/// Assert only the listed properties exist on the Emacs AST node and compare their values to the values on the rust AST node.
///
/// Example invocation:
/// ```
///     if let Some((new_status, new_message)) = compare_properties!(
///         emacs,
///         rust,
///         (
///             EmacsField::Required(":key"),
///             |r| Some(r.key),
///             compare_property_quoted_string
///         ),
///         (
///             EmacsField::Required(":value"),
///             |r| Some(r.contents),
///             compare_property_quoted_string
///         ),
///         (EmacsField::Required(":pre-blank"), compare_identity, compare_noop)
///     )? {
///         this_status = new_status;
///         message = new_message;
///     }
/// ```
///
/// Or if the node has no properties aside from :standard-properties, we can still assert that the node has no unexpected properties:
/// ```
///     if let Some((new_status, new_message)) = compare_properties!(emacs)? {
///         this_status = new_status;
///         message = new_message;
///     }
/// ```
macro_rules! compare_properties {
    ($source:expr, $emacs:expr, $rust:expr, $(($emacs_field:expr, $rust_value_getter:expr, $compare_fn: expr)),+) => {
        {
            let mut new_status = Vec::new();
            let children = $emacs.as_list()?;
            let attributes_child = children
            .iter()
            .nth(1)
            .ok_or("Should have an attributes child.")?;
            let attributes_map = attributes_child.as_map()?;
            let mut emacs_keys: BTreeSet<&str> = attributes_map.keys().map(|s| *s).collect();
            if emacs_keys.contains(":standard-properties") {
                emacs_keys.remove(":standard-properties");
            } else {
                new_status.push(ComparePropertiesResult::SelfChange(DiffStatus::Bad, Some(format!(
                    "Emacs token lacks :standard-properties field.",
                ))));
            }
            $(
            match $emacs_field {
                EmacsField::Required(name) if emacs_keys.contains(name) => {
                    emacs_keys.remove(name);
                },
                EmacsField::Optional(name) if emacs_keys.contains(name) => {
                    emacs_keys.remove(name);
                },
                EmacsField::Required(name) => {
                    new_status.push(ComparePropertiesResult::SelfChange(DiffStatus::Bad, Some(format!(
                        "Emacs token lacks required field: {}",
                        name
                    ))));
                },
                EmacsField::Optional(_name) => {},
            }
            )+

            if !emacs_keys.is_empty() {
                let unexpected_keys: Vec<&str> = emacs_keys.into_iter().collect();
                let unexpected_keys = unexpected_keys.join(", ");
                new_status.push(ComparePropertiesResult::SelfChange(DiffStatus::Bad, Some(format!(
                    "Emacs token had extra field(s): {}",
                    unexpected_keys
                ))));
            }

            $(
            let emacs_name = match $emacs_field {
                EmacsField::Required(name) => {
                    name
                },
                EmacsField::Optional(name) => {
                    name
                },
            };
            let result = $compare_fn($source, $emacs, $rust, emacs_name, $rust_value_getter)?;
            match result {
                ComparePropertiesResult::SelfChange(DiffStatus::Good, _) => unreachable!("No comparison functions should return SelfChange() when DiffStatus is good."),
                ComparePropertiesResult::NoChange => {},
                result => {
                    new_status.push(result);
                }
            }
            )+

            new_status
        }
    };
    // Default case for when there are no expected properties except for :standard-properties
    ($emacs:expr) => {
        {
            let mut new_status = Vec::new();
            let children = $emacs.as_list()?;
            let attributes_child = children
            .iter()
            .nth(1)
            .ok_or("Should have an attributes child.")?;
            let attributes_map = attributes_child.as_map()?;
            let mut emacs_keys: BTreeSet<&str> = attributes_map.keys().map(|s| *s).collect();
            if emacs_keys.contains(":standard-properties") {
                emacs_keys.remove(":standard-properties");
            } else {
                new_status.push(ComparePropertiesResult::SelfChange(DiffStatus::Bad, Some(format!(
                    "Emacs token lacks :standard-properties field.",
                ))));
            }

            if !emacs_keys.is_empty() {
                let unexpected_keys: Vec<&str> = emacs_keys.into_iter().collect();
                let unexpected_keys = unexpected_keys.join(", ");
                new_status.push(ComparePropertiesResult::SelfChange(DiffStatus::Bad, Some(format!(
                    "Emacs token had extra field(s): {}",
                    unexpected_keys
                ))));
            }
            new_status
        }
    };
}

pub(crate) use compare_properties;