use std::borrow::Borrow;
use std::borrow::Cow;
use std::collections::BTreeSet;
use std::fmt::Debug;
use std::str::FromStr;

use super::diff::artificial_diff_scope;
use super::diff::artificial_owned_diff_scope;
use super::diff::compare_ast_node;
use super::diff::DiffEntry;
use super::diff::DiffStatus;
use super::sexp::unquote;
use super::sexp::Token;
use super::util::get_property;
use super::util::get_property_numeric;
use super::util::get_property_quoted_string;
use super::util::get_property_unquoted_atom;
use crate::types::AstNode;
use crate::types::CharOffsetInLine;
use crate::types::LineNumber;
use crate::types::RetainLabels;
use crate::types::SwitchNumberLines;

#[derive(Debug)]
pub(crate) enum EmacsField<'s> {
    Required(&'s str),
    Optional(&'s str),
}

#[derive(Debug)]
pub(crate) enum ComparePropertiesResult<'b, 's> {
    NoChange,
    /// Return when you want the status for "this" node to change (as opposed to collecting child status).
    SelfChange(DiffStatus, Option<String>),
    DiffEntry(DiffEntry<'b, 's>),
}

impl<'b, 's> ComparePropertiesResult<'b, 's> {
    pub(crate) fn apply(
        self,
        child_status: &mut Vec<DiffEntry<'b, 's>>,
        this_status: &mut DiffStatus,
        message: &mut Option<String>,
    ) {
        match self {
            ComparePropertiesResult::NoChange => {}
            ComparePropertiesResult::SelfChange(new_status, new_message) => {
                *this_status = new_status;
                *message = new_message
            }
            ComparePropertiesResult::DiffEntry(diff_entry) => child_status.push(diff_entry),
        }

        // foo
    }
}

/// Do no comparison.
///
/// This is for when you want to acknowledge that a field exists in the emacs token, but you do not have any validation for it when using the compare_properties!() macro. Ideally, this should be kept to a minimum since this represents untested values.
pub(crate) fn compare_noop<'b, 's, R, RG>(
    _source: &'s str,
    _emacs: &'b Token<'s>,
    _rust_node: R,
    _emacs_field: &str,
    _rust_value_getter: RG,
) -> Result<ComparePropertiesResult<'b, 's>, Box<dyn std::error::Error>> {
    Ok(ComparePropertiesResult::NoChange)
}

/// Do no comparison.
///
/// This is for when you want to acknowledge that a field exists in the emacs token, but you do not have any validation for it when using the compare_properties!() macro. Ideally, this should be kept to a minimum since this represents untested values.
pub(crate) fn compare_identity() {}

/// Assert that the emacs value is always nil or absent.
///
/// This is usually used for fields which, in my testing, are always nil. Using this compare function instead of simply doing a compare_noop will enable us to be alerted when we finally come across an org-mode document that has a value other than nil for the property.
pub(crate) fn compare_property_always_nil<'b, 's, R, RG>(
    _source: &'s str,
    emacs: &'b Token<'s>,
    _rust_node: R,
    emacs_field: &str,
    _rust_value_getter: RG,
) -> Result<ComparePropertiesResult<'b, 's>, Box<dyn std::error::Error>> {
    let value = get_property(emacs, emacs_field)?;
    if value.is_some() {
        let this_status = DiffStatus::Bad;
        let message = Some(format!(
            "{} was expected to always be nil: {:?}",
            emacs_field, value
        ));
        Ok(ComparePropertiesResult::SelfChange(this_status, message))
    } else {
        Ok(ComparePropertiesResult::NoChange)
    }
}

pub(crate) fn compare_property_quoted_string<
    'b,
    's,
    R,
    RV: AsRef<str> + std::fmt::Debug,
    RG: Fn(R) -> Option<RV>,
>(
    _source: &'s str,
    emacs: &'b Token<'s>,
    rust_node: R,
    emacs_field: &str,
    rust_value_getter: RG,
) -> Result<ComparePropertiesResult<'b, 's>, Box<dyn std::error::Error>> {
    let value = get_property_quoted_string(emacs, emacs_field)?;
    let rust_value = rust_value_getter(rust_node);
    if rust_value.as_ref().map(|s| s.as_ref()) != value.as_deref() {
        let this_status = DiffStatus::Bad;
        let message = Some(format!(
            "{} mismatch (emacs != rust) {:?} != {:?}",
            emacs_field, value, rust_value
        ));
        Ok(ComparePropertiesResult::SelfChange(this_status, message))
    } else {
        Ok(ComparePropertiesResult::NoChange)
    }
}

