vacro-parser-macro 0.1.16

use quote::{format_ident, ToTokens};
use syn::{parse_quote, Ident, Item, Pat};

use crate::codegen::logic::Compiler;

impl Compiler {
    pub fn define_invisible_item(&mut self, item: Item) {
        let mod_ident = self.get_private_scope_ident();
        if let Some(Item::Mod(m)) = self.shared_definition.get_mut(0) {
            if let Some((_, items)) = m.content.as_mut() {
                items.push(item);
                return;
            }
        }
        // Module doesn't exist yet (shared_definition is empty or [0] is not a module), create it
        let mod_definition: Item = parse_quote! {
            #[doc(hidden)]
            #[allow(non_snake_case)]
            pub mod #mod_ident {
                use super::*;
                use ::syn::parse::Parse;
                #item
            }
        };
        self.scoped_definition.push(parse_quote! {
            #[allow(unused_imports)]
            use #mod_ident::*;
        });
        self.shared_definition.insert(0, mod_definition);
    }
    pub fn get_private_scope_ident(&self) -> Ident {
        format_ident!("__private_scope_for_{}", self.target)
    }
    pub fn pat_to_ident(pat: &Pat) -> Ident {
        // 1. 将 Pattern 转为 TokenStream 字符串
        let raw_string = pat.to_token_stream().to_string();

        // 2. 处理字符
        let mut sanitized = String::with_capacity(raw_string.len());
        let mut last_was_underscore = false;

        for c in raw_string.chars() {
            if c.is_alphanumeric() {
                sanitized.push(c.to_ascii_lowercase());
                last_was_underscore = false;
            } else {
                // 只有当上一个字符不是下划线时，才添加下划线（去重）
                if !last_was_underscore {
                    sanitized.push('_');
                    last_was_underscore = true;
                }
            }
        }

        // 3. 去除首尾的下划线
        let final_str = sanitized.trim_matches('_');

        // 4. 处理特殊情况：如果结果为空（例如 pattern 只有符号），默认为 "_"
        let valid_name = if final_str.is_empty() { "_" } else { final_str };

        // 5. 创建 Ident，保留原始 Pattern 的 Span 以便于错误定位
        format_ident!("{valid_name}")
    }
}