package middleware

import (
	"github.com/gin-gonic/gin"
)

// SecurityHeaders 安全响应头中间件
// 为所有响应添加安全头，降低 XSS、点击劫持、MIME 嗅探等风险
func SecurityHeaders() gin.HandlerFunc {
	return func(c *gin.Context) {
		// CSP：限制资源加载来源，降低 XSS 危害
		c.Header("Content-Security-Policy",
			"default-src 'self'; "+
				"script-src 'self' 'unsafe-inline'; "+
				"style-src 'self' 'unsafe-inline'; "+
				"img-src 'self' data: https:; "+
				"font-src 'self' data:; "+
				"connect-src 'self'; "+
				"frame-ancestors 'none'; "+
				"base-uri 'self'; "+
				"form-action 'self'")

		// HSTS：强制 HTTPS（生产环境生效，dev 模式浏览器会忽略）
		c.Header("Strict-Transport-Security", "max-age=31536000; includeSubDomains; preload")

		// 点击劫持防护
		c.Header("X-Frame-Options", "DENY")

		// MIME 嗅探防护
		c.Header("X-Content-Type-Options", "nosniff")

		// 控制 Referer 信息泄露
		c.Header("Referrer-Policy", "strict-origin-when-cross-origin")

		// 禁止浏览器缓存敏感页面（可按需覆盖）
		// c.Header("Cache-Control", "no-store, no-cache, must-revalidate, max-age=0")

		c.Next()
	}
}