// SPDX-License-Identifier: LGPL-3.0-or-later
// See Notices.txt for copyright information
use crate::{
    hdl_type_common::{
        common_derives, get_target, ItemOptions, MakeHdlTypeExpr, MaybeParsed, ParsedField,
        ParsedFieldsNamed, ParsedGenerics, SplitForImpl, TypesParser, WrappedInConst,
    },
    kw, Errors, HdlAttr, PairsIterExt,
};
use proc_macro2::TokenStream;
use quote::{format_ident, quote_spanned, ToTokens};
use syn::{
    parse_quote, parse_quote_spanned,
    punctuated::{Pair, Punctuated},
    spanned::Spanned,
    token::Brace,
    AngleBracketedGenericArguments, Attribute, Field, FieldMutability, Fields, FieldsNamed,
    GenericParam, Generics, Ident, ItemStruct, Path, Token, Type, Visibility,
};

#[derive(Clone, Debug)]
pub(crate) struct ParsedBundle {
    pub(crate) attrs: Vec<Attribute>,
    pub(crate) options: HdlAttr<ItemOptions, kw::hdl>,
    pub(crate) vis: Visibility,
    pub(crate) struct_token: Token![struct],
    pub(crate) ident: Ident,
    pub(crate) generics: MaybeParsed<ParsedGenerics, Generics>,
    pub(crate) fields: MaybeParsed<ParsedFieldsNamed, FieldsNamed>,
    pub(crate) field_flips: Vec<Option<HdlAttr<kw::flip, kw::hdl>>>,
    pub(crate) mask_type_ident: Ident,
    pub(crate) mask_type_match_variant_ident: Ident,
    pub(crate) match_variant_ident: Ident,
    pub(crate) builder_ident: Ident,
    pub(crate) mask_type_builder_ident: Ident,
}

impl ParsedBundle {
    fn parse_field(
        errors: &mut Errors,
        field: &mut Field,
        index: usize,
    ) -> Option<HdlAttr<kw::flip, kw::hdl>> {
        let Field {
            attrs,
            vis: _,
            mutability,
            ident,
            colon_token,
            ty,
        } = field;
        let ident = ident.get_or_insert_with(|| format_ident!("_{}", index, span = ty.span()));
        if !matches!(mutability, FieldMutability::None) {
            // FIXME: use mutability as the spanned tokens,
            // blocked on https://github.com/dtolnay/syn/issues/1717
            errors.error(&ident, "field mutability is not supported");
            *mutability = FieldMutability::None;
        }
        *mutability = FieldMutability::None;
        colon_token.get_or_insert(Token![:](ident.span()));
        errors.unwrap_or_default(HdlAttr::parse_and_take_attr(attrs))
    }
    fn parse(item: ItemStruct) -> syn::Result<Self> {
        let ItemStruct {
            mut attrs,
            vis,
            struct_token,
            ident,
            mut generics,
            fields,
            semi_token,
        } = item;
        let mut errors = Errors::new();
        let mut options = errors
            .unwrap_or_default(HdlAttr::<ItemOptions, kw::hdl>::parse_and_take_attr(
                &mut attrs,
            ))
            .unwrap_or_default();
        errors.ok(options.body.validate());
        let ItemOptions {
            outline_generated: _,
            target: _,
            custom_bounds,
            no_static: _,
            no_runtime_generics: _,
        } = options.body;
        let mut fields = match fields {
            syn::Fields::Named(fields) => fields,
            syn::Fields::Unnamed(fields) => {
                errors.error(&fields, "#[hdl] struct must use curly braces: {}");
                FieldsNamed {
                    brace_token: Brace(fields.paren_token.span),
                    named: fields.unnamed,
                }
            }
            syn::Fields::Unit => {
                errors.error(&fields, "#[hdl] struct must use curly braces: {}");
                FieldsNamed {
                    brace_token: Brace(semi_token.unwrap_or_default().span),
                    named: Punctuated::default(),
                }
            }
        };
        let mut field_flips = Vec::with_capacity(fields.named.len());
        for (index, field) in fields.named.iter_mut().enumerate() {
            field_flips.push(Self::parse_field(&mut errors, field, index));
        }
        let generics = if custom_bounds.is_some() {
            MaybeParsed::Unrecognized(generics)
        } else if let Some(generics) = errors.ok(ParsedGenerics::parse(&mut generics)) {
            MaybeParsed::Parsed(generics)
        } else {
            MaybeParsed::Unrecognized(generics)
        };
        let fields = TypesParser::maybe_run(generics.as_ref(), fields, &mut errors);
        errors.finish()?;
        Ok(Self {
            attrs,
            options,
            vis,
            struct_token,
