alef 0.58.3

//! NAPI-RS tagged-enum From-impl code generation (binding ↔ core conversions).

use crate::{
    codegen::{
        conversions::helpers::{
            sanitized_field_to_binding_expr, sanitized_map_field_to_core_expr, sanitized_vec_field_to_core_expr,
        },
        naming::wire_variant_value,
    },
    core::ir::{EnumDef, TypeRef},
};

use super::enums::{
    tagged_enum_binding_struct_fields, tagged_enum_field_is_tuple, tagged_enum_field_name,
    tagged_enum_mixed_named_fields, variant_data_field_names,
};
use super::functions::{core_prim_str, needs_napi_cast};

/// Build the binding→core conversion expression for a sanitized tagged-enum field, gated to
/// the specific shapes this backend can invert (`Vec<Vec<String>>` and `Map<String, String>`,
/// matching what `sanitized_vec_field_to_core_expr`/`sanitized_map_field_to_core_expr`
/// support). Every other sanitized shape keeps the pre-#218 `Default::default()` fallback,
/// which always compiles. The binding-side struct field is always `Option<T>` regardless of
/// the core field's own optionality (see `tagged_enum_binding_struct_fields` field emission in
/// `enums.rs`), so `optional` only changes whether the *result* is re-wrapped in `Option<_>`.
fn sanitized_binding_to_core_expr(binding_field_name: &str, ty: &TypeRef, optional: bool) -> String {
    let is_vec_vec_string = matches!(
        ty,
        TypeRef::Vec(outer) if matches!(outer.as_ref(), TypeRef::Vec(inner) if matches!(inner.as_ref(), TypeRef::String))
    );
    if is_vec_vec_string {
        return if optional {
            format!(
                "val.{binding_field_name}.map(|v| {})",
                sanitized_vec_field_to_core_expr("v", ty)
            )
        } else {
            sanitized_vec_field_to_core_expr(&format!("val.{binding_field_name}.as_deref().unwrap_or_default()"), ty)
        };
    }
    if optional {
        if let Some(inner) = sanitized_map_field_to_core_expr("m", ty) {
            return format!("val.{binding_field_name}.map(|m| {inner})");
        }
    } else if let Some(expr) =
        sanitized_map_field_to_core_expr(&format!("val.{binding_field_name}.unwrap_or_default()"), ty)
    {
        return expr;
    }
    "Default::default()".to_string()
}

/// Build the core→binding field-init expression for a sanitized tagged-enum field, gated to
/// the same shapes as [`sanitized_binding_to_core_expr`] via
/// `sanitized_field_to_binding_expr`. `f` is the already-destructured core-side variable
/// name; unsupported shapes fall back to `None`, which always compiles (and matches the
/// `destructured` pattern binding that field with an ignored `_`-prefixed name).
fn sanitized_core_to_binding_expr(f: &str, ty: &TypeRef, optional: bool) -> String {
    if optional {
        return match sanitized_field_to_binding_expr("v", ty) {
            Some(inner) => format!("{f}: {f}.map(|v| {inner})"),
            None => format!("{f}: None"),
        };
    }
    match sanitized_field_to_binding_expr(f, ty) {
        Some(expr) => format!("{f}: Some({expr})"),
        None => format!("{f}: None"),
    }
}

/// Generate `From<JsTaggedEnum> for core::TaggedEnum` for a flattened struct representation.
pub(super) fn gen_tagged_enum_binding_to_core(
    enum_def: &EnumDef,
    core_import: &str,
    prefix: &str,
    struct_names: &ahash::AHashSet<String>,
) -> String {
    let core_path = crate::codegen::conversions::core_enum_path(enum_def, core_import);
    let binding_name = format!("{prefix}{}", enum_def.name);
    let tag_field = enum_def.serde_tag.as_deref().unwrap_or("type");

    let fields_with_binding_struct = tagged_enum_binding_struct_fields(enum_def, struct_names);
    let mixed_named_fields = tagged_enum_mixed_named_fields(enum_def);

    let variants = enum_def
        .variants
        .iter()
        .map(|variant| {
            let tag_value = wire_variant_value(
                &variant.name,
                variant.serde_rename.as_deref(),
                enum_def.serde_rename_all.as_deref(),
            );
            let is_tuple = crate::codegen::conversions::is_tuple_variant(&variant.fields);
            let is_empty = variant.fields.is_empty();

