//! Utility methods for transpiling

use shulkerbox::util::{MacroString, MacroStringPart};

fn normalize_program_identifier<S>(identifier: S) -> String
where
    S: AsRef<str>,
{
    identifier
        .as_ref()
        .split('/')
        .fold(Vec::new(), |mut acc, el| match el {
            "." | "" => acc,
            ".." => {
                acc.pop();
                acc
            }
            _ => {
                acc.push(el);
                acc
            }
        })
        .join("/")
}

/// Calculate the identifier to import the function based on the current identifier and the import path
#[must_use]
pub fn calculate_import_identifier<S, T>(current_identifier: S, import_path: T) -> String
where
    S: AsRef<str>,
    T: AsRef<str>,
{
    if import_path.as_ref().starts_with('/') {
        normalize_program_identifier(&import_path.as_ref()[1..])
    } else {
        let mut identifier_elements = current_identifier.as_ref().split('/').collect::<Vec<_>>();
        identifier_elements.pop();
        normalize_program_identifier(identifier_elements.join("/") + "/" + import_path.as_ref())
    }
}

/// Join multiple macro strings into one
#[must_use]
pub fn join_macro_strings<I>(strings: I) -> MacroString
where
    I: IntoIterator<Item = MacroString>,
{
    strings
        .into_iter()
        .fold(MacroString::String(String::new()), |acc, cur| match acc {
            MacroString::String(mut s) => match cur {
                MacroString::String(cur) => {
                    s.push_str(&cur);
                    MacroString::String(s)
                }
                MacroString::MacroString(cur) => {
                    let mut parts = vec![MacroStringPart::String(s)];
                    parts.extend(cur);
                    MacroString::MacroString(parts)
                }
            },
            MacroString::MacroString(mut parts) => match cur {
                MacroString::String(cur) => {
                    parts.push(MacroStringPart::String(cur));
                    MacroString::MacroString(parts)
                }
                MacroString::MacroString(cur) => {
                    parts.extend(cur);
                    MacroString::MacroString(parts)
                }
            },
        })
}