package api

import (
	"encoding/json"
	"net/http"
	"strings"

	"proxmox-router/internal/firewall"
	"proxmox-router/internal/network"
	"proxmox-router/internal/routing"
	"proxmox-router/internal/system"
	"proxmox-router/internal/vpn"
)

type Server struct {
	netMgr     *network.Manager
	persistMgr *network.PersistenceManager
	metaMgr    *network.MetadataManager
	vpnMgr     *vpn.Manager
	fwMgr      *firewall.FirewallManager
	routingMgr *routing.RoutingManager
	mux        *http.ServeMux
	fsHandler  http.Handler
}

func NewServer(netMgr *network.Manager, persistMgr *network.PersistenceManager, metaMgr *network.MetadataManager, vpnMgr *vpn.Manager, fwMgr *firewall.FirewallManager, routingMgr *routing.RoutingManager, fsHandler http.Handler) *Server {
	s := &Server{
		netMgr:     netMgr,
		persistMgr: persistMgr,
		metaMgr:    metaMgr,
		vpnMgr:     vpnMgr,
		fwMgr:      fwMgr,
		routingMgr: routingMgr,
		mux:        http.NewServeMux(),
		fsHandler:  fsHandler,
	}
	s.registerRoutes()
	return s
}

func (s *Server) registerRoutes() {
	// API Endpoints
	s.mux.HandleFunc("GET /api/system/status", s.handleSystemStatus)

	// Routing & Policy Rules (/ip route & /ip route rule)
	s.mux.HandleFunc("GET /api/routes", s.handleListRoutes)
	s.mux.HandleFunc("POST /api/routes", s.handleSaveRoute)
	s.mux.HandleFunc("DELETE /api/routes/{id}", s.handleDeleteRoute)
	s.mux.HandleFunc("POST /api/routes/{id}/state", s.handleSetRouteState)

	s.mux.HandleFunc("GET /api/routing/rules", s.handleListPolicyRules)
	s.mux.HandleFunc("POST /api/routing/rules", s.handleSavePolicyRule)
	s.mux.HandleFunc("DELETE /api/routing/rules/{id}", s.handleDeletePolicyRule)

	s.mux.HandleFunc("GET /api/routing/tables", s.handleListRoutingTables)
	s.mux.HandleFunc("POST /api/routing/tables", s.handleSaveRoutingTable)

	// Firewall Endpoints (/ip firewall)
	s.mux.HandleFunc("GET /api/firewall/summary", s.handleFirewallSummary)
	s.mux.HandleFunc("POST /api/firewall/reset-counters", s.handleResetFirewallCounters)

	// Filter Rules
	s.mux.HandleFunc("GET /api/firewall/filter", s.handleListFilterRules)
	s.mux.HandleFunc("POST /api/firewall/filter", s.handleSaveFilterRule)
	s.mux.HandleFunc("DELETE /api/firewall/filter/{id}", s.handleDeleteFilterRule)
	s.mux.HandleFunc("POST /api/firewall/filter/{id}/move", s.handleMoveFilterRule)
	s.mux.HandleFunc("POST /api/firewall/filter/{id}/state", s.handleSetFilterRuleState)

	// NAT Rules
	s.mux.HandleFunc("GET /api/firewall/nat", s.handleListNATRules)
	s.mux.HandleFunc("POST /api/firewall/nat", s.handleSaveNATRule)
	s.mux.HandleFunc("DELETE /api/firewall/nat/{id}", s.handleDeleteNATRule)
	s.mux.HandleFunc("POST /api/firewall/nat/{id}/move", s.handleMoveNATRule)
	s.mux.HandleFunc("POST /api/firewall/nat/{id}/state", s.handleSetNATRuleState)

	// Mangle Rules
	s.mux.HandleFunc("GET /api/firewall/mangle", s.handleListMangleRules)
	s.mux.HandleFunc("POST /api/firewall/mangle", s.handleSaveMangleRule)
	s.mux.HandleFunc("DELETE /api/firewall/mangle/{id}", s.handleDeleteMangleRule)
	s.mux.HandleFunc("POST /api/firewall/mangle/{id}/move", s.handleMoveMangleRule)
	s.mux.HandleFunc("POST /api/firewall/mangle/{id}/state", s.handleSetMangleRuleState)

	// Address Lists
	s.mux.HandleFunc("GET /api/firewall/address-lists", s.handleListAddressLists)
	s.mux.HandleFunc("POST /api/firewall/address-lists", s.handleSaveAddressListEntry)
	s.mux.HandleFunc("DELETE /api/firewall/address-lists/{id}", s.handleDeleteAddressListEntry)

