feat: Add game asset management tools and new game development skills…

internal/gameassets/download.go

@@ -0,0 +1,58 @@
+package gameassets
+
+import (
+	"context"
+	"fmt"
+	"io"
+	"net/http"
+	"net/url"
+	"os"
+	"time"
+)
+
+var httpClient = &http.Client{Timeout: 30 * time.Second}
+
+// DownloadFile fetches a URL and writes the response body to destPath.
+// Only HTTPS URLs are allowed. The response must be 200 OK with a non-empty body.
+func DownloadFile(ctx context.Context, rawURL, destPath string) error {
+	parsed, err := url.Parse(rawURL)
+	if err != nil {
+		return fmt.Errorf("invalid URL: %w", err)
+	}
+	if parsed.Scheme != "https" {
+		return fmt.Errorf("only HTTPS URLs are allowed, got %q", parsed.Scheme)
+	}
+
+	req, err := http.NewRequestWithContext(ctx, http.MethodGet, rawURL, nil)
+	if err != nil {
+		return fmt.Errorf("failed to create request: %w", err)
+	}
+
+	resp, err := httpClient.Do(req)
+	if err != nil {
+		return fmt.Errorf("download failed: %w", err)
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode != http.StatusOK {
+		return fmt.Errorf("download returned HTTP %d for %s", resp.StatusCode, rawURL)
+	}
+
+	out, err := os.Create(destPath)
+	if err != nil {
+		return fmt.Errorf("failed to create output file: %w", err)
+	}
+	defer out.Close()
+
+	n, err := io.Copy(out, resp.Body)
+	if err != nil {
+		os.Remove(destPath)
+		return fmt.Errorf("failed to write file: %w", err)
+	}
+	if n == 0 {
+		os.Remove(destPath)
+		return fmt.Errorf("downloaded file is empty")
+	}
+
+	return nil
+}

