feat: leveling system

internal/rankcard/rankcard.go

@@ -0,0 +1,178 @@
+package rankcard
+
+import (
+	"bytes"
+	"context"
+	"fmt"
+	"image"
+	"image/png"
+	"io"
+	"math"
+	"net/http"
+	"time"
+
+	"github.com/fogleman/gg"
+	"golang.org/x/image/draw"
+	"golang.org/x/image/font"
+	"golang.org/x/image/font/gofont/goregular"
+	"golang.org/x/image/font/opentype"
+)
+
+type Data struct {
+	Name    string
+	Level   int
+	XP      int64
+	Percent float64 // 0..1 progress towards next level
+	Avatar  string  // URL
+}
+
+func RenderPNG(ctx context.Context, d Data) ([]byte, error) {
+	const (
+		w  = 900
+		h  = 300
+		px = 30
+
+		avatarSize = 150
+		barX       = 30
+		barY       = 220
+		barW       = 650
+		barH       = 40
+	)
+
+	percent := clamp01(d.Percent)
+
+	dc := gg.NewContext(w, h)
+	dc.SetHexColor("#141414")
+	dc.Clear()
+
+	// Right white polygon
+	dc.SetHexColor("#FFFFFF")
+	dc.NewSubPath()
+	dc.MoveTo(600, 0)
+	dc.LineTo(750, 300)
+	dc.LineTo(900, 300)
+	dc.LineTo(900, 0)
+	dc.ClosePath()
+	dc.Fill()
+
+	// Avatar (circle clip)
+	if img, err := fetchImage(ctx, d.Avatar); err == nil && img != nil {
+		img = resizeImage(img, avatarSize, avatarSize)
+		dc.Push()
+		dc.DrawCircle(px+avatarSize/2, px+avatarSize/2, avatarSize/2)
+		dc.Clip()
+		dc.DrawImage(img, px, px)
+		dc.Pop()
+		// Defensive: ensure no clip leaks past avatar drawing.
+		dc.ResetClip()
+	}
+
+	// Progress bar background
+	dc.SetHexColor("#FFFFFF")
+	dc.DrawRoundedRectangle(barX, barY, barW, barH, 20)
+	dc.Fill()
+
+	// Progress bar fill
+	fillW := barW * percent
+	if fillW > 0 {
+		dc.SetHexColor("#282828")
+		// Keep radius from looking weird on small widths
+		r := math.Min(20, fillW/2)
+		dc.DrawRoundedRectangle(barX, barY, fillW, barH, r)
+		dc.Fill()
+	}
+
+	// Text
+	titleFace, smallFace, err := loadFontFaces()
+	if err != nil {
+		return nil, err
+	}
+
+	dc.SetHexColor("#FFFFFF")
+	dc.SetFontFace(titleFace)
+	dc.DrawStringAnchored(d.Name, 200, 60, 0, 0.5)
+
+	dc.SetLineWidth(2)
+	dc.DrawLine(200, 100, 550, 100)
+	dc.Stroke()
+
+	dc.SetFontFace(smallFace)
+	dc.DrawStringAnchored(
+		fmt.Sprintf("Level - %d | XP - %d | %d%%", d.Level, d.XP, int64(math.Round(percent*100))),
+		200,
+		145,
+		0,
+		0.5,
+	)
+
+	// Watermark to verify latest render is running
+	dc.SetFontFace(smallFace)
+	dc.SetHexColor("#FFCC00")
+	dc.DrawStringAnchored("velox-go rankcard", 890, 290, 1, 1)
+
+	var buf bytes.Buffer
+	if err := png.Encode(&buf, dc.Image()); err != nil {
+		return nil, err
+	}
+	return buf.Bytes(), nil
+}
+
+func clamp01(v float64) float64 {
+	if v < 0 {
+		return 0
+	}
+	if v > 1 {
+		return 1
+	}
+	return v
+}
+
+func loadFontFaces() (title font.Face, small font.Face, err error) {
+	f, err := opentype.Parse(goregular.TTF)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	title, err = opentype.NewFace(f, &opentype.FaceOptions{Size: 40, DPI: 72, Hinting: font.HintingFull})
+	if err != nil {
+		return nil, nil, err
+	}
+	small, err = opentype.NewFace(f, &opentype.FaceOptions{Size: 30, DPI: 72, Hinting: font.HintingFull})
+	if err != nil {
+		return nil, nil, err
+	}
+
+	return title, small, nil
+}
+
+func fetchImage(ctx context.Context, url string) (image.Image, error) {
+	if url == "" {
+		return nil, fmt.Errorf("empty avatar url")
+	}
+
+	req, err := http.NewRequestWithContext(ctx, http.MethodGet, url, nil)
+	if err != nil {
+		return nil, err
+	}
+
+	client := &http.Client{Timeout: 10 * time.Second}
+	resp, err := client.Do(req)
+	if err != nil {
+		return nil, err
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode < 200 || resp.StatusCode >= 300 {
+		io.Copy(io.Discard, resp.Body)
+		return nil, fmt.Errorf("avatar fetch status %d", resp.StatusCode)
+	}
+
+	img, _, err := image.Decode(resp.Body)
+	return img, err
+}
+
+func resizeImage(src image.Image, w, h int) image.Image {
+	dst := image.NewRGBA(image.Rect(0, 0, w, h))
+	draw.CatmullRom.Scale(dst, dst.Bounds(), src, src.Bounds(), draw.Over, nil)
+	return dst
+}