mod string_pool;

mod scoped_buffer;

mod sets;

mod raw_vec;

// TODO: Finish this later, use alloc::alloc and alloc::Layout

// mod freelist;

pub(crate) use string_pool::{StringPool, StringRef};

pub(crate) use scoped_buffer::{ScopedBuffer, ScopedSection};

pub(crate) use raw_vec::RawVec;

use std::path::Component;

use crate::protocol::eval::ValueGroup;

use crate::runtime2::branch::{BranchId, ExecTree, QueueKind};

use crate::runtime2::ConnectorId;

use crate::runtime2::inbox2::{DataHeader, SyncHeader};

use crate::runtime2::port::{Port, PortIdLocal};

use crate::runtime2::scheduler::ComponentCtxFancy;

use super::inbox2::PortAnnotation;

struct BranchAnnotation {

    port_mapping: Vec<PortAnnotation>,

}

/// The consensus algorithm. Currently only implemented to find the component

/// with the highest ID within the sync region and letting it handle all the

/// local solutions.

///

/// The type itself serves as an experiment to see how code should be organized.

// TODO: Flatten all datastructures

// TODO: Have a "branch+port position hint" in case multiple operations are

//  performed on the same port to prevent repeated lookups

pub(crate) struct Consensus {

    // Local component's state

    highest_connector_id: ConnectorId,

    branch_annotations: Vec<BranchAnnotation>,

    last_finished_handled: Option<BranchId>,

    // Gathered state (in case we are currently the leader of the distributed

    // consensus protocol)

    // Workspaces

    workspace_ports: Vec<PortIdLocal>,

}

#[derive(Clone, Copy, PartialEq, Eq)]

pub(crate) enum Consistency {

    Valid,

    Inconsistent,

}

impl Consensus {

    pub fn new() -> Self {

        return Self {

            highest_connector_id: ConnectorId::new_invalid(),

            branch_annotations: Vec::new(),

            last_finished_handled: None,

            workspace_ports: Vec::new(),

        }

    }

    // --- Controlling sync round and branches

    /// Returns whether the consensus algorithm is running in sync mode

    pub fn is_in_sync(&self) -> bool {

        return !self.branch_annotations.is_empty();

    }

    /// TODO: Remove this once multi-fire is in place

    pub fn get_annotation(&self, branch_id: BranchId, port_id: PortIdLocal) -> &PortAnnotation {

        let branch = &self.branch_annotations[branch_id.index as usize];

        let port = branch.port_mapping.iter().find(|v| v.port_id == port_id).unwrap();

        return port;

    }

    /// Sets up the consensus algorithm for a new synchronous round. The

    /// provided ports should be the ports the component owns at the start of

    /// the sync round.

    pub fn start_sync(&mut self, ports: &[Port]) {

        debug_assert!(self.branch_annotations.is_empty());

        debug_assert!(!self.highest_connector_id.is_valid());

        };

        // TODO: Handle multiple firings. Right now we just assign the current

        //  branch to the `None` value because we know we can only send once.

        debug_assert!(branch.port_mapping.iter().find(|v| v.port_id == source_port_id).unwrap().registered_id.is_none());

        let port_info = ctx.get_port_by_id(source_port_id).unwrap();

        let data_header = DataHeader{

            expected_mapping: branch.port_mapping.clone(),

            sending_port: port_info.peer_id,

            target_port: port_info.peer_id,

            new_mapping: branch_id

        };

        for mapping in &mut branch.port_mapping {

            if mapping.port_id == source_port_id {

                mapping.expected_firing = Some(true);

                mapping.registered_id = Some(branch_id);

            }

        }

        return (sync_header, data_header);

    }

    pub fn handle_received_sync_header(&mut self, sync_header: &SyncHeader, ctx: &mut ComponentCtxFancy) {

    }

    /// Checks data header and consults the stored port mapping and the

    /// execution tree to see which branches may receive the data message's

    /// contents.

