package server

import (
	"bytes"
	"html/template"
	"log"
	"net/http"

	"github.com/x-grk/longpolling-remote-access/internal/proto"
)

// A panel page is either a fragment - its content alone, for the shell to put
// in place without reloading - or the shell with that content already in it.

func isFrag(r *http.Request) bool { return r.URL.Query().Get("frag") == "1" }

// pageView is the shell's view a page is shown in; the machine pages (Порты,
// Статус, Изменить) open as a dialog over the machines view.
var pageView = map[string]string{"dashboard": "dashboard", "settings": "settings"}

func (s *Server) renderPage(w http.ResponseWriter, r *http.Request, name string, data map[string]any) {
	w.Header().Set("Content-Type", "text/html; charset=utf-8")
	w.Header().Set("Cache-Control", "no-store")
	if data == nil {
		data = map[string]any{}
	}
	data["IsAdmin"] = s.currentAdmin(r).IsAdmin()
	if !isFrag(r) {
		if _, ok := pageView[name]; !ok {
			// A machine page asked for whole: the machines view with it in
			// a dialog.
			s.shell(w, r, map[string]any{"View": "dashboard", "Dialog": r.URL.Path})
			return
		}
	}
	var body bytes.Buffer
	if err := s.tmpl.ExecuteTemplate(&body, name+"-body", data); err != nil {
		log.Printf("template %s: %v", name, err)
		http.Error(w, "internal error", http.StatusInternalServerError)
		return
	}
	if isFrag(r) {
		_, _ = w.Write(body.Bytes())
		return
	}
	data["View"] = pageView[name]
	data["Body"] = template.HTML(body.String())
	s.shell(w, r, data)
}

// shell writes the shell page with data (View, Body, Open, Dialog).
func (s *Server) shell(w http.ResponseWriter, r *http.Request, data map[string]any) {
	data["IsAdmin"] = s.currentAdmin(r).IsAdmin()
	data["EditLimit"] = proto.FSReadCap
	if a := s.currentAdmin(r); a != nil {
		data["Prefs"] = s.prefs(a.ID)
	}
	if data["View"] == "dashboard" && data["Body"] == nil {
		// The machines list under a dialog: draw it too.
		var body bytes.Buffer
		if err := s.tmpl.ExecuteTemplate(&body, "dashboard-body", s.dashboardData(r)); err == nil {
			data["Body"] = template.HTML(body.String())
		}
	}
	w.Header().Set("Content-Type", "text/html; charset=utf-8")
	w.Header().Set("Cache-Control", "no-store")
	if err := s.tmpl.ExecuteTemplate(w, "app.html", data); err != nil {
		log.Printf("template app.html: %v", err)
	}
}

// handleShell serves the shell alone: the terminal view, or with a pane of
// a machine opened at once (/agents/{id}/terminal, /agents/{id}/files).
func (s *Server) handleShell(w http.ResponseWriter, r *http.Request) {
	data := map[string]any{"View": "terminal"}
	if id := r.PathValue("id"); id != "" {
		a, _ := s.db.GetAgent(id)
		if a == nil {
			http.NotFound(w, r)
			return
		}
		kind := "term"
		switch r.PathValue("kind") {
		case "", "terminal":
		case "files":
			kind = "files"
		default:
			http.NotFound(w, r)
			return
		}
		data["Open"] = map[string]any{"kind": kind, "agent": map[string]string{"id": a.ID, "name": a.Name, "host": a.Hostname, "user": a.TerminalUser()}}
	}
	s.shell(w, r, data)
}