oxinat_derive 0.8.0

extern crate proc_macro;
mod uri;
mod model;
mod version;

use proc_macro::TokenStream;

use proc_macro2::{Ident, Span};
use quote::quote;
use syn::{parse_macro_input, Attribute, Data, DeriveInput, Fields};

use uri::uribuilder;
use crate::version::{
    derive_version_parse_legacy,
    derive_version_parse_root_uri,
    derive_version_parse_data_uri
};

/// Shortcut to avoid repetive usage of the same
/// derive parsing boilerplate. Exposes the
/// declared fields from an input parsed as
/// `syn::DeriveInput`
macro_rules! derive_input_boilerplate {
    ($($field:ident),+ $(,)?; from $input:ident) => {
        let temp_input = $input.clone();
        let DeriveInput {
            $(
                $field,
            )+
            ..
        } = parse_macro_input!(temp_input as DeriveInput);
    };
}

/// Shortcut to avoid repetive usage of the same
/// implementation pattern. Specifically in cases
/// where a trait is entirely comprised of inline
/// definitions.
macro_rules! empty_impl {
    ($derive_name:path; from $input:ident) => {
        {
            derive_input_boilerplate!(ident, generics; from $input);
            let where_clause = &generics.where_clause;
            let crate_ident  = get_crate_ident();
            quote! {
                impl #generics #crate_ident::$derive_name for #ident #generics #where_clause {}
            }
        }
    };
}

/// Shortcut to create an ambiguous ident token.
macro_rules! new_ambiguous_ident {
    ($e:expr, $($vars:expr),+ $(,)?) => {
        Ident::new(
            &format!($e, $($vars,)+),
            Span::call_site()
        )
    };
    ($e:expr) => {
        Ident::new($e, Span::call_site())
    }
}

/// Alias for `Vec<syn::Attribute>`.
type Attributes = Vec<Attribute>;

fn get_crate_ident() -> Ident {
    let pkg_name = std::env::var("CARGO_PKG_NAME").unwrap_or("crate".into());
    new_ambiguous_ident!(if pkg_name == "oxinat_core" {
        "crate"
    } else {
        "oxinat_core"
    })
}

#[proc_macro_derive(FullUri)]
pub fn derive_alluri(input: TokenStream) -> TokenStream {
    let mut gen = TokenStream::new();
    [
        derive_adminuri,
        derive_archiveuri,
        derive_authuri,
        derive_dicomuri,
        derive_eventuri,
        derive_experimenturi,
        derive_pluginuri,
        derive_projectsuri,
        derive_serviceuri,
        derive_subjecturi,
        derive_sysuri,
        derive_usersuri
    ].iter().for_each(|deriver| gen.extend(deriver(input.clone())));
    gen
}

/// Generates the methods required to implement a
/// `AdminUri` or `AdminUriLegacy` trait, allowing
/// for a type to represent the administrative
/// endpoints available.
#[proc_macro_derive(AdminUri)]
pub fn derive_adminuri(input: TokenStream) -> TokenStream {
    derive_input_boilerplate!(attrs; from input);

    // Conditionally implement legacy endpoints.
    let mut gen = quote! {};
    if !derive_version_parse_legacy(&attrs) {
        gen.extend(empty_impl!(AdminUri; from input));
    }
    gen.extend(empty_impl!(AdminUriLegacy; from input));
    gen.into()
}

/// Generates the methods required to implement a
/// `ArchiveUri` trait, allowing for a type to
/// represent the XNAT archive access endpoints.
#[proc_macro_derive(ArchiveUri)]
pub fn derive_archiveuri(input: TokenStream) -> TokenStream {
    empty_impl!(ArchiveUri; from input).into()
}

/// Generates the methods required to implement a
/// `AuthUri` trait, allowing for a type to
/// represent the user authentication endpoints.
#[proc_macro_derive(AuthUri)]
pub fn derive_authuri(input: TokenStream) -> TokenStream {
    empty_impl!(AuthUriLegacy; from input).into()
}