	// Active Connections
	s.mux.HandleFunc("GET /api/firewall/connections", s.handleListConnections)
	s.mux.HandleFunc("POST /api/firewall/connections/kill", s.handleKillConnection)

	s.mux.HandleFunc("GET /api/interfaces", s.handleListInterfaces)
	s.mux.HandleFunc("GET /api/interfaces/{name}", s.handleGetInterface)
	s.mux.HandleFunc("POST /api/interfaces/{name}/state", s.handleSetInterfaceState)
	s.mux.HandleFunc("POST /api/interfaces/{name}/mtu", s.handleSetInterfaceMTU)
	s.mux.HandleFunc("POST /api/interfaces/{name}/ip", s.handleAddInterfaceIP)
	s.mux.HandleFunc("DELETE /api/interfaces/{name}/ip", s.handleDeleteInterfaceIP)
	s.mux.HandleFunc("POST /api/interfaces/{name}/metadata", s.handleSetInterfaceMetadata)

	s.mux.HandleFunc("GET /api/vlans", s.handleListVLANs)
	s.mux.HandleFunc("POST /api/vlans", s.handleCreateVLAN)
	s.mux.HandleFunc("DELETE /api/vlans/{name}", s.handleDeleteVLAN)

	s.mux.HandleFunc("GET /api/debian/config", s.handleGetDebianConfig)
	s.mux.HandleFunc("POST /api/debian/apply", s.handleSaveDebianConfig)

	// VPN & WAN Endpoints
	s.mux.HandleFunc("GET /api/vpn/status", s.handleOverallVPNStatus)

	// PPPoE Multi-Instance
	s.mux.HandleFunc("GET /api/vpn/pppoe/clients", s.handleListPPPoE)
	s.mux.HandleFunc("POST /api/vpn/pppoe/clients", s.handleSavePPPoE)
	s.mux.HandleFunc("DELETE /api/vpn/pppoe/clients/{name}", s.handleDeletePPPoE)
	s.mux.HandleFunc("POST /api/vpn/pppoe/clients/{name}/state", s.handleSetPPPoEState)
	s.mux.HandleFunc("POST /api/vpn/pppoe/clients/{name}/connect", s.handleConnectPPPoE)
	s.mux.HandleFunc("POST /api/vpn/pppoe/clients/{name}/disconnect", s.handleDisconnectPPPoE)

	// WireGuard Multi-Interface & Multi-Peer
	s.mux.HandleFunc("GET /api/vpn/wireguard/interfaces", s.handleListWireGuardInterfaces)
	s.mux.HandleFunc("POST /api/vpn/wireguard/interfaces", s.handleSaveWireGuardInterface)
	s.mux.HandleFunc("DELETE /api/vpn/wireguard/interfaces/{name}", s.handleDeleteWireGuardInterface)
	s.mux.HandleFunc("POST /api/vpn/wireguard/interfaces/{name}/state", s.handleSetWireGuardInterfaceState)
	s.mux.HandleFunc("POST /api/vpn/wireguard/interfaces/{name}/start", s.handleStartWireGuardInterface)
	s.mux.HandleFunc("POST /api/vpn/wireguard/interfaces/{name}/stop", s.handleStopWireGuardInterface)
	s.mux.HandleFunc("GET /api/vpn/wireguard/peers", s.handleListWireGuardPeers)
	s.mux.HandleFunc("POST /api/vpn/wireguard/peers", s.handleSaveWireGuardPeer)
	s.mux.HandleFunc("DELETE /api/vpn/wireguard/peers/{iface}/{pubkey}", s.handleDeleteWireGuardPeer)
	s.mux.HandleFunc("POST /api/vpn/wireguard/genkeys", s.handleWireGuardGenKeys)

	// PPTP Multi-Instance
	s.mux.HandleFunc("GET /api/vpn/pptp/clients", s.handleListPPTP)
	s.mux.HandleFunc("POST /api/vpn/pptp/clients", s.handleSavePPTP)
	s.mux.HandleFunc("DELETE /api/vpn/pptp/clients/{name}", s.handleDeletePPTP)
	s.mux.HandleFunc("POST /api/vpn/pptp/clients/{name}/state", s.handleSetPPTPState)
	s.mux.HandleFunc("POST /api/vpn/pptp/clients/{name}/connect", s.handleConnectPPTP)
	s.mux.HandleFunc("POST /api/vpn/pptp/clients/{name}/disconnect", s.handleDisconnectPPTP)