            if is_empty {
                minijinja::context! {
                    name => variant.name.clone(),
                    tag_value => tag_value.to_string(),
                    is_empty => true,
                    is_tuple => false,
                }
            } else {
                let field_exprs: Vec<String> = variant
                    .fields
                    .iter()
                    .map(|f| {
                        let binding_field_name = tagged_enum_field_name(variant, f);
                        let has_binding = fields_with_binding_struct.contains(f.name.as_str());
                        let is_single_tuple_named = variant.fields.len() == 1
                            && tagged_enum_field_is_tuple(f)
                            && matches!(&f.ty, TypeRef::Named(_));
                        let is_mixed = !is_single_tuple_named && mixed_named_fields.contains(&f.name);
                        if f.sanitized {
                            let expr = sanitized_binding_to_core_expr(&binding_field_name, &f.ty, f.optional);
                            if f.is_boxed { format!("Box::new({expr})") } else { expr }
                        } else if f.optional {
                            match &f.ty {
                                TypeRef::Path => {
                                    format!("val.{binding_field_name}.map(std::path::PathBuf::from)")
                                }
                                TypeRef::Named(n) if is_mixed => {
                                    let core_type = format!("{core_import}::{n}");
                                    format!(
                                        "val.{}.and_then(|s| serde_json::from_str::<{core_type}>(&s).ok())",
                                        binding_field_name
                                    )
                                }
                                TypeRef::Named(_) if has_binding => {
                                    format!("val.{binding_field_name}.map(|v| v.into())")
                                }
                                TypeRef::Named(_) => {
                                    format!("val.{binding_field_name}.map(|v| v.into())")
                                }
                                TypeRef::Primitive(p) if needs_napi_cast(p) => {
                                    let core_ty = core_prim_str(p);
                                    format!("val.{binding_field_name}.map(|v| v as {core_ty})")
                                }
                                TypeRef::Vec(inner) if matches!(inner.as_ref(), TypeRef::Named(_)) => {
                                    format!(
                                        "val.{binding_field_name}.map(|v| v.into_iter().map(Into::into).collect())"
                                    )
                                }
                                _ => {
                                    format!("val.{binding_field_name}")
                                }
                            }
                        } else {
                            let expr = match &f.ty {
                                TypeRef::Named(n) if is_mixed => {
                                    let core_type = format!("{core_import}::{n}");
                                    format!(
                                        "val.{}.and_then(|s| serde_json::from_str::<{core_type}>(&s).ok()).unwrap_or_default()",
                                        binding_field_name
                                    )
                                }
                                TypeRef::Named(_) if has_binding => {
                                    format!("val.{binding_field_name}.map(|v| v.into()).unwrap_or_default()")
                                }
                                TypeRef::Named(_) => {
                                    format!("val.{binding_field_name}.map(|v| v.into()).unwrap_or_default()")
                                }
                                TypeRef::Path => {
                                    format!(
                                        "val.{binding_field_name}.map(std::path::PathBuf::from).unwrap_or_default()"
                                    )
                                }
                                TypeRef::Primitive(p) if needs_napi_cast(p) => {
                                    let core_ty = core_prim_str(p);
                                    format!("val.{binding_field_name}.map(|v| v as {core_ty}).unwrap_or_default()")
                                }
                                TypeRef::Vec(inner) if matches!(inner.as_ref(), TypeRef::Named(_)) => {
                                    format!(
                                        "val.{binding_field_name}.map(|v| v.into_iter().map(Into::into).collect()).unwrap_or_default()"
                                    )
                                }
                                _ => {
                                    format!("val.{binding_field_name}.unwrap_or_default()")
                                }
                            };
                            if f.is_boxed { format!("Box::new({expr})") } else { expr }
                        }
                    })
                    .collect();

                let field_inits: Vec<String> = variant
                    .fields
                    .iter()
                    .zip(field_exprs.iter())
                    .map(|(f, expr)| format!("{}: {expr}", f.name))
                    .collect();

                minijinja::context! {
                    name => variant.name.clone(),
                    tag_value => tag_value,
                    is_empty => false,
                    is_tuple => is_tuple,
                    field_exprs => field_exprs,
                    field_inits => field_inits,
                }
            }
        })
        .collect::<Vec<_>>();

