use std::collections::BTreeMap;

use core::fmt::Debug;

//TODO: write good documentation on this! ~niklasdewally

use crate::{

    ast::{DeclarationPtr, Expression, Literal, Name, SymbolTable},

    rule_engine::ApplicationError,

};

pub trait Representation: Send + Sync + Debug {

    /// Creates a representation object for the given name.

    fn init(name: &Name, symtab: &SymbolTable) -> Option<Self>

    where

        Self: Sized;

    /// The variable being represented.

    fn variable_name(&self) -> &Name;

    /// Given an assignment for `self`, creates assignments for its representation variables.

    fn value_down(&self, value: Literal) -> Result<BTreeMap<Name, Literal>, ApplicationError>;

    /// Given assignments for its representation variables, creates an assignment for `self`.

    fn value_up(&self, values: &BTreeMap<Name, Literal>) -> Result<Literal, ApplicationError>;

    /// Returns [`Expression`]s representing each representation variable.

    fn expression_down(

        &self,

        symtab: &SymbolTable,

    ) -> Result<BTreeMap<Name, Expression>, ApplicationError>;

    /// Creates declarations for the representation variables of `self`.

    fn declaration_down(&self) -> Result<Vec<DeclarationPtr>, ApplicationError>;

    /// The rule name for this representaion.

    fn repr_name(&self) -> &str;

    /// The identity of this representation.

    fn repr_id(&self) -> super::ReprId;

    /// Makes a clone of `self` into a `Representation` trait object.

    fn box_clone(&self) -> Box<dyn Representation>;

}

impl Clone for Box<dyn Representation> {

}