Initial backend repository commit.

Set up project files and add .gitignore to exclude local build/runtime artifacts.

Made-with: Cursor

internal/pkg/avatar/avatar.go

@@ -0,0 +1,115 @@
+package avatar
+
+import (
+	"encoding/base64"
+	"fmt"
+	"unicode/utf8"
+)
+
+// 预定义一组好看的颜色
+var colors = []string{
+	"#FF6B6B", "#4ECDC4", "#45B7D1", "#96CEB4",
+	"#FFEAA7", "#DDA0DD", "#98D8C8", "#F7DC6F",
+	"#BB8FCE", "#85C1E9", "#F8B500", "#00CED1",
+	"#E74C3C", "#3498DB", "#2ECC71", "#9B59B6",
+	"#1ABC9C", "#F39C12", "#E67E22", "#16A085",
+}
+
+// SVG模板
+const svgTemplate = `<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 100 100" width="%d" height="%d">
+  <rect width="100" height="100" fill="%s"/>
+  <text x="50" y="50" font-family="Arial, sans-serif" font-size="40" font-weight="bold" fill="#ffffff" text-anchor="middle" dominant-baseline="central">%s</text>
+</svg>`
+
+// GenerateSVGAvatar 根据用户名生成SVG头像
+// username: 用户名
+// size: 头像尺寸（像素）
+func GenerateSVGAvatar(username string, size int) string {
+	initials := getInitials(username)
+	color := stringToColor(username)
+	return fmt.Sprintf(svgTemplate, size, size, color, initials)
+}
+
+// GenerateAvatarDataURI 生成Data URI格式的头像
+// 可以直接在HTML img标签或CSS background-image中使用
+func GenerateAvatarDataURI(username string, size int) string {
+	svg := GenerateSVGAvatar(username, size)
+	encoded := base64.StdEncoding.EncodeToString([]byte(svg))
+	return fmt.Sprintf("data:image/svg+xml;base64,%s", encoded)
+}
+
+// getInitials 获取用户名首字母
+// 中文取第一个字，英文取首字母（最多2个）
+func getInitials(username string) string {
+	if username == "" {
+		return "?"
+	}
+
+	// 检查是否是中文字符
+	firstRune, _ := utf8.DecodeRuneInString(username)
+	if isChinese(firstRune) {
+		// 中文直接返回第一个字符
+		return string(firstRune)
+	}
+
+	// 英文处理：取前两个单词的首字母
+	// 例如: "John Doe" -> "JD", "john" -> "J"
+	result := []rune{}
+	for i, r := range username {
+		if i == 0 {
+			result = append(result, toUpper(r))
+		} else if r == ' ' || r == '_' || r == '-' {
+			// 找到下一个字符作为第二个首字母
+			nextIdx := i + 1
+			if nextIdx < len(username) {
+				nextRune, _ := utf8.DecodeRuneInString(username[nextIdx:])
+				if nextRune != utf8.RuneError && nextRune != ' ' {
+					result = append(result, toUpper(nextRune))
+					break
+				}
+			}
+		}
+	}
+
+	if len(result) == 0 {
+		return "?"
+	}
+
+	// 最多返回2个字符
+	if len(result) > 2 {
+		result = result[:2]
+	}
+
+	return string(result)
+}
+
+// isChinese 判断是否是中文字符
+func isChinese(r rune) bool {
+	return r >= 0x4E00 && r <= 0x9FFF
+}
+
+// toUpper 将字母转换为大写
+func toUpper(r rune) rune {
+	if r >= 'a' && r <= 'z' {
+		return r - 32
+	}
+	return r
+}
+
+// stringToColor 根据字符串生成颜色
+// 使用简单的哈希算法确保同一用户名每次生成的颜色一致
+func stringToColor(s string) string {
+	if s == "" {
+		return colors[0]
+	}
+
+	hash := 0
+	for _, r := range s {
+		hash = (hash*31 + int(r)) % len(colors)
+	}
+	if hash < 0 {
+		hash = -hash
+	}
+
+	return colors[hash%len(colors)]
+}

internal/pkg/avatar/avatar_test.go

@@ -0,0 +1,118 @@
+package avatar
+
+import (
+	"strings"
+	"testing"
+)
+
+func TestGetInitials(t *testing.T) {
+	tests := []struct {
+		name     string
+		username string
+		want     string
+	}{
+		{"中文用户名", "张三", "张"},
+		{"英文用户名", "John", "J"},
+		{"英文全名", "John Doe", "JD"},
+		{"带下划线", "john_doe", "JD"},
+		{"带连字符", "john-doe", "JD"},
+		{"空字符串", "", "?"},
+		{"小写英文", "alice", "A"},
+		{"中文复合", "李小龙", "李"},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := getInitials(tt.username)
+			if got != tt.want {
+				t.Errorf("getInitials(%q) = %q, want %q", tt.username, got, tt.want)
+			}
+		})
+	}
+}
+
+func TestStringToColor(t *testing.T) {
+	// 测试同一用户名生成的颜色一致
+	color1 := stringToColor("张三")
+	color2 := stringToColor("张三")
+	if color1 != color2 {
+		t.Errorf("stringToColor should return consistent colors for the same input")
+	}
+
+	// 测试不同用户名生成不同颜色（大概率）
+	color3 := stringToColor("李四")
+	if color1 == color3 {
+		t.Logf("Warning: different usernames generated the same color (possible but unlikely)")
+	}
+
+	// 测试空字符串
+	color4 := stringToColor("")
+	if color4 == "" {
+		t.Errorf("stringToColor should return a color for empty string")
+	}
+
+	// 验证颜色格式
+	if !strings.HasPrefix(color4, "#") {
+		t.Errorf("stringToColor should return hex color format starting with #")
+	}
+}
+
+func TestGenerateSVGAvatar(t *testing.T) {
+	svg := GenerateSVGAvatar("张三", 100)
+
+	// 验证SVG结构
+	if !strings.Contains(svg, "<svg") {
+		t.Errorf("SVG should contain <svg tag")
+	}
+	if !strings.Contains(svg, "</svg>") {
+		t.Errorf("SVG should contain </svg> tag")
+	}
+	if !strings.Contains(svg, "width=\"100\"") {
+		t.Errorf("SVG should have width=100")
+	}
+	if !strings.Contains(svg, "height=\"100\"") {
+		t.Errorf("SVG should have height=100")
+	}
+	if !strings.Contains(svg, "张") {
+		t.Errorf("SVG should contain the initial character")
+	}
+}
+
+func TestGenerateAvatarDataURI(t *testing.T) {
+	dataURI := GenerateAvatarDataURI("张三", 100)
+
+	// 验证Data URI格式
+	if !strings.HasPrefix(dataURI, "data:image/svg+xml;base64,") {
+		t.Errorf("Data URI should start with data:image/svg+xml;base64,")
+	}
+
+	// 验证base64部分不为空
+	parts := strings.Split(dataURI, ",")
+	if len(parts) != 2 {
+		t.Errorf("Data URI should have two parts separated by comma")
+	}
+	if parts[1] == "" {
+		t.Errorf("Base64 part should not be empty")
+	}
+}
+
+func TestIsChinese(t *testing.T) {
+	tests := []struct {
+		r    rune
+		want bool
+	}{
+		{'中', true},
+		{'文', true},
+		{'a', false},
+		{'Z', false},
+		{'0', false},
+		{'_', false},
+	}
+
+	for _, tt := range tests {
+		got := isChinese(tt.r)
+		if got != tt.want {
+			t.Errorf("isChinese(%q) = %v, want %v", tt.r, got, tt.want)
+		}
+	}
+}