package server

import (
	"embed"
	"html/template"
	"io/fs"
	"log/slog"
	"net/http"
	"strings"
	"time"

	"github.com/go-chi/chi/v5"
	"github.com/go-chi/chi/v5/middleware"

	"git.hubris.network/dtoro/artifacto/internal/auth"
	"git.hubris.network/dtoro/artifacto/internal/store"
	"git.hubris.network/dtoro/artifacto/internal/visitor"
)

//go:embed templates/*.html
var templateFS embed.FS

//go:embed static/*
var staticFS embed.FS

type Config struct {
	BaseURL      string
	MaxUploadMB  int64
	Secure       bool // set cookies as Secure
	Logger       *slog.Logger
}

type Server struct {
	cfg         Config
	store       *store.Store
	admin       *auth.Admin
	artifact    *auth.Artifact
	salter      *visitor.DailySalter
	rateLimiter *RateLimiter
	tmpl        *template.Template
}

func New(cfg Config, s *store.Store, admin *auth.Admin, art *auth.Artifact) (*Server, error) {
	t, err := parseTemplates()
	if err != nil {
		return nil, err
	}
	return &Server{
		cfg:         cfg,
		store:       s,
		admin:       admin,
		artifact:    art,
		salter:      visitor.NewDailySalter(s),
		rateLimiter: NewRateLimiter(5, 10*time.Minute),
		tmpl:        t,
	}, nil
}

func (s *Server) Handler() http.Handler {
	r := chi.NewRouter()
	r.Use(middleware.RealIP)
	r.Use(middleware.RequestID)
	r.Use(middleware.Recoverer)
	r.Use(securityHeaders)

	r.Get("/healthz", func(w http.ResponseWriter, r *http.Request) {
		w.Write([]byte("ok"))
	})

	// Static assets
	sub, _ := fs.Sub(staticFS, "static")
	r.Handle("/static/*", http.StripPrefix("/static/", http.FileServer(http.FS(sub))))

	// Public routes
	r.Get("/login", s.getLogin)
	r.Post("/login", s.postLogin)

	// Artifact serving (public; password gating is per-artifact)
	r.Get("/p/{slug}", s.getArtifact)
	r.Post("/p/{slug}/unlock", s.postUnlock)

	// Admin-only routes
	r.Group(func(r chi.Router) {
		r.Use(s.admin.Middleware)
		r.Get("/", s.getDashboard)
		r.Post("/logout", s.postLogout)
		r.Get("/a/{slug}", s.getArtifactDetail)
		r.Delete("/a/{slug}", s.deleteArtifact)
		r.Post("/api/publish", s.postPublish)
	})

	return r
}

func (s *Server) visitorID(r *http.Request) string {
	salt, err := s.salter.SaltFor(visitor.Today())
	if err != nil {
		return "nosalt"
	}
	return visitor.Hash(visitor.ClientIP(r), r.UserAgent(), salt)
}

// RollupLoop rolls up yesterday's raw views into daily_stats and prunes old raw rows.
// Runs on a rough daily cadence; also fires once at startup to catch up after downtime.
func (s *Server) RollupLoop(stop <-chan struct{}) {
	do := func() {
		yesterday := time.Now().AddDate(0, 0, -1)
		if err := s.store.Rollup(yesterday); err != nil {
			s.cfg.Logger.Error("rollup failed", "err", err)
		}
		if err := s.store.PruneRawViews(30); err != nil {
			s.cfg.Logger.Error("prune failed", "err", err)
		}
	}
	do()
	t := time.NewTicker(6 * time.Hour)
	defer t.Stop()
	for {
		select {
		case <-t.C:
			do()
		case <-stop:
			return
		}
	}
}

func securityHeaders(next http.Handler) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		// Note: no CSP on /p/{slug} since artifact HTML often uses inline scripts + CDNs.
		if !strings.HasPrefix(r.URL.Path, "/p/") {
			w.Header().Set("Content-Security-Policy",
				"default-src 'self'; "+
					"script-src 'self' https://unpkg.com https://cdn.tailwindcss.com 'unsafe-inline'; "+
					"style-src 'self' https://cdn.tailwindcss.com 'unsafe-inline'; "+
					"img-src 'self' data:; "+
					"font-src 'self' data:")
		}
		w.Header().Set("X-Content-Type-Options", "nosniff")
		w.Header().Set("Referrer-Policy", "strict-origin-when-cross-origin")
		next.ServeHTTP(w, r)
	})
}