pub(crate) fn compare_property_unquoted_atom<'b, 's, 'x, R, RG: Fn(R) -> Option<&'s str>>(
    _source: &'s str,
    emacs: &'b Token<'s>,
    rust_node: R,
    emacs_field: &'x str,
    rust_value_getter: RG,
) -> Result<ComparePropertiesResult<'b, 's>, Box<dyn std::error::Error>> {
    let value = get_property_unquoted_atom(emacs, emacs_field)?;
    let rust_value = rust_value_getter(rust_node);
    if rust_value != value {
        let this_status = DiffStatus::Bad;
        let message = Some(format!(
            "{} mismatch (emacs != rust) {:?} != {:?}",
            emacs_field, value, rust_value
        ));
        Ok(ComparePropertiesResult::SelfChange(this_status, message))
    } else {
        Ok(ComparePropertiesResult::NoChange)
    }
}

pub(crate) fn compare_property_numeric<
    'b,
    's,
    'x,
    R,
    RV: FromStr + PartialEq + Debug,
    RG: Fn(R) -> Option<RV>,
>(
    _source: &'s str,
    emacs: &'b Token<'s>,
    rust_node: R,
    emacs_field: &'x str,
    rust_value_getter: RG,
) -> Result<ComparePropertiesResult<'b, 's>, Box<dyn std::error::Error + 's>>
where
    <RV as FromStr>::Err: std::error::Error,
    <RV as FromStr>::Err: 's,
{
    let value = get_property_numeric::<RV>(emacs, emacs_field)?;
    let rust_value = rust_value_getter(rust_node);
    if rust_value != value {
        let this_status = DiffStatus::Bad;
        let message = Some(format!(
            "{} mismatch (emacs != rust) {:?} != {:?}",
            emacs_field, value, rust_value
        ));
        Ok(ComparePropertiesResult::SelfChange(this_status, message))
    } else {
        Ok(ComparePropertiesResult::NoChange)
    }
}

pub(crate) fn compare_property_list_of_quoted_string<
    'b,
    's,
    R,
    RV: AsRef<str> + std::fmt::Debug,
    RI: Iterator<Item = RV>,
    RG: Fn(R) -> Option<RI>,
>(
    _source: &'s str,
    emacs: &'b Token<'s>,
    rust_node: R,
    emacs_field: &str,
    rust_value_getter: RG,
) -> Result<ComparePropertiesResult<'b, 's>, Box<dyn std::error::Error>> {
    let value = get_property(emacs, emacs_field)?
        .map(Token::as_list)
        .map_or(Ok(None), |r| r.map(Some))?;
    let rust_value = rust_value_getter(rust_node);
    // TODO: Seems we are needlessly coverting to a vec here.
    let rust_value: Option<Vec<RV>> = rust_value.map(|it| it.collect());
    match (value, &rust_value) {
        (None, None) => {}
        (None, Some(_)) | (Some(_), None) => {
            let this_status = DiffStatus::Bad;
            let message = Some(format!(
                "{} mismatch (emacs != rust) {:?} != {:?}",
                emacs_field, value, rust_value
            ));
            return Ok(ComparePropertiesResult::SelfChange(this_status, message));
        }
        (Some(el), Some(rl)) if el.len() != rl.len() => {
            let this_status = DiffStatus::Bad;
            let message = Some(format!(
                "{} mismatch (emacs != rust) {:?} != {:?}",
                emacs_field, value, rust_value
            ));
            return Ok(ComparePropertiesResult::SelfChange(this_status, message));
        }
        (Some(el), Some(rl)) => {
            for (e, r) in el.iter().zip(rl) {
                let e = unquote(e.as_atom()?)?;
                let r = r.as_ref();
                if e != r {
                    let this_status = DiffStatus::Bad;
                    let message = Some(format!(
                        "{} mismatch (emacs != rust) {:?} != {:?}. Full list: {:?} != {:?}",
                        emacs_field, e, r, value, rust_value
                    ));
                    return Ok(ComparePropertiesResult::SelfChange(this_status, message));
                }
            }
        }
    }
    Ok(ComparePropertiesResult::NoChange)
}

