package net

import (
	"crypto/tls"
	"fmt"
	"log"
	"net"
	"net/http"
	"sync"

	"thehouseoficarus/internal/behavior"
	"thehouseoficarus/internal/color"
	"thehouseoficarus/internal/config"
	"thehouseoficarus/internal/player"
)

type SessionState int

const (
	StateAccountName SessionState = iota
	StatePassword
	StateNewAccountPass
	StateNewAccount
	StateMenu
	StateNewCharName
	StateNewCharConfirm
	StateRenameAccount
	StateRenameChar
	StateRenameCharName
	StateDeleteChar
	StatePurgeAccount
	StateGame
	StateChangeDesc
	StateTalk
	StateDropAllConfirm
	StateRecipeChoice
	StateHowMany
	StateSmithProduct
	StateFletchProduct
	StateCraftProduct
	StateProductChoice
	StateColorChoice
	StateShop
	StateBank
	StateHacking
	StateDangerConfirm
)

type Session struct {
	Conn              Conn
	State             SessionState
	Account           *player.Account
	Player            *player.Player
	PendingChar       string
	PendingPass       string
	PendingMenu       []map[string]string
	PendingItemID     string
	PendingSkill      string
	PendingLastFlag   string
	PendingBackground bool
	Disconnecting     bool
	DisconnectTicks   int
	Shop              *behavior.ShopConfig
	writeMu           sync.Mutex
}

type Server struct {
	config      *config.Config
	telnetLn    net.Listener
	telnetTLSLn net.Listener
	httpServer  *http.Server
	httpsServer *http.Server
	hub         *Hub
	handler     func(*Session, string)
}

type Hub struct {
	mu       sync.Mutex
	sessions map[*Session]bool
	rooms    map[int]map[*Session]bool
	onRemove func(*Session)
}

func NewHub() *Hub {
	return &Hub{
		sessions: make(map[*Session]bool),
		rooms:    make(map[int]map[*Session]bool),
	}
}

func (h *Hub) OnRemove(cb func(*Session)) {
	h.mu.Lock()
	defer h.mu.Unlock()
	h.onRemove = cb
}

func (h *Hub) Add(s *Session) {
	h.mu.Lock()
	defer h.mu.Unlock()
	h.sessions[s] = true
}

func (h *Hub) Remove(s *Session) {
	h.mu.Lock()
	defer h.mu.Unlock()
	if s.Player != nil && s.State == StateGame && !s.Disconnecting {
		s.Disconnecting = true
		s.DisconnectTicks = 10
		return
	}
	h.hardRemoveLocked(s)
}

func (h *Hub) HardRemove(s *Session) {
	h.mu.Lock()
	defer h.mu.Unlock()
	h.hardRemoveLocked(s)
}

func (h *Hub) hardRemoveLocked(s *Session) {
	delete(h.sessions, s)
	for _, room := range h.rooms {
		delete(room, s)
	}
	if h.onRemove != nil {
		h.onRemove(s)
	}
}

func (h *Hub) EnterRoom(s *Session, roomID int) {
	h.mu.Lock()
	defer h.mu.Unlock()
	h.leaveRoomLocked(s)
	if h.rooms[roomID] == nil {
		h.rooms[roomID] = make(map[*Session]bool)
	}
	h.rooms[roomID][s] = true
}

func (h *Hub) LeaveRoom(s *Session) {
	h.mu.Lock()
	defer h.mu.Unlock()
	h.leaveRoomLocked(s)
}

func (h *Hub) leaveRoomLocked(s *Session) {
	for _, room := range h.rooms {
		delete(room, s)
	}
}

func (h *Hub) AllSessions() []*Session {
	h.mu.Lock()
	defer h.mu.Unlock()
	var out []*Session
	for s := range h.sessions {
		out = append(out, s)
	}
	return out
}

func (h *Hub) PlayersInRoom(roomID int) []*Session {
	h.mu.Lock()
	defer h.mu.Unlock()
	var out []*Session
	if room, ok := h.rooms[roomID]; ok {
		for s := range room {
			out = append(out, s)
		}
	}
	return out
}

func NewServer(cfg *config.Config) (*Server, error) {
	s := &Server{
		config: cfg,
		hub:    NewHub(),
	}

	if cfg.Telnet.Enabled {
		addr := fmt.Sprintf(":%d", cfg.Telnet.Port)
		ln, err := net.Listen("tcp", addr)
		if err != nil {
			return nil, fmt.Errorf("telnet listen: %w", err)
		}
		s.telnetLn = ln
	}

	if cfg.TelnetTLS.Enabled {
		if cfg.TelnetTLS.CertFile == "" || cfg.TelnetTLS.KeyFile == "" {
			return nil, fmt.Errorf("telnet_tls enabled but cert_file and key_file are required")
		}
		cert, err := tls.LoadX509KeyPair(cfg.TelnetTLS.CertFile, cfg.TelnetTLS.KeyFile)
		if err != nil {
			return nil, fmt.Errorf("telnet_tls cert: %w", err)
		}
		tlsCfg := &tls.Config{
			Certificates: []tls.Certificate{cert},
			MinVersion:   tls.VersionTLS12,
		}
		addr := fmt.Sprintf(":%d", cfg.TelnetTLS.Port)
		ln, err := net.Listen("tcp", addr)
		if err != nil {
			return nil, fmt.Errorf("telnet_tls listen: %w", err)
		}
		s.telnetTLSLn = tls.NewListener(ln, tlsCfg)
	}