    let default_variant = enum_def.variants.first().map(|first| {
        let is_tuple = crate::codegen::conversions::is_tuple_variant(&first.fields);
        let is_empty = first.fields.is_empty();

        if is_empty {
            minijinja::context! {
                name => first.name.clone(),
                is_empty => true,
                is_tuple => false,
            }
        } else if is_tuple {
            let defaults: Vec<&str> = first.fields.iter().map(|_| "Default::default()").collect();
            minijinja::context! {
                name => first.name.clone(),
                is_empty => false,
                is_tuple => true,
                defaults => defaults,
            }
        } else {
            let default_fields: Vec<String> = first
                .fields
                .iter()
                .map(|f| format!("{}: Default::default()", f.name))
                .collect();
            minijinja::context! {
                name => first.name.clone(),
                is_empty => false,
                is_tuple => false,
                default_fields => default_fields,
            }
        }
    });

    crate::backends::napi::template_env::render(
        "gen_tagged_enum_binding_to_core.jinja",
        minijinja::context! {
            binding_name => binding_name,
            core_path => core_path,
            tag_field => tag_field,
            variants => variants,
            default_variant => default_variant,
        },
    )
}

/// Generate `From<core::TaggedEnum> for JsTaggedEnum` for a flattened struct representation.
pub(super) fn gen_tagged_enum_core_to_binding(
    enum_def: &EnumDef,
    core_import: &str,
    prefix: &str,
    struct_names: &ahash::AHashSet<String>,
) -> String {
    let core_path = crate::codegen::conversions::core_enum_path(enum_def, core_import);
    let binding_name = format!("{prefix}{}", enum_def.name);
    let tag_field = enum_def.serde_tag.as_deref().unwrap_or("type");
    let fields_with_binding_struct = tagged_enum_binding_struct_fields(enum_def, struct_names);
    let mixed_named_fields = tagged_enum_mixed_named_fields(enum_def);

    let all_fields: Vec<String> = {
        let mut fields = std::collections::BTreeSet::new();
        for v in &enum_def.variants {
            for f in &v.fields {
                if tagged_enum_field_is_tuple(f) && matches!(&f.ty, crate::core::ir::TypeRef::Named(_)) {
                    continue;
                }
                fields.insert(tagged_enum_field_name(v, f));
            }
        }
        fields.into_iter().collect()
    };

    let synth_field_names = variant_data_field_names(enum_def);

    let variants = enum_def
        .variants
        .iter()
        .map(|variant| {
            let tag_value = wire_variant_value(
                &variant.name,
                variant.serde_rename.as_deref(),
                enum_def.serde_rename_all.as_deref(),
            );
            let this_synth_field = if variant.fields.len() == 1 {
                let field = &variant.fields[0];
                if tagged_enum_field_is_tuple(field) && matches!(&field.ty, crate::core::ir::TypeRef::Named(_)) {
                    Some(tagged_enum_field_name(variant, field))
                } else {
                    None
                }
            } else {
                None
            };