pub(crate) fn compare_property_set_of_quoted_string<
    'a,
    'b,
    's,
    'x,
    R,
    RV: AsRef<str> + std::fmt::Debug + Ord + 'a + ?Sized,
    RI: Iterator<Item = &'a RV>,
    RG: Fn(R) -> Option<RI>,
>(
    _source: &'s str,
    emacs: &'b Token<'s>,
    rust_node: R,
    emacs_field: &'x str,
    rust_value_getter: RG,
) -> Result<ComparePropertiesResult<'b, 's>, Box<dyn std::error::Error>> {
    let value = get_property(emacs, emacs_field)?
        .map(Token::as_list)
        .map_or(Ok(None), |r| r.map(Some))?;
    let empty = Vec::new();
    let value = value.unwrap_or(&empty);
    let rust_value = rust_value_getter(rust_node);
    let rust_value = if let Some(rust_value) = rust_value {
        let slices: BTreeSet<&str> = rust_value.map(|rv| rv.as_ref()).collect();
        slices
    } else {
        BTreeSet::new()
    };
    let value: Vec<&str> = value
        .iter()
        .map(|e| e.as_atom())
        .collect::<Result<Vec<_>, _>>()?;
    let value: Vec<Cow<'_, str>> = value
        .into_iter()
        .map(unquote)
        .collect::<Result<Vec<_>, _>>()?;
    let value: BTreeSet<&str> = value.iter().map(|e| e.borrow()).collect();
    let mismatched: Vec<_> = value.symmetric_difference(&rust_value).copied().collect();
    if !mismatched.is_empty() {
        let this_status = DiffStatus::Bad;
        let message = Some(format!(
            "{} mismatch. Mismatched values: {}",
            emacs_field,
            mismatched.join(", ")
        ));
        return Ok(ComparePropertiesResult::SelfChange(this_status, message));
    }
    Ok(ComparePropertiesResult::NoChange)
}

pub(crate) fn compare_property_optional_pair<
    'b,
    's,
    R,
    RV: AsRef<str> + std::fmt::Debug,
    ROV: AsRef<str> + std::fmt::Debug,
    RG: Fn(R) -> Option<(Option<ROV>, RV)>,
>(
    _source: &'s str,
    emacs: &'b Token<'s>,
    rust_node: R,
    emacs_field: &str,
    rust_value_getter: RG,
) -> Result<ComparePropertiesResult<'b, 's>, Box<dyn std::error::Error>> {
    let value = get_property(emacs, emacs_field)?
        .map(Token::as_list)
        .map_or(Ok(None), |r| r.map(Some))?;
    let rust_value = rust_value_getter(rust_node);
    match (value, &rust_value) {
        (None, None) => {}
        (None, Some(_)) | (Some(_), None) => {
            let this_status = DiffStatus::Bad;
            let message = Some(format!(
                "{} mismatch (emacs != rust) {:?} != {:?}",
                emacs_field, value, rust_value
            ));
            return Ok(ComparePropertiesResult::SelfChange(this_status, message));
        }
        (Some(el), Some((Some(_), _))) if el.len() != 3 => {
            let this_status = DiffStatus::Bad;
            let message = Some(format!(
                "{} mismatch (emacs != rust) {:?} != {:?}",
                emacs_field, value, rust_value
            ));
            return Ok(ComparePropertiesResult::SelfChange(this_status, message));
        }
        (Some(el), Some((None, _))) if el.len() != 1 => {
            let this_status = DiffStatus::Bad;
            let message = Some(format!(
                "{} mismatch (emacs != rust) {:?} != {:?}",
                emacs_field, value, rust_value
            ));
            return Ok(ComparePropertiesResult::SelfChange(this_status, message));
        }
        (Some(el), Some((Some(orl), rl))) => {
            let e = el
                .first()
                .map(Token::as_atom)
                .map_or(Ok(None), |r| r.map(Some))?
                .map(unquote)
                .map_or(Ok(None), |r| r.map(Some))?
                .expect("Above match proved length to be 3.");
            let oe = el
                .get(2)
                .map(Token::as_atom)
                .map_or(Ok(None), |r| r.map(Some))?
                .map(unquote)
                .map_or(Ok(None), |r| r.map(Some))?
                .expect("Above match proved length to be 3.");
            let r = rl.as_ref();
            let or = orl.as_ref();
            if e != r {
                let this_status = DiffStatus::Bad;
                let message = Some(format!(
                    "{} mismatch (emacs != rust) {:?} != {:?}. Full list: {:?} != {:?}",
                    emacs_field, e, r, value, rust_value
                ));
                return Ok(ComparePropertiesResult::SelfChange(this_status, message));
            }
            if oe != or {
                let this_status = DiffStatus::Bad;
                let message = Some(format!(
                    "{} mismatch (emacs != rust) {:?} != {:?}. Full list: {:?} != {:?}",
                    emacs_field, e, r, value, rust_value
                ));
                return Ok(ComparePropertiesResult::SelfChange(this_status, message));
            }
        }
        (Some(el), Some((None, rl))) => {
            let e = el
                .first()
                .map(Token::as_atom)
                .map_or(Ok(None), |r| r.map(Some))?
                .map(unquote)
                .map_or(Ok(None), |r| r.map(Some))?
                .expect("Above match proved length to be 1.");
            let r = rl.as_ref();
            if e != r {
                let this_status = DiffStatus::Bad;
                let message = Some(format!(
                    "{} mismatch (emacs != rust) {:?} != {:?}. Full list: {:?} != {:?}",
                    emacs_field, e, r, value, rust_value
                ));
                return Ok(ComparePropertiesResult::SelfChange(this_status, message));
            }
        }
    }
    Ok(ComparePropertiesResult::NoChange)
}

