/*
 * Copyright (C) 2017 Mentor Graphics Development (Deutschland) GmbH
 *
 * 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.
 */

#include "app.hpp"
#include "json_helper.hpp"
#include "layers.hpp"
#include "layout.hpp"
#include "util.hpp"
#include "wayland.hpp"

#include <cstdio>
#include <memory>

#include <cassert>

#include <json-c/json.h>

#include <algorithm>
#include <bits/signum.h>
#include <csignal>
#include <fstream>
#include <json.hpp>
#include <regex>
#include <thread>

namespace wm {

namespace {
App *g_app;

using nlohmann::json;

result<json> file_to_json(char const *filename) {
   std::ifstream i(filename);
   if (i.fail()) {
      return Err<json>("Could not open config file");
   }
   json j;
   i >> j;
   return Ok(j);
}

struct result<layer_map> load_layer_map(char const *filename) {
   logdebug("loading IDs from %s", filename);

   auto j = file_to_json(filename);
   if (j.is_err()) {
      return Err<layer_map>(j.unwrap_err());
   }
   json jids = j.unwrap();

   return to_layer_map(jids);
}

}  // namespace

//       _                    _                  _                 _
//   ___| | __ _ ___ ___     / \   _ __  _ __   (_)_ __ ___  _ __ | |
//  / __| |/ _` / __/ __|   / _ \ | '_ \| '_ \  | | '_ ` _ \| '_ \| |
// | (__| | (_| \__ \__ \  / ___ \| |_) | |_) | | | | | | | | |_) | |
//  \___|_|\__,_|___/___/ /_/   \_\ .__/| .__/  |_|_| |_| |_| .__/|_|
//                                |_|   |_|                 |_|
App::App(wl::display *d)
   : api{this},
     chooks{this},
     display{d},
     controller{},
     outputs(),
     config(),
     layers(),
     id_alloc{},
     pending_events(false),
     policy{} {
   assert(g_app == nullptr);
   g_app = this;

   try {
      {
         auto l = load_layer_map(
            this->config.get_string("layers.json").value().c_str());
         if (l.is_ok()) {
            this->layers = l.unwrap();
         } else {
            logerror("%s", l.err().value());
         }
      }
   } catch (std::exception &e) {
      logerror("Loading of configuration failed: %s", e.what());
   }
}

App::~App() { g_app = nullptr; }

int App::init() {
   if (!this->display->ok()) {
      return -1;
   }

   if (this->layers.mapping.empty()) {
      logerror("No surface -> layer mapping loaded");
      return -1;
   }

   this->display->add_global_handler(
      "wl_output", [this](wl_registry *r, uint32_t name, uint32_t v) {
         this->outputs.emplace_back(std::make_unique<wl::output>(r, name, v));
      });

   this->display->add_global_handler(
      "ivi_controller", [this](wl_registry *r, uint32_t name, uint32_t v) {
         this->controller =
            std::make_unique<struct genivi::controller>(r, name, v);

         // Init controller hooks
         this->controller->chooks = &this->chooks;

         // XXX: This protocol needs the output, so lets just add our mapping
         // here...
         this->controller->add_proxy_to_id_mapping(
            this->outputs.back()->proxy.get(),
            wl_proxy_get_id(reinterpret_cast<struct wl_proxy *>(
               this->outputs.back()->proxy.get())));
      });

   // First level objects
   this->display->roundtrip();
   // Second level objects
   this->display->roundtrip();
   // Third level objects
   this->display->roundtrip();

   return init_layers();
}

int App::dispatch_events() {
   if (this->dispatch_events() == 0) {
      return 0;
   }

   int ret = this->display->dispatch();
   if (ret == -1) {
      logerror("wl_display_dipatch() returned error %d",
               this->display->get_error());
      return -1;
   }
   this->display->flush();

   return 0;
}

int App::dispatch_pending_events() {
   if (this->pop_pending_events()) {
      this->display->dispatch_pending();
      return 0;
   }
   return -1;
}

bool App::pop_pending_events() {
   bool x{true};
   return this->pending_events.compare_exchange_strong(
      x, false, std::memory_order_consume);
}

void App::set_pending_events() {
   this->pending_events.store(true, std::memory_order_release);
}

optional<int> App::lookup_id(char const *name) {
   return this->id_alloc.lookup(std::string(name));
}
optional<std::string> App::lookup_name(int id) {
   return this->id_alloc.lookup(id);
}

