agents

%% quantum_protocol.erl
%% Quantum-inspired distribution protocol with entanglement and coherence
-module(quantum_protocol).
-behaviour(gen_server).

%% API
-export([
    start_link/1,
    send_entangled/3,
    create_superposition/2,
    measure_state/1,
    establish_entanglement/2,
    quantum_teleport/3,
    create_quantum_cluster/2
]).

%% gen_server callbacks
-export([init/1, handle_call/3, handle_cast/2, handle_info/2, terminate/2, code_change/3]).

%% Internal exports
-export([
    quantum_channel_handler/3,
    coherence_maintainer/2,
    entanglement_monitor/1
]).

-define(QUANTUM_CHANNEL_TABLE, quantum_channels).
-define(ENTANGLEMENT_TABLE, quantum_entanglements).
-define(SUPERPOSITION_TABLE, quantum_superpositions).

-record(state, {
    node_id :: atom(),
    quantum_state :: map(),
    entanglements :: map(),
    superpositions :: map(),
    coherence_time :: integer(),
    decoherence_rate :: float(),
    quantum_gates :: map(),
    error_correction :: boolean()
}).

-record(quantum_channel, {
    id :: reference(),
    node1 :: atom(),
    node2 :: atom(),
    entanglement_strength :: float(),
    coherence_time :: integer(),
    last_measurement :: erlang:timestamp(),
    error_rate :: float(),
    correction_code :: atom()
}).

-record(entangled_pair, {
    id :: reference(),
    pid1 :: pid(),
    pid2 :: pid(),
    entanglement_type :: atom(),
    creation_time :: erlang:timestamp(),
    measurement_history :: [term()],
    decoherence_factor :: float()
}).

-record(quantum_state, {
    amplitude :: {float(), float()}, % Complex number as {real, imaginary}
    phase :: float(),
    measurement_basis :: atom(),
    entangled_with :: [reference()],
    last_interaction :: erlang:timestamp()
}).

%% ============================================================================
%% API Functions
%% ============================================================================

start_link(Options) ->
    gen_server:start_link({local, ?MODULE}, ?MODULE, Options, []).

%% Send message using quantum entanglement (instantaneous)
send_entangled(EntanglementId, Message, Options) ->
    gen_server:call(?MODULE, {send_entangled, EntanglementId, Message, Options}).

%% Create quantum superposition of multiple states
create_superposition(States, Amplitudes) ->
    gen_server:call(?MODULE, {create_superposition, States, Amplitudes}).

%% Measure quantum state (collapses superposition)
measure_state(StateId) ->
    gen_server:call(?MODULE, {measure_state, StateId}).

%% Establish quantum entanglement between two processes
establish_entanglement(Pid1, Pid2) ->
    gen_server:call(?MODULE, {establish_entanglement, Pid1, Pid2}).

%% Quantum teleportation of process state
quantum_teleport(Pid, TargetNode, EntanglementId) ->
    gen_server:call(?MODULE, {quantum_teleport, Pid, TargetNode, EntanglementId}).

%% Create quantum cluster with all nodes entangled
create_quantum_cluster(Nodes, ClusterType) ->
    gen_server:call(?MODULE, {create_quantum_cluster, Nodes, ClusterType}).

%% ============================================================================
%% gen_server callbacks
%% ============================================================================

init(Options) ->
    %% Initialize quantum protocol tables
    setup_quantum_tables(),
    
    %% Initialize quantum state
    QuantumState = #{
        basis_state => zero,
        amplitude => {1.0, 0.0},
        phase => 0.0,
        entanglement_register => []
    },
    
    %% Start quantum subsystems
    {ok, _CoherenceMaintainer} = start_coherence_maintainer(),
    {ok, _EntanglementMonitor} = start_entanglement_monitor(),
    
    %% Initialize quantum gates
    QuantumGates = initialize_quantum_gates(),
    
    State = #state{
        node_id = node(),
        quantum_state = QuantumState,
        entanglements = #{},
        superpositions = #{},
        coherence_time = proplists:get_value(entanglement_timeout, Options, 5000),
        decoherence_rate = proplists:get_value(decoherence_rate, Options, 0.01),
        quantum_gates = QuantumGates,
        error_correction = proplists:get_value(quantum_error_correction, Options, true)
    },
    