            if variant.fields.is_empty() {
                let mut all_fields_none: Vec<String> = all_fields.iter().map(|f| format!("{f}: None")).collect();
                for sf in &synth_field_names {
                    all_fields_none.push(format!("{sf}: None"));
                }
                minijinja::context! {
                    name => variant.name.clone(),
                    tag_value => tag_value.to_string(),
                    is_empty => true,
                    is_tuple => false,
                    all_fields_none => all_fields_none,
                }
            } else {
                use crate::core::ir::TypeRef;
                let is_tuple = crate::codegen::conversions::is_tuple_variant(&variant.fields);
                let variant_field_map: std::collections::BTreeMap<String, &crate::core::ir::FieldDef> = variant
                    .fields
                    .iter()
                    .map(|f| (tagged_enum_field_name(variant, f), f))
                    .collect();
                let destructured: Vec<String> = variant
                    .fields
                    .iter()
                    .map(|f| {
                        let binding_field_name = tagged_enum_field_name(variant, f);
                        if f.sanitized && sanitized_field_to_binding_expr("_", &f.ty).is_none() {
                            if is_tuple {
                                format!("_{binding_field_name}")
                            } else {
                                format!("{}: _{}", f.name, f.name)
                            }
                        } else {
                            binding_field_name
                        }
                    })
                    .collect();
                let mut field_inits: Vec<String> = all_fields
                    .iter()
                    .map(|f| {
                        if let Some(field) = variant_field_map.get(f) {
                            let has_binding = fields_with_binding_struct.contains(f.as_str());
                            let is_mixed = mixed_named_fields.contains(field.name.as_str());
                            let boxed_deref = if field.is_boxed { "*" } else { "" };
                            if field.sanitized {
                                sanitized_core_to_binding_expr(f, &field.ty, field.optional)
                            } else if field.optional {
                                match &field.ty {
                                    TypeRef::Path => format!("{f}: {f}.map(|p| p.to_string_lossy().to_string())"),
                                    TypeRef::Named(_) if is_mixed => {
                                        format!("{f}: {f}.and_then(|v| serde_json::to_string(&v).ok())")
                                    }
                                    TypeRef::Named(_) if has_binding => {
                                        format!("{f}: {f}.map(|v| (*v).into())",)
                                    }
                                    TypeRef::Named(_) => {
                                        format!("{f}: {f}.map(|v| v.into())")
                                    }
                                    TypeRef::Vec(inner) if matches!(inner.as_ref(), TypeRef::Named(_)) => {
                                        format!("{f}: {f}.map(|v| v.into_iter().map(Into::into).collect())")
                                    }
                                    // No cast or wrap needed: the destructured binding is
                                    // already named `f`, identical to the field it fills, so
                                    // this is true field-init shorthand, not `f: f`.
                                    _ => f.clone(),
                                }
                            } else {
                                match &field.ty {
                                    TypeRef::Named(_) if is_mixed => {
                                        format!("{f}: serde_json::to_string(&{f}).ok()")
                                    }
                                    TypeRef::Named(_) if has_binding => {
                                        format!("{f}: Some(({boxed_deref}{f}).into())")
                                    }
                                    TypeRef::Named(_) => format!("{f}: Some(({boxed_deref}{f}).into())"),
                                    TypeRef::Path => format!("{f}: Some({f}.to_string_lossy().to_string())"),
                                    TypeRef::Primitive(p) if needs_napi_cast(p) => match p {
                                        crate::core::ir::PrimitiveType::F32 => format!("{f}: Some({f} as f64)"),
                                        crate::core::ir::PrimitiveType::U64
                                        | crate::core::ir::PrimitiveType::Usize
                                        | crate::core::ir::PrimitiveType::Isize => format!("{f}: Some({f} as i64)"),
                                        _ => format!("{f}: Some({f})"),
                                    },
                                    TypeRef::Vec(inner) if matches!(inner.as_ref(), TypeRef::Named(_)) => {
                                        format!("{f}: Some({f}.into_iter().map(Into::into).collect())")
                                    }
                                    _ => format!("{f}: Some({f})"),
                                }
                            }
                        } else {
                            format!("{f}: None")
                        }
                    })
                    .collect();
                for sf in &synth_field_names {
                    if this_synth_field.as_deref() == Some(sf.as_str()) {
                        let field = &variant.fields[0];
                        let var_name = tagged_enum_field_name(variant, field);
                        let is_boxed = field.is_boxed;
                        if is_boxed {
                            field_inits.push(format!("{sf}: Some((*{var_name}).into())"));
                        } else {
                            field_inits.push(format!("{sf}: Some({var_name}.into())"));
                        }
                    } else {
                        field_inits.push(format!("{sf}: None"));
                    }
                }

                minijinja::context! {
                    name => variant.name.clone(),
                    tag_value => tag_value,
                    is_empty => false,
                    is_tuple => is_tuple,
                    destructured => destructured,
                    field_inits => field_inits,
                }
            }
        })
        .collect::<Vec<_>>();

    let has_excluded_variants = !enum_def.excluded_variants.is_empty();

    crate::backends::napi::template_env::render(
        "gen_tagged_enum_core_to_binding.jinja",
        minijinja::context! {
            binding_name => binding_name,
            core_path => core_path,
            tag_field => tag_field,
            variants => variants,
            has_excluded_variants => has_excluded_variants,
        },
    )
}