use std::borrow::Cow;
use std::collections::HashMap;
use std::fmt;
use std::rc::Rc;

use clang::{Availability, Entity, EntityKind, ExceptionSpecification};
use once_cell::sync::Lazy;
use regex::bytes::Regex;

pub use desc::{FuncCppBody, FuncDesc, FuncRustBody, FuncRustExtern};
pub use func_id::FuncId;
pub use kind::{FuncKind, OperatorKind, ReturnKind};
use slice_arg_finder::SliceArgFinder;

use crate::comment::strip_doxygen_comment_markers;
use crate::debug::{DefinitionLocation, LocationName};
use crate::element::ExcludeKind;
use crate::entity::WalkAction;
use crate::field::FieldDesc;
use crate::settings::{TypeRefFactory, ARG_OVERRIDE_SELF};
use crate::type_ref::{Constness, CppNameStyle, TypeRefDesc, TypeRefTypeHint};
use crate::writer::rust_native::element::RustElement;
use crate::writer::rust_native::type_ref::TypeRefExt;
use crate::{
	debug, settings, Class, DefaultElement, Element, EntityExt, Field, GeneratedType, GeneratorEnv, IteratorExt, NameDebug,
	NameStyle, StrExt, StringExt, TypeRef,
};

mod desc;
mod func_id;
mod kind;
mod slice_arg_finder;

#[derive(Clone)]
pub enum Func<'tu, 'ge> {
	Clang {
		entity: Entity<'tu>,
		rust_custom_leafname: Option<Rc<str>>,
		gen_env: &'ge GeneratorEnv<'tu>,
	},
	Desc(Rc<FuncDesc<'tu, 'ge>>),
}

impl<'tu, 'ge> Func<'tu, 'ge> {
	pub fn new(entity: Entity<'tu>, gen_env: &'ge GeneratorEnv<'tu>) -> Self {
		Self::Clang {
			entity,
			rust_custom_leafname: None,
			gen_env,
		}
	}

	pub fn new_ext(entity: Entity<'tu>, rust_custom_leafname: Option<Rc<str>>, gen_env: &'ge GeneratorEnv<'tu>) -> Self {
		Self::Clang {
			entity,
			rust_custom_leafname,
			gen_env,
		}
	}

	pub fn new_desc(desc: FuncDesc<'tu, 'ge>) -> Self {
		Self::Desc(Rc::new(desc))
	}

	/// Sets custom rust_leafname for this func, used to e.g. disambiguate function names
	pub fn set_rust_custom_leafname(&mut self, rust_custom_leafname: Option<Rc<str>>) {
		match self {
			Self::Clang {
				rust_custom_leafname: old_rust_custom_leafname,
				..
			} => *old_rust_custom_leafname = rust_custom_leafname,
			Self::Desc(desc) => {
				if desc.rust_custom_leafname != rust_custom_leafname {
					Rc::make_mut(desc).rust_custom_leafname = rust_custom_leafname;
				}
			}
		}
	}

	pub fn rust_custom_leafname(&self) -> Option<&str> {
		match self {
			Self::Clang {
				rust_custom_leafname, ..
			} => rust_custom_leafname.as_deref(),
			Self::Desc(desc) => desc.rust_custom_leafname.as_ref().map(|n| n.as_ref()),
		}
	}

	pub fn specialize(self, spec: &HashMap<&str, TypeRefFactory>) -> Self {
		let specialized = |type_ref: &TypeRef| -> Option<TypeRef<'static, 'static>> {
			if type_ref.kind().is_generic() {
				spec
					.get(type_ref.source().cpp_name(CppNameStyle::Declaration).as_ref())
					.map(|spec_type| type_ref.map(|_| spec_type().with_inherent_constness(type_ref.constness())))
			} else {
				None
			}
		};