//  _       _ _       _                         _    ____
// (_)_ __ (_) |_    | | __ _ _   _  ___  _   _| |_ / /\ \
// | | '_ \| | __|   | |/ _` | | | |/ _ \| | | | __| |  | |
// | | | | | | |_    | | (_| | |_| | (_) | |_| | |_| |  | |
// |_|_| |_|_|\__|___|_|\__,_|\__, |\___/ \__,_|\__| |  | |
//              |_____|       |___/                 \_\/_/
int App::init_layers() {
   if (!this->controller) {
      logerror("ivi_controller global not available");
      return -1;
   }

   if (this->outputs.empty()) {
      logerror("no output was set up!");
      return -1;
   }

   auto &c = this->controller;

   auto &o = this->outputs.front();
   auto &s = c->screens.begin()->second;
   auto &layers = c->layers;

   // XXX: Write output dimensions to ivi controller...
   c->output_size = genivi::size{uint32_t(o->width), uint32_t(o->height)};

   // Clear scene
   layers.clear();

   // Clear screen
   s->clear();

   // Quick and dirty setup of layers
   // XXX: This likely needs to be sorted by order (note, we don't (yet?)
   // do any zorder arrangement).
   for (auto const &i : this->layers.mapping) {
      c->layer_create(i.second.layer_id, o->width, o->height);
      auto &l = layers[i.second.layer_id];
      l->set_destination_rectangle(0, 0, o->width, o->height);
      l->set_visibility(1);
      logdebug("Setting up layer %s (%d) for surface role match \"%s\"",
               i.second.name.c_str(), i.second.layer_id, i.second.role.c_str());
   }

   // Add layers to screen (XXX: are they sorted correctly?)
   s->set_render_order(this->layers.layers);

   this->layout_commit();

   return 0;
}

namespace {

#ifdef WE_LIKE_NOT_TO_USE_THIS
// This can fix the HomeScreen...
void redraw_fix(App *app, std::unique_ptr<genivi::surface> &s, int x, int y,
                int w, int h) {
   {  // XXX: Work around weston redraw issues
      // trigger an update by changing the source dimensions!
      s->set_configuration(w + 1, h);
      s->set_source_rectangle(0, 0, w + 1, h);
      s->set_destination_rectangle(x, y, w + 1, h);
      app->controller->commit_changes();
      app->display->roundtrip();

      // wait some time, for the process to do its thing...
      using namespace std::chrono_literals;
      std::this_thread::sleep_for(100ms);

      // Set a different size then what we actually want.
      s->set_configuration(w, h);
      s->set_source_rectangle(0, 0, w, h);
      s->set_destination_rectangle(x, y, w, h);
      app->controller->commit_changes();
      app->display->roundtrip();
   }
}
#endif

}  // namespace

void App::surface_set_layout(int surface_id, optional<int> sub_surface_id) {
   if (!this->controller->surface_exists(surface_id)) {
      logerror("Surface %d does not exist", surface_id);
      return;
   }

   auto o_layer_id = this->layers.get_layer_id(surface_id);

   if (!o_layer_id) {
      logerror("Surface %d is not associated with any layer!", surface_id);
      return;
   }

   uint32_t layer_id = *o_layer_id;

   auto const &layer = this->layers.get_layer(layer_id);
   auto rect = layer.value().rect;
   auto &s = this->controller->surfaces[surface_id];

   int x = rect.x;
   int y = rect.y;
   int w = rect.w;
   int h = rect.h;

