use crate::args;
use crate::args::{InterfaceField, InterfaceFieldArgument};
use crate::output_type::OutputType;
use crate::utils::{generate_default, get_crate_name, get_rustdoc, GeneratorResult};
use darling::ast::{Data, Style};
use inflector::Inflector;
use proc_macro::TokenStream;
use proc_macro2::{Ident, Span};
use quote::quote;
use std::collections::HashSet;
use syn::{Error, Type};
pub fn generate(interface_args: &args::Interface) -> GeneratorResult<TokenStream> {
let crate_name = get_crate_name(interface_args.internal);
let ident = &interface_args.ident;
let generics = &interface_args.generics;
let s = match &interface_args.data {
Data::Enum(s) => s,
_ => {
return Err(
Error::new_spanned(ident, "Interface can only be applied to an enum.").into(),
)
}
};
let extends = interface_args.extends;
let mut enum_names = Vec::new();
let mut enum_items = HashSet::new();
let mut type_into_impls = Vec::new();
let gql_typename = interface_args
.name
.clone()
.unwrap_or_else(|| ident.to_string());
let desc = get_rustdoc(&interface_args.attrs)?
.map(|s| quote! { Some(#s) })
.unwrap_or_else(|| quote! {None});
let mut registry_types = Vec::new();
let mut possible_types = Vec::new();
let mut get_introspection_typename = Vec::new();
let mut collect_all_fields = Vec::new();
for variant in s {
let enum_name = &variant.ident;
let ty = match variant.fields.style {
Style::Tuple if variant.fields.fields.len() == 1 => &variant.fields.fields[0],
Style::Tuple => {
return Err(Error::new_spanned(
enum_name,
"Only single value variants are supported",
)
.into())
}
Style::Unit => {
return Err(
Error::new_spanned(enum_name, "Empty variants are not supported").into(),
)
}
Style::Struct => {
return Err(Error::new_spanned(
enum_name,
"Variants with named fields are not supported",
)
.into())
}
};
if let Type::Path(p) = ty {
if !enum_items.insert(p) {
return Err(
Error::new_spanned(ty, "This type already used in another variant").into(),
);
}
type_into_impls.push(quote! {
#[allow(clippy::all, clippy::pedantic)]
impl #generics ::std::convert::From<#p> for #ident #generics {
fn from(obj: #p) -> Self {
#ident::#enum_name(obj)
}
}
});
enum_names.push(enum_name);
registry_types.push(quote! {
<#p as #crate_name::Type>::create_type_info(registry);
registry.add_implements(&<#p as #crate_name::Type>::type_name(), #gql_typename);
});
possible_types.push(quote! {
possible_types.insert(<#p as #crate_name::Type>::type_name().to_string());
});
get_introspection_typename.push(quote! {
#ident::#enum_name(obj) => <#p as #crate_name::Type>::type_name()
});
collect_all_fields.push(quote! {
#ident::#enum_name(obj) => obj.collect_all_fields(ctx, fields)
});
} else {
return Err(Error::new_spanned(ty, "Invalid type").into());
}
}
let mut methods = Vec::new();
let mut schema_fields = Vec::new();
let mut resolvers = Vec::new();
for InterfaceField {
name,
method,
desc,
ty,
args,
deprecation,
external,
provides,
requires,
} in &interface_args.fields
{
let (name, method_name) = if let Some(method) = method {
(name.to_string(), Ident::new(method, Span::call_site()))
} else {
let method_name = Ident::new(&name, Span::call_site());
(name.to_camel_case(), method_name)
};
let ty = match syn::parse_str::<syn::Type>(&ty.value()) {
Ok(ty) => ty,
Err(_) => return Err(Error::new_spanned(&ty, "Expect type").into()),
};
let mut calls = Vec::new();
let mut use_params = Vec::new();
let mut decl_params = Vec::new();
let mut get_params = Vec::new();
let mut schema_args = Vec::new();
let requires = match &requires {
Some(requires) => quote! { Some(#requires) },
None => quote! { None },
};
let provides = match &provides {
Some(provides) => quote! { Some(#provides) },
None => quote! { None },
};
decl_params.push(quote! { ctx: &'ctx #crate_name::Context<'ctx> });
use_params.push(quote! { ctx });
for InterfaceFieldArgument {
name,
desc,
ty,
default,
default_with,
} in args
{
let ident = Ident::new(name, Span::call_site());
let name = name.to_camel_case();
let ty = match syn::parse_str::<syn::Type>(&ty.value()) {
Ok(ty) => ty,
Err(_) => return Err(Error::new_spanned(&ty, "Expect type").into()),
};
decl_params.push(quote! { #ident: #ty });
use_params.push(quote! { #ident });
let default = generate_default(&default, &default_with)?;
let get_default = match &default {
Some(default) => quote! { Some(|| -> #ty { #default }) },