            generics,
            fields,
            field_flips,
            mask_type_ident: format_ident!("__{}__MaskType", ident),
            mask_type_match_variant_ident: format_ident!("__{}__MaskType__MatchVariant", ident),
            match_variant_ident: format_ident!("__{}__MatchVariant", ident),
            mask_type_builder_ident: format_ident!("__{}__MaskType__Builder", ident),
            builder_ident: format_ident!("__{}__Builder", ident),
            ident,
        })
    }
}

#[derive(Clone, Debug)]
struct Builder {
    vis: Visibility,
    struct_token: Token![struct],
    ident: Ident,
    target: Path,
    generics: Generics,
    fields: FieldsNamed,
}

#[derive(Copy, Clone, Eq, PartialEq, Debug)]
enum BuilderFieldState {
    Unfilled,
    Generic,
    Filled,
}

impl Builder {
    fn phantom_field_name(&self) -> Ident {
        format_ident!("__phantom", span = self.ident.span())
    }
    fn phantom_field(&self) -> Field {
        let target = &self.target;
        let type_generics = self.generics.split_for_impl().1;
        Field {
            attrs: vec![],
            vis: Visibility::Inherited,
            mutability: FieldMutability::None,
            ident: Some(self.phantom_field_name()),
            colon_token: Some(Token![:](self.ident.span())),
            ty: parse_quote_spanned! {self.ident.span()=>
                ::fayalite::__std::marker::PhantomData<#target #type_generics>
            },
        }
    }
    fn builder_struct_generics(
        &self,
        mut get_field_state: impl FnMut(usize) -> BuilderFieldState,
    ) -> Generics {
        let mut retval = self.generics.clone();
        for param in retval.params.iter_mut() {
            match param {
                GenericParam::Lifetime(_) => {}
                GenericParam::Type(param) => param.default = None,
                GenericParam::Const(param) => param.default = None,
            }
        }
        for (field_index, field) in self.fields.named.iter().enumerate() {
            match get_field_state(field_index) {
                BuilderFieldState::Unfilled | BuilderFieldState::Filled => continue,
                BuilderFieldState::Generic => {}
            }
            if !retval.params.empty_or_trailing() {
                retval.params.push_punct(Token![,](self.ident.span()));
            }
            retval.params.push_value(GenericParam::Type(
                type_var_for_field_name(field.ident.as_ref().unwrap()).into(),
            ));
        }
        retval
    }
    fn builder_struct_ty(
        &self,
        mut get_field_state: impl FnMut(usize) -> BuilderFieldState,
    ) -> Type {
        let mut ty_arguments: AngleBracketedGenericArguments = if self.generics.params.is_empty() {
            parse_quote_spanned! {self.ident.span()=>
                <>
            }
        } else {
            let builder_type_generics = self.generics.split_for_impl().1;
            parse_quote! { #builder_type_generics }
        };
        for (field_index, Field { ident, ty, .. }) in self.fields.named.iter().enumerate() {
            let ident = ident.as_ref().unwrap();
            if !ty_arguments.args.empty_or_trailing() {
                ty_arguments.args.push_punct(Token![,](self.ident.span()));
            }
            ty_arguments
                .args
                .push_value(match get_field_state(field_index) {
                    BuilderFieldState::Unfilled => parse_quote_spanned! {self.ident.span()=>
                        ::fayalite::bundle::Unfilled<#ty>
                    },
                    BuilderFieldState::Generic => {
                        let type_var = type_var_for_field_name(ident);
                        parse_quote_spanned! {self.ident.span()=>
                            #type_var
                        }
                    }
                    BuilderFieldState::Filled => parse_quote_spanned! {self.ident.span()=>
                        ::fayalite::expr::Expr<#ty>
                    },
                });
        }
        let ident = &self.ident;
        parse_quote_spanned! {ident.span()=>
            #ident #ty_arguments
        }
    }
}

fn type_var_for_field_name(ident: &Ident) -> Ident {
    format_ident!("__T_{}", ident)
}

fn field_fn_for_field_name(ident: &Ident) -> Ident {
    format_ident!("field_{}", ident)
}

impl ToTokens for Builder {
    fn to_tokens(&self, tokens: &mut TokenStream) {
        let Self {
            vis,
            struct_token,