   // less-than-0 values refer to MAX + 1 - $VALUE
   // e.g. MAX is either screen width or height
   if (w < 0) {
      w = this->controller->output_size.w + 1 + w;
   }
   if (h < 0) {
      h = this->controller->output_size.h + 1 + h;
   }

   if (sub_surface_id) {
      if (o_layer_id != this->layers.get_layer_id(*sub_surface_id)) {
         logerror(
            "surface_set_layout: layers of surfaces (%d and %d) don't match!",
            surface_id, *sub_surface_id);
         return;
      }

      int x_off = 0;
      int y_off = 0;

      // split along major axis
      if (w > h) {
         w /= 2;
         x_off = w;
      } else {
         h /= 2;
         y_off = h;
      }

      auto &ss = this->controller->surfaces[*sub_surface_id];

      logdebug("surface_set_layout for sub surface %u on layer %u",
               *sub_surface_id, layer_id);

      // configure surface to wxh dimensions
      ss->set_configuration(w, h);
      // set source reactangle, even if we should not need to set it.
      ss->set_source_rectangle(0, 0, w, h);
      // set destination to the display rectangle
      ss->set_destination_rectangle(x + x_off, y + y_off, w, h);
   }

   logdebug("surface_set_layout for surface %u on layer %u", surface_id,
            layer_id);

   // configure surface to wxh dimensions
   s->set_configuration(w, h);
   // set source reactangle, even if we should not need to set it.
   s->set_source_rectangle(0, 0, w, h);
   // set destination to the display rectangle
   s->set_destination_rectangle(x, y, w, h);

   // redraw_fix(this, s, x, y, w, h);
   // redraw_fix(this, ss, x+x_off, y+y_off, w, h);

   logdebug("Surface %u now on layer %u with rect { %d, %d, %d, %d }",
            surface_id, layer_id, x, y, w, h);
}

void App::layout_commit() {
   this->controller->commit_changes();
   this->display->flush();
}

char const *App::api_activate_surface(char const *drawing_name) {
   ST();
   auto const &surface_id = this->lookup_id(drawing_name);

   if (!surface_id) {
      return "Surface does not exist";
   }

   if (!this->controller->surface_exists(*surface_id)) {
      return "Surface does not exist in controller!";
   }

   auto layer_id = this->layers.get_layer_id(*surface_id);

   if (!layer_id) {
      return "Surface is not on any layer!";
   }

   auto o_state = *this->layers.get_layout_state(*surface_id);

   if (o_state == nullptr) {
      return "Could not find layer for surface";
   }

   struct LayoutState &state = *o_state;

   // disable layers that are above our current layer
   for (auto const &l : this->layers.mapping) {
      if (l.second.layer_id <= *layer_id) {
         continue;
      }

      bool flush = false;
      if (l.second.state.main != -1) {
         this->deactivate(l.second.state.main);
         l.second.state.main = -1;
         flush = true;
      }

      if (l.second.state.sub != -1) {
         this->deactivate(l.second.state.sub);
         l.second.state.sub = -1;
         flush = true;
      }

      if (flush) {
         this->layout_commit();
      }
   }

   if (state.main == *surface_id || state.sub == *surface_id) {
      return "Surface already active";
   }


   if (state.main == -1) {
      this->try_layout(
         state, LayoutState{*surface_id}, [&] (LayoutState const &nl) {
            this->surface_set_layout(*surface_id);
            // XXX do we need to activate after enddraw?
            this->activate(*surface_id);
            state = nl;
            this->layout_commit();
            this->emit_syncdraw(drawing_name);
            this->enqueue_flushdraw(state.main);
         });
   } else {
      bool can_split = this->can_split(state, *surface_id);

