vespera_macro 0.1.34

use std::collections::{BTreeMap, HashSet};

use syn::{FnArg, PatType, Type};
use vespera_core::route::{MediaType, RequestBody};
use vespera_core::schema::{Schema, SchemaRef, SchemaType};

use super::schema::parse_type_to_schema_ref_with_schemas;

fn is_string_like(ty: &Type) -> bool {
    match ty {
        Type::Path(type_path) => type_path
            .path
            .segments
            .last()
            .is_some_and(|seg| seg.ident == "String" || seg.ident == "str"),
        Type::Reference(type_ref) => is_string_like(&type_ref.elem),
        _ => false,
    }
}

/// Analyze function signature and extract `RequestBody`
#[allow(clippy::too_many_lines)]
pub fn parse_request_body(
    arg: &FnArg,
    known_schemas: &HashSet<String>,
    struct_definitions: &std::collections::HashMap<String, String>,
) -> Option<RequestBody> {
    match arg {
        FnArg::Receiver(_) => None,
        FnArg::Typed(PatType { ty, .. }) => {
            if let Type::Path(type_path) = ty.as_ref() {
                let path = &type_path.path;

                // Check the last segment (handles both Json<T> and vespera::axum::Json<T>)
                let segment = path.segments.last().unwrap();
                let ident_str = segment.ident.to_string();

                if ident_str == "Json"
                    && let syn::PathArguments::AngleBracketed(args) = &segment.arguments
                    && let Some(syn::GenericArgument::Type(inner_ty)) = args.args.first()
                {
                    let schema = parse_type_to_schema_ref_with_schemas(
                        inner_ty,
                        known_schemas,
                        struct_definitions,
                    );
                    let mut content = BTreeMap::new();
                    content.insert(
                        "application/json".to_string(),
                        MediaType {
                            schema: Some(schema),
                            example: None,
                            examples: None,
                        },
                    );
                    return Some(RequestBody {
                        description: None,
                        required: Some(true),
                        content,
                    });
                }

                // Form<T> extractor → application/x-www-form-urlencoded request body
                if ident_str == "Form"
                    && let syn::PathArguments::AngleBracketed(args) = &segment.arguments
                    && let Some(syn::GenericArgument::Type(inner_ty)) = args.args.first()
                {
                    let schema = parse_type_to_schema_ref_with_schemas(
                        inner_ty,
                        known_schemas,
                        struct_definitions,
                    );
                    let mut content = BTreeMap::new();
                    content.insert(
                        "application/x-www-form-urlencoded".to_string(),
                        MediaType {
                            schema: Some(schema),
                            example: None,
                            examples: None,
                        },
                    );
                    return Some(RequestBody {
                        description: None,
                        required: Some(true),
                        content,
                    });
                }

                // TypedMultipart<T> extractor → multipart/form-data request body
                if ident_str == "TypedMultipart"
                    && let syn::PathArguments::AngleBracketed(args) = &segment.arguments
                    && let Some(syn::GenericArgument::Type(inner_ty)) = args.args.first()
                {
                    let schema = parse_type_to_schema_ref_with_schemas(
                        inner_ty,
                        known_schemas,
                        struct_definitions,
                    );
                    let mut content = BTreeMap::new();
                    content.insert(
                        "multipart/form-data".to_string(),
                        MediaType {
                            schema: Some(schema),
                            example: None,
                            examples: None,
                        },
                    );
                    return Some(RequestBody {
                        description: None,
                        required: Some(true),
                        content,
                    });
                }

                // Raw Multipart extractor (untyped) → multipart/form-data with generic object schema
                if ident_str == "Multipart" && matches!(segment.arguments, syn::PathArguments::None)
                {
                    let mut content = BTreeMap::new();
                    content.insert(
                        "multipart/form-data".to_string(),
                        MediaType {
                            schema: Some(SchemaRef::Inline(Box::new(Schema::new(
                                SchemaType::Object,
                            )))),
                            example: None,
                            examples: None,
                        },
                    );
                    return Some(RequestBody {
                        description: None,
                        required: Some(true),
                        content,
                    });
                }
            }

            if is_string_like(ty.as_ref()) {
                let schema =
                    parse_type_to_schema_ref_with_schemas(ty, known_schemas, struct_definitions);
                let mut content = BTreeMap::new();
                content.insert(
                    "text/plain".to_string(),
                    MediaType {
                        schema: Some(schema),
                        example: None,
                        examples: None,
                    },
                );

                return Some(RequestBody {
                    description: None,
                    required: Some(true),
                    content,
                });
            }
            None
        }
    }
}

#[cfg(test)]
mod tests {
    use std::collections::HashMap;

    use insta::{assert_debug_snapshot, with_settings};
    use rstest::rstest;

    use super::*;

    #[rstest]
    #[case("String", true)]
    #[case("str", true)]
    #[case("&String", true)]
    #[case("&str", true)]
    #[case("i32", false)]
    #[case("Vec<String>", false)]
    #[case("!", false)]
    fn test_is_string_like_cases(#[case] ty_src: &str, #[case] expected: bool) {
        let ty: Type = syn::parse_str(ty_src).expect("type parse failed");
        assert_eq!(is_string_like(&ty), expected);
    }

    #[rstest]
    #[case::json("fn test(Json(payload): Json<User>) {}", true, "json")]
    #[case::form("fn test(Form(input): Form<User>) {}", true, "form")]
    #[case::string("fn test(just_string: String) {}", true, "string")]
    #[case::str("fn test(just_str: &str) {}", true, "str")]
    #[case::i32("fn test(just_i32: i32) {}", false, "i32")]
    #[case::vec_string("fn test(just_vec_string: Vec<String>) {}", false, "vec_string")]
    #[case::typed_multipart(
        "fn test(TypedMultipart(req): TypedMultipart<UploadRequest>) {}",
        true,
        "typed_multipart"
    )]
    #[case::multipart_raw("fn test(multipart: Multipart) {}", true, "multipart_raw")]
    #[case::self_ref("fn test(&self) {}", false, "self_ref")]
    fn test_parse_request_body_cases(
        #[case] func_src: &str,
        #[case] has_body: bool,
        #[case] suffix: &str,
    ) {
        let func: syn::ItemFn = syn::parse_str(func_src).unwrap();
        let arg = func.sig.inputs.first().unwrap();
        let body = parse_request_body(arg, &HashSet::new(), &HashMap::new());
        assert_eq!(body.is_some(), has_body);
        with_settings!({ snapshot_suffix => format!("req_body_{}", suffix) }, {
            assert_debug_snapshot!(body);
        });
    }
}