package router

import (
	"bytes"
	"os"
	"os/exec"
	"sync/atomic"

	"github.com/kardianos/service"

	"github.com/Control-D-Inc/ctrld"
	"github.com/Control-D-Inc/ctrld/internal/router/ddwrt"
	"github.com/Control-D-Inc/ctrld/internal/router/edgeos"
	"github.com/Control-D-Inc/ctrld/internal/router/firewalla"
	"github.com/Control-D-Inc/ctrld/internal/router/merlin"
	"github.com/Control-D-Inc/ctrld/internal/router/openwrt"
	"github.com/Control-D-Inc/ctrld/internal/router/pfsense"
	"github.com/Control-D-Inc/ctrld/internal/router/synology"
	"github.com/Control-D-Inc/ctrld/internal/router/tomato"
	"github.com/Control-D-Inc/ctrld/internal/router/ubios"
)

// Service is the interface to manage ctrld service on router.
type Service interface {
	ConfigureService(*service.Config) error
	Install(*service.Config) error
	Uninstall(*service.Config) error
}

// Config is the interface to manage ctrld config on router.
type Config interface {
	Configure() error
}

// Router is the interface for managing ctrld running on router.
type Router interface {
	Service
	Config

	PreRun() error
	Setup() error
	Cleanup() error
}

// New returns new Router interface.
func New(cfg *ctrld.Config) Router {
	switch Name() {
	case ddwrt.Name:
		return ddwrt.New(cfg)
	case merlin.Name:
		return merlin.New(cfg)
	case openwrt.Name:
		return openwrt.New(cfg)
	case edgeos.Name:
		return edgeos.New(cfg)
	case ubios.Name:
		return ubios.New(cfg)
	case synology.Name:
		return synology.New(cfg)
	case tomato.Name:
		return tomato.New(cfg)
	case pfsense.Name:
		return pfsense.New(cfg)
	case firewalla.Name:
		return firewalla.New(cfg)
	}
	return NewDummyRouter()
}

// IsGLiNet reports whether the router is an GL.iNet router.
func IsGLiNet() bool {
	if Name() != openwrt.Name {
		return false
	}
	buf, _ := os.ReadFile("/proc/version")
	// The output of /proc/version contains "(glinet@glinet)".
	return bytes.Contains(buf, []byte(" (glinet"))
}

// IsOldOpenwrt reports whether the router is an "old" version of Openwrt,
// aka versions which don't have "service" command.
func IsOldOpenwrt() bool {
	if Name() != openwrt.Name {
		return false
	}
	cmd, _ := exec.LookPath("service")
	return cmd == ""
}

var routerPlatform atomic.Pointer[router]

type router struct {
	name           string
	sendClientInfo bool
}

// IsSupported reports whether the given platform is supported by ctrld.
func IsSupported(platform string) bool {
	switch platform {
	case ddwrt.Name,
		edgeos.Name,
		firewalla.Name,
		merlin.Name,
		openwrt.Name,
		pfsense.Name,
		synology.Name,
		tomato.Name,
		ubios.Name:
		return true
	}
	return false
}

// SupportedPlatforms return all platforms that can be configured to run with ctrld.
func SupportedPlatforms() []string {
	return []string{
		ddwrt.Name,
		edgeos.Name,
		firewalla.Name,
		merlin.Name,
		openwrt.Name,
		pfsense.Name,
		synology.Name,
		tomato.Name,
		ubios.Name,
	}
}

// Name returns name of the router platform.
func Name() string {
	if r := routerPlatform.Load(); r != nil {
		return r.name
	}
	r := &router{}
	r.name = distroName()
	routerPlatform.Store(r)
	return r.name
}

func distroName() string {
	switch {
	case bytes.HasPrefix(unameO(), []byte("DD-WRT")):
		return ddwrt.Name
	case bytes.HasPrefix(unameO(), []byte("ASUSWRT-Merlin")):
		return merlin.Name
	case haveFile("/etc/openwrt_version"):
		return openwrt.Name
	case haveDir("/data/unifi"):
		return ubios.Name
	case bytes.HasPrefix(unameU(), []byte("synology")):
		return synology.Name
	case bytes.HasPrefix(unameO(), []byte("Tomato")):
		return tomato.Name
	case haveDir("/config/scripts/post-config.d"):
		return edgeos.Name
	case haveFile("/etc/ubnt/init/vyatta-router"):
		return edgeos.Name // For 2.x
	case isPfsense():
		return pfsense.Name
	case haveFile("/etc/firewalla_release"):
		return firewalla.Name
	}
	return ""
}

func haveFile(file string) bool {
	_, err := os.Stat(file)
	return err == nil
}

func haveDir(dir string) bool {
	fi, _ := os.Stat(dir)
	return fi != nil && fi.IsDir()
}

func unameO() []byte {
	out, _ := exec.Command("uname", "-o").Output()
	return out
}

func unameU() []byte {
	out, _ := exec.Command("uname", "-u").Output()
	return out
}

func isPfsense() bool {
	b, err := os.ReadFile("/etc/platform")
	return err == nil && bytes.HasPrefix(b, []byte("pfSense"))
}