// Load font (heavyweight, do once)
source, err := text.NewFontSourceFromFile("Roboto-Regular.ttf")
if err != nil {
    log.Fatal(err)
}
defer source.Close()

// Create face at specific size (lightweight)
face := source.Face(24)

// Use with gg.Context (dc = drawing context)
dc := gg.NewContext(800, 600)
dc.SetFont(face)
dc.DrawString("Hello, GoGPU!", 100, 100)

// Shape text to positioned glyphs
glyphs := text.Shape("Hello", face)
for _, g := range glyphs {
    fmt.Printf("GID=%d X=%.1f Y=%.1f\n", g.GID, g.X, g.Y)
}

// Segment mixed-direction text
segments := text.SegmentText("Hello שלום مرحبا")
for _, seg := range segments {
    fmt.Printf("'%s' Dir=%s Script=%s\n",
        seg.Text, seg.Direction, seg.Script)
}

// RTL base direction
segments = text.SegmentTextRTL("مرحبا Hello")

// Layout with options
opts := text.LayoutOptions{
    MaxWidth:    400,
    LineSpacing: 1.2,
    Alignment:   text.AlignCenter,
    Direction:   text.DirectionLTR,
    WrapMode:    text.WrapWordChar, // Word-first, char fallback (default)
}
layout := text.LayoutText(longText, face, opts)

// Access lines
for _, line := range layout.Lines {
    fmt.Printf("Y=%.1f Width=%.1f Glyphs=%d\n",
        line.Y, line.Width, len(line.Glyphs))
}

// Simple layout (no wrapping)
layout = text.LayoutTextSimple("Hello\nWorld", face)

// WrapWordChar (default) — Word boundaries first, character fallback for long words
opts := text.LayoutOptions{
    MaxWidth: 200,
    WrapMode: text.WrapWordChar,
}

// WrapWord — Word boundaries only, long words overflow
opts.WrapMode = text.WrapWord

// WrapChar — Character boundaries, any character can break
opts.WrapMode = text.WrapChar

// WrapNone — No wrapping, text may exceed MaxWidth
opts.WrapMode = text.WrapNone

// Standalone wrapping API
results := text.WrapText("Hello World", face, 100, text.WrapWordChar)
for _, r := range results {
    fmt.Printf("Line: '%s' (%d-%d)\n", r.Text, r.Start, r.End)
}

// Measure text width
width := text.MeasureText("Hello World", face)

// Enable HarfBuzz-level shaping for ligatures, kerning, and complex scripts
shaper := text.NewGoTextShaper()
text.SetShaper(shaper)
defer text.SetShaper(nil) // Reset to BuiltinShaper

// Shape text — now uses go-text/typesetting HarfBuzz engine
glyphs := text.Shape("Hello", face)

// Implement custom shaper
type MyShaper struct {
    // ...
}

func (s *MyShaper) Shape(text string, face text.Face) []text.ShapedGlyph {
    // Custom shaping logic
}

// Set as global shaper
text.SetShaper(&MyShaper{})
defer text.SetShaper(nil) // Reset to default

type ShapedGlyph struct {
    GID      GlyphID  // Glyph index in font
    Cluster  int      // Source character index
    X, Y     float64  // Position relative to origin
    XAdvance float64  // Horizontal advance
    YAdvance float64  // Vertical advance (for TTB)
}

type Segment struct {
    Text      string    // Segment text
    Start     int       // Byte offset in original text
    End       int       // End byte offset
    Direction Direction // LTR or RTL
    Script    Script    // Unicode script
    Level     int       // Bidi embedding level
}

type Layout struct {
    Lines  []Line   // Positioned lines
    Width  float64  // Maximum line width
    Height float64  // Total height
}

type Line struct {
    Runs    []ShapedRun   // Runs with uniform style
    Glyphs  []ShapedGlyph // All positioned glyphs
    Width   float64       // Line width
    Ascent  float64       // Max ascent
    Descent float64       // Max descent
    Y       float64       // Baseline Y position
}