    ///

    /// This function is generally called for freshly received messages that

    /// should be matched against previously halted branches.

    pub fn handle_received_data_header(&mut self, exec_tree: &ExecTree, data_header: &DataHeader, target_ids: &mut Vec<BranchId>) {

        for branch in exec_tree.iter_queue(QueueKind::AwaitingMessage, None) {

            if branch.awaiting_port == data_header.target_port {

                // Found a branch awaiting the message, but we need to make sure

                // the mapping is correct

                if self.branch_can_receive(branch.id, data_header) {

                    target_ids.push(branch.id);

                }

            }

        }

    }

    pub fn notify_of_received_message(&mut self, branch_id: BranchId, data_header: &DataHeader, content: &ValueGroup) {

        debug_assert!(self.branch_can_receive(branch_id, data_header));

        let branch = &mut self.branch_annotations[branch_id.index as usize];

        for mapping in &mut branch.port_mapping {

            if mapping.port_id == data_header.target_port {

                // Found the port in which the message should be inserted

                mapping.registered_id = Some(data_header.new_mapping);

                // Check for sent ports

                debug_assert!(self.workspace_ports.is_empty());

                find_ports_in_value_group(content, &mut self.workspace_ports);

                if !self.workspace_ports.is_empty() {

                    todo!("handle received ports");

                    self.workspace_ports.clear();

                }

                return;

            }

        }

        // If here, then the branch didn't actually own the port? Means the

        // caller made a mistake

        unreachable!("incorrect notify_of_received_message");

    }

    /// Matches the mapping between the branch and the data message. If they

    /// match then the branch can receive the message.

        let annotation = &self.branch_annotations[branch_id.index as usize];

        for expected in &data_header.expected_mapping {

            // If we own the port, then we have an entry in the

            // annotation, check if the current mapping matches

            for current in &annotation.port_mapping {

                if expected.port_id == current.port_id {

                    if expected.registered_id != current.registered_id {

                        // IDs do not match, we cannot receive the

                        // message in this branch

                        return false;

                    }

                }

            }

        }

        return true;

    }

}

/// Recursively goes through the value group, attempting to find ports.

/// Duplicates will only be added once.

pub(crate) fn find_ports_in_value_group(value_group: &ValueGroup, ports: &mut Vec<PortIdLocal>) {

    // Helper to check a value for a port and recurse if needed.

    use crate::protocol::eval::Value;

    fn find_port_in_value(group: &ValueGroup, value: &Value, ports: &mut Vec<PortIdLocal>) {

        match value {

            Value::Input(port_id) | Value::Output(port_id) => {

                // This is an actual port

                let cur_port = PortIdLocal::new(port_id.0.u32_suffix);

                for prev_port in ports.iter() {

                    if *prev_port == cur_port {

                        // Already added

                        return;

                    }

                }

                ports.push(cur_port);

            },

            Value::Array(heap_pos) |

            Value::Message(heap_pos) |

#[derive(Debug, Copy, Clone)]

pub(crate) struct PortAnnotation {

    pub port_id: PortIdLocal,

    pub registered_id: Option<BranchId>,

    pub expected_firing: Option<bool>,

}

/// The header added by the synchronization algorithm to all.

#[derive(Debug, Clone)]

pub(crate) struct SyncHeader {

    pub sending_component_id: ConnectorId,

    pub highest_component_id: ConnectorId,

}

/// The header added to data messages

#[derive(Debug, Clone)]

pub(crate) struct DataHeader {

    pub expected_mapping: Vec<PortAnnotation>,

    pub sending_port: PortIdLocal,

    pub target_port: PortIdLocal,

    pub new_mapping: BranchId,

}

/// A data message is a message that is intended for the receiver's PDL code,

#[derive(Debug, Clone)]

pub(crate) struct DataMessageFancy {

    pub sync_header: SyncHeader,

    pub data_header: DataHeader,

    pub content: ValueGroup,

}

#[derive(Debug)]

pub(crate) enum SyncContent {

}

/// A sync message is a message that is intended only for the consensus

/// algorithm.

#[derive(Debug)]

pub(crate) struct SyncMessageFancy {

    pub sync_header: SyncHeader,

    pub content: SyncContent,

}

/// A control message is a message intended for the scheduler that is executing

/// a component.

#[derive(Debug)]

pub(crate) struct ControlMessageFancy {

    pub id: u32, // generic identifier, used to match request to response

    pub sending_component_id: ConnectorId,

    pub content: ControlContent,

}

#[derive(Debug)]

pub(crate) enum ControlContent {

    PortPeerChanged(PortIdLocal, ConnectorId),

    CloseChannel(PortIdLocal),

    Ack,

    Ping,

}

/// Combination of data message and control messages.

#[derive(Debug)]

pub(crate) enum MessageFancy {

    Data(DataMessageFancy),