		let arguments = self
			.arguments()
			.iter()
			.map(|arg| {
				let arg_type_ref = arg.type_ref();
				specialized(&arg_type_ref).map_or_else(
					|| arg.clone(),
					|type_ref| {
						Field::new_desc(FieldDesc {
							cpp_fullname: arg.cpp_name(CppNameStyle::Reference).into(),
							type_ref,
							default_value: arg.default_value().map(|v| v.into()),
						})
					},
				)
			})
			.collect();
		let return_type_ref = self.return_type_ref();
		let kind = match self.kind().into_owned() {
			FuncKind::GenericFunction => FuncKind::Function,
			FuncKind::GenericInstanceMethod(cls) => FuncKind::InstanceMethod(cls),
			kind => kind,
		};
		let generic = spec
			.values()
			.map(|s| s().cpp_name(CppNameStyle::Reference).into_owned())
			.join(", ");
		let mut desc = self.to_desc(InheritConfig::empty().kind().arguments().return_type_ref());
		let desc_mut = Rc::make_mut(&mut desc);
		desc_mut.kind = kind;
		desc_mut.type_hint = FuncTypeHint::Specialized;
		desc_mut.arguments = arguments;
		desc_mut.return_type_ref = specialized(&return_type_ref).unwrap_or(return_type_ref);
		desc_mut.cpp_body = FuncCppBody::ManualCall(format!("{{{{name}}}}<{generic}>({{{{args}}}})").into());
		Self::Desc(desc)
	}

	pub(crate) fn to_desc(&self, skip_config: InheritConfig) -> Rc<FuncDesc<'tu, 'ge>> {
		match self {
			Func::Clang { .. } => {
				let kind = if skip_config.kind {
					FuncKind::Function
				} else {
					self.kind().into_owned()
				};
				let cpp_name = if skip_config.name {
					Rc::from("")
				} else {
					self.cpp_name(CppNameStyle::Reference).into()
				};
				let doc_comment = if skip_config.doc_comment {
					Rc::from("")
				} else {
					self.doc_comment().into()
				};
				let arguments: Rc<[Field]> = if skip_config.arguments {
					Rc::new([])
				} else {
					self.arguments().into_owned().into()
				};
				let return_type_ref = if skip_config.return_type_ref {
					TypeRefDesc::void()
				} else {
					self.return_type_ref()
				};
				let def_loc = if skip_config.definition_location {
					DefinitionLocation::Generated
				} else {
					self.file_line_name().location
				};
				Rc::new(FuncDesc {
					kind,
					type_hint: FuncTypeHint::None,
					constness: self.constness(),
					return_kind: self.return_kind(),
					cpp_name,
					rust_custom_leafname: self.rust_custom_leafname().map(Rc::from),
					rust_module: self.rust_module().into(),
					doc_comment,
					def_loc,
					rust_generic_decls: Rc::new([]),
					arguments,
					return_type_ref,
					cpp_body: FuncCppBody::Auto,
					rust_body: FuncRustBody::Auto,
					rust_extern_definition: FuncRustExtern::Auto,
				})
			}
			Func::Desc(desc) => {
				let kind = if skip_config.kind {
					FuncKind::Function
				} else {
					desc.kind.clone()
				};
				let return_type_ref = if skip_config.return_type_ref {
					TypeRefDesc::void()
				} else {
					desc.return_type_ref.clone()
				};
				let def_loc = if skip_config.definition_location {
					DefinitionLocation::Generated
				} else {
					desc.def_loc.clone()
				};
				let mut desc = Rc::clone(desc);
				let desc_mut = Rc::make_mut(&mut desc);
				desc_mut.kind = kind;
				desc_mut.return_type_ref = return_type_ref;
				desc_mut.def_loc = def_loc;
				desc
			}
		}
	}

	pub fn inherit(&mut self, ancestor: &Func<'tu, 'ge>, inherit_config: InheritConfig) {
		#[inline]
		fn transfer<'tu, 'ge>(desc: &mut FuncDesc<'tu, 'ge>, ancestor: &Func<'tu, 'ge>, config: InheritConfig) {
			if config.kind {
				desc.kind = ancestor.kind().into_owned();
			}
			if config.name {
				desc.cpp_name = ancestor.cpp_name(CppNameStyle::Reference).into();
			}
			if config.doc_comment {
				desc.doc_comment = ancestor.doc_comment_overloaded().into();
			}
			if config.arguments {
				desc.arguments = ancestor.arguments().into();
			}
			if config.return_type_ref {
				desc.return_type_ref = ancestor.return_type_ref();
			}
			if config.definition_location {
				desc.def_loc = ancestor.file_line_name().location;
			}
		}

		match self {
			Func::Clang { .. } => {
				if inherit_config.any_enabled() {
					let mut desc = self.to_desc(inherit_config);
					transfer(Rc::make_mut(&mut desc), ancestor, inherit_config);
					*self = Func::Desc(desc);
				}
			}
			Func::Desc(desc) => transfer(Rc::make_mut(desc), ancestor, inherit_config),
		}
	}