         if (can_split) {
            this->try_layout(
               state,
               LayoutState{state.main, *surface_id},
               [&] (LayoutState const &nl) {
                  std::string main =
                     std::move(*this->lookup_name(state.main));

                  this->surface_set_layout(state.main, surface_id);
                  this->activate(*surface_id);
                  if (state.sub != -1) {
                     this->deactivate(state.sub);
                  }
                  state = nl;

                  this->layout_commit();
                  this->emit_syncdraw(drawing_name);
                  this->emit_syncdraw(main.c_str());
                  this->enqueue_flushdraw(state.main);
                  this->enqueue_flushdraw(state.sub);
               });
         } else {
            this->try_layout(
               state, LayoutState{*surface_id}, [&] (LayoutState const &nl) {
                  this->surface_set_layout(*surface_id);
                  this->deactivate(state.main);
                  this->activate(*surface_id);
                  if (state.sub != -1) {
                     this->deactivate(state.sub);
                  }
                  state = nl;

                  this->layout_commit();
                  this->emit_syncdraw(drawing_name);
                  this->enqueue_flushdraw(state.main);
               });
         }
   }

   // no error
   return nullptr;
}

char const *App::api_deactivate_surface(char const *drawing_name) {
   ST();
   auto const &surface_id = this->lookup_id(drawing_name);

   if (!surface_id) {
      return "Surface does not exist";
   }

   if (*surface_id == this->layers.main_surface) {
      return "Cannot deactivate main_surface";
   }

   auto o_state = *this->layers.get_layout_state(*surface_id);

   if (o_state == nullptr) {
      return "Could not find layer for surface";
   }

   struct LayoutState &state = *o_state;

   if (state.main == -1) {
      return "No surface active";
   }

   // XXX: check against main_surface, main_surface_name is the configuration
   // item.
   if (*surface_id == this->layers.main_surface) {
      logdebug("Refusing to deactivate main_surface %d", *surface_id);
      return nullptr;
   }

   if (state.main == *surface_id) {
      if (state.sub != -1) {
         this->try_layout(
            state, LayoutState{state.sub, -1}, [&] (LayoutState const &nl) {
               std::string sub = std::move(*this->lookup_name(state.sub));

               this->deactivate(*surface_id);
               this->surface_set_layout(state.sub);
               state = nl;

               this->layout_commit();
               this->emit_syncdraw(sub.c_str());
               this->enqueue_flushdraw(state.sub);
            });
      } else {
         this->try_layout(state, LayoutState{-1, -1}, [&] (LayoutState const &nl) {
            this->deactivate(*surface_id);
            state = nl;
            this->layout_commit();
         });
      }
   } else if (state.sub == *surface_id) {
      this->try_layout(
         state, LayoutState{state.main, -1}, [&] (LayoutState const &nl) {
            std::string main = std::move(*this->lookup_name(state.main));

            this->deactivate(*surface_id);
            this->surface_set_layout(state.main);
            state = nl;

            this->layout_commit();
            this->emit_syncdraw(main.c_str());
            this->enqueue_flushdraw(state.main);
         });
   } else {
      return "Surface is not active";
   }

   return nullptr;
}

void App::enqueue_flushdraw(int surface_id) {
   this->check_flushdraw(surface_id);
   logdebug("Enqueuing EndDraw for surface_id %d", surface_id);
   this->pending_end_draw.push_back(surface_id);
}

void App::check_flushdraw(int surface_id) {
   auto i = std::find(std::begin(this->pending_end_draw),
                      std::end(this->pending_end_draw), surface_id);
   if (i != std::end(this->pending_end_draw)) {
      auto n = this->lookup_name(surface_id);
      logerror("Application %s (%d) has pending EndDraw call(s)!",
               n ? n->c_str() : "unknown-name", surface_id);
      std::swap(this->pending_end_draw[std::distance(
                   std::begin(this->pending_end_draw), i)],
                this->pending_end_draw.back());
      this->pending_end_draw.resize(this->pending_end_draw.size() - 1);
   }
}