    %% Register with distributed quantum network
    register_quantum_node(State),
    
    {ok, State}.

handle_call({send_entangled, EntanglementId, Message, Options}, _From, State) ->
    %% Send message using quantum entanglement
    Result = execute_entangled_send(EntanglementId, Message, Options, State),
    {reply, Result, State};

handle_call({create_superposition, States, Amplitudes}, _From, State) ->
    %% Create quantum superposition
    SuperpositionId = create_quantum_superposition(States, Amplitudes, State),
    {reply, {ok, SuperpositionId}, State};

handle_call({measure_state, StateId}, _From, State) ->
    %% Measure quantum state (collapse superposition)
    {Result, NewState} = measure_quantum_state(StateId, State),
    {reply, Result, NewState};

handle_call({establish_entanglement, Pid1, Pid2}, _From, State) ->
    %% Create quantum entanglement between processes
    {EntanglementId, NewState} = create_process_entanglement(Pid1, Pid2, State),
    {reply, {ok, EntanglementId}, NewState};

handle_call({quantum_teleport, Pid, TargetNode, EntanglementId}, _From, State) ->
    %% Teleport process state using quantum entanglement
    Result = execute_quantum_teleport(Pid, TargetNode, EntanglementId, State),
    {reply, Result, State};

handle_call({create_quantum_cluster, Nodes, ClusterType}, _From, State) ->
    %% Create quantum cluster with entangled nodes
    {ClusterId, NewState} = create_entangled_cluster(Nodes, ClusterType, State),
    {reply, {ok, ClusterId}, NewState};

handle_call(_Request, _From, State) ->
    {reply, {error, unknown_request}, State}.

handle_cast({quantum_measurement, EntanglementId, Result}, State) ->
    %% Handle quantum measurement results
    NewState = process_quantum_measurement(EntanglementId, Result, State),
    {noreply, NewState};

handle_cast({decoherence_event, EntityId, DecoherenceLevel}, State) ->
    %% Handle quantum decoherence
    NewState = handle_decoherence(EntityId, DecoherenceLevel, State),
    {noreply, NewState};

handle_cast({error_correction, EntanglementId, Errors}, State) ->
    %% Apply quantum error correction
    NewState = apply_error_correction(EntanglementId, Errors, State),
    {noreply, NewState};

handle_cast(_Msg, State) ->
    {noreply, State}.

handle_info({quantum_coherence_check}, State) ->
    %% Periodic coherence maintenance
    NewState = maintain_quantum_coherence(State),
    schedule_coherence_check(),
    {noreply, NewState};

handle_info({entanglement_decay, EntanglementId}, State) ->
    %% Handle entanglement decay
    NewState = process_entanglement_decay(EntanglementId, State),
    {noreply, NewState};

handle_info(_Info, State) ->
    {noreply, State}.

terminate(_Reason, _State) ->
    cleanup_quantum_resources(),
    ok.

code_change(_OldVsn, State, _Extra) ->
    {ok, State}.

%% ============================================================================
%% Quantum Channel Management
%% ============================================================================

quantum_channel_handler(ChannelId, Pid1, Pid2) ->
    %% Handle quantum channel communication
    receive
        {quantum_send, Message, Options} ->
            %% Apply quantum encoding
            EncodedMessage = apply_quantum_encoding(Message, Options),
            
            %% Send through quantum channel with error correction
            send_with_error_correction(Pid2, EncodedMessage, ChannelId),
            
            quantum_channel_handler(ChannelId, Pid1, Pid2);
            
        {quantum_receive, EncodedMessage, SenderId} ->
            %% Decode quantum message
            DecodedMessage = apply_quantum_decoding(EncodedMessage, SenderId),
            
            %% Forward to target process
            Pid1 ! {quantum_message, DecodedMessage, SenderId},
            
            quantum_channel_handler(ChannelId, Pid1, Pid2);
            
        {measurement_collapse, _MeasurementResult} ->
            %% Handle measurement-induced state collapse
            %% Placeholder for handle_measurement_collapse(ChannelId, MeasurementResult),
            quantum_channel_handler(ChannelId, Pid1, Pid2);
            
        stop ->
            cleanup_quantum_channel(ChannelId),
            ok
    end.

