//! This module implements a delegation system for the agent.

use ::std::borrow::Borrow;
use std::thread;
use std::time::{Duration, Instant};

#[cfg(feature = "mqtt")]
pub mod mqtt;

pub mod transport;
pub mod transport_messages;

use futures::join;
use yaaral::RuntimeInterface;

use crate::{agent, decision, delegation, module, uuid, Result};

//   ____   _____   ____
//  / ___| |  ___| |  _ \
// | |     | |_    | |_) |
// | |___  |  _|   |  __/
//  \____| |_|     |_|

/// Represents a call for proposal
#[derive(Clone, serde::Deserialize, serde::Serialize)]
pub struct CFP
{
  /// uuid of the CFP
  pub uuid: uuid::Uuid,
  /// URI for the agent which resuest the delegation of the task.
  pub requester_uri: String,
  /// the URI of the team
  pub team_uri: Option<String>,
  /// the URI for the type of the task
  pub task_type: String,
  /// a string description of a task
  pub task_description: String,
  /// a cryptographic dignature for the CFP
  pub signature: Vec<u8>,
}

//  ____                                                 _
// |  _ \   _ __    ___    _ __     ___    ___    __ _  | |
// | |_) | | '__|  / _ \  | '_ \   / _ \  / __|  / _` | | |
// |  __/  | |    | (_) | | |_) | | (_) | \__ \ | (_| | | |
// |_|     |_|     \___/  | .__/   \___/  |___/  \__,_| |_|
//                        |_|

/// Represents a proposal to compmete a CFP.
#[derive(Clone, serde::Deserialize, serde::Serialize)]
pub struct Proposal
{
  /// uri of this agent
  pub agent_uri: String,
  /// cost for executing the given task
  pub cost: f32,
  /// uuid of the CFP/Task
  pub task_uuid: uuid::Uuid,
  /// signature it ingludes the agent_uri, cost, uuid and description
  pub signature: Vec<u8>,
}

//  ____    _             _
// / ___|  | |_    __ _  | |_   _   _   ___
// \___ \  | __|  / _` | | __| | | | | / __|
//  ___) | | |_  | (_| | | |_  | |_| | \__ \
// |____/   \__|  \__,_|  \__|  \__,_| |___/

/// Enum representing the statuts of a delegation and its execution
#[derive(Clone, Debug, serde::Deserialize, serde::Serialize)]
pub enum Status
{
  /// The CFP was sent
  SendCFP,
  /// A number of proposals have been received
  ReceivedProposals(usize),
  /// A proposal was accepted
  ProposalAccepted,
  /// No proposals were received before the timeout
  NoReceivedProposals,
  /// No proposal was accepted
  NoAcceptedProposal,
  /// The execution started
  ExecutionStarted,
  /// The execution of a specific node started
  NodeExecutionStarted
  {
    /// uuid of the executed node
    node: uuid::Uuid,
  },
  /// The execution of a specific node was completed
  NodeExecutionCompleted
  {
    /// uuid of the completed node
    node: uuid::Uuid,
  },
}

//  _____                 _
// |_   _|   __ _   ___  | | __
//   | |    / _` | / __| | |/ /
//   | |   | (_| | \__ \ |   <
//   |_|    \__,_| |___/ |_|\_\

/// Base trait for representing tasks in the delegation
pub trait Task: Sized
{
  /// Create a task from a text description (aka json string...)
  fn from_description(task_type: &String, description: &String) -> Result<Self>;
  /// The type of the task (tst, goalspec...)
  fn task_type(&self) -> &str;
  /// Convert into a string representation
  fn to_description(&self) -> String;
  /// An UUID for the task
  fn task_id(&self) -> uuid::Uuid;
}

//  ___                   _   __  __
// |_ _|_ __  _ __  _   _| |_|  \/  | ___  ___ ___  __ _  __ _  ___
//  | || '_ \| '_ \| | | | __| |\/| |/ _ \/ __/ __|/ _` |/ _` |/ _ \
//  | || | | | |_) | |_| | |_| |  | |  __/\__ \__ \ (_| | (_| |  __/
// |___|_| |_| .__/ \__,_|\__|_|  |_|\___||___/___/\__,_|\__, |\___|
//           |_|                                         |___/

/// Input message from the delegation module
#[derive(Clone)]
pub enum InputMessage
{
  /// Tell the delegation module to start a delegation
  StartDelegation
  {
    /// Call for proposal
    cfp: CFP,
  },
}

impl InputMessage
{
  /// Convenience function for creating a CFP and wrap it into a start delegation message
  pub(crate) fn create_start_delegation(
    requester_uri: String,
    task: impl Task,
    team_uri: Option<String>,
  ) -> InputMessage
  {
    InputMessage::StartDelegation {
      cfp: CFP {
        uuid: task.task_id(),
        requester_uri,
        team_uri,
        task_type: task.task_type().into(),
        task_description: task.to_description(),
        signature: Vec::<u8>::default(),
      },
    }
  }
}