pub(crate) fn compare_property_boolean<'b, 's, R, RG: Fn(R) -> bool>(
    _source: &'s str,
    emacs: &'b Token<'s>,
    rust_node: R,
    emacs_field: &str,
    rust_value_getter: RG,
) -> Result<ComparePropertiesResult<'b, 's>, Box<dyn std::error::Error>> {
    // get_property already converts nil to None.
    let value = get_property(emacs, emacs_field)?.is_some();
    let rust_value = rust_value_getter(rust_node);
    if rust_value != value {
        let this_status = DiffStatus::Bad;
        let message = Some(format!(
            "{} mismatch (emacs != rust) {:?} != {:?}",
            emacs_field, value, rust_value
        ));
        Ok(ComparePropertiesResult::SelfChange(this_status, message))
    } else {
        Ok(ComparePropertiesResult::NoChange)
    }
}

pub(crate) fn compare_property_single_ast_node<
    'b,
    's,
    'x: 'b + 's,
    R,
    RV: std::fmt::Debug,
    RG: Fn(R) -> Option<RV>,
>(
    source: &'s str,
    emacs: &'b Token<'s>,
    rust_node: R,
    emacs_field: &'x str,
    rust_value_getter: RG,
) -> Result<ComparePropertiesResult<'b, 's>, Box<dyn std::error::Error>>
where
    AstNode<'b, 's>: From<RV>,
{
    let value = get_property(emacs, emacs_field)?;
    let rust_value = rust_value_getter(rust_node);
    match (value, rust_value) {
        (None, None) => {}
        (None, rv @ Some(_)) | (Some(_), rv @ None) => {
            let this_status = DiffStatus::Bad;
            let message = Some(format!(
                "{} mismatch (emacs != rust) {:?} != {:?}",
                emacs_field, value, rv
            ));
            return Ok(ComparePropertiesResult::SelfChange(this_status, message));
        }
        (Some(ev), Some(rv)) => {
            let child_status: Vec<DiffEntry<'b, 's>> =
                vec![compare_ast_node(source, ev, rv.into())?];
            let diff_scope = artificial_diff_scope(emacs_field, child_status)?;
            return Ok(ComparePropertiesResult::DiffEntry(diff_scope));
        }
    }
    Ok(ComparePropertiesResult::NoChange)
}