            ident,
            target,
            generics: _,
            fields,
        } = self;
        let phantom_field_name = self.phantom_field_name();
        let builder_struct = ItemStruct {
            attrs: vec![parse_quote_spanned! {ident.span()=>
                #[allow(non_camel_case_types, dead_code)]
            }],
            vis: vis.clone(),
            struct_token: *struct_token,
            ident: ident.clone(),
            generics: self.builder_struct_generics(|_| BuilderFieldState::Generic),
            fields: Fields::Named(FieldsNamed {
                brace_token: fields.brace_token,
                named: Punctuated::from_iter(
                    [Pair::Punctuated(
                        self.phantom_field(),
                        Token![,](self.ident.span()),
                    )]
                    .into_iter()
                    .chain(fields.named.pairs().map_pair_value_ref(|field| {
                        let ident = field.ident.as_ref().unwrap();
                        let type_var = type_var_for_field_name(ident);
                        Field {
                            vis: Visibility::Inherited,
                            ty: parse_quote_spanned! {ident.span()=>
                                #type_var
                            },
                            ..field.clone()
                        }
                    })),
                ),
            }),
            semi_token: None,
        };
        builder_struct.to_tokens(tokens);
        let field_idents = Vec::from_iter(
            self.fields
                .named
                .iter()
                .map(|field| field.ident.as_ref().unwrap()),
        );
        for (
            field_index,
            Field {
                vis,
                ident: field_ident,
                ty,
                ..
            },
        ) in self.fields.named.iter().enumerate()
        {
            let field_ident = field_ident.as_ref().unwrap();
            let fn_ident = field_fn_for_field_name(field_ident);
            let fn_generics = self.builder_struct_generics(|i| {
                if i == field_index {
                    BuilderFieldState::Unfilled
                } else {
                    BuilderFieldState::Generic
                }
            });
            let (impl_generics, _, where_clause) = fn_generics.split_for_impl();
            let unfilled_ty = self.builder_struct_ty(|i| {
                if i == field_index {
                    BuilderFieldState::Unfilled
                } else {
                    BuilderFieldState::Generic
                }
            });
            let filled_ty = self.builder_struct_ty(|i| {
                if i == field_index {
                    BuilderFieldState::Filled
                } else {
                    BuilderFieldState::Generic
                }
            });
            let pat_fields =
                Vec::from_iter(self.fields.named.iter().enumerate().map(|(i, field)| {
                    let field_ident = field.ident.as_ref().unwrap();
                    if field_index == i {
                        quote_spanned! {self.ident.span()=>
                            #field_ident: _,
                        }
                    } else {
                        quote_spanned! {self.ident.span()=>
                            #field_ident,
                        }
                    }
                }));
            quote_spanned! {self.ident.span()=>
                #[automatically_derived]
                #[allow(non_camel_case_types, non_snake_case, dead_code)]
                impl #impl_generics #unfilled_ty
                #where_clause
                {
                    #vis fn #fn_ident(
                        self,
                        #field_ident: impl ::fayalite::expr::ToExpr<Type = #ty>,
                    ) -> #filled_ty {
                        let Self {
                            #phantom_field_name: _,
                            #(#pat_fields)*
                        } = self;
                        let #field_ident = ::fayalite::expr::ToExpr::to_expr(&#field_ident);
                        #ident {
                            #phantom_field_name: ::fayalite::__std::marker::PhantomData,
                            #(#field_idents,)*
                        }
                    }
                }
            }
            .to_tokens(tokens);
        }
        let unfilled_generics = self.builder_struct_generics(|_| BuilderFieldState::Unfilled);
