use std::fmt::{Debug, Display};

use std::sync::{Arc, RwLock};

use derivative::Derivative;

use serde::{Deserialize, Serialize};

use crate::ast::{DecisionVariable, Domain, Expression, Name, SymbolTable};

use crate::context::Context;

use crate::ast::pretty::{pretty_expressions_as_top_level, pretty_variable_declaration};

/// Represents a computational model containing variables, constraints, and a shared context.

///

/// The `Model` struct holds a set of variables and constraints for manipulating and evaluating symbolic expressions.

///

/// # Fields

/// - `constraints`:

///   - Type: `Vec<Expression>`

///   - Represents the logical constraints applied to the model's variables.

///   - Can be a single constraint or a combination of various expressions, such as logical operations (e.g., `AND`, `OR`),

///     arithmetic operations (e.g., `SafeDiv`, `UnsafeDiv`), or specialized constraints like `SumEq`.

///

/// - `context`:

///   - Type: `Arc<RwLock<Context<'static>>>`

///   - A shared object that stores global settings and state for the model.

///   - Can be safely read or changed by multiple parts of the program at the same time, making it good for multi-threaded use.

///

/// # Usage

/// This struct is typically used to:

/// - Define a set of variables and constraints for rule-based evaluation.

/// - Have transformations, optimizations, and simplifications applied to it using a set of rules.

#[derive(Derivative, Clone, Debug, Serialize, Deserialize)]

#[derivative(PartialEq, Eq)]

pub struct Model {

    pub constraints: Vec<Expression>,

    symbols: SymbolTable,

    #[serde(skip)]

    #[derivative(PartialEq = "ignore")]

    pub context: Arc<RwLock<Context<'static>>>,

}

impl Model {

    /// Creates a new model.

    /// The global symbol table for this model.

    /// The global symbol table for this model, as a mutable reference.

    // Function to update a DecisionVariable based on its Name

    /// Gets the domain of `name` if it exists and has one.

    /// Adds a decision variable to the model.

    ///

    /// Returns `None` if there is a decision variable or other object with that name in the symbol

    /// table.

    /// Returns an arbitrary variable name that is not in the model.

    /// Extends the models symbol table with the given symbol table, updating the gensym counter if

    /// necessary.

}

impl Display for Model {

    #[allow(clippy::unwrap_used)] // [rustdocs]: should only fail iff the formatter fails

        }

}