use std::rc::Rc;

mod rope;
use rope::Rope;

pub struct TextBuffer {
    contents: Rc<Rope>,
}

pub enum Point {
    End,
}

impl TextBuffer {
    pub fn new() -> Self {
        Self {
            contents: Rope::empty(),
        }
    }

    pub fn num_bytes(&self) -> usize {
        self.contents.total_bytes()
    }

    pub fn num_chars(&self) -> usize {
        self.contents.total_chars()
    }

    pub fn num_lines(&self) -> usize {
        let num_chars = self.num_chars();
        if num_chars == 0 {
            0
        } else {
            dbg!(self.contents.total_lines())
                + if self
                    .contents
                    .get_char_at_index(self.contents.total_chars() - 1)
                    == '\n'
                {
                    0
                } else {
                    1
                }
        }
    }

    pub fn insert_char(&mut self, c: char, point: Point) {
        match point {
            Point::End => {
                self.contents = self
                    .contents
                    .insert_at_char_index(self.contents.total_chars(), c)
            }
        }
    }
}

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

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn new_creates_empty_buffer() {
        let target = TextBuffer::new();
        assert_eq!(0, target.num_bytes());
        assert_eq!(0, target.num_chars());
        assert_eq!(0, target.num_lines());
    }

    #[test]
    fn insert_char_at_end_increases_counts_as_expected() {
        let mut target = TextBuffer::new();
        target.insert_char('A', Point::End);
        assert_eq!(1, target.num_bytes());
        assert_eq!(1, target.num_chars());
        assert_eq!(1, target.num_lines());
        target.insert_char(' ', Point::End);
        assert_eq!(2, target.num_bytes());
        assert_eq!(2, target.num_chars());
        assert_eq!(1, target.num_lines());
        target.insert_char('c', Point::End);
        assert_eq!(3, target.num_bytes());
        assert_eq!(3, target.num_chars());
        assert_eq!(1, target.num_lines());
        target.insert_char('a', Point::End);
        assert_eq!(4, target.num_bytes());
        assert_eq!(4, target.num_chars());
        assert_eq!(1, target.num_lines());
        target.insert_char('t', Point::End);
        assert_eq!(5, target.num_bytes());
        assert_eq!(5, target.num_chars());
        assert_eq!(1, target.num_lines());
        target.insert_char('\n', Point::End);
        assert_eq!(6, target.num_bytes());
        assert_eq!(6, target.num_chars());
        assert_eq!(1, target.num_lines());
        target.insert_char('A', Point::End);
        assert_eq!(7, target.num_bytes());
        assert_eq!(7, target.num_chars());
        assert_eq!(2, target.num_lines());
        target.insert_char('\n', Point::End);
        assert_eq!(8, target.num_bytes());
        assert_eq!(8, target.num_chars());
        assert_eq!(2, target.num_lines());
        target.insert_char('\n', Point::End);
        assert_eq!(9, target.num_bytes());
        assert_eq!(9, target.num_chars());
        assert_eq!(3, target.num_lines());
        target.insert_char('*', Point::End);
        assert_eq!(10, target.num_bytes());
        assert_eq!(10, target.num_chars());
        assert_eq!(4, target.num_lines());
        target.insert_char('*', Point::End);
        assert_eq!(11, target.num_bytes());
        assert_eq!(11, target.num_chars());
        assert_eq!(4, target.num_lines());
        target.insert_char(' ', Point::End);
        assert_eq!(12, target.num_bytes());
        assert_eq!(12, target.num_chars());
        assert_eq!(4, target.num_lines());
        target.insert_char('猫', Point::End);
        assert_eq!(15, target.num_bytes());
        assert_eq!(13, target.num_chars());
        assert_eq!(4, target.num_lines());
        target.insert_char(' ', Point::End);
        assert_eq!(16, target.num_bytes());
        assert_eq!(14, target.num_chars());
        assert_eq!(4, target.num_lines());
        target.insert_char('\n', Point::End);
        assert_eq!(17, target.num_bytes());
        assert_eq!(15, target.num_chars());
        assert_eq!(4, target.num_lines());
        target.insert_char('_', Point::End);
        assert_eq!(18, target.num_bytes());
        assert_eq!(16, target.num_chars());
        assert_eq!(5, target.num_lines());
    }
}