use std::fmt;

use style::Style;


/// Styles have a special `Debug` implementation that only shows the fields that
/// are set. Fields that haven’t been touched aren’t included in the output.
///
/// This behaviour gets bypassed when using the alternate formatting mode
/// `format!("{:#?}")`.
///
///     use ansi_term::Colour::{Red, Blue};
///     assert_eq!("Style { fg(Red), on(Blue), bold, italic }",
///                format!("{:?}", Red.on(Blue).bold().italic()));
impl fmt::Debug for Style {
    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
        if fmt.alternate() {
            fmt.debug_struct("Style")
               .field("foreground",    &self.foreground)
               .field("background",    &self.background)
               .field("blink",         &self.is_blink)
               .field("bold",          &self.is_bold)
               .field("dimmed",        &self.is_dimmed)
               .field("hidden",        &self.is_hidden)
               .field("italic",        &self.is_italic)
               .field("reverse",       &self.is_reverse)
               .field("strikethrough", &self.is_strikethrough)
               .field("underline",     &self.is_underline)
               .finish()
        }
        else if self.is_plain() {
            fmt.write_str("Style {}")
        }
        else {
            fmt.write_str("Style { ")?;

            let mut written_anything = false;

            if let Some(fg) = self.foreground {
                if written_anything { fmt.write_str(", ")? }
                written_anything = true;
                write!(fmt, "fg({:?})", fg)?
            }

            if let Some(bg) = self.background {
                if written_anything { fmt.write_str(", ")? }
                written_anything = true;
                write!(fmt, "on({:?})", bg)?
            }

            {
                let mut write_flag = |name| {
                    if written_anything { fmt.write_str(", ")? }
                    written_anything = true;
                    fmt.write_str(name)
                };

                if self.is_blink          { write_flag("blink")? }
                if self.is_bold           { write_flag("bold")? }
                if self.is_dimmed         { write_flag("dimmed")? }
                if self.is_hidden         { write_flag("hidden")? }
                if self.is_italic         { write_flag("italic")? }
                if self.is_reverse        { write_flag("reverse")? }
                if self.is_strikethrough  { write_flag("strikethrough")? }
                if self.is_underline      { write_flag("underline")? }
            }

            write!(fmt, " }}")
        }
    }
}


#[cfg(test)]
mod test {
    use style::Colour::*;
    use style::Style;

    fn style() -> Style {
        Style::new()
    }

    macro_rules! test {
        ($name: ident: $obj: expr => $result: expr) => {
            #[test]
            fn $name() {
                assert_eq!($result, format!("{:?}", $obj));
            }
        };
    }

    test!(empty:   style()                  => "Style {}");
    test!(bold:    style().bold()           => "Style { bold }");
    test!(italic:  style().italic()         => "Style { italic }");
    test!(both:    style().bold().italic()  => "Style { bold, italic }");

    test!(red:     Red.normal()                     => "Style { fg(Red) }");
    test!(redblue: Red.normal().on(RGB(3, 2, 4))    => "Style { fg(Red), on(RGB(3, 2, 4)) }");

    test!(everything:
            Red.on(Blue).blink().bold().dimmed().hidden().italic().reverse().strikethrough().underline() =>
            "Style { fg(Red), on(Blue), blink, bold, dimmed, hidden, italic, reverse, strikethrough, underline }");

    #[test]
    fn long_and_detailed() {
        let debug = r##"Style {
    foreground: Some(
        Blue
    ),
    background: None,
    blink: false,
    bold: true,
    dimmed: false,
    hidden: false,
    italic: false,
    reverse: false,
    strikethrough: false,
    underline: false
}"##;
        assert_eq!(debug, format!("{:#?}", Blue.bold()));
    }
}