package sendoverhttp

import (
	"fmt"
	"io/fs"
	"log"
	"net"
	"net/http"
	"os"
	"path/filepath"
)

func preferredIP() (*net.IP, error) {
	ips, err := net.InterfaceAddrs()
	if err != nil {
		return nil, err
	}
	for _, addr := range ips {
		ipNet, ok := addr.(*net.IPNet)
		if !ok {
			continue
		}
		if ipNet.IP.IsLoopback() {
			continue
		}
		return &ipNet.IP, nil
	}
	return nil, nil
}

type Server struct {
	filepath string

	closeCh chan struct{}
	mr      *MultiRunner
}

type SingleFileDir string

func (s SingleFileDir) Open(name string) (http.File, error) {
	if name == "index.html" {
		return nil, fs.ErrNotExist
	}

	fp := string(s)
	stat, err := os.Stat(fp)
	if err != nil {
		return nil, err
	}
	if stat.IsDir() {
		return http.Dir(fp).Open(name)
	}

	switch name {
	case "/":
		return nil, os.ErrNotExist
	case "/" + filepath.Base(fp):
		return os.Open(fp)
	default:
		return nil, os.ErrNotExist

	}
}

func NewServer(fp string) *Server {
	return &Server{
		closeCh:  make(chan struct{}),
		filepath: fp,
		mr:       NewMultiRunner(),
	}
}

func (s *Server) Start() error {
	ip, err := preferredIP()
	if err != nil {
		return err
	}

	prot := "http"
	port := "8081"

	url := fmt.Sprintf("%s://%s:%s", prot, ip, port)
	if stat, _ := os.Stat(s.filepath); !stat.IsDir() {
		url += "/" + filepath.Base(s.filepath)
	}

	qrCodeShower := NewTerminalQRShower(url)
	go s.mr.Run(qrCodeShower)

	httpRunner := NewRunner()
	httpSrv := &http.Server{
		Addr: ":" + port,
	}

	var d http.FileSystem = http.Dir(s.filepath)
	if stat, _ := os.Stat(s.filepath); !stat.IsDir() {
		// Show user the name of the file
		d = SingleFileDir(s.filepath)
	}
	httpSrv.Handler = http.FileServer(d)

	httpRunner.OnStart = func() error {
		l, err := net.Listen("tcp4", ip.String()+":"+port)
		if err != nil {
			log.Fatal(err)
		}
		return httpSrv.Serve(l)
	}
	httpRunner.OnStop = func() {
		_ = httpSrv.Close()
	}
	go s.mr.Run(httpRunner)

	<-s.closeCh
	close(s.closeCh)
	return nil
}

func (s *Server) Stop() {
	s.mr.Stop()
	return
}