/// Generates the methods required to implement a
/// `DicomUri` trait, allowing for a type to
/// represent the DICOM management endpoints.
#[proc_macro_derive(DicomUri)]
pub fn derive_dicomuri(input: TokenStream) -> TokenStream {
    empty_impl!(DicomUri; from input).into()
}

/// Generates the methods required to implement a
/// `EventsUri` trait, allowing for a type to
/// represent the XNAT event system.
#[proc_macro_derive(EventUri)]
pub fn derive_eventuri(input: TokenStream) -> TokenStream {
    empty_impl!(EventsUri; from input).into()
}

/// Generates the methods required to implement a
/// `ExperimentsUri` trait, allowing for atype to
/// represent the XNAT experiments system.
#[proc_macro_derive(ExperimentUri)]
pub fn derive_experimenturi(input: TokenStream) -> TokenStream {
    let mut gen = quote! {};
    gen.extend(empty_impl!(ExperimentUri; from input));
    gen.extend(empty_impl!(ExperimentUriArchive; from input));
    gen.into()
}

/// Generates the methods required to implement a
/// `PluginUri` trait, allowing for a type to
/// represent the plugin management endpoints.
#[proc_macro_derive(PluginUri)]
pub fn derive_pluginuri(input: TokenStream) -> TokenStream {
    empty_impl!(PluginUri; from input).into()
}

/// Generates the methods required to implement a
/// `ProjectUri` trait, allowing for a type to
/// represent the endpoints available for project
/// management.
#[proc_macro_derive(ProjectUri)]
pub fn derive_projectsuri(input: TokenStream) -> TokenStream {
    derive_input_boilerplate!(attrs; from input);
    let mut gen = quote! {};
    if !derive_version_parse_legacy(&attrs) {
        gen.extend(empty_impl!(ProjectUri; from input))
    }
    gen.extend(empty_impl!(ProjectUriArchive; from input));
    gen.extend(empty_impl!(ProjectUriLegacy; from input));
    gen.into()
}

/// Generates the methods required to implement a
/// `ServicesUri` trait. allowing for a type to
/// represent certain service endpoints
/// available.
#[proc_macro_derive(ServicesUri)]
pub fn derive_serviceuri(input: TokenStream) -> TokenStream {
    empty_impl!(ServicesUriLegacy; from input).into()
}

/// Generates the methods required to implement a
/// `SubjectUri` trait, allowing for a type to
/// represent the endpoints available for subject
/// management.
#[proc_macro_derive(SubjectUri)]
pub fn derive_subjecturi(input: TokenStream) -> TokenStream {
    let mut gen = quote! {};
    gen.extend(empty_impl!(SubjectUriLegacy; from input));
    gen.extend(empty_impl!(SubjectUriArchive; from input));
    gen.into()
}

/// Generates the methods required to implement a
/// `SystemUri` trait, allowing for a type to
/// represent the administrative endpoints
/// available.
#[proc_macro_derive(SystemUri)]
pub fn derive_sysuri(input: TokenStream) -> TokenStream {
    empty_impl!(SystemUri; from input).into()
}

/// Generates the methods required to implement a
/// `UsersUri` trait, allowing for a type to
/// represent the user administrative endpoints
/// available.
#[proc_macro_derive(UsersUri)]
pub fn derive_usersuri(input: TokenStream) -> TokenStream {
    derive_input_boilerplate!(attrs; from input);

    let mut gen = quote! {};
    if !derive_version_parse_legacy(&attrs) {
        gen.extend(empty_impl!(UsersUri; from input));
    }
    gen.extend(empty_impl!(UsersUriLegacy; from input));
    gen.into()
}

/// Implements `serde::Deserialize` with a custom
/// implementation for model properties.
/// 
/// ## Panics ##
/// This macro will panic if the deriving struct
/// is not a tuple struct.
#[proc_macro_derive(ModelField)]
pub fn derive_model_field(input: TokenStream) -> TokenStream {
    model::build_property(input)
}

