pub fn parse_essence_file_native(

    path: &str,

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

) -> Result<Model, EssenceParseError> {

    let source_code = fs::read_to_string(path)

        .unwrap_or_else(|_| panic!("Failed to read the source code file {path}"));

    parse_essence_with_context(&source_code, context)

}

pub fn parse_essence_with_context(

    src: &str,

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

) -> Result<Model, EssenceParseError> {

    let (tree, source_code) = match get_tree(src) {

        Some(tree) => tree,

    let mut model = Model::new(context);

    let root_node = tree.root_node();

    let symbols_ptr = model.as_submodel().symbols_ptr_unchecked().clone();

    for statement in named_children(&root_node) {

        match statement.kind() {

            "single_line_comment" => {}

            "language_declaration" => {}

            "find_statement" => {

                let var_hashmap =

                    parse_find_statement(statement, &source_code, Some(symbols_ptr.clone()))?;

                for (name, domain) in var_hashmap {

                    model

                        .as_submodel_mut()

                        .symbols_mut()

                        .insert(DeclarationPtr::new_find(name, domain));

                }

            "bool_expr" | "atom" | "comparison_expr" => {

                model.as_submodel_mut().add_constraint(parse_expression(

                    statement,

                    &source_code,

                    &statement,

                    Some(symbols_ptr.clone()),

                )?);

            "language_label" => {}

            "letting_statement" => {

                let letting_vars =

                    parse_letting_statement(statement, &source_code, Some(symbols_ptr.clone()))?;

                model.as_submodel_mut().symbols_mut().extend(letting_vars);

        let result = keyword_as_identifier(root_node, &source_code);

        result?

    Ok(model)

}

fn keyword_as_identifier(root: tree_sitter::Node, src: &str) -> Result<(), EssenceParseError> {

    let mut stack = vec![root];

    while let Some(node) = stack.pop() {

        if (node.kind() == "variable" || node.kind() == "identifier" || node.kind() == "parameter")

            && let Ok(text) = node.utf8_text(src.as_bytes())

            let ident = text.trim();

            if KEYWORDS.contains(&ident) {

                let start_point = node.start_position();

                let end_point = node.end_position();

                return Err(EssenceParseError::syntax_error(

                    format!("Keyword '{ident}' used as identifier"),

                    Some(tree_sitter::Range {

                        start_byte: node.start_byte(),

                        end_byte: node.end_byte(),

                        start_point,

                        end_point,

                    }),

                ));

            }

        }

        for i in 0..node.child_count() {

            if let Some(child) = u32::try_from(i).ok().and_then(|i| node.child(i)) {

                stack.push(child);

            }

    Ok(())

}

pub fn parse_essence(src: &str) -> Result<Model, EssenceParseError> {

    let context = Arc::new(RwLock::new(Context::default()));

    parse_essence_with_context(src, context)

}

    pub fn test_parse_xyz() {

        let src = "

        find x, y, z : int(1..4)

        such that x + y + z = 4

        such that x >= y

        ";

        let model = parse_essence(src).unwrap();

        let st = model.as_submodel().symbols();

        let x = st.lookup(&Name::user("x")).unwrap();

        let y = st.lookup(&Name::user("y")).unwrap();

        let z = st.lookup(&Name::user("z")).unwrap();

        assert_eq!(x.domain(), Some(domain_int!(1..4)));

        assert_eq!(y.domain(), Some(domain_int!(1..4)));

        assert_eq!(z.domain(), Some(domain_int!(1..4)));

        let constraints = model.as_submodel().constraints();

        assert_eq!(constraints.len(), 2);

        let c1 = constraints[0].clone();

        let x_e = Expression::Atomic(Metadata::new(), Atom::new_ref(x));

        let y_e = Expression::Atomic(Metadata::new(), Atom::new_ref(y));

        let z_e = Expression::Atomic(Metadata::new(), Atom::new_ref(z));

        assert_eq!(

            Expression::Eq(

                Metadata::new(),

                Moo::new(Expression::Sum(

                    Metadata::new(),

                    Moo::new(matrix_expr!(

                        Expression::Sum(

                            Metadata::new(),

                            Moo::new(matrix_expr!(x_e.clone(), y_e.clone()))

                        ),

                        z_e

                    ))

                )),

                Moo::new(Expression::Atomic(Metadata::new(), 4.into()))

            )

        let c2 = constraints[1].clone();

        assert_eq!(

            Expression::Geq(Metadata::new(), Moo::new(x_e), Moo::new(y_e))

    }

    pub fn test_parse_letting_index() {

        let src = "

        letting a be [ [ 1,2,3 ; int(1,2,4) ], [ 1,3,2 ; int(1,2,4) ], [ 3,2,1 ; int(1,2,4) ] ; int(-2..0) ]

        find b: int(1..5)

        such that

        b < a[-2,2],

        allDiff(a[-2,..])

        ";

        let model = parse_essence(src).unwrap();

        let st = model.as_submodel().symbols();

        let a_decl = st.lookup(&Name::user("a")).unwrap();

        let a = a_decl.as_value_letting().unwrap().deref().clone();

        assert_eq!(

            matrix_expr!(

                matrix_expr!(1.into(), 2.into(), 3.into() ; domain_int!(1, 2, 4)),

                matrix_expr!(1.into(), 3.into(), 2.into() ; domain_int!(1, 2, 4)),

                matrix_expr!(3.into(), 2.into(), 1.into() ; domain_int!(1, 2, 4));

                domain_int!(-2..0)

    }