libtableformat/content/

content_style.rs

use colored::Color;

#[derive(Debug, Clone)]
pub enum CellWidth {
    // The cell width is fixed
    Fixed(usize),
    // The cell is always at least a minimum width
    Minimum(usize),
    // The cell takes on the width of its content
    Content,
}

impl CellWidth {
    pub fn default() -> CellWidth {
        CellWidth::Content
    }
}

/// Describes how content should be aligned.
#[derive(Debug, Clone)]
#[derive(PartialEq)]
pub enum Alignment {
    Left,
    Center,
    Right
}

impl Alignment {
    fn from_token(token: char) -> Option<Alignment> {
        match token {
            '<' => Some(Alignment::Left),
            '^' => Some(Alignment::Center),
            '>' => Some(Alignment::Right),
            _ => None
        }
    }
}

/// Describes whether content will wrap or truncate.
#[derive(Debug, Clone)]
pub enum Wrap {
    /// Content will be truncated when over-width
    Truncate,
    // Content will wrap when over-width
    Wrap
}

impl Wrap {
    fn from_token(token: char) -> Option<Wrap> {
        match token {
            ';' => Some(Wrap::Wrap),
            '.' => Some(Wrap::Truncate),
            _ => None
        }
    }
}

#[allow(unused_macros)]
#[macro_export]
macro_rules! content_style {
    ( $style:literal ) => {
        ContentStyle::from_format($style)
    }
}

/// Represents the style to apply to a line of content.
#[derive(Debug, Clone)]
pub struct ContentStyle {
    pub foreground_color: Option<Color>,
    pub background_color: Option<Color>,
    pub alignment: Alignment,
    pub wrap: Wrap,
    pub width: CellWidth
}

impl ContentStyle {
    #[must_use]
    pub fn default() -> ContentStyle {
        ContentStyle {
            foreground_color: None,
            background_color: None,
            alignment: Alignment::Left,
            wrap: Wrap::Truncate,
            width: CellWidth::Content,
        }
    }

    #[must_use]
    pub fn new(
        foreground_color: Option<Color>,
        background_color: Option<Color>,
        alignment: Alignment,
        wrap: Wrap,
        width: CellWidth
    ) -> ContentStyle {
        ContentStyle {
            foreground_color,
            background_color,
            alignment,
            wrap,
            width,
        }
    }

    /// Returns a `ContentStyle` from a format string.
    ///
    /// # Arguments
    ///
    /// * `format` - The format string to parse.
    ///
    /// # Panics
    ///
    /// If width specifiers are not well formatted.
    #[must_use]
    pub fn from_format(format: &str) -> ContentStyle {
        // Start with defaults
        let mut style = ContentStyle::default();

        // Iterate tokens
        let tokens: Vec<char> = format[1..format.len() - 1].chars().collect();
        let mut token_ix = 0;
        while token_ix < tokens.len() {
            let token = tokens[token_ix];

            // Foreground color
            if let Some(color) = ContentStyle::color_from_token(token) {
                style.foreground_color = Some(color)
            }
            // Alignment
            if let Some(alignment) = Alignment::from_token(token) {
                style.alignment = alignment
            }
            // Wrap
            if let Some(wrap) = Wrap::from_token(token) {
                style.wrap = wrap
            }

            // Background color (consumes two tokens)
            if token == '-' {
                // Avoid problem if - is last token (with no color code)
                if tokens.len() > token_ix + 1 {
                    style.background_color = 
                        ContentStyle::color_from_token(tokens[token_ix + 1]);
                    // Consume next token (to skip the background color code)
                    token_ix += 1;
                }
            }
            token_ix += 1;

            // Width specifier (consumes until matching token)
            if token == ':' {
                // TODO: Clean up this logic (should be a common width fn)
                if let Some(ix) = format[token_ix+1..=tokens.len()].find(':') {
                    let width = format[token_ix+1..=token_ix+ix].parse::<usize>().unwrap();
                    style.width = CellWidth::Fixed(width);
                    token_ix += ix + 1;
                }
            }

            // Width specifier (consumes until matching token)
            if token == '|' {
                // TODO: Clean up this logic (should be a common width fn)

                if let Some(ix) = format[token_ix+1..=tokens.len()].find('|') {
                        let width = format[token_ix+1..=token_ix+ix].parse::<usize>().unwrap();
                        style.width = CellWidth::Minimum(width);
                        token_ix += ix + 1;
                }
            }
        }

        style
    }

    fn color_from_token(
        token: char
    ) -> Option<Color> {
        match token {
            'w' => Some(Color::White),
            'l' => Some(Color::Black),
            'r' => Some(Color::Red),
            'g' => Some(Color::Green),
            'y' => Some(Color::Yellow),
            'b' => Some(Color::Blue),
            'm' => Some(Color::Magenta),
            'c' => Some(Color::Cyan),
            'W' => Some(Color::BrightWhite),
            'L' => Some(Color::BrightBlack),
            'R' => Some(Color::BrightRed),
            'G' => Some(Color::BrightGreen),
            'Y' => Some(Color::BrightYellow),
            'B' => Some(Color::BrightBlue),
            'M' => Some(Color::BrightMagenta),
            'C' => Some(Color::BrightCyan),
            _ => None,
        }
    }
}

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

   #[test]
   fn from_format_fixed_width() {
        let style = ContentStyle::from_format("{c^;:15:}");
   
        let expected = 
            ContentStyle {
                foreground_color: Some(Color::Cyan),
                background_color: None,
                alignment: Alignment::Center,
                wrap: Wrap::Wrap,
                width: CellWidth::Fixed(15)
            };

        assert_eq!(
            format!("{:?}", style),
            format!("{:?}", expected)
        );
    }

}