package handler

import (
	"crypto/rand"
	"encoding/hex"
	"fmt"
	"net/http"
	"strings"

	"github.com/freefire/jiang13-bbs/middleware"
	"github.com/freefire/jiang13-bbs/model"
	"github.com/freefire/jiang13-bbs/service"
	"github.com/gin-gonic/gin"
)

func newVisitorID() string {
	var b [16]byte
	_, _ = rand.Read(b[:])
	// 伪 UUID 形态，满足 ValidVisitorID
	return fmt.Sprintf("%s-%s-%s-%s-%s",
		hex.EncodeToString(b[0:4]),
		hex.EncodeToString(b[4:6]),
		hex.EncodeToString(b[6:8]),
		hex.EncodeToString(b[8:10]),
		hex.EncodeToString(b[10:16]),
	)
}

// POST /api/telemetry/pageview — 轻量 PV/UV 埋点（公开，需 CSRF + 限流）。
// 只组装事件并入队即返回，落库由后台协程攒批完成。
func (h *Handlers) TelemetryPageView(c *gin.Context) {
	if !h.Visit.Enabled() {
		c.Status(http.StatusNoContent)
		return
	}

	var body struct {
		Path string `json:"path"`
		Ref  string `json:"ref"`
	}
	if err := c.ShouldBindJSON(&body); err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": "参数无效"})
		return
	}
	path := strings.TrimSpace(body.Path)
	if !strings.HasPrefix(path, "/") {
		c.JSON(http.StatusBadRequest, gin.H{"error": "参数无效"})
		return
	}
	if len(path) > 512 {
		path = path[:512]
	}

	vid, _ := c.Cookie(service.VisitorCookieName)
	if !service.ValidVisitorID(vid) {
		vid = newVisitorID()
		secure := c.Request.TLS != nil || c.GetHeader("X-Forwarded-Proto") == "https"
		// HttpOnly：仅服务端读 UV，前端埋点不依赖可读 cookie
		c.SetCookie(service.VisitorCookieName, vid, 365*24*3600, "/", "", secure, true)
	}

	ua := c.Request.UserAgent()
	ev := model.VisitEvent{Path: path}
	if bot := service.ClassifyBot(ua); bot != "" {
		// UA 命中爬虫：只进明细，不计 PV/UV
		ev.Kind = model.VisitKindBot
		ev.Bot = bot
	} else {
		ev.Kind = model.VisitKindPageview
	}
	host, kind := service.ClassifyReferrer(body.Ref, c.Request.Host)
	ev.RefHost = host
	ev.RefKind = kind
	if service.ValidVisitorID(vid) {
		ev.VidHash = service.HashVisitorID(vid)
	}
	if u := middleware.CurrentUser(c); u != nil {
		ev.UserID = u.ID
	}
	ev.IP = service.CanonicalIP(c.ClientIP())
	p := service.ParseUserAgent(ua)
	ev.Device = p.Kind
	ev.OS = p.OS
	ev.Browser = p.Browser
	h.Visit.Enqueue(ev)

	c.JSON(http.StatusOK, gin.H{"ok": true})
}

// GET /api/admin/analytics/overview?range=7d|30d
func (h *Handlers) AdminAnalyticsOverview(c *gin.Context) {
	rangeQ := c.DefaultQuery("range", "7d")
	actor := middleware.CurrentActor(c)
	scoped := actor != nil && actor.Role == model.RoleBoardAdmin
	var boardIDs []uint
	if scoped {
		boardIDs = actor.BoardIDs
	}
	data, err := h.Analytics.Overview(rangeQ, boardIDs, scoped)
	if err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": "获取分析数据失败"})
		return
	}
	c.JSON(http.StatusOK, data)
}