pub(crate) fn compare_property_list_of_ast_nodes<
    'b,
    's,
    'x: 'b + 's,
    R,
    RV: std::fmt::Debug,
    RI: Iterator<Item = RV>,
    RG: Fn(R) -> Option<RI>,
>(
    source: &'s str,
    emacs: &'b Token<'s>,
    rust_node: R,
    emacs_field: &'x str,
    rust_value_getter: RG,
) -> Result<ComparePropertiesResult<'b, 's>, Box<dyn std::error::Error>>
where
    AstNode<'b, 's>: From<RV>,
{
    let value = get_property(emacs, emacs_field)?
        .map(Token::as_list)
        .map_or(Ok(None), |r| r.map(Some))?;
    let rust_value = rust_value_getter(rust_node);
    // TODO: Seems we are needlessly coverting to a vec here.
    let rust_value: Option<Vec<RV>> = rust_value.map(|it| it.collect());
    match (value, rust_value) {
        (None, None) => {}
        (Some(el), None)
            if el.len() == 1 && el.iter().all(|t| matches!(t.as_atom(), Ok(r#""""#))) => {}
        (None, rv @ Some(_)) | (Some(_), rv @ None) => {
            let this_status = DiffStatus::Bad;
            let message = Some(format!(
                "{} mismatch (emacs != rust) {:?} != {:?}",
                emacs_field, value, rv
            ));
            return Ok(ComparePropertiesResult::SelfChange(this_status, message));
        }
        (Some(el), Some(rl)) if el.len() != rl.len() => {
            let this_status = DiffStatus::Bad;
            let message = Some(format!(
                "{} mismatch (emacs != rust) {:?} != {:?}",
                emacs_field, el, rl
            ));
            return Ok(ComparePropertiesResult::SelfChange(this_status, message));
        }
        (Some(el), Some(rl)) => {
            let mut child_status: Vec<DiffEntry<'b, 's>> = Vec::with_capacity(rl.len());
            for (e, r) in el.iter().zip(rl) {
                child_status.push(compare_ast_node(source, e, r.into())?);
            }
            let diff_scope = artificial_diff_scope(emacs_field, child_status)?;
            return Ok(ComparePropertiesResult::DiffEntry(diff_scope));
        }
    }
    Ok(ComparePropertiesResult::NoChange)
}

pub(crate) fn compare_property_object_tree<
    'b,
    's,
    'x,
    R,
    RV: std::fmt::Debug + 'b,
    ROV: std::fmt::Debug + 'b,
    RI: Iterator<Item = &'b (Option<Vec<ROV>>, Vec<RV>)> + ExactSizeIterator + std::fmt::Debug,
    RG: Fn(R) -> Option<RI>,
>(
    source: &'s str,
    emacs: &'b Token<'s>,
    rust_node: R,
    emacs_field: &'x str,
    rust_value_getter: RG,
) -> Result<ComparePropertiesResult<'b, 's>, Box<dyn std::error::Error>>
where
    AstNode<'b, 's>: From<&'b RV>,
    AstNode<'b, 's>: From<&'b ROV>,
{
    let value = get_property(emacs, emacs_field)?
        .map(Token::as_list)
        .map_or(Ok(None), |r| r.map(Some))?;
    let rust_value = rust_value_getter(rust_node);
    let (outer_emacs_list, outer_rust_list) = match (value, rust_value) {
        (None, None) => {
            return Ok(ComparePropertiesResult::NoChange);
        }
        (None, rv @ Some(_)) | (Some(_), rv @ None) => {
            let this_status = DiffStatus::Bad;
            let message = Some(format!(
                "{} mismatch (emacs != rust) {:?} != {:?}",
                emacs_field, value, rv
            ));
            return Ok(ComparePropertiesResult::SelfChange(this_status, message));
        }
        (Some(el), Some(rl)) if el.len() != rl.len() => {
            let this_status = DiffStatus::Bad;
            let message = Some(format!(
                "{} mismatch (emacs != rust) {:?} != {:?}",
                emacs_field, el, rl
            ));
            return Ok(ComparePropertiesResult::SelfChange(this_status, message));
        }
        (Some(el), Some(rl)) => (el, rl),
    };
    let mut full_status: Vec<DiffEntry<'b, 's>> = Vec::with_capacity(outer_rust_list.len());