char const *App::api_enddraw(char const *drawing_name) {
   for (unsigned i = 0, iend = this->pending_end_draw.size(); i < iend; i++) {
      auto n = this->lookup_name(this->pending_end_draw[i]);
      if (n && *n == drawing_name) {
         std::swap(this->pending_end_draw[i], this->pending_end_draw[iend - 1]);
         this->pending_end_draw.resize(iend - 1);
         // XXX: Please tell the compositor to thaw the surface...
         this->emit_flushdraw(drawing_name);
         return nullptr;
      }
   }
   return "No EndDraw pending for surface";
}

void App::api_ping() { this->dispatch_pending_events(); }

//                      _          _   _____                 _
//  _ __  _ __ _____  _(_) ___  __| | | ____|_   _____ _ __ | |_ ___
// | '_ \| '__/ _ \ \/ / |/ _ \/ _` | |  _| \ \ / / _ \ '_ \| __/ __|
// | |_) | | | (_) >  <| |  __/ (_| | | |___ \ V /  __/ | | | |_\__ \
// | .__/|_|  \___/_/\_\_|\___|\__,_| |_____| \_/ \___|_| |_|\__|___/
// |_|
void App::surface_created(uint32_t surface_id) {
   auto layer_id = this->layers.get_layer_id(surface_id);
   if (!layer_id) {
      logdebug("Newly created surfce %d is not associated with any layer!",
               surface_id);
      return;
   }

   logdebug("surface_id is %u, layer_id is %u", surface_id, *layer_id);

   this->controller->layers[*layer_id]->add_surface(
      this->controller->surfaces[surface_id].get());

   // activate the main_surface right away
   if (surface_id == static_cast<unsigned>(this->layers.main_surface)) {
      logdebug("Activating main_surface (%d)", surface_id);

      this->api_activate_surface(
         this->lookup_name(surface_id).value_or("unknown-name").c_str());
   }
}

void App::surface_removed(uint32_t surface_id) {
   logdebug("surface_id is %u", surface_id);

   // We cannot normally deactivate the main_surface, so be explicit
   // about it:
   if (int(surface_id) == this->layers.main_surface) {
      this->deactivate_main_surface();
   } else {
      auto drawing_name = this->lookup_name(surface_id);
      if (drawing_name) {
         this->api_deactivate_surface(drawing_name->c_str());
      }
   }

   this->id_alloc.remove_id(surface_id);
   this->layers.remove_surface(surface_id);
}

void App::emit_activated(char const *label) {
   this->api.send_event("active", label);
}

void App::emit_deactivated(char const *label) {
   this->api.send_event("inactive", label);
}

void App::emit_syncdraw(char const *label) {
   this->api.send_event("syncdraw", label);
}

void App::emit_flushdraw(char const *label) {
   this->api.send_event("flushdraw", label);
}

void App::emit_visible(char const *label, bool is_visible) {
   this->api.send_event(is_visible ? "visible" : "invisible", label);
}

void App::emit_invisible(char const *label) {
   return emit_visible(label, false);
}

void App::emit_visible(char const *label) { return emit_visible(label, true); }

result<int> App::api_request_surface(char const *drawing_name) {
   auto lid = this->layers.get_layer_id(std::string(drawing_name));
   if (!lid) {
      // XXX: to we need to put these applications on the App layer?
      return Err<int>("Drawing name does not match any role");
   }

   auto rname = this->lookup_id(drawing_name);
   if (!rname) {
      // name does not exist yet, allocate surface id...
      auto id = int(this->id_alloc.generate_id(drawing_name));
      this->layers.add_surface(id, *lid);