        let unfilled_ty = self.builder_struct_ty(|_| BuilderFieldState::Unfilled);
        let (unfilled_impl_generics, _, unfilled_where_clause) = unfilled_generics.split_for_impl();
        quote_spanned! {self.ident.span()=>
            #[automatically_derived]
            #[allow(non_camel_case_types, dead_code)]
            impl #unfilled_impl_generics ::fayalite::__std::default::Default for #unfilled_ty
            #unfilled_where_clause
            {
                fn default() -> Self {
                    #ident {
                        #phantom_field_name: ::fayalite::__std::marker::PhantomData,
                        #(#field_idents: ::fayalite::__std::default::Default::default(),)*
                    }
                }
            }
        }
        .to_tokens(tokens);
        let filled_generics = self.builder_struct_generics(|_| BuilderFieldState::Filled);
        let filled_ty = self.builder_struct_ty(|_| BuilderFieldState::Filled);
        let (filled_impl_generics, _, filled_where_clause) = filled_generics.split_for_impl();
        let type_generics = self.generics.split_for_impl().1;
        quote_spanned! {self.ident.span()=>
            #[automatically_derived]
            #[allow(non_camel_case_types, dead_code)]
            impl #filled_impl_generics ::fayalite::expr::ToExpr for #filled_ty
            #filled_where_clause
            {
                type Type = #target #type_generics;
                fn to_expr(
                    &self,
                ) -> ::fayalite::expr::Expr<<Self as ::fayalite::expr::ToExpr>::Type> {
                    let __ty = #target {
                        #(#field_idents: ::fayalite::expr::Expr::ty(self.#field_idents),)*
                    };
                    let __field_values = [
                        #(::fayalite::expr::Expr::canonical(self.#field_idents),)*
                    ];
                    ::fayalite::expr::ToExpr::to_expr(
                        &::fayalite::expr::ops::BundleLiteral::new(
                            __ty,
                            ::fayalite::intern::Intern::intern(&__field_values[..]),
                        ),
                    )
                }
            }
        }
        .to_tokens(tokens);
    }
}

impl ToTokens for ParsedBundle {
    fn to_tokens(&self, tokens: &mut TokenStream) {
        let Self {
            attrs,
            options,
            vis,
            struct_token,
            ident,
            generics,
            fields,
            field_flips,
            mask_type_ident,
            mask_type_match_variant_ident,
            match_variant_ident,
            builder_ident,
            mask_type_builder_ident,
        } = self;
        let span = ident.span();
        let ItemOptions {
            outline_generated: _,
            target,
            custom_bounds: _,
            no_static,
            no_runtime_generics,
        } = &options.body;
        let target = get_target(target, ident);
        let mut item_attrs = attrs.clone();
        item_attrs.push(common_derives(span));
        ItemStruct {
            attrs: item_attrs,
            vis: vis.clone(),
            struct_token: *struct_token,
            ident: ident.clone(),
            generics: generics.into(),
            fields: Fields::Named(fields.clone().into()),
            semi_token: None,
        }
        .to_tokens(tokens);
        let (impl_generics, type_generics, where_clause) = generics.split_for_impl();
        if let (MaybeParsed::Parsed(generics), MaybeParsed::Parsed(fields), None) =
            (generics, fields, no_runtime_generics)
        {
            generics.make_runtime_generics(tokens, vis, ident, &target, |context| {
                let fields: Vec<_> = fields
                    .named
                    .iter()
                    .map(|ParsedField { ident, ty, .. }| {
                        let ident = ident.as_ref().unwrap();
                        let expr = ty.make_hdl_type_expr(context);
                        quote_spanned! {span=>
                            #ident: #expr,
                        }
                    })
                    .collect();
                parse_quote_spanned! {span=>
                    #target {
                        #(#fields)*
                    }
                }
            })
        }
        let mut wrapped_in_const = WrappedInConst::new(tokens, span);
        let tokens = wrapped_in_const.inner();