apply_quantum_encoding(Message, Options) ->
    %% Apply quantum encoding for secure transmission
    EntanglementKey = maps:get(entanglement_key, Options, default_key),
    PhaseRotation = maps:get(phase_rotation, Options, 0),
    
    %% Simulate quantum encoding
    EncodedBits = quantum_encode_bits(term_to_binary(Message)),
    RotatedBits = apply_phase_rotation(EncodedBits, PhaseRotation),
    
    #{
        encoded_data => RotatedBits,
        entanglement_key => EntanglementKey,
        encoding_timestamp => erlang:monotonic_time(nanosecond),
        error_correction_bits => generate_error_correction_bits(RotatedBits)
    }.

apply_quantum_decoding(EncodedMessage, _SenderId) ->
    %% Decode quantum-encoded message
    EncodedData = maps:get(encoded_data, EncodedMessage),
    ErrorCorrectionBits = maps:get(error_correction_bits, EncodedMessage),
    
    %% Apply error correction
    CorrectedData = apply_quantum_error_correction(EncodedData, ErrorCorrectionBits),
    
    %% Decode to original message
    DecodedBits = quantum_decode_bits(CorrectedData),
    binary_to_term(DecodedBits).

%% ============================================================================
%% Coherence Maintenance
%% ============================================================================

coherence_maintainer(State, CoherenceTime) ->
    %% Maintain quantum coherence across the system
    receive
        {maintain_coherence} ->
            %% Check all entanglements for coherence
            maintain_all_entanglements(State),
            
            %% Apply decoherence corrections
            apply_decoherence_corrections(State),
            
            %% Schedule next maintenance
            erlang:send_after(CoherenceTime, self(), {maintain_coherence}),
            
            coherence_maintainer(State, CoherenceTime);
            
        {update_coherence_time, NewTime} ->
            coherence_maintainer(State, NewTime);
            
        stop ->
            ok
    end.

maintain_all_entanglements(State) ->
    %% Maintain coherence for all active entanglements
    Entanglements = State#state.entanglements,
    
    maps:foreach(fun(EntanglementId, EntanglementData) ->
        maintain_entanglement_coherence(EntanglementId, EntanglementData)
    end, Entanglements).

maintain_entanglement_coherence(EntanglementId, EntanglementData) ->
    %% Apply coherence maintenance to specific entanglement
    CurrentCoherence = calculate_current_coherence(EntanglementData),
    
    case CurrentCoherence < 0.8 of
        true ->
            %% Apply coherence restoration
            apply_coherence_restoration(EntanglementId, EntanglementData);
        false ->
            ok
    end.

%% ============================================================================
%% Entanglement Monitoring
%% ============================================================================

entanglement_monitor(State) ->
    %% Monitor entanglement health and performance
    receive
        {monitor_entanglements} ->
            %% Check entanglement strength
            check_entanglement_strength(State),
            
            %% Monitor error rates
            monitor_error_rates(State),
            
            %% Check for Bell inequality violations
            verify_bell_inequalities(State),
            
            %% Schedule next monitoring
            erlang:send_after(1000, self(), {monitor_entanglements}),
            
            entanglement_monitor(State);
            
        {entanglement_violation, EntanglementId, ViolationType} ->
            %% Handle entanglement violations
            handle_entanglement_violation(EntanglementId, ViolationType),
            entanglement_monitor(State);
            
        stop ->
            ok
    end.

check_entanglement_strength(State) ->
    %% Measure entanglement strength for all pairs
    Entanglements = State#state.entanglements,
    
    maps:foreach(fun(EntanglementId, EntanglementData) ->
        Strength = measure_entanglement_strength(EntanglementData),
        
        case Strength < 0.5 of
            true ->
                %% Strengthen weak entanglement
                strengthen_entanglement(EntanglementId, EntanglementData);
            false ->
                ok
        end
    end, Entanglements).

