use crate::args;
use crate::output_type::OutputType;
use crate::utils::{build_value_repr, check_reserved_name, get_crate_name};
use inflector::Inflector;
use proc_macro::TokenStream;
use quote::quote;
use syn::{Error, FnArg, ImplItem, ItemImpl, Pat, Result, ReturnType, Type, TypeReference};
pub fn generate(object_args: &args::Object, item_impl: &mut ItemImpl) -> Result<TokenStream> {
let crate_name = get_crate_name(object_args.internal);
let (self_ty, self_name) = match item_impl.self_ty.as_ref() {
Type::Path(path) => (
path,
path.path
.segments
.last()
.map(|s| s.ident.to_string())
.unwrap(),
),
_ => return Err(Error::new_spanned(&item_impl.self_ty, "Invalid type")),
};
let generics = &item_impl.generics;
let gql_typename = object_args
.name
.clone()
.unwrap_or_else(|| self_name.clone());
check_reserved_name(&gql_typename, object_args.internal)?;
let desc = object_args
.desc
.as_ref()
.map(|s| quote! {Some(#s)})
.unwrap_or_else(|| quote! {None});
let mut resolvers = Vec::new();
let mut schema_fields = Vec::new();
for item in &mut item_impl.items {
if let ImplItem::Method(method) = item {
if let Some(field) = args::Field::parse(&method.attrs)? {
if method.sig.asyncness.is_none() {
return Err(Error::new_spanned(
&method.sig.output,
"Must be asynchronous",
));
}
let field_name = field
.name
.clone()
.unwrap_or_else(|| method.sig.ident.to_string().to_camel_case());
let field_desc = field
.desc
.as_ref()
.map(|s| quote! {Some(#s)})
.unwrap_or_else(|| quote! {None});
let field_deprecation = field
.deprecation
.as_ref()
.map(|s| quote! {Some(#s)})
.unwrap_or_else(|| quote! {None});
let ty = match &method.sig.output {
ReturnType::Type(_, ty) => OutputType::parse(ty)?,
ReturnType::Default => {
return Err(Error::new_spanned(&method.sig.output, "Missing type"))
}
};
let cache_control = {
let public = field.cache_control.public;
let max_age = field.cache_control.max_age;
quote! {
#crate_name::CacheControl {
public: #public,
max_age: #max_age,
}
}
};
let mut arg_ctx = false;
let mut args = Vec::new();
for (idx, arg) in method.sig.inputs.iter_mut().enumerate() {
if let FnArg::Receiver(receiver) = arg {
if idx != 0 {
return Err(Error::new_spanned(
receiver,
"The self receiver must be the first parameter.",
));
}
} else if let FnArg::Typed(pat) = arg {
if idx == 0 {
return Err(Error::new_spanned(
pat,
"The self receiver must be the first parameter.",
));
}
match (&*pat.pat, &*pat.ty) {
(Pat::Ident(arg_ident), Type::Path(arg_ty)) => {
args.push((
arg_ident,
arg_ty,
args::Argument::parse(&crate_name, &pat.attrs)?,
));
pat.attrs.clear();
}
(_, Type::Reference(TypeReference { elem, .. })) => {
if let Type::Path(path) = elem.as_ref() {
if idx != 1
|| path.path.segments.last().unwrap().ident != "Context"
{
return Err(Error::new_spanned(
arg,
"The Context must be the second argument.",
));
}
arg_ctx = true;
}
}
_ => return Err(Error::new_spanned(arg, "Invalid argument type.")),
}
}
}
let mut schema_args = Vec::new();
let mut use_params = Vec::new();
let mut get_params = Vec::new();
for (
ident,
ty,
args::Argument {
name,
desc,
default,
validator,
},
) in args
{
let name = name
.clone()
.unwrap_or_else(|| ident.ident.to_string().to_camel_case());
let desc = desc
.as_ref()
.map(|s| quote! {Some(#s)})
.unwrap_or_else(|| quote! {None});
let schema_default = default
.as_ref()
.map(|v| {
