use crate::args;
use crate::args::{InterfaceField, InterfaceFieldArgument};
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 proc_macro2::{Ident, Span};
use quote::quote;
use syn::{Data, DeriveInput, Error, Fields, Result, Type};
pub fn generate(interface_args: &args::Interface, input: &DeriveInput) -> Result<TokenStream> {
let crate_name = get_crate_name(interface_args.internal);
let ident = &input.ident;
let generics = &input.generics;
let attrs = &input.attrs;
let vis = &input.vis;
let s = match &input.data {
Data::Struct(s) => s,
_ => return Err(Error::new_spanned(input, "It should be a struct.")),
};
let fields = match &s.fields {
Fields::Unnamed(fields) => fields,
_ => return Err(Error::new_spanned(input, "All fields must be unnamed.")),
};
let mut enum_names = Vec::new();
let mut enum_items = Vec::new();
let mut type_into_impls = Vec::new();
let gql_typename = interface_args
.name
.clone()
.unwrap_or_else(|| ident.to_string());
check_reserved_name(&gql_typename, interface_args.internal)?;
let desc = interface_args
.desc
.as_ref()
.map(|s| quote! {Some(#s)})
.unwrap_or_else(|| quote! {None});
let mut registry_types = Vec::new();
let mut possible_types = Vec::new();
let mut collect_inline_fields = Vec::new();
for field in &fields.unnamed {
if let Type::Path(p) = &field.ty {
let enum_name = &p.path.segments.last().unwrap().ident;
enum_names.push(enum_name);
enum_items.push(quote! { #enum_name(#p) });
type_into_impls.push(quote! {
impl #generics From<#p> for #ident #generics {
fn from(obj: #p) -> Self {
#ident::#enum_name(obj)
}
}
});
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());
});
collect_inline_fields.push(quote! {
if name == <#p as #crate_name::Type>::type_name() {
if let #ident::#enum_name(obj) = self {
return #crate_name::collect_fields(ctx, obj, futures);
}
unreachable!()
}
});
} else {
return Err(Error::new_spanned(field, "Invalid type"));
}
}
let mut methods = Vec::new();
let mut schema_fields = Vec::new();
let mut resolvers = Vec::new();
for InterfaceField {
name,
desc,
ty,
args,
deprecation,
context,
} in &interface_args.fields
{
let method_name = Ident::new(name, Span::call_site());
let name = name.to_camel_case();
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();
if *context {
decl_params.push(quote! { ctx: &'ctx #crate_name::Context<'ctx> });
use_params.push(quote! { ctx });
}
for InterfaceFieldArgument {
name,
desc,
ty,
default,
} in args
{
let ident = Ident::new(name, Span::call_site());
let name = name.to_camel_case();
decl_params.push(quote! { #ident: #ty });
use_params.push(quote! { #ident });
let param_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, #param_default)?;
});
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: None,
});
});
}
for enum_name in &enum_names {
calls.push(quote! {
#ident::#enum_name(obj) => obj.#method_name(#(#use_params),*).await
});
}
let ctx_lifetime = if *context {
quote! { <'ctx> }
} else {
quote! {}
};
methods.push(quote! {
async fn #method_name #ctx_lifetime(&self, #(#decl_params),*) -> #ty {
match self {
#(#calls,)*
}
}
});
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 ty = OutputType::parse(ty)?;
let schema_ty = ty.value_type();
schema_fields.push(quote! {
fields.insert(#name.to_string(), #crate_name::registry::Field {
name: #name.to_string(),
description: #desc,
args: {
let mut args = std::collections::HashMap::new();
#(#schema_args)*
args
},
ty: <#schema_ty as #crate_name::Type>::create_type_info(registry),
deprecation: #deprecation,
cache_control: Default::default(),
});
});
let resolve_obj = match &ty {
OutputType::Value(_) => quote! {
self.#method_name(#(#use_params),*).await
},
OutputType::Result(_, _) => {
quote! {
self.#method_name(#(#use_params),*).await.
map_err(|err| err.with_position(field.position))?
}
}
};
resolvers.push(quote! {
if field.name.as_str() == #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());
}
});
}
let expanded = quote! {
#(#attrs)*
#vis enum #ident #generics { #(#enum_items),* }
#(#type_into_impls)*
impl #generics #ident #generics {
#(#methods)*
}
impl #generics #crate_name::Type for #ident #generics {
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| {
#(#registry_types)*
#crate_name::registry::Type::Interface {
name: #gql_typename.to_string(),
description: #desc,
fields: {
let mut fields = std::collections::HashMap::new();
#(#schema_fields)*
fields
},
possible_types: {
let mut possible_types = std::collections::HashSet::new();
#(#possible_types)*
possible_types
},
}
})
}
}
#[#crate_name::async_trait::async_trait]
impl #generics #crate_name::ObjectType for #ident #generics {
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));
}
fn collect_inline_fields<'a>(
&'a self,
name: &str,
ctx: &#crate_name::ContextSelectionSet<'a>,
futures: &mut Vec<#crate_name::BoxFieldFuture<'a>>,
) -> #crate_name::Result<()> {
#(#collect_inline_fields)*
#crate_name::anyhow::bail!(#crate_name::QueryError::UnrecognizedInlineFragment {
object: #gql_typename.to_string(),
name: name.to_string(),
});
}
}
#[#crate_name::async_trait::async_trait]
impl #generics #crate_name::OutputValueType for #ident #generics {
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())
}