_generators, workload_monitor)
    
    {:ok, results}
  end
  
  defp start_operation_generator(operation, workload_pattern) do
    spawn_link(fn ->
      operation_generator_loop(operation, workload_pattern)
    end)
  end
  
  defp operation_generator_loop(operation, workload_pattern) do
    # Calculate interval based on frequency
    interval = 1000 / operation.frequency  # milliseconds between operations
    
    # Execute operation based on type
    execute_operation(operation.type)
    
    # Wait for next execution
    Process.sleep(round(interval))
    
    # Continue loop
    operation_generator_loop(operation, workload_pattern)
  end
  
  defp execute_operation(:create_auction) do
    auction_spec = generate_realistic_auction_spec()
    MABEAM.Economics.AuctionManager.create_auction(auction_spec)
  end
  
  defp execute_operation(:place_bid) do
    # Find active auction and place bid
    case get_random_active_auction() do
      {:ok, auction_id} ->
        bid = generate_realistic_bid(auction_id)
        MABEAM.Economics.AuctionManager.place_bid_async(auction_id, bid)
      {:error, :no_active_auctions} ->
        :no_op
    end
  end
  
  defp execute_operation(:coordinate_agents) do
    agent_group = generate_realistic_agent_group()
    MABEAM.Coordination.AgentCoordinator.coordinate_agent_group(agent_group)
  end
  
  defp execute_operation(:consensus_voting) do
    proposal = generate_realistic_proposal()
    case MABEAM.Coordination.ConsensusProtocol.initiate_consensus(proposal) do
      {:ok, consensus_id} ->
        # Simulate voting from multiple agents
        simulate_consensus_voting(consensus_id, proposal)
      {:error, _reason} ->
        :no_op
    end
  end
  
  # Realistic data generation functions
  defp generate_realistic_auction_spec() do
    %{
      id: "auction_#{:rand.uniform(1_000_000)}",
      title: Enum.random(["Server Resources", "Data Processing", "ML Training", "Storage"]),
      duration: :rand.uniform(3600) + 300,  # 5 minutes to 1 hour
      starting_price: :rand.uniform(1000) + 100,
      reserve_price: :rand.uniform(2000) + 500
    }
  end
  
  defp generate_realistic_bid(auction_id) do
    %{
      auction_id: auction_id,
      bidder_id: "bidder_#{:rand.uniform(100)}",
      amount: :rand.uniform(5000) + 200,
      timestamp: DateTime.utc_now()
    }
  end
end

defmodule Foundation.Test.CIPipeline do
  @moduledoc """
  Continuous integration pipeline for comprehensive system testing.
  """
  
  @test_stages [
    %{
      name: "Unit Tests",
      duration: 300,  # 5 minutes
      parallel: true,
      required: true
    },
    %{
      name: "Service Integration Tests", 
      duration: 600,  # 10 minutes
      parallel: true,
      required: true
    },
    %{
      name: "Multi-Node Integration Tests",
      duration: 1200,  # 20 minutes
      parallel: false,
      required: true
    },
    %{
      name: "Performance Tests",
      duration: 900,  # 15 minutes
      parallel: false,
      required: false  # Optional for feature branches
    },
    %{
      name: "Chaos Engineering Tests",
      duration: 1800,  # 30 minutes
      parallel: false,
      required: false  # Only for release candidates
    }
  ]
  
  @spec run_ci_pipeline(pipeline_config()) :: {:ok, pipeline_result()} | {:error, term()}
  def run_ci_pipeline(config) do
    Logger.info("Starting CI pipeline", config: config)
    
    # Filter test stages based on configuration
    stages_to_run = filter_stages_for_context(config)
    
    # Execute stages
    case execute_pipeline_stages(stages_to_run, config) do
      {:ok, results} ->
        generate_pipeline_report(results, config)
        {:ok, results}
      {:error, {stage, reason, partial_results}} ->
        generate_failure_report(stage, reason, partial_results, config)
        {:error, {stage, reason}}
    end
  end
  
  defp execute_pipeline_stages(stages, config) do
    Enum.reduce_while(stages, {:ok, []}, fn stage, {:ok, results} ->
      case execute_pipeline_stage(stage, config) do
        {:ok, stage_result} ->
          {:cont, {:ok, [stage_result | results]}}
        {:error, reason} ->
          {:halt, {:error, {stage.name, reason, results}}}
      end
    end)
  end
  
  defp execute_pipeline_stage(%{name: "Multi-Node Integration Tests"} = stage, config) do
    # Setup test cluster
    cluster_config = build_ci_cluster_config(config)
    
    case Foundation.Test.ClusterManager.start_test_cluster(cluster_config) do
      {:ok, cluster_state} ->
        # Run integration test suite
        test_results = run_integration_test_suite(cluster_state)
        
        # Cleanup cluster
        Foundation.Test.ClusterManager.stop_test_cluster(cluster_state)
        
        {:ok, %{stage: stage.name, results: test_results}}
      {:error, reason} ->
        {:error, {:cluster_setup_failed, reason}}
    end
  end
  
  defp execute_pipeline_stage(%{name: "Performance Tests"} = stage, config) do
    # Setup performance test environment
    cluster_config = build_performance_cluster_config(config)
    
    case Foundation.Test.ClusterManager.start_test_cluster(cluster_config) do
      {:ok, cluster_state} ->
        # Run performance test suite
        performance_results = run_performance_test_suite(cluster_state)
        
        # Cleanup
        Foundation.Test.ClusterManager.stop_test_cluster(cluster_state)
        
        case validate_performance_criteria(performance_results, config) do
          :ok -> {:ok, %{stage: stage.name, results: performance_results}}
          {:error, violations} -> {:error, {:performance_criteria_failed, violations}}
        end
      {:error, reason} ->
        {:error, {:performance_cluster_setup_failed, reason}}
    end
  end
  
  defp run_integration_test_suite(cluster_state) do
    test_modules = [
      Foundation.Test.DistributedApplicationTest,
      Foundation.Test.NetworkPartitionTest,
      Foundation.Test.EndToEndWorkflows,
      Foundation.Test.ServiceContractValidation
    ]
    
    Enum.map(test_modules, fn test_module ->
      {test_module, ExUnit.run_module(test_module, cluster_state)}
    end)
  end
  
  defp validate_performance_criteria(performance_results, config) do
    criteria = config.performance_criteria || default_performance_criteria()
    
    violations = Enum.reduce(criteria, [], fn {metric, threshold}, acc ->
      actual_value = get_performance_metric(performance_results, metric)
      
      if meets_criteria?(metric, actual_value, threshold) do
        acc
      else
        [{metric, actual_value, threshold} | acc]
      end
    end)
    
    if Enum.empty?(violations) do
      :ok
    else
      {:error, violations}
    end
  end
  
  defp default_performance_criteria() do
    %{
      average_response_time: 100,  # milliseconds
      p95_response_time: 500,      # milliseconds
      error_rate: 0.01,            # 1%
      throughput: 1000,            # operations per second
      memory_usage: 0.8            # 80% of available memory
    }
  end
end