%% ============================================================================
%% Multi-Agent Quantum Cluster
%% ============================================================================

create_entangled_cluster(Nodes, ClusterType, State) ->
    %% Create quantum cluster with all nodes entangled
    ClusterId = generate_cluster_id(),
    
    %% Create entanglement topology based on cluster type
    EntanglementTopology = case ClusterType of
        full_mesh ->
            create_full_mesh_entanglement(Nodes);
        ring ->
            create_ring_entanglement(Nodes);
        star ->
            create_star_entanglement(Nodes);
        hypercube ->
            create_hypercube_entanglement(Nodes)
    end,
    
    %% Establish quantum channels
    QuantumChannels = establish_cluster_channels(EntanglementTopology),
    
    %% Initialize cluster quantum state
    ClusterQuantumState = initialize_cluster_quantum_state(Nodes, ClusterType),
    
    %% Store cluster information
    ClusterInfo = #{
        id => ClusterId,
        nodes => Nodes,
        type => ClusterType,
        entanglement_topology => EntanglementTopology,
        quantum_channels => QuantumChannels,
        quantum_state => ClusterQuantumState,
        creation_time => erlang:timestamp()
    },
    
    %% Update state
    NewState = State#state{
        entanglements = maps:put(ClusterId, ClusterInfo, State#state.entanglements)
    },
    
    {ClusterId, NewState}.

create_full_mesh_entanglement(Nodes) ->
    %% Create full mesh entanglement (every node connected to every other)
    Pairs = [{N1, N2} || N1 <- Nodes, N2 <- Nodes, N1 < N2],
    
    lists:map(fun({Node1, Node2}) ->
        EntanglementId = generate_entanglement_id(),
        establish_node_entanglement(EntanglementId, Node1, Node2)
    end, Pairs).

create_ring_entanglement(Nodes) ->
    %% Create ring topology entanglement
    IndexedNodes = lists:zip(lists:seq(1, length(Nodes)), Nodes),
    
    lists:map(fun({Index, Node}) ->
        NextIndex = case Index of
            Len when Len =:= length(Nodes) -> 1;
            _ -> Index + 1
        end,
        NextNode = lists:nth(NextIndex, Nodes),
        
        EntanglementId = generate_entanglement_id(),
        establish_node_entanglement(EntanglementId, Node, NextNode)
    end, IndexedNodes).

create_hypercube_entanglement(Nodes) ->
    %% Create hypercube topology (each node connected to log2(N) others)
    NodeCount = length(Nodes),
    Dimension = trunc(math:log2(NodeCount)),
    
    IndexedNodes = lists:zip(lists:seq(0, NodeCount - 1), Nodes),
    
    lists:flatmap(fun({Index, Node}) ->
        %% Connect to nodes that differ by one bit
        Connections = [Index bxor (1 bsl Bit) || Bit <- lists:seq(0, Dimension - 1),
                       Index bxor (1 bsl Bit) < NodeCount],
        
        lists:map(fun(ConnectedIndex) ->
            ConnectedNode = lists:nth(ConnectedIndex + 1, Nodes),
            EntanglementId = generate_entanglement_id(),
            establish_node_entanglement(EntanglementId, Node, ConnectedNode)
        end, Connections)
    end, IndexedNodes).

%% ============================================================================
%% Quantum Error Correction
%% ============================================================================

apply_quantum_error_correction(Data, ErrorCorrectionBits) ->
    %% Apply quantum error correction using stabilizer codes
    ErrorSyndrome = calculate_error_syndrome(Data, ErrorCorrectionBits),
    
    case ErrorSyndrome of
        no_error ->
            Data;
        {bit_flip, Position} ->
            correct_bit_flip(Data, Position);
        {phase_flip, Position} ->
            correct_phase_flip(Data, Position);
        {both, Position} ->
            Data1 = correct_bit_flip(Data, Position),
            correct_phase_flip(Data1, Position)
    end.

calculate_error_syndrome(Data, ErrorCorrectionBits) ->
    %% Calculate syndrome for error detection
    %% This is a simplified implementation
    case erlang:crc32(Data) =:= ErrorCorrectionBits of
        true -> no_error;
        false -> {bit_flip, rand:uniform(bit_size(Data))}
    end.

