package utils

import (
	"regexp"
	"strings"
)

type UAResult struct {
	OS         string
	OSVersion  string
	Browser    string
	BrowserVer string
}

// ParseUA 解析 UA，返回结构化信息
func ParseUA(ua string) UAResult {
	r := UAResult{}
	// 1. 操作系统 + 版本
	osRe := []*regexp.Regexp{
		regexp.MustCompile(`\(Macintosh;.*Mac OS X ([0-9_]+)\)`),
		regexp.MustCompile(`\(Windows NT ([0-9.]+)\)`),
		regexp.MustCompile(`\(iPhone;.*OS ([0-9_]+)`),
		regexp.MustCompile(`\(Android ([0-9.]+)`),
		regexp.MustCompile(`\(X11;.*Linux `),
	}
	for _, re := range osRe {
		if m := re.FindStringSubmatch(ua); len(m) > 1 {
			switch {
			case strings.Contains(m[0], "Macintosh"):
				r.OS, r.OSVersion = "macOS", strings.Replace(m[1], "_", ".", -1)
			case strings.Contains(m[0], "Windows NT"):
				r.OS, r.OSVersion = "Windows", m[1]
			case strings.Contains(m[0], "iPhone"):
				r.OS, r.OSVersion = "iOS", strings.Replace(m[1], "_", ".", -1)
			case strings.Contains(m[0], "Android"):
				r.OS, r.OSVersion = "Android", m[1]
			case strings.Contains(m[0], "Linux"):
				r.OS = "Linux"
			}
			break
		}
	}

	// 2. 浏览器 + 版本（按优先级匹配）
	browserRe := []struct {
		re   *regexp.Regexp
		name string
	}{
		{regexp.MustCompile(`Edg/([\d.]+)`), "Edge"},
		{regexp.MustCompile(`Chrome/([\d.]+)`), "Chrome"},
		{regexp.MustCompile(`Firefox/([\d.]+)`), "Firefox"},
		{regexp.MustCompile(`Version/([\d.]+).*Safari`), "Safari"},
		{regexp.MustCompile(`OPR/([\d.]+)`), "Opera"},
	}
	for _, b := range browserRe {
		if m := b.re.FindStringSubmatch(ua); len(m) > 1 {
			r.Browser, r.BrowserVer = b.name, m[1]
			break
		}
	}
	return r
}