#include "wayfire/plugins/common/input-grab.hpp"
#include "wayfire/plugins/common/util.hpp"
#include "wayfire/plugins/ipc/ipc-activator.hpp"
#include "wayfire/render-manager.hpp"
#include "wayfire/scene-input.hpp"
#include "wayfire/scene.hpp"
#include "wayfire/signal-definitions.hpp"
#include "wayfire/view.hpp"
#include <memory>
#include <wayfire/per-output-plugin.hpp>
#include <wayfire/output.hpp>
#include <wayfire/core.hpp>
#include <wayfire/output-layout.hpp>
#include <wayfire/debug.hpp>
#include "wayfire/plugins/wobbly/wobbly-signal.hpp"

#include <wayfire/plugins/common/workspace-wall.hpp>
#include <wayfire/plugins/common/geometry-animation.hpp>
#include <wayfire/plugins/common/move-drag-interface.hpp>
#include <wayfire/plugins/common/shared-core-data.hpp>
#include <wayfire/plugins/common/key-repeat.hpp>

/* TODO: this file should be included in some header maybe(plugin.hpp) */
#include <linux/input-event-codes.h>

class wayfire_expo : public wf::per_output_plugin_instance_t, public wf::keyboard_interaction_t,
    public wf::pointer_interaction_t, public wf::touch_interaction_t
{
  private:
    wf::point_t convert_workspace_index_to_coords(int index)
    {
        index--; // compensate for indexing from 0
        auto wsize = output->wset()->get_workspace_grid_size();
        int x = index % wsize.width;
        int y = index / wsize.width;

        return wf::point_t{x, y};
    }

    wf::option_wrapper_t<wf::color_t> background_color{"expo/background"};
    wf::option_wrapper_t<wf::animation_description_t> zoom_duration{"expo/duration"};
    wf::option_wrapper_t<int> delimiter_offset{"expo/offset"};
    wf::option_wrapper_t<bool> keyboard_interaction{"expo/keyboard_interaction"};
    wf::option_wrapper_t<double> inactive_brightness{"expo/inactive_brightness"};
    wf::option_wrapper_t<int> transition_length{"expo/transition_length"};
    wf::geometry_animation_t zoom_animation{zoom_duration};

    wf::option_wrapper_t<bool> move_enable_snap_off{"move/enable_snap_off"};
    wf::option_wrapper_t<int> move_snap_off_threshold{"move/snap_off_threshold"};
    wf::option_wrapper_t<bool> move_join_views{"move/join_views"};

    wf::shared_data::ref_ptr_t<wf::move_drag::core_drag_t> drag_helper;

    wf::option_wrapper_t<wf::config::compound_list_t<wf::activatorbinding_t>>
    workspace_bindings{"expo/workspace_bindings"};

    std::vector<wf::activator_callback> keyboard_select_cbs;
    std::vector<wf::option_sptr_t<wf::activatorbinding_t>> keyboard_select_options;

    struct
    {
        bool active = false;
        bool button_pressed = false;
        bool zoom_in = false;
        bool accepting_input = false;
    } state;

    wf::point_t target_ws, initial_ws;
    std::unique_ptr<wf::workspace_wall_t> wall;

    wf::key_repeat_t key_repeat;
    uint32_t key_pressed = 0;

    /* fade animations for each workspace */
    std::vector<std::vector<wf::animation::simple_animation_t>> ws_fade;
    std::unique_ptr<wf::input_grab_t> input_grab;

  public:
    void setup_workspace_bindings_from_config()
    {
        for (const auto& [workspace, binding] : workspace_bindings.value())
        {
            int workspace_index = atoi(workspace.c_str());
            auto wsize = output->wset()->get_workspace_grid_size();
            if ((workspace_index > (wsize.width * wsize.height)) ||
                (workspace_index < 1))
            {
                continue;
            }

            wf::point_t target = convert_workspace_index_to_coords(workspace_index);

            keyboard_select_options.push_back(wf::create_option(binding));
            keyboard_select_cbs.push_back([=] (auto)
            {
                if (!state.active)
                {
                    return false;
                } else
                {
                    if (!zoom_animation.running() || state.zoom_in)
                    {
                        if (target_ws != target)
                        {
                            shade_workspace(target_ws, true);
                            target_ws = target;
                            shade_workspace(target_ws, false);
                        }

