/*
 * Copyright (c) 2017 TOYOTA MOTOR CORPORATION
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#ifndef TMCAGLWM_APP_HPP
#define TMCAGLWM_APP_HPP

#include <json-c/json.h>

#include <atomic>
#include <memory>
#include <unordered_map>
#include <unordered_set>
#include <experimental/optional>

#include "afb_binding_api.hpp"
#include "config.hpp"
#include "controller_hooks.hpp"
#include "layers.hpp"
#include "layout.hpp"
#include "policy.hpp"
#include "result.hpp"
#include "wayland.hpp"
#include "hmi-debug.h"

namespace wl {
struct display;
}

namespace compositor {
struct controller;
}

namespace wm {

using std::experimental::optional;

/* DrawingArea name used by "{layout}.{area}" */
static const char *kNameLayoutNormal = "normal";
static const char *kNameLayoutSplit = "split";
static const char *kNameAreaFull = "full";
static const char *kNameAreaMain = "main";
static const char *kNameAreaSub = "sub";

/* Key for json obejct */
static const char *kKeyDrawingName = "drawing_name";
static const char *kKeyDrawingArea = "drawing_area";

struct id_allocator {
   unsigned next = 1;

   // Surfaces that where requested but not yet created
   std::unordered_map<unsigned, std::string> id2name;
   // std::unordered_set<unsigned> pending_surfaces;
   std::unordered_map<std::string, unsigned> name2id;

   id_allocator(id_allocator const &) = delete;
   id_allocator(id_allocator &&) = delete;
   id_allocator &operator=(id_allocator const &);
   id_allocator &operator=(id_allocator &&) = delete;

   // Insert and return a new ID
   unsigned generate_id(std::string const &name) {
      unsigned sid = this->next++;
      this->id2name[sid] = name;
      // this->pending_surfaces.insert({sid});
      this->name2id[name] = sid;
      HMI_DEBUG("wm", "allocated new id %u with name %s", sid, name.c_str());
      return sid;
   }

   // Lookup by ID or by name
   optional<unsigned> lookup(std::string const &name) const {
      auto i = this->name2id.find(name);
      return i == this->name2id.end() ? nullopt : optional<unsigned>(i->second);
   }

   optional<std::string> lookup(unsigned id) const {
      auto i = this->id2name.find(id);
      return i == this->id2name.end() ? nullopt
                                       : optional<std::string>(i->second);
   }

   // Remove a surface id and name
   void remove_id(std::string const &name) {
      auto i = this->name2id.find(name);
      if (i != this->name2id.end()) {
         this->id2name.erase(i->second);
         this->name2id.erase(i);
      }
   }

   void remove_id(unsigned id) {
      auto i = this->id2name.find(id);
      if (i != this->id2name.end()) {
         this->name2id.erase(i->second);
         this->id2name.erase(i);
      }
   }
};

struct App {
   enum EventType {
      Event_Val_Min = 0,

      Event_Active = Event_Val_Min,
      Event_Inactive,

      Event_Visible,
      Event_Invisible,

      Event_SyncDraw,
      Event_FlushDraw,

      Event_Val_Max = Event_FlushDraw,
   };

   const std::vector<const char *> kListEventName{
     "active",
     "inactive",
     "visible",
     "invisible",
     "syncdraw",
     "flushdraw"
   };

   struct binding_api api;
   struct controller_hooks chooks;

   // This is the one thing, we do not own.
   struct wl::display *display;

   std::unique_ptr<struct compositor::controller> controller;
   std::vector<std::unique_ptr<struct wl::output>> outputs;

   struct config config;

   // track current layouts separately
   layer_map layers;

   // ID allocation and proxy methods for lookup
   struct id_allocator id_alloc;

   // Set by AFB API when wayland events need to be dispatched
   std::atomic<bool> pending_events;

   std::vector<int> pending_end_draw;

   Policy policy;

   std::map<const char *, struct afb_event> map_afb_event;

   explicit App(wl::display *d);
   ~App() = default;

   App(App const &) = delete;
   App &operator=(App const &) = delete;
   App(App &&) = delete;
   App &operator=(App &&) = delete;

   int init();

   int dispatch_events();
   int dispatch_pending_events();

   void set_pending_events();

   result<int> api_request_surface(char const *drawing_name);
   char const *api_activate_surface(char const *drawing_name, char const *drawing_area);
   char const *api_deactivate_surface(char const *drawing_name);
   char const *api_enddraw(char const *drawing_name);
   char const *api_subscribe(afb_req *req, char const *event_name);
   void api_ping();

   // Events from the compositor we are interested in
   void surface_created(uint32_t surface_id);
   void surface_removed(uint32_t surface_id);

private:
   optional<int> lookup_id(char const *name);
   optional<std::string> lookup_name(int id);

   bool pop_pending_events();

   void enqueue_flushdraw(int surface_id);
   void check_flushdraw(int surface_id);

   int init_layers();

   void surface_set_layout(int surface_id, optional<int> sub_surface_id = nullopt);
   void layout_commit();

   // TMC WM Events to clients
   void emit_activated(char const *label);
   void emit_deactivated(char const *label);
   void emit_syncdraw(char const *label, char const *area);
   void emit_flushdraw(char const *label);
   void emit_visible(char const *label, bool is_visible);
   void emit_invisible(char const *label);
   void emit_visible(char const *label);

   void activate(int id);
   void deactivate(int id);
   void deactivate_main_surface();

   bool can_split(struct LayoutState const &state, int new_id);
   void try_layout(struct LayoutState &state,
                   struct LayoutState const &new_layout,
                   std::function<void(LayoutState const &nl)> apply);
};

}  // namespace wm

#endif  // TMCAGLWM_APP_HPP