internal/gameassets/placement.go

@@ -0,0 +1,166 @@
+package gameassets
+
+import (
+	"encoding/json"
+	"fmt"
+	"io"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"regexp"
+	"strings"
+)
+
+// PlaceImageAsset copies srcPath into Assets.xcassets/<assetName>.imageset/
+// and writes the corresponding Contents.json. It converts non-PNG images
+// to PNG using macOS sips. Returns the relative path to the placed file.
+func PlaceImageAsset(projectDir, appName, assetName, srcPath string) (string, error) {
+	assetName = SanitizeAssetName(assetName)
+	imagesetDir := filepath.Join(projectDir, appName, "Assets.xcassets", assetName+".imageset")
+	if err := os.MkdirAll(imagesetDir, 0o755); err != nil {
+		return "", fmt.Errorf("failed to create imageset directory: %w", err)
+	}
+
+	dstName := assetName + ".png"
+	dstPath := filepath.Join(imagesetDir, dstName)
+
+	if err := convertToPNG(srcPath, dstPath); err != nil {
+		return "", fmt.Errorf("failed to convert image: %w", err)
+	}
+
+	contentsJSON := ImageSetContentsJSON(dstName)
+	contentsPath := filepath.Join(imagesetDir, "Contents.json")
+	if err := os.WriteFile(contentsPath, contentsJSON, 0o644); err != nil {
+		return "", fmt.Errorf("failed to write Contents.json: %w", err)
+	}
+
+	relPath := filepath.Join(appName, "Assets.xcassets", assetName+".imageset", dstName)
+	return relPath, nil
+}
+
+// PlaceSoundAsset copies srcPath into <appName>/Sounds/<assetName>.<ext>.
+// Returns the relative path to the placed file.
+func PlaceSoundAsset(projectDir, appName, assetName, srcPath string) (string, error) {
+	assetName = SanitizeAssetName(assetName)
+	soundsDir := filepath.Join(projectDir, appName, "Sounds")
+	if err := os.MkdirAll(soundsDir, 0o755); err != nil {
+		return "", fmt.Errorf("failed to create Sounds directory: %w", err)
+	}
+
+	ext := filepath.Ext(srcPath)
+	if ext == "" {
+		ext = ".wav"
+	}
+	dstName := assetName + ext
+	dstPath := filepath.Join(soundsDir, dstName)
+
+	if err := copyFile(srcPath, dstPath); err != nil {
+		return "", fmt.Errorf("failed to copy sound file: %w", err)
+	}
+
+	relPath := filepath.Join(appName, "Sounds", dstName)
+	return relPath, nil
+}
+
+// PlaceModelAsset copies srcPath into <appName>/Models/<assetName>.<ext>.
+// SceneKit loads USDZ/OBJ/DAE/SCN files natively — no conversion needed.
+// Returns the relative path to the placed file.
+func PlaceModelAsset(projectDir, appName, assetName, srcPath string) (string, error) {
+	assetName = SanitizeAssetName(assetName)
+	modelsDir := filepath.Join(projectDir, appName, "Models")
+	if err := os.MkdirAll(modelsDir, 0o755); err != nil {
+		return "", fmt.Errorf("failed to create Models directory: %w", err)
+	}
+
+	ext := filepath.Ext(srcPath)
+	if ext == "" {
+		ext = ".usdz"
+	}
+	dstName := assetName + ext
+	dstPath := filepath.Join(modelsDir, dstName)
+
+	if err := copyFile(srcPath, dstPath); err != nil {
+		return "", fmt.Errorf("failed to copy model file: %w", err)
+	}
+
+	relPath := filepath.Join(appName, "Models", dstName)
+	return relPath, nil
+}
+
+// ImageSetContentsJSON returns a standard Xcode imageset Contents.json
+// for a universal idiom with the given filename.
+func ImageSetContentsJSON(filename string) []byte {
+	contents := map[string]any{
+		"images": []map[string]string{
+			{
+				"filename": filename,
+				"idiom":    "universal",
+			},
+		},
+		"info": map[string]any{
+			"version": 1,
+			"author":  "xcode",
+		},
+	}
+	data, _ := json.MarshalIndent(contents, "", "  ")
+	return data
+}
+
+// SanitizeAssetName converts a name to a valid Xcode asset catalog name.
+// Lowercase, spaces/underscores to hyphens, strip non-alphanumeric except hyphens.
+func SanitizeAssetName(name string) string {
+	name = strings.ToLower(strings.TrimSpace(name))
+	name = strings.ReplaceAll(name, " ", "-")
+	name = strings.ReplaceAll(name, "_", "-")
+	re := regexp.MustCompile(`[^a-z0-9\-]`)
+	name = re.ReplaceAllString(name, "")
+	// Collapse multiple hyphens
+	re = regexp.MustCompile(`-{2,}`)
+	name = re.ReplaceAllString(name, "-")
+	name = strings.Trim(name, "-")
+	if name == "" {
+		name = "asset"
+	}
+	return name
+}
+
+// convertToPNG converts an image file to PNG using macOS sips.
+// If the source is already PNG, it copies directly.
+func convertToPNG(src, dst string) error {
+	ext := strings.ToLower(filepath.Ext(src))
+	if ext == ".png" {
+		return copyFile(src, dst)
+	}
+
+	// Strip xattrs that can cause sips to reject the file
+	_ = exec.Command("xattr", "-c", src).Run()
+
+	cmd := exec.Command("sips", "-s", "format", "png", src, "--out", dst)
+	if out, err := cmd.CombinedOutput(); err != nil {
+		return fmt.Errorf("sips conversion failed: %s: %w", string(out), err)
+	}
+
+	info, err := os.Stat(dst)
+	if err != nil || info.Size() == 0 {
+		return fmt.Errorf("sips output file missing or empty after conversion")
+	}
+	return nil
+}
+
+func copyFile(src, dst string) error {
+	if src == dst {
+		return nil
+	}
+	in, err := os.Open(src)
+	if err != nil {
+		return err
+	}
+	defer in.Close()
+	out, err := os.Create(dst)
+	if err != nil {
+		return err
+	}
+	defer out.Close()
+	_, err = io.Copy(out, in)
+	return err
+}