package web

import (
	"log"
	"net/http"
	"net/url"
	"os"
	"sort"
	"strings"

	"nasmon/internal/collect"
	"nasmon/internal/sched"
	"nasmon/internal/shares"
)

// ---- /shares: SMB + NFS management

type smbForm struct {
	Orig, Name, Path, Comment            string
	ReadOnly, Guest, Browseable, HideSys bool
	Users                                []string
	New                                  bool
}

type nfsForm struct {
	Orig, Path, Clients, Squash string
	ReadOnly, Async             bool
	New                         bool
}

type sharesVM struct {
	C           shares.Config
	Svc         collect.ShareServices
	Users       []string
	Mountpoints []string
	Owner       string
	Host        string
	Form        smbForm
	NForm       nfsForm
	ApplyErr    string // last Apply failure: config saved but not live
	Squashes    []string
}

func (s *Server) applyErr() string {
	s.mu.Lock()
	defer s.mu.Unlock()
	return s.shareErr
}

func (s *Server) setApplyErr(e string) {
	s.mu.Lock()
	s.shareErr = e
	s.mu.Unlock()
}

// mountpoints lists dataset mountpoints — the only places shares may point to.
func mountpoints(st sched.Status) []string {
	var out []string
	for _, d := range st.Datasets {
		if strings.HasPrefix(d.Mountpoint, "/") {
			out = append(out, d.Mountpoint)
		}
	}
	sort.Strings(out)
	return out
}

func (s *Server) sharesView(st sched.Status, form smbForm, nform nfsForm) sharesVM {
	c := s.shares.Get()
	vm := sharesVM{C: c, Svc: st.Services, Mountpoints: mountpoints(st), Owner: s.shm.Owner, Host: st.Host,
		Form: form, NForm: nform, ApplyErr: s.applyErr(), Squashes: []string{"root", "all", "none"}}
	if vm.Form.Name == "" && vm.Form.Orig == "" {
		vm.Form.New, vm.Form.Guest, vm.Form.Browseable, vm.Form.HideSys = true, true, true, true
	}
	if vm.NForm.Path == "" && vm.NForm.Orig == "" {
		vm.NForm.New = true
		if vm.NForm.Squash == "" {
			vm.NForm.Squash = "root"
		}
	}
	if u, err := s.shm.ListUsers(); err == nil {
		vm.Users = u
	} else {
		log.Printf("shares: list users: %v", err)
	}
	return vm
}

func smbToForm(sh shares.SMBShare) smbForm {
	return smbForm{Orig: sh.Name, Name: sh.Name, Path: sh.Path, Comment: sh.Comment, ReadOnly: sh.ReadOnly,
		Guest: sh.Guest, Browseable: sh.Browseable, HideSys: sh.HideSysFiles, Users: sh.Users}
}

func nfsToForm(e shares.NFSExport) nfsForm {
	return nfsForm{Orig: e.Path, Path: e.Path, Clients: strings.Join(e.Clients, ", "), Squash: e.Squash, ReadOnly: e.ReadOnly, Async: e.Async}
}

func (s *Server) sharesPage(w http.ResponseWriter, r *http.Request) {
	st := s.sch.Status()
	c := s.shares.Get()
	q := r.URL.Query()
	var form smbForm
	var nform nfsForm
	if i := c.FindSMB(q.Get("edit")); i >= 0 {
		form = smbToForm(c.SMB.Shares[i])
	}
	if i := c.FindNFS(q.Get("nedit")); i >= 0 {
		nform = nfsToForm(c.NFS.Exports[i])
	}
	if p := q.Get("path"); p != "" { // "share…" link from the ZFS page
		if form.Orig == "" {
			form.Path = p
			form.Name = strings.Trim(p[strings.LastIndex(p, "/")+1:], "/")
		}
		if nform.Orig == "" {
			nform.Path = p
		}
	}
	s.render(w, r, "shares", pageData{Title: "Shares", Data: s.sharesView(st, form, nform), Alerts: len(st.Alerts), Flash: q.Get("msg")})
}

// saveAndApply persists the config and pushes it to the daemons. Returns the
// message for the user and whether everything went live.
func (s *Server) saveAndApply(c shares.Config) error {
	if err := s.shares.Save(c); err != nil {
		return err
	}
	if err := s.shm.Apply(c); err != nil {
		s.setApplyErr(err.Error())
		log.Printf("shares: apply failed: %v", err)
		return nil
	}
	s.setApplyErr("")
	s.sch.RefreshStorage()
	return nil
}

func (s *Server) sharesFail(w http.ResponseWriter, r *http.Request, msg string, form smbForm, nform nfsForm) {
	st := s.sch.Status()
	s.render(w, r, "shares", pageData{Title: "Shares", Data: s.sharesView(st, form, nform), Alerts: len(st.Alerts), Error: msg})
}

func (s *Server) sharesDone(w http.ResponseWriter, r *http.Request, msg, anchor string) {
	if e := s.applyErr(); e != "" {
		msg += " — but applying failed: " + e
	}
	http.Redirect(w, r, "/shares?msg="+url.QueryEscape(msg)+anchor, http.StatusSeeOther)
}