                        deactivate();
                    }
                }

                return true;
            });
        }
    }

    wf::plugin_activation_data_t grab_interface = {
        .name = "expo",
        .capabilities = wf::CAPABILITY_MANAGE_COMPOSITOR,
        .cancel = [=] () { finalize_and_exit(); },
    };

    void init() override
    {
        input_grab = std::make_unique<wf::input_grab_t>("expo", output, this, this, this);

        setup_workspace_bindings_from_config();
        wall = std::make_unique<wf::workspace_wall_t>(this->output);

        drag_helper->connect(&on_drag_output_focus);
        drag_helper->connect(&on_drag_snap_off);
        drag_helper->connect(&on_drag_done);
    }

    bool handle_toggle()
    {
        if (!state.active)
        {
            return activate();
        } else if (!zoom_animation.running() || state.zoom_in)
        {
            deactivate();
        }

        return true;
    }

    void handle_pointer_button(const wlr_pointer_button_event& event) override
    {
        if (event.button != BTN_LEFT)
        {
            return;
        }

        auto gc = output->get_cursor_position();
        handle_input_press(gc.x, gc.y, event.state);
    }

    void handle_pointer_motion(wf::pointf_t pointer_position, uint32_t time_ms) override
    {
        handle_input_move({(int)pointer_position.x, (int)pointer_position.y});
    }

    void handle_keyboard_key(wf::seat_t*, wlr_keyboard_key_event event) override
    {
        if (event.state == WLR_KEY_PRESSED)
        {
            if (should_handle_key())
            {
                handle_key_pressed(event.keycode);
            }
        } else
        {
            if (event.keycode == key_pressed)
            {
                key_repeat.disconnect();
                key_pressed = 0;
            }
        }
    }

    void handle_touch_down(uint32_t time_ms, int finger_id, wf::pointf_t position) override
    {
        if (finger_id > 0)
        {
            return;
        }

        auto og = output->get_layout_geometry();
        handle_input_press(position.x - og.x, position.y - og.y, WLR_BUTTON_PRESSED);
    }

    void handle_touch_up(uint32_t time_ms, int finger_id, wf::pointf_t lift_off_position) override
    {
        if (finger_id > 0)
        {
            return;
        }

        handle_input_press(0, 0, WLR_BUTTON_RELEASED);
    }

    void handle_touch_motion(uint32_t time_ms, int finger_id, wf::pointf_t position) override
    {
        if (finger_id > 0) // we handle just the first finger
        {
            return;
        }

        handle_input_move({(int)position.x, (int)position.y});
    }

    bool can_handle_drag()
    {
        return output->is_plugin_active(grab_interface.name);
    }

    wf::signal::connection_t<wf::move_drag::drag_focus_output_signal> on_drag_output_focus =
        [=] (wf::move_drag::drag_focus_output_signal *ev)
    {
        if ((ev->focus_output == output) && can_handle_drag())
        {
            state.button_pressed = true;
            auto [vw, vh] = output->wset()->get_workspace_grid_size();
            drag_helper->set_scale(std::max(vw, vh));
            input_grab->set_wants_raw_input(true);
        }
    };

    wf::signal::connection_t<wf::move_drag::snap_off_signal> on_drag_snap_off =
        [=] (wf::move_drag::snap_off_signal *ev)
    {
        if ((ev->focus_output == output) && can_handle_drag())
        {
            wf::move_drag::adjust_view_on_snap_off(drag_helper->view);
        }
    };

    wf::signal::connection_t<wf::move_drag::drag_done_signal> on_drag_done =
        [=] (wf::move_drag::drag_done_signal *ev)
    {
        if ((ev->focused_output == output) && can_handle_drag() && !drag_helper->is_view_held_in_place())
        {
            bool same_output = ev->main_view->get_output() == output;

            auto offset = wf::origin(output->get_layout_geometry());
            auto local  = input_coordinates_to_output_local_coordinates(
                ev->grab_position + -offset);

            for (auto& v :
                 wf::move_drag::get_target_views(ev->main_view, ev->join_views))
            {
                translate_wobbly(v, local - (ev->grab_position - offset));
            }

            ev->grab_position = local + offset;
            wf::move_drag::adjust_view_on_output(ev);