%% ============================================================================
%% Utility Functions
%% ============================================================================

setup_quantum_tables() ->
    ets:new(?QUANTUM_CHANNEL_TABLE, [named_table, public, set, {write_concurrency, true}]),
    ets:new(?ENTANGLEMENT_TABLE, [named_table, public, set, {write_concurrency, true}]),
    ets:new(?SUPERPOSITION_TABLE, [named_table, public, set, {write_concurrency, true}]).

initialize_quantum_state() ->
    #{
        basis_state => zero,
        amplitude => {1.0, 0.0},  % Complex number (real, imaginary)
        phase => 0.0,
        entanglement_register => []
    }.

initialize_quantum_gates() ->
    #{
        hadamard => fun quantum_hadamard_gate/1,
        pauli_x => fun quantum_pauli_x_gate/1,
        pauli_y => fun quantum_pauli_y_gate/1,
        pauli_z => fun quantum_pauli_z_gate/1,
        cnot => fun quantum_cnot_gate/2,
        phase => fun quantum_phase_gate/2,
        toffoli => fun quantum_toffoli_gate/3
    }.

register_quantum_node(State) ->
    %% Register this node in the quantum network
    pg:join(quantum_nodes, self()),
    
    %% Announce quantum capabilities
    NodeCapabilities = #{
        node_id => State#state.node_id,
        quantum_gates => maps:keys(State#state.quantum_gates),
        entanglement_capacity => 1000,
        coherence_time => State#state.coherence_time,
        error_correction => State#state.error_correction
    },
    
    pg:join({quantum_capabilities, State#state.node_id}, NodeCapabilities).

generate_cluster_id() ->
    list_to_binary("cluster_" ++ integer_to_list(erlang:unique_integer())).

generate_entanglement_id() ->
    make_ref().

start_coherence_maintainer() ->
    Pid = spawn_link(?MODULE, coherence_maintainer, [#{}, 1000]),
    Pid ! {maintain_coherence},
    {ok, Pid}.

start_entanglement_monitor() ->
    Pid = spawn_link(?MODULE, entanglement_monitor, [#{}]),
    Pid ! {monitor_entanglements},
    {ok, Pid}.

schedule_coherence_check() ->
    erlang:send_after(1000, self(), {quantum_coherence_check}).

%% Placeholder implementations for quantum operations
execute_entangled_send(_, Message, _, _) -> {ok, Message}.
create_quantum_superposition(States, _, _) -> {ok, States}.
measure_quantum_state(StateId, State) -> {{measured, StateId}, State}.
create_process_entanglement(_Pid1, _Pid2, State) -> {make_ref(), State}.
execute_quantum_teleport(_, _, _, _) -> {ok, teleported}.
process_quantum_measurement(_, _, State) -> State.
handle_decoherence(_, _, State) -> State.
apply_error_correction(_, _, State) -> State.
maintain_quantum_coherence(State) -> State.
process_entanglement_decay(_, State) -> State.
cleanup_quantum_resources() -> ok.
send_with_error_correction(Pid, Message, _) -> Pid ! Message.
cleanup_quantum_channel(_) -> ok.
quantum_encode_bits(Binary) -> Binary.
apply_phase_rotation(Bits, _) -> Bits.
generate_error_correction_bits(Data) -> erlang:crc32(Data).
quantum_decode_bits(Bits) -> Bits.
apply_decoherence_corrections(_) -> ok.
calculate_current_coherence(_) -> 0.9.
apply_coherence_restoration(_, _) -> ok.
monitor_error_rates(_) -> ok.
verify_bell_inequalities(_) -> ok.
handle_entanglement_violation(_, _) -> ok.
measure_entanglement_strength(_) -> 0.8.
strengthen_entanglement(_, _) -> ok.
establish_cluster_channels(Topology) -> Topology.
initialize_cluster_quantum_state(_, _) -> #{}.
establish_node_entanglement(Id, Node1, Node2) -> {Id, Node1, Node2}.
create_star_entanglement(Nodes) ->
    %% Create star topology with first node as center
    case Nodes of
        [] -> [];
        [Center | Others] ->
            lists:map(fun(Node) ->
                EntanglementId = generate_entanglement_id(),
                establish_node_entanglement(EntanglementId, Center, Node)
            end, Others)
    end.
correct_bit_flip(Data, _) -> Data.
correct_phase_flip(Data, _) -> Data.
quantum_hadamard_gate(_) -> ok.
quantum_pauli_x_gate(_) -> ok.
quantum_pauli_y_gate(_) -> ok.
quantum_pauli_z_gate(_) -> ok.
quantum_cnot_gate(_, _) -> ok.
quantum_phase_gate(_, _) -> ok.
quantum_toffoli_gate(_, _, _) -> ok.