// pathOK checks that a share path exists and lies inside a ZFS dataset.
func (s *Server) pathOK(st sched.Status, p string) error {
	if err := shares.ValidatePath(p); err != nil {
		return err
	}
	if !shares.UnderRoots(p, mountpoints(st)) {
		return errPathOutside
	}
	if !s.dirExists(p) {
		return errPathMissing
	}
	return nil
}

func statDir(p string) bool {
	fi, err := os.Stat(p)
	return err == nil && fi.IsDir()
}

type strErr string

func (e strErr) Error() string { return string(e) }

const (
	errPathOutside = strErr("path must be inside a ZFS dataset (see the list of mountpoints)")
	errPathMissing = strErr("path does not exist or is not a directory")
)

func (s *Server) smbSettings(w http.ResponseWriter, r *http.Request) {
	if err := r.ParseForm(); err != nil {
		http.Error(w, err.Error(), http.StatusBadRequest)
		return
	}
	c := s.shares.Get()
	c.SMB.Enabled = r.FormValue("enabled") != ""
	c.SMB.Workgroup = strings.ToUpper(strings.TrimSpace(r.FormValue("workgroup")))
	c.SMB.ServerString = strings.TrimSpace(r.FormValue("server_string"))
	if err := shares.ValidateComment(c.SMB.ServerString); err != nil {
		s.sharesFail(w, r, "Not saved: server description: "+err.Error(), smbForm{}, nfsForm{})
		return
	}
	if err := s.saveAndApply(c); err != nil {
		s.sharesFail(w, r, "Not saved: "+err.Error(), smbForm{}, nfsForm{})
		return
	}
	s.sharesDone(w, r, "SMB settings saved", "#smb")
}

func (s *Server) smbSave(w http.ResponseWriter, r *http.Request) {
	if err := r.ParseForm(); err != nil {
		http.Error(w, err.Error(), http.StatusBadRequest)
		return
	}
	f := smbForm{
		Orig: strings.TrimSpace(r.FormValue("orig")), Name: strings.TrimSpace(r.FormValue("name")),
		Path: strings.TrimSpace(r.FormValue("path")), Comment: strings.TrimSpace(r.FormValue("comment")),
		ReadOnly: r.FormValue("read_only") != "", Guest: r.FormValue("guest") != "",
		Browseable: r.FormValue("browseable") != "", HideSys: r.FormValue("hide_sys") != "",
		Users: r.Form["users"],
	}
	if len(f.Path) > 1 {
		f.Path = strings.TrimRight(f.Path, "/")
	}
	st := s.sch.Status()
	sh := shares.SMBShare{Name: f.Name, Path: f.Path, Comment: f.Comment, ReadOnly: f.ReadOnly, Guest: f.Guest,
		Users: f.Users, Browseable: f.Browseable, HideSysFiles: f.HideSys}
	if sh.Guest {
		sh.Users = nil
	}
	if err := sh.Validate(); err != nil {
		s.sharesFail(w, r, "Not saved: "+err.Error(), f, nfsForm{})
		return
	}
	if err := s.pathOK(st, sh.Path); err != nil {
		s.sharesFail(w, r, "Not saved: "+err.Error(), f, nfsForm{})
		return
	}
	c := s.shares.Get()
	if i := c.FindSMB(f.Orig); f.Orig != "" && i >= 0 {
		if sh.Name != f.Orig && c.FindSMB(sh.Name) >= 0 {
			s.sharesFail(w, r, "Not saved: share "+sh.Name+" already exists", f, nfsForm{})
			return
		}
		c.SMB.Shares[i] = sh
	} else {
		if c.FindSMB(sh.Name) >= 0 {
			s.sharesFail(w, r, "Not saved: share "+sh.Name+" already exists — edit it instead", f, nfsForm{})
			return
		}
		c.SMB.Shares = append(c.SMB.Shares, sh)
	}
	if err := s.saveAndApply(c); err != nil {
		s.sharesFail(w, r, "Not saved: "+err.Error(), f, nfsForm{})
		return
	}
	log.Printf("shares: SMB share %s -> %s saved (guest=%v users=%v ro=%v)", sh.Name, sh.Path, sh.Guest, sh.Users, sh.ReadOnly)
	s.sharesDone(w, r, "Share "+sh.Name+" saved", "#smb")
}

func (s *Server) smbDelete(w http.ResponseWriter, r *http.Request) {
	name := strings.TrimSpace(r.FormValue("name"))
	c := s.shares.Get()
	i := c.FindSMB(name)
	if i < 0 {
		s.sharesFail(w, r, "No such share: "+name, smbForm{}, nfsForm{})
		return
	}
	c.SMB.Shares = append(c.SMB.Shares[:i], c.SMB.Shares[i+1:]...)
	if err := s.saveAndApply(c); err != nil {
		s.sharesFail(w, r, "Not deleted: "+err.Error(), smbForm{}, nfsForm{})
		return
	}
	log.Printf("shares: SMB share %s deleted", name)
	s.sharesDone(w, r, "Share "+name+" deleted", "#smb")
}