//   ___        _               _   __  __
//  / _ \ _   _| |_ _ __  _   _| |_|  \/  | ___  ___ ___  __ _  __ _  ___
// | | | | | | | __| '_ \| | | | __| |\/| |/ _ \/ __/ __|/ _` |/ _` |/ _ \
// | |_| | |_| | |_| |_) | |_| | |_| |  | |  __/\__ \__ \ (_| | (_| |  __/
//  \___/ \__,_|\__| .__/ \__,_|\__|_|  |_|\___||___/___/\__,_|\__, |\___|
//                 |_|                                         |___/

/// Output message from the delegation module
#[derive(Clone)]
pub enum OutputMessage
{
  /// Status of the delegation
  Status
  {
    /// Uuid of the task
    uuid: uuid::Uuid,
    /// Status
    status: Status,
  },
}

//  __  __           _       _      ___       _             __
// |  \/  | ___   __| |_   _| | ___|_ _|_ __ | |_ ___ _ __ / _| __ _  ___ ___
// | |\/| |/ _ \ / _` | | | | |/ _ \| || '_ \| __/ _ \ '__| |_ / _` |/ __/ _ \
// | |  | | (_) | (_| | |_| | |  __/| || | | | ||  __/ |  |  _| (_| | (_|  __/
// |_|  |_|\___/ \__,_|\__,_|_|\___|___|_| |_|\__\___|_|  |_|  \__,_|\___\___|

/// Module interface for the delegation modue
pub type ModuleInterface = module::ModuleInterface<InputMessage, OutputMessage>;

//  __  __           _       _
// |  \/  | ___   __| |_   _| | ___
// | |\/| |/ _ \ / _` | | | | |/ _ \
// | |  | | (_) | (_| | |_| | |  __/
// |_|  |_|\___/ \__,_|\__,_|_|\___|

module::create_module_private_interface!(ModulePrivateInterface, InputMessage, OutputMessage);

/// This structure implements a delegation module
pub(crate) struct Module {}

impl Module
{
  /// Create a new delegation module
  pub(crate) async fn start(
    agent_data: agent::AgentData,
    module_interfaces: (
      crate::module::ModuleInterface<InputMessage, OutputMessage>,
      ModulePrivateInterface,
    ),
    transport_interface: transport::ModuleInterface,
    decision_interface: decision::ModuleInterface,
  ) -> ()
  {
    let (module_interface, module_private_interface) = module_interfaces;

    let mut input_receiver = module_private_interface.input_receiver.activate();
    let output_sender = module_private_interface.output_sender;
    let transport_interface = transport_interface;

    let ir_fut = {
      let agent_data = agent_data.clone();
      let transport_interface = transport_interface.clone();
      async move {
        loop
        {
          let msg = input_receiver.recv().await;
          if let Ok(msg) = msg
          {
            match msg
            {
              InputMessage::StartDelegation { cfp } =>
              {
                let output_sender = output_sender.clone();
                let transport_input_sender = transport_interface.input_sender();
                let mut transport_output_receiver = transport_interface.output_receiver();
                let delegation = async move {
                  let cfp_uuid = cfp.uuid.to_owned();

                  // Send CFP to transport
                  match transport_input_sender
                    .broadcast_direct(transport::InputMessage::SendCFP { cfp: cfp })
                    .await
                  {
                    Ok(_) =>
                    {}
                    Err(e) => println!("While sending CFP: {:?}", e),
                  }

                  // Accumulate proposals
                  let mut proposals = Vec::<delegation::Proposal>::new();
                  let start = Instant::now();
                  while start.elapsed().as_secs() < 30
                  {
                    let msg = async_std::future::timeout(
                      Duration::from_millis(60 * 1000 - start.elapsed().as_millis() as u64),
                      transport_output_receiver.recv(),
                    )
                    .await;
                    if let Ok(Ok(msg)) = msg
                    {
                      match msg
                      {
                        transport::OutputMessage::ReceivedProposal { proposal } =>
                        {
                          if proposal.task_uuid == cfp_uuid
                          {
                            proposals.push(proposal);
                          }
                        }
                        _ =>
                        {}
                      }
                    }
                  }
                  log::info!(
                    "Received {} proposals for delegation {:?}",
                    proposals.len(),
                    cfp_uuid
                  );

                  // Sort proposals
                  println!("sorting");
                  proposals.sort_by(|a, b| a.cost.partial_cmp(b.cost.borrow()).unwrap());
                  println!("done sorting");
                  if proposals.is_empty()
                  {
                    println!("empty proposals");
                    output_sender
                      .broadcast_direct(OutputMessage::Status {
                        uuid: cfp_uuid,
                        status: Status::NoReceivedProposals,
                      })
                      .await;
                    return;
                  }
                  else
                  {
                    println!("send status update");
                    output_sender.broadcast(OutputMessage::Status {
                      uuid: cfp_uuid.to_owned(),
                      status: Status::ReceivedProposals(proposals.len()),
                    });
                    println!("finish sending statu update");
                  }