	/// Returns true if function was specialized
	///
	/// It's used to add the return type to function identifier because otherwise it will generate identical function names when
	/// we specialize only on the return type.
	pub fn is_specialized(&self) -> bool {
		match self {
			&Self::Clang { .. } => false,
			Self::Desc(desc) => matches!(desc.type_hint, FuncTypeHint::Specialized),
		}
	}

	pub fn kind(&self) -> Cow<FuncKind<'tu, 'ge>> {
		match self {
			&Self::Clang { entity, gen_env, .. } => {
				const OPERATOR: &str = "operator";
				Cow::Owned(match entity.get_kind() {
					EntityKind::FunctionDecl => {
						if let Some(operator) = entity.cpp_name(CppNameStyle::Declaration).strip_prefix(OPERATOR) {
							let arg_count = entity.get_arguments().map_or(0, |v| v.len());
							FuncKind::FunctionOperator(OperatorKind::new(operator.trim(), arg_count))
						} else {
							FuncKind::Function
						}
					}
					EntityKind::Constructor => FuncKind::Constructor(Class::new(
						entity.get_semantic_parent().expect("Can't get parent of constructor"),
						gen_env,
					)),
					EntityKind::Method => {
						let class = Class::new(entity.get_semantic_parent().expect("Can't get parent of method"), gen_env);
						if entity.is_static_method() {
							FuncKind::StaticMethod(class)
						} else if let Some(operator) = entity.cpp_name(CppNameStyle::Declaration).strip_prefix(OPERATOR) {
							let arg_count = entity.get_arguments().map_or(0, |v| v.len());
							FuncKind::InstanceOperator(class, OperatorKind::new(operator.trim(), arg_count))
						} else {
							FuncKind::InstanceMethod(class)
						}
					}
					EntityKind::ConversionFunction => FuncKind::ConversionMethod(Class::new(
						entity.get_semantic_parent().expect("Can't get parent of method"),
						gen_env,
					)),
					EntityKind::FunctionTemplate => match entity.get_template_kind() {
						Some(EntityKind::Method) => FuncKind::GenericInstanceMethod(Class::new(
							entity.get_semantic_parent().expect("Can't get parent of generic method"),
							gen_env,
						)),
						_ => FuncKind::GenericFunction,
					},
					_ => unreachable!("Unknown function entity: {:#?}", entity),
				})
			}
			Self::Desc(desc) => Cow::Borrowed(&desc.kind),
		}
	}

	pub fn constness(&self) -> Constness {
		match self {
			&Self::Clang { entity, .. } => Constness::from_is_const(entity.is_const_method()),
			Self::Desc(desc) => desc.constness,
		}
	}

	pub fn is_abstract(&self) -> bool {
		match self {
			Self::Clang { entity, .. } => entity.is_pure_virtual_method(),
			Self::Desc(_) => false,
		}
	}

	pub fn is_generic(&self) -> bool {
		match self.kind().as_ref() {
			FuncKind::GenericFunction | FuncKind::GenericInstanceMethod(..) => true,
			FuncKind::Function
			| FuncKind::Constructor(..)
			| FuncKind::InstanceMethod(..)
			| FuncKind::StaticMethod(..)
			| FuncKind::FieldAccessor(..)
			| FuncKind::ConversionMethod(..)
			| FuncKind::FunctionOperator(..)
			| FuncKind::InstanceOperator(..) => false,
		}
	}

	/// Like [Self::doc_comment], but processes `@overload` and `@copybrief` directives if possible by copying the corresponding
	/// doccomment
	pub fn doc_comment_overloaded(&self) -> Cow<str> {
		let mut out = self.doc_comment();
		match self {
			Func::Clang { gen_env, .. } => {
				let line = self.file_line_name().location.as_file().map_or(0, |(_, line)| line);
				const OVERLOAD: &str = "@overload";
				if let Some(idx) = out.find(OVERLOAD) {
					let rep = if let Some(copy) = gen_env.get_func_comment(line, self.cpp_name(CppNameStyle::Reference).as_ref()) {
						Cow::Owned(format!("{copy}\n\n## Overloaded parameters\n"))
					} else {
						"This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.".into()
					};
					out.to_mut().replace_range(idx..idx + OVERLOAD.len(), &rep);
				}
				static COPY_BRIEF: Lazy<Regex> = Lazy::new(|| Regex::new(r"@copybrief\s+(\w+)").unwrap());
				out.to_mut().replace_in_place_regex_cb(&COPY_BRIEF, |comment, caps| {
					let copy_name = caps.get(1).map(|(s, e)| &comment[s..e]).expect("Impossible");
					let mut copy_full_name = self.cpp_namespace().into_owned();
					copy_full_name.extend_sep("::", copy_name);
					if let Some(copy) = gen_env.get_func_comment(line, &copy_full_name) {
						Some(copy.into())
					} else {
						Some("".into())
					}
				});
			}
			Func::Desc(_) => {}
		}
		out
	}