	// L2TP Multi-Instance
	s.mux.HandleFunc("GET /api/vpn/l2tp/clients", s.handleListL2TP)
	s.mux.HandleFunc("POST /api/vpn/l2tp/clients", s.handleSaveL2TP)
	s.mux.HandleFunc("DELETE /api/vpn/l2tp/clients/{name}", s.handleDeleteL2TP)
	s.mux.HandleFunc("POST /api/vpn/l2tp/clients/{name}/state", s.handleSetL2TPState)
	s.mux.HandleFunc("POST /api/vpn/l2tp/clients/{name}/connect", s.handleConnectL2TP)
	s.mux.HandleFunc("POST /api/vpn/l2tp/clients/{name}/disconnect", s.handleDisconnectL2TP)

	// IPSec Multi-Tunnel
	s.mux.HandleFunc("GET /api/vpn/ipsec/tunnels", s.handleListIPSec)
	s.mux.HandleFunc("POST /api/vpn/ipsec/tunnels", s.handleSaveIPSecTunnel)
	s.mux.HandleFunc("DELETE /api/vpn/ipsec/tunnels/{name}", s.handleDeleteIPSecTunnel)
	s.mux.HandleFunc("POST /api/vpn/ipsec/tunnels/{name}/state", s.handleSetIPSecState)
	s.mux.HandleFunc("POST /api/vpn/ipsec/tunnels/{name}/start", s.handleInitiateIPSecTunnel)
	s.mux.HandleFunc("POST /api/vpn/ipsec/tunnels/{name}/stop", s.handleTerminateIPSecTunnel)

	// Web UI Static Files
	if s.fsHandler != nil {
		s.mux.Handle("/", s.fsHandler)
	}
}

func (s *Server) ServeHTTP(w http.ResponseWriter, r *http.Request) {
	// Enable CORS for local development/testing
	w.Header().Set("Access-Control-Allow-Origin", "*")
	w.Header().Set("Access-Control-Allow-Methods", "GET, POST, DELETE, OPTIONS, PUT")
	w.Header().Set("Access-Control-Allow-Headers", "Content-Type, Authorization")

	if r.Method == http.MethodOptions {
		w.WriteHeader(http.StatusOK)
		return
	}

	s.mux.ServeHTTP(w, r)
}

func (s *Server) handleSystemStatus(w http.ResponseWriter, r *http.Request) {
	status, err := system.GetStatus()
	if err != nil {
		writeError(w, http.StatusInternalServerError, err.Error())
		return
	}

	ifaces, err := s.netMgr.ListInterfaces()
	if err == nil {
		status.TotalIfaces = len(ifaces)
		for _, iface := range ifaces {
			if iface.State == "UP" {
				status.UpIfaces++
			} else {
				status.DownIfaces++
			}
			if iface.IsVLAN {
				status.VlanIfaces++
			}
		}
	}

	writeJSON(w, http.StatusOK, status)
}

func (s *Server) handleRoutes(w http.ResponseWriter, r *http.Request) {
	routes, err := system.GetRoutingTable()
	if err != nil {
		writeError(w, http.StatusInternalServerError, err.Error())
		return
	}
	writeJSON(w, http.StatusOK, routes)
}

func (s *Server) handleListInterfaces(w http.ResponseWriter, r *http.Request) {
	ifaces, err := s.netMgr.ListInterfaces()
	if err != nil {
		writeError(w, http.StatusInternalServerError, err.Error())
		return
	}
	writeJSON(w, http.StatusOK, ifaces)
}

func (s *Server) handleGetInterface(w http.ResponseWriter, r *http.Request) {
	name := r.PathValue("name")
	iface, err := s.netMgr.GetInterface(name)
	if err != nil {
		writeError(w, http.StatusNotFound, err.Error())
		return
	}
	writeJSON(w, http.StatusOK, iface)
}

func (s *Server) handleSetInterfaceState(w http.ResponseWriter, r *http.Request) {
	name := r.PathValue("name")
	var req struct {
		State string `json:"state"` // "up" or "down"
	}
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		writeError(w, http.StatusBadRequest, "invalid request body")
		return
	}

	up := strings.ToLower(req.State) == "up"
	if err := s.netMgr.SetInterfaceState(name, up); err != nil {
		writeError(w, http.StatusInternalServerError, err.Error())
		return
	}

	writeJSON(w, http.StatusOK, map[string]any{"success": true, "name": name, "state": req.State})
}

func (s *Server) handleSetInterfaceMTU(w http.ResponseWriter, r *http.Request) {
	name := r.PathValue("name")
	var req struct {
		MTU int `json:"mtu"`
	}
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		writeError(w, http.StatusBadRequest, "invalid request body")
		return
	}