let s = v.to_string();
quote! {Some(#s)}
})
.unwrap_or_else(|| quote! {None});
schema_args.push(quote! {
args.insert(#name, #crate_name::registry::InputValue {
name: #name,
description: #desc,
ty: <#ty as #crate_name::Type>::create_type_info(registry),
default_value: #schema_default,
validator: #validator,
});
});
use_params.push(quote! { #ident });
let default = match &default {
Some(default) => {
let repr = build_value_repr(&crate_name, &default);
quote! {|| #repr }
}
None => quote! { || #crate_name::Value::Null },
};
get_params.push(quote! {
let #ident: #ty = ctx.param_value(#name, #default)?;
});
}
let schema_ty = ty.value_type();
schema_fields.push(quote! {
fields.insert(#field_name.to_string(), #crate_name::registry::Field {
name: #field_name.to_string(),
description: #field_desc,
args: {
let mut args = std::collections::HashMap::new();
#(#schema_args)*
args
},
ty: <#schema_ty as #crate_name::Type>::create_type_info(registry),
deprecation: #field_deprecation,
cache_control: #cache_control,
});
});
let ctx_field = if arg_ctx {
quote! { &ctx, }
} else {
quote! {}
};
let field_ident = &method.sig.ident;
let resolve_obj = match &ty {
OutputType::Value(_) => quote! {
self.#field_ident(#ctx_field #(#use_params),*).await
},
OutputType::Result(_, _) => {
quote! {
self.#field_ident(#ctx_field #(#use_params),*).await.
map_err(|err| err.with_position(field.position))?
}
}
};
resolvers.push(quote! {
if field.name.as_str() == #field_name {
#(#get_params)*
let ctx_obj = ctx.with_selection_set(&field.selection_set);
return #crate_name::OutputValueType::resolve(&#resolve_obj, &ctx_obj).await.
map_err(|err| err.with_position(field.position).into());
}
});
method.attrs.remove(
method
.attrs
.iter()
.enumerate()
.find(|(_, a)| a.path.is_ident("field"))
.map(|(idx, _)| idx)
.unwrap(),
);
}
}
}
let cache_control = {
let public = object_args.cache_control.public;
let max_age = object_args.cache_control.max_age;
quote! {
#crate_name::CacheControl {
public: #public,
max_age: #max_age,
}
}
};
let expanded = quote! {
#item_impl
impl #generics #crate_name::Type for #self_ty {
fn type_name() -> std::borrow::Cow<'static, str> {
std::borrow::Cow::Borrowed(#gql_typename)
}
fn create_type_info(registry: &mut #crate_name::registry::Registry) -> String {
registry.create_type::<Self, _>(|registry| #crate_name::registry::Type::Object {
name: #gql_typename.to_string(),
description: #desc,
fields: {
let mut fields = std::collections::HashMap::new();
#(#schema_fields)*
fields
},
cache_control: #cache_control,
})
}
}
#[#crate_name::async_trait::async_trait]
impl#generics #crate_name::ObjectType for #self_ty {
async fn resolve_field(&self, ctx: &#crate_name::Context<'_>, field: &#crate_name::graphql_parser::query::Field) -> #crate_name::Result<#crate_name::serde_json::Value> {
use #crate_name::ErrorWithPosition;
#(#resolvers)*
#crate_name::anyhow::bail!(#crate_name::QueryError::FieldNotFound {
field_name: field.name.clone(),
object: #gql_typename.to_string(),
}
.with_position(field.position));
}
}
#[#crate_name::async_trait::async_trait]
impl #generics #crate_name::OutputValueType for #self_ty {
async fn resolve(value: &Self, ctx: &#crate_name::ContextSelectionSet<'_>) -> #crate_name::Result<#crate_name::serde_json::Value> {
#crate_name::do_resolve(ctx, value).await
}
}
};
Ok(expanded.into())
}