	pub fn return_kind(&self) -> ReturnKind {
		match self {
			Self::Clang { entity, .. } => {
				let is_infallible = matches!(
					entity.get_exception_specification(),
					Some(ExceptionSpecification::BasicNoexcept) | Some(ExceptionSpecification::Unevaluated)
				) || settings::FORCE_INFALLIBLE.contains(&self.func_id());
				if is_infallible {
					let return_type_ref = self.return_type_ref();
					if return_type_ref.kind().return_as_naked(return_type_ref.type_hint()) {
						ReturnKind::InfallibleNaked
					} else {
						ReturnKind::InfallibleViaArg
					}
				} else {
					ReturnKind::Fallible
				}
			}
			Self::Desc(desc) => desc.return_kind,
		}
	}

	pub fn safety(&self) -> Safety {
		Safety::from_unsafe(
			settings::FUNC_UNSAFE.contains(&self.func_id())
				|| self.arguments().iter().any(|a| {
					let type_ref = a.type_ref();
					type_ref.kind().is_rust_by_ptr(type_ref.type_hint()) && !a.is_user_data()
				}),
		)
	}

	pub fn is_default_constructor(&self) -> bool {
		match self {
			&Self::Clang { entity, .. } => entity.is_default_constructor() && !self.has_arguments(),
			Self::Desc(_) => false,
		}
	}

	pub fn is_clone(&self) -> bool {
		if self.cpp_name(CppNameStyle::Declaration) == "clone" {
			if let Some(c) = self.kind().as_instance_method() {
				!self.has_arguments() && self.return_type_ref().kind().as_class().map_or(false, |r| r.as_ref() == c)
			} else {
				false
			}
		} else {
			false
		}
	}

	pub fn is_no_discard(&self) -> bool {
		match self {
			&Self::Clang { entity, gen_env, .. } => gen_env.get_export_config(entity).map_or(false, |c| c.no_discard),
			Self::Desc(_) => false,
		}
	}

	pub fn return_type_ref(&self) -> TypeRef<'tu, 'ge> {
		match self {
			&Self::Clang { entity, gen_env, .. } => {
				let mut out = match self.kind().as_ref() {
					FuncKind::Constructor(cls) => cls.type_ref(),
					// `operator =` returns a reference to the `self` value and it's quite cumbersome to handle correctly
					FuncKind::InstanceOperator(_, OperatorKind::Set) => TypeRefDesc::void(),
					FuncKind::Function
					| FuncKind::InstanceMethod(..)
					| FuncKind::StaticMethod(..)
					| FuncKind::FieldAccessor(..)
					| FuncKind::ConversionMethod(..)
					| FuncKind::GenericInstanceMethod(..)
					| FuncKind::GenericFunction
					| FuncKind::FunctionOperator(..)
					| FuncKind::InstanceOperator(..) => {
						let out = TypeRef::new(entity.get_result_type().expect("Can't get return type"), gen_env);
						out.kind().as_reference().map(|cow| cow.into_owned()).unwrap_or(out)
					}
				};
				if let Some(return_hint) = settings::RETURN_OVERRIDE.get(&self.func_id()) {
					out.set_type_hint(return_hint.clone());
					// if we're returning a BoxedRef then assign its mutability to the mutability of the borrowed argument
					if let Some((_, borrow_arg_name, _)) = return_hint.as_boxed_as_ref() {
						let borrow_arg_constness = if borrow_arg_name == ARG_OVERRIDE_SELF {
							self.constness()
						} else {
							self
								.arguments()
								.iter()
								.find(|arg| arg.cpp_name(CppNameStyle::Declaration) == *borrow_arg_name)
								.map(|arg| arg.type_ref().constness())
								.unwrap_or_else(|| panic!("BoxedAsRef refers to the non-existent argument name: {}", borrow_arg_name))
						};
						out.set_inherent_constness(borrow_arg_constness);
					}
				} else if !out.kind().is_char_ptr_string(out.type_hint()) {
					out.set_type_hint(TypeRefTypeHint::PrimitivePtrAsRaw);
				}
				out
			}
			Self::Desc(desc) => desc.return_type_ref.clone(),
		}
	}

