package sandbar

import (
	_ "embed"
	"log"
	"net/http"
	"sync"
	"time"
)

//go:embed web/index.html
var indexHTML []byte

//go:embed web/status.html
var statusHTML []byte

type SMTPConfig struct{ Host, Port, User, Password, From string }

// Options configures a Server. Zero values are sensible defaults.
type Options struct {
	DataDir      string
	URL          string // public URL, used for links in notifications
	MasterKey    string
	MetricsToken string
	SMTP         SMTPConfig
	MessageDays  int  // how long topic messages are kept (default 30)
	CheckDays    int  // how long monitor results are kept (default 30)
	HitDays      int  // how long website analytics are kept (default 365)
	TrustProxy   bool // take the client address from X-Forwarded-For, for use behind a reverse proxy

	// Self-update (see update.go). Version is the running release, such as v0.2.0; anything else
	// ("dev") never updates. Restart is called after a new binary is installed and should close
	// what the process holds open before re-executing it.
	Version      string
	AutoUpdate   bool
	UpdateServer string // default https://git.veillax.com
	UpdateRepo   string // default Veillax/sandbar
	Restart      func(exe string) error

	// Tests replace these.
	Now        func() time.Time
	HTTPClient *http.Client
	Mailer     func(to, subject, body string) error
}

type Server struct {
	opts Options
	st   *Store
	hub  *hub

	// monitor runtime state
	mu      sync.Mutex
	running map[string]bool // monitor ids with a check in flight

	loginMu  sync.Mutex
	loginTry map[string][]time.Time

	upd updateState

	anaMu     sync.Mutex // website analytics: the visitor salt and a per-address rate limit
	anaSecret string
	anaTry    map[string][]time.Time

	stop chan struct{}
	wg   sync.WaitGroup
}

func New(opts Options, st *Store) *Server {
	if opts.MessageDays <= 0 {
		opts.MessageDays = 30
	}
	if opts.CheckDays <= 0 {
		opts.CheckDays = 30
	}
	if opts.HitDays <= 0 {
		opts.HitDays = 365
	}
	return &Server{opts: opts, st: st, hub: newHub(), running: map[string]bool{}, loginTry: map[string][]time.Time{}, anaTry: map[string][]time.Time{}, stop: make(chan struct{})}
}

func (s *Server) now() time.Time {
	if s.opts.Now != nil {
		return s.opts.Now()
	}
	return time.Now()
}

// Start runs the background workers: monitor scheduler, escalation, pruning.
func (s *Server) Start() {
	s.every(time.Second, func() { s.runDueMonitors(s.now()) })
	s.every(5*time.Second, func() { s.escalate(s.now()) })
	s.every(time.Hour, func() { s.st.prune(s.now(), s.opts.MessageDays, s.opts.CheckDays, s.opts.HitDays) })
}

func (s *Server) Close() {
	close(s.stop)
	s.wg.Wait()
}

func (s *Server) every(d time.Duration, f func()) {
	s.wg.Add(1)
	go func() {
		defer s.wg.Done()
		t := time.NewTicker(d)
		defer t.Stop()
		for {
			select {
			case <-s.stop:
				return
			case <-t.C:
				func() {
					defer func() {
						if r := recover(); r != nil {
							log.Printf("worker panic: %v", r)
						}
					}()
					f()
				}()
			}
		}
	}()
}

func (s *Server) link(path string) string {
	if s.opts.URL == "" {
		return ""
	}
	return s.opts.URL + path
}

// BootstrapAdmin creates the first administrator from the environment when there are no users yet.
func (s *Server) BootstrapAdmin(email, password string) {
	if email == "" || password == "" || s.countUsers() > 0 {
		return
	}
	if _, err := s.createUser("Admin", email, password, "admin", ""); err != nil {
		log.Printf("SANDBAR_ADMIN_EMAIL: %v", err)
	}
}