package state

import "fmt"

// Color is an internal representation of a hexadecimal color string.
// It can take one of these formats:
// #RRGGBBAA
// #RRGGBB
// #RGBA
// #RGB
// When marshaling, it will always choose the most efficient format, but any format can be used when unmarshaling.
type Color struct {
	// R is the red component of the color.
	R uint8
	// G is the green component of the color.
	G uint8
	// B is the blue component of the color.
	B uint8
	// A is the alpha component of the color.
	A uint8
}

// String prints the Color as an abbreviated notation.
// Specifically, short form is used when possible (i.e., when all components are evenly divisible by 0x11).
// The alpha component is left out if it's 0xFF.
func (c Color) String() string {
	if c.R%0x11 == 0 && c.G%0x11 == 0 && c.B%0x11 == 0 && c.A%0x11 == 0 {
		// Short form works.
		if c.A == 0xFF {
			// It's great when it's easy!
			return fmt.Sprintf("#%01X%01X%01X", c.R/0x11, c.G/0x11, c.B/0x11)
		} else {
			// Just need to add the alpha.
			return fmt.Sprintf("#%01X%01X%01X%01X", c.R/0x11, c.G/0x11, c.B/0x11, c.A/0x11)
		}
	} else {
		// Gotta use long form.
		if c.A == 0xFF {
			// Can skip the alpha channel, though.
			return fmt.Sprintf("#%02X%02X%02X", c.R, c.G, c.B)
		} else {
			// Doing things the hard way.
			return fmt.Sprintf("#%02X%02X%02X%02X", c.R, c.G, c.B, c.A)
		}
	}
}