use darling::FromAttributes;
use proc_macro::TokenStream;
use quote::quote;
use std::error::Error;
use syn::{DataStruct, Ident, ext::IdentExt, spanned::Spanned};
use crate::jsjson::attributes::{ContainerOpts, FieldOpts};
fn is_vec_u8(ty: &syn::Type) -> bool {
let Ok(vec_u8_type) = syn::parse2::<syn::Type>(quote! { Vec<u8> }) else {
emit_error!(ty.span(), "Unreachable: Unable to parse Vec<u8>");
return false;
};
ty == &vec_u8_type
}
pub(super) fn impl_js_json_struct(
name: &Ident,
data: &DataStruct,
container_opts: ContainerOpts,
) -> Result<TokenStream, Box<dyn Error>> {
let mut field_list = Vec::new();
for field in &data.fields {
let Some(field_name) = &field.ident else {
return super::newtypes::impl_js_json_newtype(name, data);
};
let attrs = &field.attrs;
field_list.push((field_name, attrs, &field.ty));
}
let mut list_to_json = Vec::new();
let mut list_from_json = Vec::new();
for (field_name, attrs, field_ty) in field_list {
let field_unraw = field_name.unraw().to_string();
let field_opts = FieldOpts::from_attributes(attrs)?;
if field_opts.skip {
list_from_json.push(quote! {
#field_name: Default::default(),
});
continue;
}
let json_key = match field_opts.rename {
Some(json_key) => json_key,
None => match container_opts.rename_all {
Some(rule) => rule.rename(&field_unraw),
None => field_unraw.clone(),
},
};
let unpack_expr = match field_opts.default {
Some(darling::util::Override::Explicit(default_expr)) => quote! {
.unwrap_or_else(|_| #default_expr)
},
Some(darling::util::Override::Inherit) => quote! {
.unwrap_or_default()
},
None => quote! { ? },
};
if is_vec_u8(field_ty) {
list_to_json.push(quote! {
(#json_key.to_string(), vertigo::JsJson::Vec(self.#field_name)),
});
list_from_json.push(quote! {
#field_name: json.get_property_jsjson(&context, #json_key).and_then(|item| {
match item {
vertigo::JsJson::Vec(v) => Ok(v),
other => {
let message = ["Vec<u8> expected, received ", other.typename()].concat();
Err(context.add(message))
}
}
})#unpack_expr,
})
} else if field_opts.stringify {
let is_option = match field_ty {
syn::Type::Path(ty_path) => ty_path
.path
.segments
.last()
.is_some_and(|last| last.ident == "Option"),
_ => false,
};
if is_option {
list_to_json.push(quote! {
(#json_key.to_string(), match &self.#field_name {
Some(val) => vertigo::JsJson::String(format!("{}", val)),
None => vertigo::JsJson::Null,
}),
});
list_from_json.push(quote! {
#field_name: json.get_property(&context, #json_key).and_then(|item| {
match item {
vertigo::JsJson::String(v) => {
match v.parse() {
Ok(v) => Ok(Some(v)),
Err(e) => {
let message = format!("Error parsing string '{}': {}", v, e);
Err(context.add(message))
}
}
},
vertigo::JsJson::Null => Ok(None),
other => {
let message = ["String or null expected, received ", other.typename()].concat();
Err(context.add(message))
}
}
})#unpack_expr,
})
} else {
list_to_json.push(quote! {
(#json_key.to_string(), vertigo::JsJson::String(format!("{}", self.#field_name))),
});
list_from_json.push(quote! {
#field_name: json.get_property(&context, #json_key).and_then(|item| {
match item {
vertigo::JsJson::String(v) => {
match v.parse() {
Ok(v) => Ok(v),
Err(e) => {
let message = format!("Error parsing string '{}': {}", v, e);
Err(context.add(message))
}
}
},
other => {
let message = ["String expected, received ", other.typename()].concat();
Err(context.add(message))
}
}
})#unpack_expr,
})
}
} else {
list_to_json.push(quote! {
(#json_key.to_string(), self.#field_name.to_json()),
});
list_from_json.push(quote! {
#field_name: json.get_property(&context, #json_key)#unpack_expr,
})
}
}
let result = quote! {
impl vertigo::JsJsonSerialize for #name {
fn to_json(self) -> vertigo::JsJson {
vertigo::JsJson::Object(::std::collections::BTreeMap::from([
#(#list_to_json)*
]))
}
}
impl vertigo::JsJsonDeserialize for #name {
fn from_json(context: vertigo::JsJsonContext, mut json: vertigo::JsJson) -> Result<Self, vertigo::JsJsonContext> {
Ok(Self {
#(#list_from_json)*
})
}
}
};
Ok(result.into())
}