        let builder = Builder {
            vis: vis.clone(),
            struct_token: *struct_token,
            ident: builder_ident.clone(),
            target: target.clone(),
            generics: generics.into(),
            fields: fields.clone().into(),
        };
        builder.to_tokens(tokens);
        let unfilled_builder_ty = builder.builder_struct_ty(|_| BuilderFieldState::Unfilled);
        let filled_builder_ty = builder.builder_struct_ty(|_| BuilderFieldState::Filled);
        let mut mask_type_fields = FieldsNamed::from(fields.clone());
        for Field { ty, .. } in &mut mask_type_fields.named {
            *ty = parse_quote_spanned! {span=>
                <#ty as ::fayalite::ty::Type>::MaskType
            };
        }
        let mask_type_builder = Builder {
            vis: vis.clone(),
            struct_token: *struct_token,
            ident: mask_type_builder_ident.clone(),
            target: mask_type_ident.clone().into(),
            generics: generics.into(),
            fields: mask_type_fields.clone(),
        };
        mask_type_builder.to_tokens(tokens);
        let unfilled_mask_type_builder_ty =
            mask_type_builder.builder_struct_ty(|_| BuilderFieldState::Unfilled);
        let filled_mask_type_builder_ty =
            mask_type_builder.builder_struct_ty(|_| BuilderFieldState::Filled);
        ItemStruct {
            attrs: vec![
                common_derives(span),
                parse_quote_spanned! {span=>
                    #[allow(non_camel_case_types, dead_code)]
                },
            ],
            vis: vis.clone(),
            struct_token: *struct_token,
            ident: mask_type_ident.clone(),
            generics: generics.into(),
            fields: Fields::Named(mask_type_fields.clone()),
            semi_token: None,
        }
        .to_tokens(tokens);
        let mut mask_type_match_variant_fields = mask_type_fields;
        for Field { ty, .. } in &mut mask_type_match_variant_fields.named {
            *ty = parse_quote_spanned! {span=>
                ::fayalite::expr::Expr<#ty>
            };
        }
        ItemStruct {
            attrs: vec![
                common_derives(span),
                parse_quote_spanned! {span=>
                    #[allow(non_camel_case_types, dead_code)]
                },
            ],
            vis: vis.clone(),
            struct_token: *struct_token,
            ident: mask_type_match_variant_ident.clone(),
            generics: generics.into(),
            fields: Fields::Named(mask_type_match_variant_fields),
            semi_token: None,
        }
        .to_tokens(tokens);
        let mut match_variant_fields = FieldsNamed::from(fields.clone());
        for Field { ty, .. } in &mut match_variant_fields.named {
            *ty = parse_quote_spanned! {span=>
                ::fayalite::expr::Expr<#ty>
            };
        }
        ItemStruct {
            attrs: vec![
                common_derives(span),
                parse_quote_spanned! {span=>
                    #[allow(non_camel_case_types, dead_code)]
                },
            ],
            vis: vis.clone(),
            struct_token: *struct_token,
            ident: match_variant_ident.clone(),
            generics: generics.into(),
            fields: Fields::Named(match_variant_fields),
            semi_token: None,
        }
        .to_tokens(tokens);
        let this_token = Ident::new("__this", span);
        let fields_token = Ident::new("__fields", span);
        let self_token = Token![self](span);
        let match_variant_body_fields = Vec::from_iter(fields.named().into_iter().map(|field| {
            let ident: &Ident = field.ident().as_ref().unwrap();
            let ident_str = ident.to_string();
            quote_spanned! {span=>
                #ident: ::fayalite::expr::Expr::field(#this_token, #ident_str),
            }
        }));
        let mask_type_body_fields = Vec::from_iter(fields.named().into_iter().map(|field| {
            let ident: &Ident = field.ident().as_ref().unwrap();
            quote_spanned! {span=>
                #ident: ::fayalite::ty::Type::mask_type(&#self_token.#ident),
            }
        }));
        let from_canonical_body_fields =
            Vec::from_iter(fields.named().into_iter().enumerate().zip(field_flips).map(
                |((index, field), flip)| {
                    let ident: &Ident = field.ident().as_ref().unwrap();
                    let ident_str = ident.to_string();
