//! The entries of `memory.md` and `user.md`: text separated by a line holding only `§` (M5a spec,
//! section 3). A file's size is the characters of its entries joined by separator lines, which
//! is what `render` writes, less the final newline.

use proto::memory::SEPARATOR;

/// The entries of a file's text: split at lines that are only `§` (spaces around it allowed),
/// each trimmed, empty ones left out.
pub fn parse(text: &str) -> Vec<String> {
    let mut entries: Vec<String> = Vec::new();
    let mut current: Vec<&str> = Vec::new();
    for line in text.lines() {
        if line.trim() == SEPARATOR {
            push(&mut entries, &current);
            current.clear();
        } else {
            current.push(line);
        }
    }
    push(&mut entries, &current);
    entries
}

fn push(entries: &mut Vec<String>, lines: &[&str]) {
    let joined = lines.join("\n");
    let trimmed = joined.trim();
    if !trimmed.is_empty() {
        entries.push(trimmed.to_string());
    }
}

/// The entries joined by `\n§\n`, with a final newline; an empty list is an empty file.
pub fn render(entries: &[String]) -> String {
    if entries.is_empty() {
        return String::new();
    }
    let joined = entries.join(&format!("\n{SEPARATOR}\n"));
    format!("{joined}\n")
}

/// A file's size in characters, the one its limit is measured against.
pub fn size(entries: &[String]) -> usize {
    render(entries).trim_end_matches('\n').chars().count()
}