                  // Select proposals
                  for p in proposals
                  {
                    println!("selected proposals");
                    transport_input_sender
                      .broadcast(transport::InputMessage::SendProposalAcceptance {
                        acceptance: delegation::transport_messages::Acceptance {
                          agent_uri: p.agent_uri.to_owned(),
                          acceptance: true,
                          uuid: p.task_uuid,
                          signature: Default::default(),
                        },
                      })
                      .await;
                    println!("wait for confirmation");
                    let start = Instant::now();
                    while start.elapsed().as_secs() < 10
                    {
                      let msg = async_std::future::timeout(
                        Duration::from_millis(10 * 1000 - start.elapsed().as_millis() as u64),
                        transport_output_receiver.recv(),
                      )
                      .await;
                      println!("confirmation maybe received");
                      if let Ok(Ok(msg)) = msg
                      {
                        match msg
                        {
                          transport::OutputMessage::ReceivedProposalAccepted { acceptance } =>
                          {
                            if acceptance.uuid == cfp_uuid
                            {
                              if (acceptance.acceptance)
                              {
                                output_sender
                                  .broadcast(OutputMessage::Status {
                                    uuid: cfp_uuid,
                                    status: Status::ProposalAccepted,
                                  })
                                  .await;
                                println!("delegation finished");
                                return;
                              }
                              else
                              {
                                break;
                              }
                            }
                          }
                          _ =>
                          {}
                        }
                      }
                    }
                    println!("cancel acceptance");
                    // Cancel the acceptance
                    transport_input_sender
                      .broadcast(transport::InputMessage::SendCancelAcceptance {
                        cancel_acceptance: transport_messages::CancelAcceptance {
                          agent_uri: p.agent_uri,
                          uuid: p.task_uuid,
                          signature: Default::default(),
                        },
                      })
                      .await;
                  }
                  // No proposal was accepted, delegation failed
                  output_sender
                    .broadcast(OutputMessage::Status {
                      uuid: cfp_uuid.to_owned(),
                      status: Status::NoAcceptedProposal,
                    })
                    .await;
                };
                agent_data.async_runtime.spawn_task(delegation);
              }
            }
          }
          else
          {
            return;
          }
        }
      }
    };
    let tr_fut = {
      let agent_data = agent_data.clone();
      let decision_input_sender = decision_interface.input_sender();
      let mut transport_output_receiver = transport_interface.output_receiver();
      async move {
        loop
        {
          match transport_output_receiver.recv().await
          {
            Ok(msg) => match msg
            {
              transport::OutputMessage::ReceivedCFP { cfp } =>
              {
                decision_input_sender
                  .broadcast(decision::InputMessage::DecideCFPAcceptance { cfp: cfp })
                  .await;
              }
              transport::OutputMessage::ReceivedProposalAccepted { acceptance } =>
              {
                if acceptance.agent_uri == agent_data.agent_uri
                {
                  decision_input_sender
                    .broadcast(decision::InputMessage::QueueExecution {
                      uuid: acceptance.uuid,
                    })
                    .await;
                }
              }
              transport::OutputMessage::ReceivedCancelAcceptance { cancel_acceptance } =>
              {
                if cancel_acceptance.agent_uri == agent_data.agent_uri
                {
                  decision_input_sender
                    .broadcast(decision::InputMessage::CancelExecution {
                      uuid: cancel_acceptance.uuid,
                    })
                    .await;
                }
              }
              _ =>
              {}
            },
            Err(_) =>
            {
              return;
            }
          }
        }
      }
    };
    let dr_fut = {
      let mut decision_output_receiver = decision_interface.output_receiver();
      let transport_input_sender = transport_interface.input_sender();
      async move {
        loop
        {
          match decision_output_receiver.recv().await
          {
            Ok(msg) => match msg
            {
              decision::OutputMessage::CFPProposal { proposal } =>
              {
                transport_input_sender
                  .broadcast(transport::InputMessage::SendProposal { proposal })
                  .await;
              }
              decision::OutputMessage::QueueExecutionResult { uuid, accepted } =>
              {
                transport_input_sender
                  .broadcast(transport::InputMessage::SendExecutionAcceptance {
                    acceptance: transport_messages::Acceptance {
                      agent_uri: agent_data.agent_uri.to_owned(),
                      acceptance: accepted,
                      uuid: uuid,
                      signature: Default::default(),
                    },
                  })
                  .await;
              }
            },
            Err(_) =>
            {
              return;
            }
          }
        }
      }
    };
    join!(ir_fut, tr_fut, dr_fut);
  }
}

impl crate::module::Module for Module
{
  type InputMessage = InputMessage;
  type OutputMessage = OutputMessage;
  type ModulePrivateInterface = ModulePrivateInterface;
}