                    let not_flipped = flip.is_none().then(|| Token![!](span));
                    quote_spanned! {span=>
                        #ident: {
                            let ::fayalite::bundle::BundleField {
                                name: __name,
                                flipped: __flipped,
                                ty: __ty,
                            } = #fields_token[#index];
                            ::fayalite::__std::assert_eq!(&*__name, #ident_str);
                            ::fayalite::__std::assert!(#not_flipped __flipped);
                            ::fayalite::ty::Type::from_canonical(__ty)
                        },
                    }
                },
            ));
        let fields_body_fields = Vec::from_iter(fields.named().into_iter().zip(field_flips).map(
            |(field, flip)| {
                let ident: &Ident = field.ident().as_ref().unwrap();
                let ident_str = ident.to_string();
                let flipped = flip.is_some();
                quote_spanned! {span=>
                    ::fayalite::bundle::BundleField {
                        name: ::fayalite::intern::Intern::intern(#ident_str),
                        flipped: #flipped,
                        ty: ::fayalite::ty::Type::canonical(&#self_token.#ident),
                    },
                }
            },
        ));
        let fields_len = fields.named().into_iter().len();
        quote_spanned! {span=>
            #[automatically_derived]
            impl #impl_generics ::fayalite::ty::Type for #mask_type_ident #type_generics
            #where_clause
            {
                type BaseType = ::fayalite::bundle::Bundle;
                type MaskType = #mask_type_ident #type_generics;
                type MatchVariant = #mask_type_match_variant_ident #type_generics;
                type MatchActiveScope = ();
                type MatchVariantAndInactiveScope = ::fayalite::ty::MatchVariantWithoutScope<
                    <Self as ::fayalite::ty::Type>::MatchVariant,
                >;
                type MatchVariantsIter = ::fayalite::__std::iter::Once<
                    <Self as ::fayalite::ty::Type>::MatchVariantAndInactiveScope,
                >;
                fn match_variants(
                    #this_token: ::fayalite::expr::Expr<Self>,
                    __source_location: ::fayalite::source_location::SourceLocation,
                ) -> <Self as ::fayalite::ty::Type>::MatchVariantsIter {
                    let __retval = #mask_type_match_variant_ident {
                        #(#match_variant_body_fields)*
                    };
                    ::fayalite::__std::iter::once(::fayalite::ty::MatchVariantWithoutScope(__retval))
                }
                fn mask_type(&#self_token) -> <Self as ::fayalite::ty::Type>::MaskType {
                    *#self_token
                }
                fn canonical(&#self_token) -> ::fayalite::ty::CanonicalType {
                    ::fayalite::ty::Type::canonical(&::fayalite::bundle::Bundle::new(::fayalite::bundle::BundleType::fields(#self_token)))
                }
                #[track_caller]
                fn from_canonical(__canonical_type: ::fayalite::ty::CanonicalType) -> Self {
                    let ::fayalite::ty::CanonicalType::Bundle(__bundle) = __canonical_type else {
                        ::fayalite::__std::panic!("expected bundle");
                    };
                    let #fields_token = ::fayalite::bundle::BundleType::fields(&__bundle);
                    ::fayalite::__std::assert_eq!(#fields_token.len(), #fields_len, "bundle has wrong number of fields");
                    Self {
                        #(#from_canonical_body_fields)*
                    }
                }
                fn source_location() -> ::fayalite::source_location::SourceLocation {
                    ::fayalite::source_location::SourceLocation::caller()
                }
            }
            #[automatically_derived]
            impl #impl_generics ::fayalite::bundle::BundleType for #mask_type_ident #type_generics
            #where_clause
            {
                type Builder = #unfilled_mask_type_builder_ty;
                type FilledBuilder = #filled_mask_type_builder_ty;
                fn fields(&#self_token) -> ::fayalite::intern::Interned<[::fayalite::bundle::BundleField]> {
                    ::fayalite::intern::Intern::intern(&[#(#fields_body_fields)*][..])
