use ropey::Rope;

pub struct TextBuffer {
    rope: Rope,
}

impl Default for TextBuffer {
    fn default() -> Self {
        Self::new()
    }
}

impl TextBuffer {
    #[must_use]
    pub fn new() -> Self {
        Self { rope: Rope::new() }
    }

    #[must_use]
    pub fn char_count(&self) -> usize {
        self.rope.len_chars()
    }

    #[must_use]
    pub fn line_count(&self) -> usize {
        self.rope.len_lines()
    }

    pub fn insert(&mut self, char_index: usize, text: &str) {
        self.rope.insert(char_index, text);
    }

    pub fn delete(&mut self, range: std::ops::Range<usize>) {
        self.rope.remove(range);
    }

    #[must_use]
    pub fn slice(&self, range: std::ops::Range<usize>) -> String {
        self.rope.slice(range).to_string()
    }

    #[must_use]
    pub fn line(&self, line_index: usize) -> String {
        let mut s = self.rope.line(line_index).to_string();
        if s.ends_with('\n') {
            s.pop();
        }
        s
    }
}

impl std::fmt::Display for TextBuffer {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        for chunk in self.rope.chunks() {
            write!(f, "{chunk}")?;
        }
        Ok(())
    }
}