    for (kw_e, kw_r) in outer_emacs_list.iter().zip(outer_rust_list) {
        match (kw_e.as_atom(), kw_r) {
            (Ok("nil"), (None, mandatory_value)) if mandatory_value.is_empty() => {
                // If its an empty keyword then it becomes nil in the elisp.
                continue;
            }
            (Ok("nil"), _) => {
                let this_status = DiffStatus::Bad;
                let message = Some(format!(
                    "{} mismatch (emacs != rust) {:?} != {:?}",
                    emacs_field, kw_e, kw_r
                ));
                return Ok(ComparePropertiesResult::SelfChange(this_status, message));
            }
            _ => {}
        }
        let kw_e = kw_e.as_list()?;
        let child_status_length = kw_r.1.len() + kw_r.0.as_ref().map(|opt| opt.len()).unwrap_or(0);
        let mut child_status: Vec<DiffEntry<'b, 's>> = Vec::with_capacity(child_status_length);
        if let Some(or) = &kw_r.0 {
            // if optional value
            let mut kw_e = kw_e.iter();
            // First element is a list representing the mandatory value.
            if let Some(val_e) = kw_e.next() {
                match (val_e.as_atom(), kw_r) {
                    (Ok("nil"), (_, mandatory_value)) if mandatory_value.is_empty() => {}
                    (Ok("nil"), _) => {
                        let this_status = DiffStatus::Bad;
                        let message = Some(format!(
                            "{} mismatch (emacs != rust) {:?} != {:?}",
                            emacs_field, kw_e, kw_r
                        ));
                        return Ok(ComparePropertiesResult::SelfChange(this_status, message));
                    }
                    _ => {
                        let el = val_e.as_list()?;
                        if el.len() != kw_r.1.len() {
                            let this_status = DiffStatus::Bad;
                            let message = Some(format!(
                                "{} mismatch (emacs != rust) {:?} != {:?}",
                                emacs_field, kw_e, kw_r
                            ));
                            return Ok(ComparePropertiesResult::SelfChange(this_status, message));
                        }
                        for (e, r) in el.iter().zip(kw_r.1.iter()) {
                            child_status.push(compare_ast_node(source, e, r.into())?);
                        }
                    }
                };
            } else {
                let this_status = DiffStatus::Bad;
                let message = Some(format!(
                    "{} mismatch (emacs != rust) {:?} != {:?}",
                    emacs_field, kw_e, kw_r
                ));
                return Ok(ComparePropertiesResult::SelfChange(this_status, message));
            }
            // Remaining elements are the optional value.
            if kw_e.len() != or.len() {
                let this_status = DiffStatus::Bad;
                let message = Some(format!(
                    "{} mismatch (emacs != rust) {:?} != {:?}",
                    emacs_field, kw_e, kw_r
                ));
                return Ok(ComparePropertiesResult::SelfChange(this_status, message));
            }
            for (e, r) in kw_e.zip(or.iter()) {
                child_status.push(compare_ast_node(source, e, r.into())?);
            }
        } else {
            // if no optional value
            if !kw_e.len() == 1 {
                let this_status = DiffStatus::Bad;
                let message = Some(format!(
                    "{} mismatch (emacs != rust) {:?} != {:?}",
                    emacs_field, kw_e, kw_r
                ));
                return Ok(ComparePropertiesResult::SelfChange(this_status, message));
            }

            let e = kw_e
                .first()
                .map(Token::as_list)
                .map_or(Ok(None), |r| r.map(Some))?
                .expect("The above if-statement proves this will be Some.")
                .iter();
            let r = kw_r.1.iter();

            if e.len() != r.len() {
                let this_status = DiffStatus::Bad;
                let message = Some(format!(
                    "{} mismatch (emacs != rust) {:?} != {:?}",
                    emacs_field, kw_e, kw_r
                ));
                return Ok(ComparePropertiesResult::SelfChange(this_status, message));
            }

            for (e, r) in e.zip(r) {
                child_status.push(compare_ast_node(source, e, r.into())?);
            }
        }
        if !child_status.is_empty() {
            let diff_scope = artificial_diff_scope("mandatory value", child_status)?;
            full_status.push(diff_scope);
        }
    }

    if full_status.is_empty() {
        Ok(ComparePropertiesResult::NoChange)
    } else {
        let diff_scope = artificial_owned_diff_scope(emacs_field, full_status)?;
        Ok(ComparePropertiesResult::DiffEntry(diff_scope))
    }
}