                }
            }
            impl #impl_generics #mask_type_ident #type_generics
            #where_clause
            {
                #vis fn __bundle_builder() -> #unfilled_mask_type_builder_ty {
                    ::fayalite::__std::default::Default::default()
                }
            }
            #[automatically_derived]
            impl #impl_generics ::fayalite::ty::TypeWithDeref for #mask_type_ident #type_generics
            #where_clause
            {
                fn expr_deref(#this_token: &::fayalite::expr::Expr<Self>) -> &<Self as ::fayalite::ty::Type>::MatchVariant {
                    let #this_token = *#this_token;
                    let __retval = #mask_type_match_variant_ident {
                        #(#match_variant_body_fields)*
                    };
                    ::fayalite::intern::Interned::into_inner(::fayalite::intern::Intern::intern_sized(__retval))
                }
            }
            #[automatically_derived]
            impl #impl_generics ::fayalite::ty::Type for #target #type_generics
            #where_clause
            {
                type BaseType = ::fayalite::bundle::Bundle;
                type MaskType = #mask_type_ident #type_generics;
                type MatchVariant = #match_variant_ident #type_generics;
                type MatchActiveScope = ();
                type MatchVariantAndInactiveScope = ::fayalite::ty::MatchVariantWithoutScope<
                    <Self as ::fayalite::ty::Type>::MatchVariant,
                >;
                type MatchVariantsIter = ::fayalite::__std::iter::Once<
                    <Self as ::fayalite::ty::Type>::MatchVariantAndInactiveScope,
                >;
                fn match_variants(
                    #this_token: ::fayalite::expr::Expr<Self>,
                    __source_location: ::fayalite::source_location::SourceLocation,
                ) -> <Self as ::fayalite::ty::Type>::MatchVariantsIter {
                    let __retval = #match_variant_ident {
                        #(#match_variant_body_fields)*
                    };
                    ::fayalite::__std::iter::once(::fayalite::ty::MatchVariantWithoutScope(__retval))
                }
                fn mask_type(&#self_token) -> <Self as ::fayalite::ty::Type>::MaskType {
                    #mask_type_ident {
                        #(#mask_type_body_fields)*
                    }
                }
                fn canonical(&#self_token) -> ::fayalite::ty::CanonicalType {
                    ::fayalite::ty::Type::canonical(&::fayalite::bundle::Bundle::new(::fayalite::bundle::BundleType::fields(#self_token)))
                }
                #[track_caller]
                fn from_canonical(__canonical_type: ::fayalite::ty::CanonicalType) -> Self {
                    let ::fayalite::ty::CanonicalType::Bundle(__bundle) = __canonical_type else {
                        ::fayalite::__std::panic!("expected bundle");
                    };
                    let #fields_token = ::fayalite::bundle::BundleType::fields(&__bundle);
                    ::fayalite::__std::assert_eq!(#fields_token.len(), #fields_len, "bundle has wrong number of fields");
                    Self {
                        #(#from_canonical_body_fields)*
                    }
                }
                fn source_location() -> ::fayalite::source_location::SourceLocation {
                    ::fayalite::source_location::SourceLocation::caller()
                }
            }
            #[automatically_derived]
            impl #impl_generics ::fayalite::bundle::BundleType for #target #type_generics
            #where_clause
            {
                type Builder = #unfilled_builder_ty;
                type FilledBuilder = #filled_builder_ty;
                fn fields(&#self_token) -> ::fayalite::intern::Interned<[::fayalite::bundle::BundleField]> {
                    ::fayalite::intern::Intern::intern(&[#(#fields_body_fields)*][..])