      // XXX: we set the main_surface[_name] here and now,
      // not sure if we want this, but it worked so far.
      if (!this->layers.main_surface_name.empty() &&
          this->layers.main_surface_name == drawing_name) {
         this->layers.main_surface = id;
         logdebug("Set main_surface id to %u", id);
      }

      return Ok<int>(id);
   }

   // Check currently registered drawing names if it is already there.
   return Err<int>("Surface already present");
}

void App::activate(int id) {
   auto ip = this->controller->sprops.find(id);
   if (ip != this->controller->sprops.end() && ip->second.visibility == 0) {
      this->controller->surfaces[id]->set_visibility(1);
      char const *label =
         this->lookup_name(id).value_or("unknown-name").c_str();
      this->emit_activated(label);
      this->emit_visible(label);
   }
}

void App::deactivate(int id) {
   auto ip = this->controller->sprops.find(id);
   if (ip != this->controller->sprops.end() && ip->second.visibility != 0) {
      this->controller->surfaces[id]->set_visibility(0);
      char const *label =
         this->lookup_name(id).value_or("unknown-name").c_str();
      this->emit_deactivated(label);
      this->emit_invisible(label);
   }
}

void App::deactivate_main_surface() {
   this->layers.main_surface = -1;
   this->api_deactivate_surface(this->layers.main_surface_name.c_str());
}

bool App::can_split(struct LayoutState const &state, int new_id) {
   if (state.main != -1 && state.main != new_id) {
      auto new_id_layer = this->layers.get_layer_id(new_id).value();
      auto current_id_layer = this->layers.get_layer_id(state.main).value();

      // surfaces are on separate layers, don't bother.
      if (new_id_layer != current_id_layer) {
         return false;
      }

      std::string const &new_id_str = this->lookup_name(new_id).value();
      std::string const &cur_id_str = this->lookup_name(state.main).value();

      auto const &layer = this->layers.get_layer(new_id_layer);

      logdebug("layer info name: %s", layer->name.c_str());

      if (layer->layouts.empty()) {
         return false;
      }

      for (auto i = layer->layouts.cbegin(); i != layer->layouts.cend(); i++) {
         logdebug("%d main_match '%s'", new_id_layer, i->main_match.c_str());
         auto rem = std::regex(i->main_match);
         if (std::regex_match(cur_id_str, rem)) {
            // build the second one only if the first already matched
            logdebug("%d sub_match '%s'", new_id_layer, i->sub_match.c_str());
            auto res = std::regex(i->sub_match);
            if (std::regex_match(new_id_str, res)) {
               logdebug("layout matched!");
               return true;
            }
         }
      }
   }

   return false;
}

void App::try_layout(struct LayoutState & /*state*/,
                     struct LayoutState const &new_layout,
                     std::function<void(LayoutState const &nl)> apply) {
   if (this->policy.layout_is_valid(new_layout)) {
      apply(new_layout);
   }
}

//                  _             _ _            _                 _
//   ___ ___  _ __ | |_ _ __ ___ | | | ___ _ __ | |__   ___   ___ | | _____
//  / __/ _ \| '_ \| __| '__/ _ \| | |/ _ \ '__|| '_ \ / _ \ / _ \| |/ / __|
// | (_| (_) | | | | |_| | | (_) | | |  __/ |   | | | | (_) | (_) |   <\__ \
//  \___\___/|_| |_|\__|_|  \___/|_|_|\___|_|___|_| |_|\___/ \___/|_|\_\___/
//                                         |_____|
void controller_hooks::surface_created(uint32_t surface_id) {
   this->app->surface_created(surface_id);
}

void controller_hooks::surface_removed(uint32_t surface_id) {
   this->app->surface_removed(surface_id);
}

void controller_hooks::surface_visibility(uint32_t /*surface_id*/,
                                          uint32_t /*v*/) {}

void controller_hooks::surface_destination_rectangle(uint32_t /*surface_id*/,
                                                     uint32_t /*x*/,
                                                     uint32_t /*y*/,
                                                     uint32_t /*w*/,
                                                     uint32_t /*h*/) {}

}  // namespace wm