	pub fn has_arguments(&self) -> bool {
		self.num_arguments() > 0
	}

	pub fn num_arguments(&self) -> usize {
		match self {
			&Func::Clang { entity, .. } => self.clang_arguments(entity).len(),
			Func::Desc(desc) => desc.arguments.len(),
		}
	}

	fn clang_arguments(&self, entity: Entity<'tu>) -> Vec<Entity<'tu>> {
		match self.kind().as_ref() {
			FuncKind::GenericFunction | FuncKind::GenericInstanceMethod(..) => {
				let mut out = Vec::with_capacity(8);
				entity.walk_children_while(|child| {
					if child.get_kind() == EntityKind::ParmDecl {
						out.push(child);
					}
					WalkAction::Continue
				});
				out
			}
			_ => entity.get_arguments().expect("Can't get arguments"),
		}
	}

	pub fn arguments(&self) -> Cow<[Field<'tu, 'ge>]> {
		match self {
			&Self::Clang { entity, gen_env, .. } => {
				let mut slice_arg_finder = SliceArgFinder::new();
				let arg_overrides = settings::ARGUMENT_OVERRIDE.get(&self.func_id());
				let mut out = self
					.clang_arguments(entity)
					.into_iter()
					.enumerate()
					.map(|(idx, a)| {
						if let Some(func_arg_override) = arg_overrides {
							if let Some(type_hint) = a.get_name().and_then(|arg_name| func_arg_override.get(arg_name.as_str())) {
								return Field::new_ext(a, type_hint.clone(), gen_env);
							}
						}
						let out = Field::new(a, gen_env);
						slice_arg_finder.feed(idx, &out);
						out
					})
					.collect::<Vec<_>>();
				for (slice_arg_indices, slice_len_arg_idx) in slice_arg_finder.finish() {
					let mut slice_arg_names = Vec::with_capacity(slice_arg_indices.len());
					for &slice_arg_idx in &slice_arg_indices {
						let slice_arg = &mut out[slice_arg_idx];
						slice_arg_names.push(slice_arg.rust_name(NameStyle::ref_()).into_owned());
						slice_arg.set_type_ref_type_hint(TypeRefTypeHint::Slice);
					}
					let slice_len_arg = &mut out[slice_len_arg_idx];
					let divisor = if slice_len_arg.cpp_name(CppNameStyle::Declaration).contains("pair") {
						2
					} else {
						1
					};
					slice_len_arg.set_type_ref_type_hint(TypeRefTypeHint::LenForSlice(slice_arg_names, divisor));
				}
				out.into()
			}
			Self::Desc(desc) => desc.arguments.as_ref().into(),
		}
	}

	pub fn generated_types(&self) -> Vec<GeneratedType<'tu, 'ge>> {
		self
			.arguments()
			.iter()
			.map(|a| a.type_ref())
			.filter(|t| !t.exclude_kind().is_ignored())
			.flat_map(|t| t.generated_types())
			.chain(self.return_type_ref().generated_types())
			.collect()
	}

	pub fn identifier(&self) -> String {
		let mut out = if let Some((_, fld)) = self.kind().as_field_accessor() {
			let mut name = self.cpp_namespace().into_owned();
			if !name.is_empty() {
				name.push('_');
			}
			let decl_name = fld.cpp_name(CppNameStyle::Declaration);
			name.reserve(decl_name.len() + 4);
			let (first_letter, rest) = decl_name.split_at(1);
			let [first_letter] = <[u8; 1]>::try_from(first_letter.as_bytes()).expect("first part of split_at(1)");
			name.push_str("prop");
			name.push(first_letter.to_ascii_uppercase().into());
			name.push_str(rest);
			name
		} else {
			self.cpp_name(CppNameStyle::Reference).into_owned()
		};
		// add return type to function id for cases when we specialize on the return type, in theory we should be able to apply
		// this to all of the functions, but it's too much work to rename all those entries in FUNC_RENAME
		if self.is_specialized() {
			out.push('_');
			let ret = self.return_type_ref();
			out.push_str(&ret.cpp_name(CppNameStyle::Reference));
		}
		if self.constness().is_const() {
			out.push_str("_const");
		}
		let args = self.arguments();
		out.reserve(args.len() * 24);
		for arg in args.as_ref() {
			out.push('_');
			out.push_str(&arg.type_ref().cpp_name_ext(CppNameStyle::Declaration, "", false));
		}
		out.cleanup_name();
		out
	}

