up3

server/player/bossbar/bossbar.go

@@ -0,0 +1,61 @@
+package bossbar
+
+import (
+	"fmt"
+	"strings"
+)
+
+// BossBar represents a boss bar that may be sent to a player. It is shown as a purple bar with text above
+// it. The health shown by the bar may be changed.
+type BossBar struct {
+	text   string
+	health float64
+	c      Colour
+}
+
+// New creates a new boss bar with the text passed. The text is formatted according to the rules of
+// fmt.Sprintln.
+// By default, the boss bar will have a full health bar. To change this, use BossBar.WithHealthPercentage().
+// The default colour of the BossBar is Purple. This can be changed using BossBar.WithColour.
+func New(text ...any) BossBar {
+	return BossBar{text: format(text), health: 1, c: Purple()}
+}
+
+// Text returns the text of the boss bar: The text passed when creating the bar using New().
+func (bar BossBar) Text() string {
+	return bar.text
+}
+
+// WithHealthPercentage sets the health percentage of the boss bar. The value passed must be between 0 and 1.
+// If a value out of that range is passed, WithHealthPercentage panics.
+// The new BossBar with the changed health percentage is returned.
+func (bar BossBar) WithHealthPercentage(v float64) BossBar {
+	if v < 0 || v > 1 {
+		panic("boss bar: value out of range: health percentage must be between 0.0 and 1.0")
+	}
+	bar.health = v
+	return bar
+}
+
+// WithColour returns a copy of the BossBar with the Colour passed.
+func (bar BossBar) WithColour(c Colour) BossBar {
+	bar.c = c
+	return bar
+}
+
+// HealthPercentage returns the health percentage of the boss bar. The number returned is a value between 0
+// and 1, with 0 being an empty boss bar and 1 being a full one.
+func (bar BossBar) HealthPercentage() float64 {
+	return bar.health
+}
+
+// Colour returns the colour of the BossBar.
+func (bar BossBar) Colour() Colour {
+	return bar.c
+}
+
+// format is a utility function to format a list of values to have spaces between them, but no newline at the
+// end, which is typically used for sending messages, popups and tips.
+func format(a []any) string {
+	return strings.TrimSuffix(fmt.Sprintln(a...), "\n")
+}

server/player/bossbar/colour.go

@@ -0,0 +1,50 @@
+package bossbar
+
+// Colour is the colour of a BossBar.
+type Colour struct{ colour }
+
+// Pink is the colour for a pink boss bar.
+func Pink() Colour {
+	return Colour{colour(0)}
+}
+
+// Blue is the colour for a blue boss bar.
+func Blue() Colour {
+	return Colour{colour(1)}
+}
+
+// Red is the colour for a red boss bar.
+func Red() Colour {
+	return Colour{colour(2)}
+}
+
+// Green is the colour for a green boss bar.
+func Green() Colour {
+	return Colour{colour(3)}
+}
+
+// Yellow is the colour for a yellow boss bar.
+func Yellow() Colour {
+	return Colour{colour(4)}
+}
+
+// Purple is the colour for a purple boss bar.
+func Purple() Colour {
+	return Colour{colour(5)}
+}
+
+// RebeccaPurple is the colour for a rebecca purple boss bar.
+func RebeccaPurple() Colour {
+	return Colour{colour(6)}
+}
+
+// White is the colour for a white boss bar.
+func White() Colour {
+	return Colour{colour(7)}
+}
+
+type colour uint8
+
+func (c colour) Uint8() uint8 {
+	return uint8(c)
+}