package server

import (
	"bytes"
	"math/rand"
	"net/http"
	"os"
	"strconv"
	"time"

	"github.com/writekitapp/writekit/internal/auth"
	"github.com/writekitapp/writekit/internal/db"
	"github.com/writekitapp/writekit/internal/tenant"
)

type ctxKey string

const (
	tenantIDKey ctxKey = "tenantID"
	demoInfoKey ctxKey = "demoInfo"
)

type DemoInfo struct {
	IsDemo    bool
	ExpiresAt time.Time
}

func GetDemoInfo(r *http.Request) DemoInfo {
	if info, ok := r.Context().Value(demoInfoKey).(DemoInfo); ok {
		return info
	}
	return DemoInfo{}
}

func demoAwareSessionMiddleware(database *db.DB) func(http.Handler) http.Handler {
	sessionMW := auth.SessionMiddleware(database)
	return func(next http.Handler) http.Handler {
		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
			if GetDemoInfo(r).IsDemo {
				next.ServeHTTP(w, r)
				return
			}
			sessionMW(next).ServeHTTP(w, r)
		})
	}
}

func (s *Server) injectDemoBanner(html []byte, expiresAt time.Time) []byte {
	scheme := "https"
	if os.Getenv("ENV") != "prod" {
		scheme = "http"
	}
	redirectURL := scheme + "://" + s.domain
	banner := demoBannerHTML(expiresAt, redirectURL)
	return bytes.Replace(html, []byte("</body>"), append([]byte(banner), []byte("</body>")...), 1)
}

func demoBannerHTML(expiresAt time.Time, redirectURL string) string {
	expiresUnix := expiresAt.Unix()
	return `<div id="demo-banner"><div class="demo-inner"><span class="demo-timer"></span><a class="demo-cta" target="_blank" href="/studio">Open Studio</a></div></div>
<style>
#demo-banner{position:fixed;bottom:0;left:0;right:0;background:rgba(220,38,38,0.95);color:#fff;font-family:system-ui,-apple-system,sans-serif;font-size:13px;z-index:99999;backdrop-filter:blur(8px);padding:10px 16px}
@media(min-width:640px){#demo-banner{bottom:auto;top:0;left:auto;right:16px;width:auto;padding:8px 16px}}
.demo-inner{display:flex;align-items:center;justify-content:center;gap:12px}
.demo-timer{font-variant-numeric:tabular-nums;font-weight:500}
.demo-timer.urgent{color:#fecaca;animation:pulse 1s infinite}
@keyframes pulse{0%,100%{opacity:1}50%{opacity:.6}}
.demo-cta{background:#fff;color:#dc2626;padding:6px 12px;text-decoration:none;font-weight:600;font-size:12px;transition:transform .15s}
.demo-cta:hover{transform:scale(1.05)}
</style>
<script>
(function(){
const exp=` + strconv.FormatInt(expiresUnix, 10) + `*1000;
const timer=document.querySelector('.demo-timer');
const cta=document.querySelector('.demo-cta');
const update=()=>{
const left=Math.max(0,exp-Date.now());
const m=Math.floor(left/60000);
const s=Math.floor((left%60000)/1000);
timer.textContent=m+':'+(s<10?'0':'')+s+' remaining';
if(left<30000)timer.classList.add('urgent');
if(left<=0){
timer.textContent='Demo expired';
setTimeout(()=>{
const sub=location.hostname.split('.')[0];
location.href='` + redirectURL + `?expired=true&subdomain='+sub;
},2000);
return;
}
requestAnimationFrame(update);
};
update();
if(location.pathname.startsWith('/studio'))cta.textContent='View Site',cta.href='/posts';
})();
</script>`
}

func generateFakeAnalytics(days int) *tenant.AnalyticsSummary {
	if days <= 0 {
		days = 30
	}

	baseViews := 25 + rand.Intn(20)
	var totalViews, totalVisitors int64
	viewsByDay := make([]tenant.DailyStats, days)

	for i := 0; i < days; i++ {
		date := time.Now().AddDate(0, 0, -days+i+1)
		weekday := date.Weekday()

		multiplier := 1.0
		if weekday == time.Saturday || weekday == time.Sunday {
			multiplier = 0.6
		} else if weekday == time.Monday {
			multiplier = 1.2
		}