            if (same_output && (move_started_ws != offscreen_point))
            {
                wf::view_change_workspace_signal data;
                data.view = ev->main_view;
                data.from = move_started_ws;
                data.to   = target_ws;
                output->emit(&data);
            }

            move_started_ws = offscreen_point;
        }

        input_grab->set_wants_raw_input(false);
        this->state.button_pressed = false;
    };

    bool activate()
    {
        if (!output->activate_plugin(&grab_interface))
        {
            return false;
        }

        input_grab->grab_input(wf::scene::layer::OVERLAY);
        state.active = true;
        state.button_pressed  = false;
        state.accepting_input = true;
        start_zoom(true);

        wall->start_output_renderer();
        output->render->add_effect(&pre_frame, wf::OUTPUT_EFFECT_PRE);
        output->render->schedule_redraw();

        auto cws = output->wset()->get_current_workspace();
        initial_ws = target_ws = cws;

        for (size_t i = 0; i < keyboard_select_cbs.size(); i++)
        {
            output->add_activator(keyboard_select_options[i], &keyboard_select_cbs[i]);
        }

        resize_ws_fade();
        on_workspace_grid_changed.disconnect();
        output->wset()->connect(&on_workspace_grid_changed);
        highlight_active_workspace();
        return true;
    }

    void start_zoom(bool zoom_in)
    {
        wall->set_background_color(background_color);
        wall->set_gap_size(this->delimiter_offset);
        if (zoom_in)
        {
            zoom_animation.set_start(wall->get_workspace_rectangle(
                output->wset()->get_current_workspace()));

            /* Make sure workspaces are centered */
            auto wsize = output->wset()->get_workspace_grid_size();
            auto size  = output->get_screen_size();
            const int maxdim = std::max(wsize.width, wsize.height);
            const int gap    = this->delimiter_offset;

            const int fullw = (gap + size.width) * maxdim + gap;
            const int fullh = (gap + size.height) * maxdim + gap;

            auto rectangle = wall->get_wall_rectangle();
            rectangle.x    -= (fullw - rectangle.width) / 2;
            rectangle.y    -= (fullh - rectangle.height) / 2;
            rectangle.width = fullw;
            rectangle.height = fullh;
            zoom_animation.set_end(rectangle);
        } else
        {
            zoom_animation.set_start(zoom_animation);
            zoom_animation.set_end(
                wall->get_workspace_rectangle(target_ws));
        }

        state.zoom_in = zoom_in;
        zoom_animation.start();
        wall->set_viewport(zoom_animation);
    }

    void deactivate()
    {
        state.accepting_input = false;
        start_zoom(false);
        output->wset()->set_workspace(target_ws);
        for (size_t i = 0; i < keyboard_select_cbs.size(); i++)
        {
            output->rem_binding(&keyboard_select_cbs[i]);
        }
    }

    wf::geometry_t get_grid_geometry()
    {
        auto wsize  = output->wset()->get_workspace_grid_size();
        auto full_g = output->get_layout_geometry();

        wf::geometry_t grid;
        grid.x     = grid.y = 0;
        grid.width = full_g.width * wsize.width;
        grid.height = full_g.height * wsize.height;

        return grid;
    }

    /**
     * Handle an input press event.
     *
     * @param x, y The position of the event in output-local coordinates.
     */
    void handle_input_press(int32_t x, int32_t y, uint32_t state)
    {
        const bool zooming = zoom_animation.running();

        if (!this->state.active)
        {
            return;
        }

        if (zooming && !this->state.zoom_in)
        {
            if (state == WLR_BUTTON_PRESSED)
            {
                // Zoom out of expo, change target workspace only
                if (update_target_workspace(x, y))
                {
                    output->wset()->set_workspace(target_ws);