func (s *Server) nfsSave(w http.ResponseWriter, r *http.Request) {
	if err := r.ParseForm(); err != nil {
		http.Error(w, err.Error(), http.StatusBadRequest)
		return
	}
	f := nfsForm{
		Orig: strings.TrimSpace(r.FormValue("orig")), Path: strings.TrimSpace(r.FormValue("path")),
		Clients: strings.TrimSpace(r.FormValue("clients")), Squash: r.FormValue("squash"),
		ReadOnly: r.FormValue("read_only") != "", Async: r.FormValue("async") != "",
	}
	if len(f.Path) > 1 {
		f.Path = strings.TrimRight(f.Path, "/")
	}
	st := s.sch.Status()
	e := shares.NFSExport{Path: f.Path, Clients: shares.SplitList(f.Clients), ReadOnly: f.ReadOnly, Squash: f.Squash, Async: f.Async}
	if err := e.Validate(); err != nil {
		s.sharesFail(w, r, "Not saved: "+err.Error(), smbForm{}, f)
		return
	}
	if err := s.pathOK(st, e.Path); err != nil {
		s.sharesFail(w, r, "Not saved: "+err.Error(), smbForm{}, f)
		return
	}
	c := s.shares.Get()
	if i := c.FindNFS(f.Orig); f.Orig != "" && i >= 0 {
		if e.Path != f.Orig && c.FindNFS(e.Path) >= 0 {
			s.sharesFail(w, r, "Not saved: "+e.Path+" is already exported", smbForm{}, f)
			return
		}
		c.NFS.Exports[i] = e
	} else {
		if c.FindNFS(e.Path) >= 0 {
			s.sharesFail(w, r, "Not saved: "+e.Path+" is already exported — edit it instead", smbForm{}, f)
			return
		}
		c.NFS.Exports = append(c.NFS.Exports, e)
	}
	if err := s.saveAndApply(c); err != nil {
		s.sharesFail(w, r, "Not saved: "+err.Error(), smbForm{}, f)
		return
	}
	log.Printf("shares: NFS export %s to %v saved (ro=%v squash=%s)", e.Path, e.Clients, e.ReadOnly, e.Squash)
	s.sharesDone(w, r, "Export "+e.Path+" saved", "#nfs")
}

func (s *Server) nfsDelete(w http.ResponseWriter, r *http.Request) {
	p := strings.TrimSpace(r.FormValue("path"))
	c := s.shares.Get()
	i := c.FindNFS(p)
	if i < 0 {
		s.sharesFail(w, r, "No such export: "+p, smbForm{}, nfsForm{})
		return
	}
	c.NFS.Exports = append(c.NFS.Exports[:i], c.NFS.Exports[i+1:]...)
	if err := s.saveAndApply(c); err != nil {
		s.sharesFail(w, r, "Not deleted: "+err.Error(), smbForm{}, nfsForm{})
		return
	}
	log.Printf("shares: NFS export %s deleted", p)
	s.sharesDone(w, r, "Export "+p+" deleted", "#nfs")
}

func (s *Server) nfsSettings(w http.ResponseWriter, r *http.Request) {
	c := s.shares.Get()
	c.NFS.Enabled = r.FormValue("enabled") != ""
	if err := s.saveAndApply(c); err != nil {
		s.sharesFail(w, r, "Not saved: "+err.Error(), smbForm{}, nfsForm{})
		return
	}
	s.sharesDone(w, r, "NFS settings saved", "#nfs")
}

func (s *Server) userSave(w http.ResponseWriter, r *http.Request) {
	name := strings.TrimSpace(r.FormValue("name"))
	pass := r.FormValue("password")
	if err := s.shm.SetPassword(name, pass); err != nil {
		s.sharesFail(w, r, "User not saved: "+err.Error(), smbForm{}, nfsForm{})
		return
	}
	http.Redirect(w, r, "/shares?msg="+url.QueryEscape("Password set for "+name)+"#users", http.StatusSeeOther)
}

func (s *Server) userDelete(w http.ResponseWriter, r *http.Request) {
	name := strings.TrimSpace(r.FormValue("name"))
	c := s.shares.Get()
	for _, sh := range c.SMB.Shares {
		for _, u := range sh.Users {
			if u == name {
				s.sharesFail(w, r, "User "+name+" is still allowed on share "+sh.Name+" — remove them there first", smbForm{}, nfsForm{})
				return
			}
		}
	}
	if err := s.shm.DeleteUser(name); err != nil {
		s.sharesFail(w, r, "User not deleted: "+err.Error(), smbForm{}, nfsForm{})
		return
	}
	http.Redirect(w, r, "/shares?msg="+url.QueryEscape("User "+name+" deleted")+"#users", http.StatusSeeOther)
}

func (s *Server) sharesApply(w http.ResponseWriter, r *http.Request) {
	if err := s.saveAndApply(s.shares.Get()); err != nil {
		s.sharesFail(w, r, err.Error(), smbForm{}, nfsForm{})
		return
	}
	s.sharesDone(w, r, "Configuration applied", "")
}