None => quote! { None },
};
get_params.push(quote! {
let #ident: #ty = ctx.param_value(#name, #get_default)?;
});
let desc = desc
.as_ref()
.map(|s| quote! {Some(#s)})
.unwrap_or_else(|| quote! {None});
let schema_default = default
.as_ref()
.map(|value| {
quote! {Some( <#ty as #crate_name::InputValueType>::to_value(&#value).to_string() )}
})
.unwrap_or_else(|| quote! {None});
schema_args.push(quote! {
args.insert(#name, #crate_name::registry::MetaInputValue {
name: #name,
description: #desc,
ty: <#ty as #crate_name::Type>::create_type_info(registry),
default_value: #schema_default,
validator: None,
});
});
}
for enum_name in &enum_names {
calls.push(quote! {
#ident::#enum_name(obj) => obj.#method_name(#(#use_params),*).await
});
}
let desc = desc
.as_ref()
.map(|s| quote! {Some(#s)})
.unwrap_or_else(|| quote! {None});
let deprecation = deprecation
.as_ref()
.map(|s| quote! {Some(#s)})
.unwrap_or_else(|| quote! {None});
let oty = OutputType::parse(&ty)?;
let ty = match oty {
OutputType::Value(ty) => ty,
OutputType::Result(_, ty) => ty,
};
let schema_ty = oty.value_type();
methods.push(quote! {
#[inline]
async fn #method_name <'ctx>(&self, #(#decl_params),*) -> #crate_name::FieldResult<#ty> {
match self {
#(#calls,)*
}
}
});
schema_fields.push(quote! {
fields.insert(#name.to_string(), #crate_name::registry::MetaField {
name: #name.to_string(),
description: #desc,
args: {
let mut args = #crate_name::indexmap::IndexMap::new();
#(#schema_args)*
args
},
ty: <#schema_ty as #crate_name::Type>::create_type_info(registry),
deprecation: #deprecation,
cache_control: Default::default(),
external: #external,
provides: #provides,
requires: #requires,
});
});
let resolve_obj = quote! {
self.#method_name(#(#use_params),*).await.
map_err(|err| err.into_error_with_path(ctx.item.pos, ctx.path_node.as_ref()))?
};
resolvers.push(quote! {
if ctx.item.node.name.node == #name {
#(#get_params)*
let ctx_obj = ctx.with_selection_set(&ctx.item.node.selection_set);
return #crate_name::OutputValueType::resolve(&#resolve_obj, &ctx_obj, ctx.item).await;
}
});
}
let introspection_type_name = if get_introspection_typename.is_empty() {
quote! { unreachable!() }
} else {
quote! {
match self {
#(#get_introspection_typename),*
}
}
};
let expanded = quote! {
#(#type_into_impls)*
#[allow(clippy::all, clippy::pedantic)]
impl #generics #ident #generics {
#(#methods)*
}
#[allow(clippy::all, clippy::pedantic)]
impl #generics #crate_name::Type for #ident #generics {
fn type_name() -> ::std::borrow::Cow<'static, str> {
::std::borrow::Cow::Borrowed(#gql_typename)
}
fn introspection_type_name(&self) -> ::std::borrow::Cow<'static, str> {
#introspection_type_name
}
fn create_type_info(registry: &mut #crate_name::registry::Registry) -> String {
registry.create_type::<Self, _>(|registry| {
#(#registry_types)*
#crate_name::registry::MetaType::Interface {
name: #gql_typename.to_string(),
description: #desc,
fields: {
let mut fields = #crate_name::indexmap::IndexMap::new();
#(#schema_fields)*
fields
},
possible_types: {
let mut possible_types = #crate_name::indexmap::IndexSet::new();
#(#possible_types)*
possible_types
},
extends: #extends,
keys: None,
}
})
}
}
#[allow(clippy::all, clippy::pedantic)]
#[#crate_name::async_trait::async_trait]
impl #generics #crate_name::resolver_utils::ObjectType for #ident #generics {
async fn resolve_field(&self, ctx: &#crate_name::Context<'_>) -> #crate_name::Result<#crate_name::serde_json::Value> {
#(#resolvers)*
Err(#crate_name::QueryError::FieldNotFound {
field_name: ctx.item.node.name.to_string(),
object: #gql_typename.to_string(),
}.into_error(ctx.item.pos))
}
fn collect_all_fields<'a>(&'a self, ctx: &#crate_name::ContextSelectionSet<'a>, fields: &mut #crate_name::resolver_utils::Fields<'a>) -> #crate_name::Result<()> {
match self {
#(#collect_all_fields),*
}
}
}
#[allow(clippy::all, clippy::pedantic)]
#[#crate_name::async_trait::async_trait]
impl #generics #crate_name::OutputValueType for #ident #generics {
async fn resolve(&self, ctx: &#crate_name::ContextSelectionSet<'_>, _field: &#crate_name::Positioned<#crate_name::parser::types::Field>) -> #crate_name::Result<#crate_name::serde_json::Value> {
#crate_name::resolver_utils::resolve_object(ctx, self).await
}
}
impl #generics #crate_name::type_mark::TypeMarkInterface for #ident #generics {}
};
Ok(expanded.into())
}