	if err := s.netMgr.SetInterfaceMTU(name, req.MTU); err != nil {
		writeError(w, http.StatusInternalServerError, err.Error())
		return
	}

	writeJSON(w, http.StatusOK, map[string]any{"success": true, "name": name, "mtu": req.MTU})
}

func (s *Server) handleAddInterfaceIP(w http.ResponseWriter, r *http.Request) {
	name := r.PathValue("name")
	var req network.AddIPRequest
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil || req.IP == "" {
		writeError(w, http.StatusBadRequest, "missing or invalid 'ip' parameter")
		return
	}

	if err := s.netMgr.AddInterfaceIP(name, req.IP); err != nil {
		writeError(w, http.StatusInternalServerError, err.Error())
		return
	}

	writeJSON(w, http.StatusOK, map[string]any{"success": true, "name": name, "ip": req.IP})
}

func (s *Server) handleDeleteInterfaceIP(w http.ResponseWriter, r *http.Request) {
	name := r.PathValue("name")
	var req network.AddIPRequest
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil || req.IP == "" {
		writeError(w, http.StatusBadRequest, "missing or invalid 'ip' parameter")
		return
	}

	if err := s.netMgr.DeleteInterfaceIP(name, req.IP); err != nil {
		writeError(w, http.StatusInternalServerError, err.Error())
		return
	}

	writeJSON(w, http.StatusOK, map[string]any{"success": true, "name": name, "ip": req.IP})
}

func (s *Server) handleSetInterfaceMetadata(w http.ResponseWriter, r *http.Request) {
	name := r.PathValue("name")
	var req struct {
		Role        string `json:"role"`
		Description string `json:"description"`
	}
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		writeError(w, http.StatusBadRequest, "invalid request body")
		return
	}

	if err := s.metaMgr.Set(name, req.Role, req.Description); err != nil {
		writeError(w, http.StatusInternalServerError, err.Error())
		return
	}

	writeJSON(w, http.StatusOK, map[string]any{"success": true, "name": name, "role": req.Role, "description": req.Description})
}

func (s *Server) handleListVLANs(w http.ResponseWriter, r *http.Request) {
	vlans, err := s.netMgr.ListVLANs()
	if err != nil {
		writeError(w, http.StatusInternalServerError, err.Error())
		return
	}
	writeJSON(w, http.StatusOK, vlans)
}

func (s *Server) handleCreateVLAN(w http.ResponseWriter, r *http.Request) {
	var req network.CreateVLANRequest
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		writeError(w, http.StatusBadRequest, "invalid request body")
		return
	}

	if req.ParentName == "" || req.VlanID <= 0 {
		writeError(w, http.StatusBadRequest, "parent_name and valid vlan_id (1-4094) are required")
		return
	}

	iface, err := s.netMgr.CreateVLAN(req)
	if err != nil {
		writeError(w, http.StatusInternalServerError, err.Error())
		return
	}

	writeJSON(w, http.StatusCreated, iface)
}

func (s *Server) handleDeleteVLAN(w http.ResponseWriter, r *http.Request) {
	name := r.PathValue("name")
	if err := s.netMgr.DeleteVLAN(name); err != nil {
		writeError(w, http.StatusInternalServerError, err.Error())
		return
	}
	writeJSON(w, http.StatusOK, map[string]any{"success": true, "name": name})
}

func (s *Server) handleGetDebianConfig(w http.ResponseWriter, r *http.Request) {
	cfg, err := s.persistMgr.GenerateDebianConfig()
	if err != nil {
		writeError(w, http.StatusInternalServerError, err.Error())
		return
	}
	writeJSON(w, http.StatusOK, map[string]string{
		"path":    network.DebianVlansCfgPath,
		"content": cfg,
	})
}

func (s *Server) handleSaveDebianConfig(w http.ResponseWriter, r *http.Request) {
	cfg, err := s.persistMgr.SaveDebianConfig()
	if err != nil {
		writeError(w, http.StatusInternalServerError, err.Error())
		return
	}
	writeJSON(w, http.StatusOK, map[string]any{
		"success": true,
		"path":    network.DebianVlansCfgPath,
		"content": cfg,
		"message": "Configuration saved to " + network.DebianVlansCfgPath,
	})
}

func writeJSON(w http.ResponseWriter, status int, data any) {
	w.Header().Set("Content-Type", "application/json")
	w.WriteHeader(status)
	_ = json.NewEncoder(w).Encode(data)
}

func writeError(w http.ResponseWriter, status int, message string) {
	writeJSON(w, status, map[string]any{
		"error":   true,
		"message": message,
	})
}