/// Generates an alias for `UriBuilder` and other
/// common traits required by subsequent
/// implementations.
///
/// Specifically, generates the alias from the
/// given `name` and then produces a declarative
/// macro, derived from the `name`.
/// 
/// 
/// e.g.
/// ```no_compile
/// use oxinat_derive::uri_builder_alias;
/// 
/// uri_builder_alias!(AliasedUriBuilder);
/// // Supports non-generics as a single pattern.
/// ImplAliasedUriBuilder! {
///     (String),
///     .. // variadic declarations.
/// }
/// // patterns that require generics need to
/// // currently be declared separately...
/// ImplAliasedUriBuilder! {
///     (TypeToImpAliasedUriBuilder<Parent>, Parent),
///     .. // variadic declarations.
/// }
/// ```
#[proc_macro]
pub fn uri_builder_alias(input: TokenStream) -> TokenStream {
    let ident = parse_macro_input!(input as Ident);
    let trait_doc = "This is an alias trait for traits common in subsequent implmentations.";
    let impl_doc  = &format!("Generate implementations of `{ident}`.");
    let impl_name = Ident::new(&format!("Impl{ident}"), Span::call_site());
    quote! {
        #[doc=#trait_doc]
        pub trait #ident: UriBuilder + Clone + Debug {}
        #[doc=#impl_doc]
        macro_rules! #impl_name {
            ($(($kind:ty)),+ $(,)?) => {
                $(impl #ident for $kind {})+
            };
            ($(($kind:ty, $parent:ident)),+ $(,)?) => {
                $( 
                    impl<$parent> #ident for $kind
                    where
                        $parent: #ident,
                    {}
                )+
            };
        }
    }.into()
}

/// Generates the methods required to implement a
/// `UriBuilder` trait, allowing the type to
/// construct URI paths.
/// 
/// Currently we do not support the implementation
/// against unions.
#[proc_macro_derive(UriBuilder, attributes(parent, match_path, param, validator))]
pub fn derive_uribuilder(input: TokenStream) -> TokenStream {
    uribuilder::build(input)
}

/// Generates the methods required to implement a
/// `Version` trait, allowing the type to
/// represent some API version.
#[proc_macro_derive(Version, attributes(version))]
pub fn derive_version(input: TokenStream) -> TokenStream {
    // Get general information related to the
    // derive input, including the raw details,
    // generic declarations and attributes passed
    // through version() calls.
    derive_input_boilerplate!(attrs, data, generics, ident; from input);
    let where_clause = &generics.where_clause;
    let crate_ident  = get_crate_ident();

    // Determine the `root_uri` attribute to be
    // passed to the actual derived
    // implementation.
    let root_uri = derive_version_parse_root_uri(&attrs)
        .unwrap_or_else(|_| ident.to_string().to_lowercase());
    let data_uri = derive_version_parse_data_uri(&attrs).unwrap();

    let mut gen = quote! {};
    gen.extend(quote! {
        impl #generics #crate_ident::Version for #ident #generics #where_clause {
            fn root_uri(&self) -> String {
                String::from(#root_uri)
            }

            fn data_uri(&self) -> String {
                String::from(#data_uri)
            }
        }
    });
    gen.extend(quote! {
        impl #generics #crate_ident::UriBuilder for #ident #generics #where_clause {
            fn build(&self) -> oxinat_core::BuildResult {
                Ok(self.root_uri())
            }
        }
    });
    gen.extend(quote! {
        impl #generics std::fmt::Display for #ident #generics #where_clause {
            fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
                write!(f, "{}", self.root_uri())
            }
        }
    });

    let mut default_calls = quote! {};
    match data {
        Data::Struct(d) => d.fields.to_owned(),
        _ => Fields::Unit,
    }
        .iter()
        .for_each(|f| {
            let field_ident = &f.ident;
            let field_type  = &f.ty;
            default_calls.extend(quote! {
                #field_ident: #field_type::default(),
            })
        });
    gen.extend(quote! {
        impl #generics Default for #ident #generics #where_clause {
            fn default() -> Self {
                Self { #default_calls }
            }
        }
    });
    gen.into()
}