	pub fn func_id(&self) -> FuncId {
		match self {
			&Self::Clang { entity, .. } => FuncId::from_entity(entity),
			Self::Desc(desc) => FuncId::from_desc(desc),
		}
	}

	pub fn rust_body(&self) -> &FuncRustBody {
		match self {
			Self::Clang { .. } => &FuncRustBody::Auto,
			Self::Desc(desc) => &desc.rust_body,
		}
	}

	pub fn rust_extern_definition(&self) -> FuncRustExtern {
		match self {
			Self::Clang { .. } => FuncRustExtern::Auto,
			Self::Desc(desc) => desc.rust_extern_definition,
		}
	}

	pub fn cpp_body(&self) -> &FuncCppBody {
		match self {
			Self::Clang { .. } => &FuncCppBody::Auto,
			Self::Desc(desc) => &desc.cpp_body,
		}
	}
}

impl Element for Func<'_, '_> {
	fn exclude_kind(&self) -> ExcludeKind {
		let func_id = self.func_id();
		if settings::FUNC_REPLACE.contains_key(&func_id) {
			return ExcludeKind::Included.with_is_excluded(|| settings::FUNC_EXCLUDE.contains(self.identifier().as_str()));
		}
		let kind = self.kind();
		DefaultElement::exclude_kind(self)
			.with_reference_exclude_kind(|| self.return_type_ref().exclude_kind())
			.with_is_excluded(|| {
				let identifier = self.identifier();
				let is_unavailable = match self {
					Func::Clang { entity, .. } => entity.get_availability() == Availability::Unavailable,
					Func::Desc(_) => false,
				};
				is_unavailable
					|| settings::FUNC_EXCLUDE.contains(identifier.as_str())
					|| (self.is_generic())
					|| self.arguments().iter().any(|a| a.type_ref().exclude_kind().is_ignored())
					|| kind.as_operator().map_or(false, |(_, kind)| match kind {
						OperatorKind::Unsupported => true,
						// filter out postfix version of ++ and --: https://en.cppreference.com/w/cpp/language/operator_incdec
						OperatorKind::Incr | OperatorKind::Decr if self.num_arguments() == 1 => true,
						_ => false,
					}) || kind.as_constructor().map_or(false, |cls| cls.is_abstract()) // don't generate constructors of abstract classes
			})
	}

	fn is_system(&self) -> bool {
		match self {
			&Self::Clang { entity, .. } => DefaultElement::is_system(entity),
			Self::Desc(_) => false,
		}
	}

	fn is_public(&self) -> bool {
		match self {
			&Self::Clang { entity, .. } => DefaultElement::is_public(entity),
			Self::Desc(_) => true,
		}
	}

	fn doc_comment(&self) -> Cow<str> {
		match self {
			&Self::Clang { entity, .. } => strip_doxygen_comment_markers(&entity.get_comment().unwrap_or_default()).into(),
			Self::Desc(desc) => desc.doc_comment.as_ref().into(),
		}
	}

	fn cpp_namespace(&self) -> Cow<str> {
		match self {
			&Self::Clang { entity, .. } => DefaultElement::cpp_namespace(entity).into(),
			Self::Desc(desc) => match self.kind().as_ref() {
				FuncKind::Function | FuncKind::FunctionOperator(_) | FuncKind::GenericFunction => desc.cpp_name.namespace().into(),
				FuncKind::Constructor(cls)
				| FuncKind::InstanceMethod(cls)
				| FuncKind::StaticMethod(cls)
				| FuncKind::FieldAccessor(cls, _)
				| FuncKind::ConversionMethod(cls)
				| FuncKind::InstanceOperator(cls, _)
				| FuncKind::GenericInstanceMethod(cls) => cls.cpp_name(CppNameStyle::Reference).into_owned().into(),
			},
		}
	}