		dailyViews := int64(float64(baseViews+rand.Intn(15)) * multiplier)
		dailyVisitors := dailyViews * int64(65+rand.Intn(15)) / 100

		totalViews += dailyViews
		totalVisitors += dailyVisitors

		viewsByDay[i] = tenant.DailyStats{
			Date:     date.Format("2006-01-02"),
			Views:    dailyViews,
			Visitors: dailyVisitors,
		}
	}

	return &tenant.AnalyticsSummary{
		TotalViews:     totalViews,
		TotalPageViews: totalViews,
		UniqueVisitors: totalVisitors,
		TotalBandwidth: totalViews * 45000,
		ViewsChange:    float64(rand.Intn(300)-100) / 10,
		ViewsByDay:     viewsByDay,
		TopPages: []tenant.PageStats{
			{Path: "/", Views: totalViews * 25 / 100},
			{Path: "/posts/shipping-a-side-project", Views: totalViews * 22 / 100},
			{Path: "/posts/debugging-production-like-a-detective", Views: totalViews * 18 / 100},
			{Path: "/posts/sqlite-in-production", Views: totalViews * 15 / 100},
			{Path: "/posts", Views: totalViews * 12 / 100},
			{Path: "/posts/my-2024-reading-list", Views: totalViews * 8 / 100},
		},
		TopReferrers: []tenant.ReferrerStats{
			{Referrer: "Google", Views: totalViews * 30 / 100},
			{Referrer: "Twitter/X", Views: totalViews * 20 / 100},
			{Referrer: "GitHub", Views: totalViews * 15 / 100},
			{Referrer: "Hacker News", Views: totalViews * 12 / 100},
			{Referrer: "LinkedIn", Views: totalViews * 10 / 100},
			{Referrer: "YouTube", Views: totalViews * 8 / 100},
			{Referrer: "Reddit", Views: totalViews * 5 / 100},
		},
		Browsers: []tenant.NamedStat{
			{Name: "Chrome", Count: totalVisitors * 55 / 100},
			{Name: "Safari", Count: totalVisitors * 25 / 100},
			{Name: "Firefox", Count: totalVisitors * 12 / 100},
			{Name: "Edge", Count: totalVisitors * 8 / 100},
		},
		OS: []tenant.NamedStat{
			{Name: "macOS", Count: totalVisitors * 45 / 100},
			{Name: "Windows", Count: totalVisitors * 30 / 100},
			{Name: "iOS", Count: totalVisitors * 15 / 100},
			{Name: "Linux", Count: totalVisitors * 7 / 100},
			{Name: "Android", Count: totalVisitors * 3 / 100},
		},
		Devices: []tenant.NamedStat{
			{Name: "Desktop", Count: totalVisitors * 70 / 100},
			{Name: "Mobile", Count: totalVisitors * 25 / 100},
			{Name: "Tablet", Count: totalVisitors * 5 / 100},
		},
		Countries: []tenant.NamedStat{
			{Name: "United States", Count: totalVisitors * 40 / 100},
			{Name: "United Kingdom", Count: totalVisitors * 12 / 100},
			{Name: "Germany", Count: totalVisitors * 10 / 100},
			{Name: "Canada", Count: totalVisitors * 8 / 100},
			{Name: "France", Count: totalVisitors * 6 / 100},
			{Name: "Australia", Count: totalVisitors * 5 / 100},
		},
	}
}

func generateFakePostAnalytics(days int) *tenant.AnalyticsSummary {
	if days <= 0 {
		days = 30
	}

	baseViews := 5 + rand.Intn(8)
	var totalViews int64
	viewsByDay := make([]tenant.DailyStats, days)

	for i := 0; i < days; i++ {
		date := time.Now().AddDate(0, 0, -days+i+1)
		dailyViews := int64(baseViews + rand.Intn(6))
		totalViews += dailyViews

		viewsByDay[i] = tenant.DailyStats{
			Date:  date.Format("2006-01-02"),
			Views: dailyViews,
		}
	}

	return &tenant.AnalyticsSummary{
		TotalViews: totalViews,
		ViewsByDay: viewsByDay,
	}
}