                }
            }
            impl #impl_generics #target #type_generics
            #where_clause
            {
                #vis fn __bundle_builder() -> #unfilled_builder_ty {
                    ::fayalite::__std::default::Default::default()
                }
            }
            #[automatically_derived]
            impl #impl_generics ::fayalite::ty::TypeWithDeref for #target #type_generics
            #where_clause
            {
                fn expr_deref(#this_token: &::fayalite::expr::Expr<Self>) -> &<Self as ::fayalite::ty::Type>::MatchVariant {
                    let #this_token = *#this_token;
                    let __retval = #match_variant_ident {
                        #(#match_variant_body_fields)*
                    };
                    ::fayalite::intern::Interned::into_inner(::fayalite::intern::Intern::intern_sized(__retval))
                }
            }
        }
        .to_tokens(tokens);
        if let (None, MaybeParsed::Parsed(generics)) = (no_static, &self.generics) {
            let static_generics = generics.clone().for_static_type();
            let (static_impl_generics, static_type_generics, static_where_clause) =
                static_generics.split_for_impl();
            let static_type_body_fields = Vec::from_iter(fields.named().into_iter().map(|field| {
                let ident: &Ident = field.ident().as_ref().unwrap();
                let ty = field.ty();
                quote_spanned! {span=>
                    #ident: <#ty as ::fayalite::ty::StaticType>::TYPE,
                }
            }));
            let static_mask_type_body_fields =
                Vec::from_iter(fields.named().into_iter().map(|field| {
                    let ident: &Ident = field.ident().as_ref().unwrap();
                    let ty = field.ty();
                    quote_spanned! {span=>
                        #ident: <#ty as ::fayalite::ty::StaticType>::MASK_TYPE,
                    }
                }));
            let type_properties = format_ident!("__type_properties", span = span);
            let type_properties_fields = Vec::from_iter(fields.named().into_iter().zip(field_flips).map(|(field, field_flip)| {
                let flipped = field_flip.is_some();
                let ty = field.ty();
                quote_spanned! {span=>
                    let #type_properties = #type_properties.field(#flipped, <#ty as ::fayalite::ty::StaticType>::TYPE_PROPERTIES);
                }
            }));
            let type_properties_mask_fields = Vec::from_iter(fields.named().into_iter().zip(field_flips).map(|(field, field_flip)| {
                let flipped = field_flip.is_some();
                let ty = field.ty();
                quote_spanned! {span=>
                    let #type_properties = #type_properties.field(#flipped, <#ty as ::fayalite::ty::StaticType>::MASK_TYPE_PROPERTIES);
                }
            }));
            quote_spanned! {span=>
                #[automatically_derived]
                impl #static_impl_generics ::fayalite::ty::StaticType for #mask_type_ident #static_type_generics
                #static_where_clause
                {
                    const TYPE: Self = Self {
                        #(#static_mask_type_body_fields)*
                    };
                    const MASK_TYPE: <Self as ::fayalite::ty::Type>::MaskType = Self {
                        #(#static_mask_type_body_fields)*
                    };
                    const TYPE_PROPERTIES: ::fayalite::ty::TypeProperties = {
                        let #type_properties = ::fayalite::bundle::BundleTypePropertiesBuilder::new();
                        #(#type_properties_mask_fields)*
                        #type_properties.finish()
                    };
                    const MASK_TYPE_PROPERTIES: ::fayalite::ty::TypeProperties = {
                        let #type_properties = ::fayalite::bundle::BundleTypePropertiesBuilder::new();
                        #(#type_properties_mask_fields)*
                        #type_properties.finish()
                    };
                }
                #[automatically_derived]
                impl #static_impl_generics ::fayalite::ty::StaticType for #target #static_type_generics
                #static_where_clause
                {
                    const TYPE: Self = Self {
                        #(#static_type_body_fields)*
                    };
                    const MASK_TYPE: <Self as ::fayalite::ty::Type>::MaskType = #mask_type_ident {
                        #(#static_mask_type_body_fields)*
                    };
                    const TYPE_PROPERTIES: ::fayalite::ty::TypeProperties = {
                        let #type_properties = ::fayalite::bundle::BundleTypePropertiesBuilder::new();
                        #(#type_properties_fields)*
                        #type_properties.finish()
                    };
                    const MASK_TYPE_PROPERTIES: ::fayalite::ty::TypeProperties = {
                        let #type_properties = ::fayalite::bundle::BundleTypePropertiesBuilder::new();
                        #(#type_properties_mask_fields)*
                        #type_properties.finish()
                    };
                }
            }
            .to_tokens(tokens);
        }
    }
}

pub(crate) fn hdl_bundle(item: ItemStruct) -> syn::Result<TokenStream> {
    let item = ParsedBundle::parse(item)?;
    let outline_generated = item.options.body.outline_generated;
    let mut contents = item.to_token_stream();
    if outline_generated.is_some() {
        contents = crate::outline_generated(contents, "hdl-bundle-");
    }
    Ok(contents)
}