pezkuwi-subxt-codegen 0.44.0

// Copyright 2019-2025 Parity Technologies (UK) Ltd.
// This file is dual-licensed as Apache-2.0 or GPL-3.0.
// see LICENSE for license details.

use super::CodegenError;
use heck::{ToSnakeCase as _, ToUpperCamelCase as _};
use pezkuwi_subxt_metadata::PalletMetadata;
use proc_macro2::TokenStream as TokenStream2;
use quote::{format_ident, quote};
use scale_typegen::{
	typegen::ir::{type_ir::CompositeIRKind, ToTokensWithSettings},
	TypeGenerator,
};

/// Generate calls from the provided pallet's metadata. Each call returns a `StaticPayload`
/// that can be passed to the subxt client to submit/sign/encode.
///
/// # Arguments
///
/// - `type_gen` - [`scale_typegen::TypeGenerator`] that contains settings and all types from the
///   runtime metadata.
/// - `pallet` - Pallet metadata from which the calls are generated.
/// - `crate_path` - The crate path under which the `subxt-core` crate is located, e.g.
///   `::pezkuwi_subxt::ext::pezkuwi_subxt_core` when using subxt as a dependency.
pub fn generate_calls(
	type_gen: &TypeGenerator,
	pallet: &PalletMetadata,
	crate_path: &syn::Path,
) -> Result<TokenStream2, CodegenError> {
	// Early return if the pallet has no calls.
	let Some(call_ty) = pallet.call_ty_id() else {
		return Ok(quote!());
	};

	let variant_names_and_struct_defs = super::generate_structs_from_variants(
		type_gen,
		call_ty,
		|name| name.to_upper_camel_case().into(),
		"Call",
	)?;
	let (call_structs, call_fns): (Vec<_>, Vec<_>) = variant_names_and_struct_defs
		.into_iter()
		.map(|var| {
			let (call_fn_args, call_args): (Vec<_>, Vec<_>) = match &var.composite.kind {
				CompositeIRKind::Named(named_fields) => named_fields
					.iter()
					.map(|(name, field)| {
						// Note: fn_arg_type this is relative the type path of the type alias when
						// prefixed with `types::`, e.g. `set_max_code_size::New`
						let fn_arg_type = field.type_path.to_token_stream(type_gen.settings());
						let call_arg = if field.is_boxed {
							quote! { #name: #crate_path::alloc::boxed::Box::new(#name) }
						} else {
							quote! { #name }
						};
						(quote!( #name: types::#fn_arg_type ), call_arg)
					})
					.unzip(),
				CompositeIRKind::NoFields => Default::default(),
				CompositeIRKind::Unnamed(_) => {
					return Err(CodegenError::InvalidCallVariant(call_ty));
				},
			};

			let pallet_name = pallet.name();
			let call_name = &var.variant_name;
			let struct_name = &var.composite.name;
			let Some(call_hash) = pallet.call_hash(call_name) else {
				return Err(CodegenError::MissingCallMetadata(
					pallet_name.into(),
					call_name.to_string(),
				));
			};
			let fn_name = format_ident!("{}", var.variant_name.to_snake_case());
			// Propagate the documentation just to `TransactionApi` methods, while
			// draining the documentation of inner call structures.
			let docs = &var.composite.docs;

			// this converts the composite into a full struct type. No Type Parameters needed here.
			let struct_def =
				type_gen.upcast_composite(&var.composite).to_token_stream(type_gen.settings());
			let alias_mod = var.type_alias_mod;
			// The call structure's documentation was stripped above.
			let call_struct = quote! {
				#struct_def
				#alias_mod

				impl #crate_path::blocks::StaticExtrinsic for #struct_name {
					const PALLET: &'static str = #pallet_name;
					const CALL: &'static str = #call_name;
				}
			};

			let client_fn = quote! {
				#docs
				pub fn #fn_name(
					&self,
					#( #call_fn_args, )*
				) -> #crate_path::tx::payload::StaticPayload<types::#struct_name> {
					#crate_path::tx::payload::StaticPayload::new_static(
						#pallet_name,
						#call_name,
						types::#struct_name { #( #call_args, )* },
						[#(#call_hash,)*]
					)
				}
			};

			Ok((call_struct, client_fn))
		})
		.collect::<Result<Vec<_>, _>>()?
		.into_iter()
		.unzip();

	let call_type = type_gen.resolve_type_path(call_ty)?.to_token_stream(type_gen.settings());
	let call_ty = type_gen.resolve_type(call_ty)?;
	let docs = type_gen.docs_from_scale_info(&call_ty.docs);

	let types_mod_ident = type_gen.types_mod_ident();

	Ok(quote! {
		#docs
		pub type Call = #call_type;
		pub mod calls {
			use super::root_mod;
			use super::#types_mod_ident;

			type DispatchError = ::pezsp_runtime::DispatchError;

			pub mod types {
				use super::#types_mod_ident;

				#( #call_structs )*
			}

			pub struct TransactionApi;

			impl TransactionApi {
				#( #call_fns )*
			}
		}
	})
}