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use crate::compiler::message::{Field, FieldType, Message, Referenced};

use crate::compiler::structure::FixedFieldType;

use crate::compiler::util::types::TypeMapper;

use crate::gen::base::map::TypePathMapper;

use crate::gen::base::Error;

use crate::gen::codec::CodecMap;

use crate::gen::template::Template;

use crate::model::protocol::Endianness;

pub trait Utilities: crate::gen::base::structure::Utilities {

    fn get_value_type(endianness: Endianness, ty: FixedFieldType) -> &'static str;

    fn get_value_type_inline(endianness: Endianness, ty: FixedFieldType) -> &'static str;

    fn gen_struct_ref_type(type_name: &str) -> String;

    fn gen_message_ref_type(type_name: &str) -> String;

}

pub struct Templates<'fragment, 'variable> {

    pub template: Template<'fragment, 'variable>,

    pub codec_map: &'fragment CodecMap<'fragment, 'variable>,

}

impl<'fragment, 'variable> Templates<'fragment, 'variable> {

    pub fn get(&self, codec: &str) -> Result<&Template<'fragment, 'variable>, Error> {

        self.codec_map.get(codec).ok_or_else(|| 
Error::CodecNotFound(codec.into())0
)

    }

}

pub fn gen_msg_field_decl<U: Utilities, T: TypeMapper>(

    field: &Field,

    templates: &Templates,

    type_path_map: &TypePathMapper<T>,

) -> Result<String, Error> {

    let codec_template = templates.get(field.codec())
?0
;

    let mut scope = templates.template.scope();

    scope.var("name", &field.name).var("description", "").var_d("info", field);

    let msg_type = match &field.ty {

        FieldType::Fixed(ty) => U::get_field_type(ty.ty).into(),

        FieldType::Ref(v) => match v {

            Referenced::Struct(v) => U::gen_struct_ref_type(&type_path_map.get(v)),

            Referenced::Message(v) => U::gen_message_ref_type(&type_path_map.get(v)),

        },

        FieldType::Buffer => codec_template.render("decl", &["buffer"]).map_err(Error::Codec)
?0
,

        FieldType::SizedBuffer(v) => codec_template

            .scope()

            .var("codec", U::get_value_type(field.endianness, v.ty))

            .render("decl", &["sized_buffer"])

            .map_err(Error::Codec)
?0
,

        FieldType::FixedContainer(_) => scope.render("", &["list"]).unwrap(),

        FieldType::Union(v) => scope.var("type_name", type_path_map.get(&v.r)).render("", &["union"]).unwrap(),

        FieldType::Container(_) => scope.render("", &["list"]).unwrap(),

        FieldType::Payload => codec_template.render("decl", &["payload"]).map_err(Error::Codec)?,

        FieldType::SizedContainer(_) => scope.render("", &["list"]).unwrap(),

    };

    let msg_type = match field.optional {

        true => codec_template.scope().var("msg_type", msg_type).render("decl", &["option"]).map_err(Error::Codec)
?0
,

        false => msg_type,

    };

    Ok(scope.var("type", msg_type).render("decl", &["field"]).unwrap())

}

fn gen_message_array_field<U: Utilities, T: TypeMapper>(

    templates: &Templates,

    function: &str,

    field: &Field,

    type_path_map: &TypePathMapper<T>,

) -> Result<Option<String>, Error> {

    let mut scope = templates.template.scope();

    let codec_template = templates.get(field.codec())
?0
;

    scope

        .var("name", &field.name)

        .var(

            "description",

            field.description.as_ref().map(U::gen_description).unwrap_or("".into()),

        )

        .var_d("info", field);

    let value = match &field.ty {

        FieldType::FixedContainer(v) => {

            scope

                .var("item_type", type_path_map.get(&v.item_type))

                .var("codec", U::get_value_type(field.endianness, v.ty));

            let type_name = codec_template

                .scope()

                .var("item_type", type_path_map.get(&v.item_type))

                .var("codec", U::get_value_type(field.endianness, v.ty))

                .render("decl", &["fixed_container"])

                .map_err(Error::Codec)
?0
;

            Some(scope.var("type_name", type_name).render(function, &["array"]).unwrap())

        }

        FieldType::Container(v) => {

            scope

                .var("item_type", type_path_map.get(&v.item_type))

                .var("codec", U::get_value_type(field.endianness, v.ty));

            let type_name = codec_template

                .scope()

                .var("item_type", type_path_map.get(&v.item_type))

                .var("codec", U::get_value_type(field.endianness, v.ty))

                .render("decl", &["container"])

                .map_err(Error::Codec)
?0
;

            Some(scope.var("type_name", type_name).render(function, &["list"]).unwrap())

        }

        FieldType::SizedContainer(v) => {

            scope

                .var("item_type", type_path_map.get(&v.item_type))

                .var("codec", U::get_value_type(field.endianness, v.ty));

            let type_name = codec_template

                .scope()

                .var("item_type", type_path_map.get(&v.item_type))

                .var("codec", U::get_value_type(field.endianness, v.ty))

                .var("size_codec", U::get_value_type(field.endianness, v.size_ty))

                .render("decl", &["sized_container"])

                .map_err(Error::Codec)
?0
;

            Some(scope.var("type_name", type_name).render(function, &["list"]).unwrap())

        }

        _ => None,

    };

    Ok(value)

}

pub fn gen_message_array_type_decls<U: Utilities, T: TypeMapper>(

    templates: &Templates,

    function: &str,

    msg: &Message,

    type_path_map: &TypePathMapper<T>,

) -> Result<String, Error> {

    msg.fields

        .iter()

        .filter_map(|field| gen_message_array_field::<U, T>(templates, function, field, type_path_map).transpose())

        .collect::<Result<Vec<String>, Error>>()

        .map(|v| v.join(""))

}

pub fn generate<'variable, U: Utilities, T: TypeMapper>(

    mut templates: Templates<'_, 'variable>,

    msg: &'variable Message,

    type_path_map: &TypePathMapper<T>,

) -> Result<String, Error> {

    templates.template.var("msg_name", &msg.name);

    templates.template.var(

        "msg_description",

        msg.description.as_ref().map(U::gen_description).unwrap_or("".into()),

    );

    let fields = msg

        .fields

        .iter()

        .map(|v| gen_msg_field_decl::<U, T>(v, &templates, type_path_map))

        .collect::<Result<Vec<String>, Error>>()
?0

        .join("");

    let mut code = templates.template.scope().var("fields", fields).render("", &["decl"]).unwrap();

    code += "\n";

    code += &gen_message_array_type_decls::<U, T>(&templates, "typealias", msg, type_path_map)
?0
;

    Ok(code)

}