	if cfg.HTTP.Enabled {
		s.httpServer = &http.Server{
			Addr:    fmt.Sprintf(":%d", cfg.HTTP.Port),
			Handler: newHTTPMux(s),
		}
	}

	if cfg.HTTPS.Enabled {
		if cfg.HTTPS.CertFile == "" || cfg.HTTPS.KeyFile == "" {
			return nil, fmt.Errorf("https enabled but cert_file and key_file are required")
		}
		s.httpsServer = &http.Server{
			Addr:      fmt.Sprintf(":%d", cfg.HTTPS.Port),
			Handler:   newHTTPMux(s),
			TLSConfig: &tls.Config{MinVersion: tls.VersionTLS12},
		}
	}

	return s, nil
}

func (s *Server) Hub() *Hub {
	return s.hub
}

func (s *Server) ListenAndServe(handler func(*Session, string)) error {
	s.handler = handler

	if s.telnetLn != nil {
		go s.serveTelnet()
	}

	if s.telnetTLSLn != nil {
		go s.serveTelnetTLS()
	}

	if s.httpServer != nil {
		go s.serveHTTP()
	}

	if s.httpsServer != nil {
		go s.serveHTTPS()
	}

	if s.telnetLn == nil && s.telnetTLSLn == nil && s.httpServer == nil && s.httpsServer == nil {
		return fmt.Errorf("no listeners configured")
	}

	select {}
}

func (s *Server) serveTelnet() {
	for {
		conn, err := s.telnetLn.Accept()
		if err != nil {
			return
		}
		sess := &Session{
			Conn:  newTCPConn(conn),
			State: StateAccountName,
		}
		s.hub.Add(sess)
		go s.handleSession(sess, s.handler)
	}
}

func (s *Server) serveTelnetTLS() {
	for {
		conn, err := s.telnetTLSLn.Accept()
		if err != nil {
			return
		}
		sess := &Session{
			Conn:  newTCPConn(conn),
			State: StateAccountName,
		}
		s.hub.Add(sess)
		go s.handleSession(sess, s.handler)
	}
}

func (s *Server) serveHTTP() {
	err := s.httpServer.ListenAndServe()
	if err != nil && err != http.ErrServerClosed {
		log.Printf("http server error: %v", err)
	}
}

func (s *Server) serveHTTPS() {
	err := s.httpsServer.ListenAndServeTLS(s.config.HTTPS.CertFile, s.config.HTTPS.KeyFile)
	if err != nil && err != http.ErrServerClosed {
		log.Printf("https server error: %v", err)
	}
}

func (s *Server) handleSession(sess *Session, handler func(*Session, string)) {
	defer func() {
		if r := recover(); r != nil {
			log.Printf("session panic: %v", r)
		}
		s.hub.Remove(sess)
		sess.Close()
	}()

	sess.Conn.Write([]byte("\033[2J\033[H"))

	sess.Write(WelcomeBanner())
	sess.Write("What's your account name? ")

	for {
		line, err := sess.Conn.ReadMessage()
		if err != nil {
			log.Printf("session read error: %v", err)
			return
		}
		if len(line) > 1024 {
			line = line[:1024]
		}
		handler(sess, line)
	}
}

// wrap applies the player's wrap_width option to outgoing text. It is a no-op
// before login (no Player) so the welcome banner is never reflowed. The width
// is clamped to a minimum of 80 columns.
func (sess *Session) wrap(msg string) string {
	if sess.Player == nil {
		return msg
	}
	width := sess.Player.OptionInt("wrap_width")
	if width < 80 {
		width = 80
	}
	return color.WrapANSI(msg, width)
}

// Write sends raw text with no wrapping. Used for prompts and partial lines.
func (sess *Session) Write(msg string) {
	sess.writeMu.Lock()
	defer sess.writeMu.Unlock()
	sess.Conn.Write([]byte(msg))
}

func (sess *Session) WriteLine(msg string) {
	msg = sess.wrap(msg)
	sess.writeMu.Lock()
	defer sess.writeMu.Unlock()
	sess.Conn.Write([]byte(msg + "\r\n"))
}

func (sess *Session) WriteLines(lines ...string) {
	sess.writeMu.Lock()
	defer sess.writeMu.Unlock()
	for _, l := range lines {
		sess.Conn.Write([]byte(sess.wrap(l) + "\r\n"))
	}
}

func (sess *Session) Writef(format string, args ...interface{}) {
	msg := sess.wrap(fmt.Sprintf(format, args...))
	sess.writeMu.Lock()
	defer sess.writeMu.Unlock()
	sess.Conn.Write([]byte(msg))
}

func (sess *Session) Close() error {
	sess.writeMu.Lock()
	defer sess.writeMu.Unlock()
	return sess.Conn.Close()
}