	fn cpp_name(&self, style: CppNameStyle) -> Cow<str> {
		let decl_name = if self.kind().as_conversion_method().is_some() {
			format!("operator {}", self.return_type_ref().cpp_name(CppNameStyle::Reference)).into()
		} else {
			match self {
				&Self::Clang { entity, .. } => DefaultElement::cpp_name(self, entity, CppNameStyle::Declaration),
				Self::Desc(desc) => desc.cpp_name.cpp_name_from_fullname(CppNameStyle::Declaration).into(),
			}
		};
		match style {
			CppNameStyle::Declaration => decl_name,
			CppNameStyle::Reference => DefaultElement::cpp_decl_name_with_namespace(self, &decl_name),
		}
	}
}

impl<'me> NameDebug<'me> for &'me Func<'_, '_> {
	fn file_line_name(self) -> LocationName<'me> {
		match self {
			Func::Clang { entity, .. } => entity.file_line_name(),
			Func::Desc(desc) => LocationName::new(desc.def_loc.clone(), self.cpp_name(CppNameStyle::Reference)),
		}
	}

	fn get_debug(self) -> String
	where
		Self: Sized,
	{
		if *debug::EMIT_DEBUG {
			let LocationName { location, name } = self.file_line_name();
			let render_lanes = self
				.arguments()
				.iter()
				.map(|a| format!("{:?}", a.type_ref().render_lane()))
				.join(", ");
			format!("// {name}({render_lanes}) {func_id} {location}", func_id = self.func_id())
		} else {
			"".to_string()
		}
	}
}

impl fmt::Debug for Func<'_, '_> {
	fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
		let mut debug_struct = f.debug_struct(match self {
			Self::Clang { .. } => "Func::Clang",
			Self::Desc(_) => "Func::Desc",
		});
		self
			.update_debug_struct(&mut debug_struct)
			.field("func_id", &self.func_id())
			.field("constness", &self.constness())
			.field("is_specialized", &self.is_specialized())
			.field("return_kind", &self.return_kind())
			.field("kind", &self.kind())
			.field("return_type", &self.return_type_ref())
			.field("arguments", &self.arguments())
			.finish()
	}
}

#[derive(Clone, Copy, Debug, PartialEq, Eq)]
pub enum Safety {
	Safe,
	Unsafe,
}

impl Safety {
	pub fn from_unsafe(is_unsafe: bool) -> Safety {
		if is_unsafe {
			Self::Unsafe
		} else {
			Self::Safe
		}
	}

	pub fn is_safe(self) -> bool {
		match self {
			Self::Safe => true,
			Self::Unsafe => false,
		}
	}

	/// Returns `""` or `"unsafe "`, for usage for unsafe blocks within functions with `self` safety
	pub fn rust_block_safety_qual(self) -> &'static str {
		match self {
			Safety::Safe => "unsafe ",
			Safety::Unsafe => "",
		}
	}

	/// Returns `""` or `"unsafe "`, for usage as function declaration specifier
	pub fn rust_func_safety_qual(self) -> &'static str {
		match self {
			Safety::Safe => "",
			Safety::Unsafe => "unsafe ",
		}
	}
}

#[derive(Copy, Clone, Debug, PartialEq, Eq)]
pub enum FuncTypeHint {
	None,
	Specialized,
}

#[derive(Debug, Clone, Copy)]
pub struct InheritConfig {
	pub kind: bool,
	pub name: bool,
	pub doc_comment: bool,
	pub arguments: bool,
	pub return_type_ref: bool,
	pub definition_location: bool,
}

impl InheritConfig {
	pub const fn empty() -> Self {
		Self {
			kind: false,
			name: false,
			doc_comment: false,
			arguments: false,
			return_type_ref: false,
			definition_location: false,
		}
	}

	pub fn kind(mut self) -> Self {
		self.kind = true;
		self
	}

	pub fn with_name(mut self) -> Self {
		self.name = true;
		self
	}

	pub fn doc_comment(mut self) -> Self {
		self.doc_comment = true;
		self
	}

	pub fn arguments(mut self) -> Self {
		self.arguments = true;
		self
	}

	pub fn return_type_ref(mut self) -> Self {
		self.return_type_ref = true;
		self
	}

	pub fn definition_location(mut self) -> Self {
		self.definition_location = true;
		self
	}

	pub fn any_enabled(self) -> bool {
		self.kind || self.name || self.arguments || self.doc_comment || self.return_type_ref || self.definition_location
	}
}