pub(crate) fn compare_property_number_lines<
    'b,
    's,
    'x,
    'y,
    R,
    RG: Fn(R) -> Option<&'y SwitchNumberLines>,
>(
    _source: &'s str,
    emacs: &'b Token<'s>,
    rust_node: R,
    emacs_field: &'x str,
    rust_value_getter: RG,
) -> Result<ComparePropertiesResult<'b, 's>, Box<dyn std::error::Error>> {
    let number_lines = get_property(emacs, emacs_field)?;
    let rust_value = rust_value_getter(rust_node);
    match (number_lines, &rust_value) {
        (None, None) => {}
        (Some(number_lines), Some(rust_number_lines)) => {
            let token_list = number_lines.as_list()?;
            let number_type = token_list
                .first()
                .map(Token::as_atom)
                .map_or(Ok(None), |r| r.map(Some))?
                .ok_or(":number-lines should have a type.")?;
            let number_value = token_list
                .get(2)
                .map(Token::as_atom)
                .map_or(Ok(None), |r| r.map(Some))?
                .map(|val| val.parse::<LineNumber>())
                .map_or(Ok(None), |r| r.map(Some))?
                .ok_or(":number-lines should have a value.")?;
            match (number_type, number_value, rust_number_lines) {
                ("new", emacs_val, SwitchNumberLines::New(rust_val)) if emacs_val == *rust_val => {}
                ("continued", emacs_val, SwitchNumberLines::Continued(rust_val))
                    if emacs_val == *rust_val => {}
                _ => {
                    let this_status = DiffStatus::Bad;
                    let message = Some(format!(
                        "{} mismatch (emacs != rust) {:?} != {:?}",
                        emacs_field, number_lines, rust_value
                    ));
                    return Ok(ComparePropertiesResult::SelfChange(this_status, message));
                }
            }
        }
        _ => {
            let this_status = DiffStatus::Bad;
            let message = Some(format!(
                "{} mismatch (emacs != rust) {:?} != {:?}",
                emacs_field, number_lines, rust_value
            ));
            return Ok(ComparePropertiesResult::SelfChange(this_status, message));
        }
    };

    Ok(ComparePropertiesResult::NoChange)
}

pub(crate) fn compare_property_retain_labels<'b, 's, 'x, 'y, R, RG: Fn(R) -> &'y RetainLabels>(
    _source: &'s str,
    emacs: &'b Token<'s>,
    rust_node: R,
    emacs_field: &'x str,
    rust_value_getter: RG,
) -> Result<ComparePropertiesResult<'b, 's>, Box<dyn std::error::Error + 's>> {
    let rust_value = rust_value_getter(rust_node);
    let retain_labels = get_property_unquoted_atom(emacs, ":retain-labels")?;
    if let Some(retain_labels) = retain_labels {
        if retain_labels == "t" {
            match rust_value {
                RetainLabels::Yes => {}
                _ => {
                    let this_status = DiffStatus::Bad;
                    let message = Some(format!(
                        "{} mismatch (emacs != rust) {:?} != {:?}",
                        emacs_field, retain_labels, rust_value
                    ));
                    return Ok(ComparePropertiesResult::SelfChange(this_status, message));
                }
            }
        } else {
            let retain_labels: CharOffsetInLine = get_property_numeric(emacs, ":retain-labels")?.expect("Cannot be None or else the earlier get_property_unquoted_atom would have been None.");
            match (retain_labels, rust_value) {
                (e, RetainLabels::Keep(r)) if e == *r => {}
                _ => {
                    let this_status = DiffStatus::Bad;
                    let message = Some(format!(
                        "{} mismatch (emacs != rust) {:?} != {:?}",
                        emacs_field, retain_labels, rust_value
                    ));
                    return Ok(ComparePropertiesResult::SelfChange(this_status, message));
                }
            }
        }
    } else {
        match rust_value {
            RetainLabels::No => {}
            _ => {
                let this_status = DiffStatus::Bad;
                let message = Some(format!(
                    "{} mismatch (emacs != rust) {:?} != {:?}",
                    emacs_field, retain_labels, rust_value
                ));
                return Ok(ComparePropertiesResult::SelfChange(this_status, message));
            }
        }
    }

    Ok(ComparePropertiesResult::NoChange)
}