                    // Calculate animation so that it appears as if we smoothly changed destination
                    wf::geometry_t cur_viewport    = zoom_animation;
                    wf::geometry_t target_viewport = wall->get_workspace_rectangle(target_ws);
                    float cur_a = std::clamp(zoom_animation.progress(), 0.01, 0.99);
                    wf::geometry_t start_viewport = wf::interpolate(cur_viewport, target_viewport,
                        1.0 - 1.0 / (1.0 - cur_a));
                    zoom_animation.set_start(start_viewport);
                    zoom_animation.set_end(target_viewport);
                }
            }

            return;
        }

        if ((state == WLR_BUTTON_RELEASED) && !this->drag_helper->view)
        {
            this->state.button_pressed = false;
            deactivate();
        } else if (state == WLR_BUTTON_RELEASED)
        {
            this->state.button_pressed = false;
            this->drag_helper->handle_input_released();
        } else
        {
            this->state.button_pressed = true;
            drag_helper->set_pending_drag(wf::get_core().get_cursor_position());
            update_target_workspace(x, y);
        }
    }

    void start_moving(wayfire_toplevel_view view, wf::point_t local_grab)
    {
        if (!(view->get_allowed_actions() & (wf::VIEW_ALLOW_WS_CHANGE | wf::VIEW_ALLOW_MOVE)))
        {
            return;
        }

        auto ws_coords = input_coordinates_to_output_local_coordinates(local_grab);
        auto bbox = wf::view_bounding_box_up_to(view, "wobbly");

        view->damage();
        // Make sure that the view is in output-local coordinates!
        translate_wobbly(view, local_grab - ws_coords);

        auto [vw, vh] = output->wset()->get_workspace_grid_size();
        wf::move_drag::drag_options_t opts;
        opts.initial_scale   = std::max(vw, vh);
        opts.enable_snap_off = move_enable_snap_off &&
            (view->pending_fullscreen() || view->pending_tiled_edges());
        opts.snap_off_threshold = move_snap_off_threshold;
        opts.join_views = move_join_views;

        drag_helper->start_drag(view, wf::move_drag::find_relative_grab(bbox, ws_coords), opts);
        move_started_ws = target_ws;
        input_grab->set_wants_raw_input(true);
    }

    const wf::point_t offscreen_point = {-10, -10};
    void handle_input_move(wf::point_t to)
    {
        if (!state.button_pressed)
        {
            return;
        }

        auto local = to - wf::origin(output->get_layout_geometry());
        if (drag_helper->view)
        {
            drag_helper->handle_motion(to);
            update_target_workspace(local.x, local.y);
            return;
        }

        if (!drag_helper->should_start_pending_drag(to) || zoom_animation.running())
        {
            /* Ignore small movements */
            return;
        }

        auto local_grab = *drag_helper->tentative_grab_position - wf::origin(output->get_layout_geometry());
        if (auto view = find_view_at_coordinates(local_grab.x, local_grab.y))
        {
            start_moving(view, local_grab);
            drag_helper->handle_motion(to);
        }

        /* As input coordinates are always positive, this will ensure that any
         * subsequent motion events while grabbed are allowed */
        update_target_workspace(local.x, local.y);
    }

    /**
     * Helper to determine if keyboard presses should be handled
     */
    bool should_handle_key()
    {
        return state.accepting_input && keyboard_interaction && !state.button_pressed;
    }

    void handle_key_pressed(uint32_t key)
    {
        wf::point_t old_target = target_ws;

        switch (key)
        {
          case KEY_ENTER:
            deactivate();
            return;

          case KEY_ESC:
            target_ws = initial_ws;
            shade_workspace(old_target, true);
            shade_workspace(target_ws, false);
            deactivate();
            return;

          case KEY_UP:
          case KEY_K:
            target_ws.y -= 1;
            break;

          case KEY_DOWN:
          case KEY_J:
            target_ws.y += 1;
            break;

          case KEY_RIGHT:
          case KEY_L:
            target_ws.x += 1;
            break;

          case KEY_LEFT:
          case KEY_H:
            target_ws.x -= 1;
            break;

          default:
            return;
        }

        /* this part is only reached if one of the arrow keys is pressed */
        if (key != key_pressed)
        {
            // update key repeat callbacks
            // (note: this will disconnect any previous callback)
            key_repeat.set_callback(key, [this] (uint32_t key)
            {
                if (!should_handle_key())
                {
                    // disconnect if key events should no longer be handled
                    key_pressed = 0;
                    return false;
                }

                handle_key_pressed(key);
                return true; // repeat
            });

            key_pressed = key;
        }

        // ensure that the new target is valid (use wrap-around)
        auto dim = output->wset()->get_workspace_grid_size();
        target_ws.x = (target_ws.x + dim.width) % dim.width;
        target_ws.y = (target_ws.y + dim.height) % dim.height;

        shade_workspace(old_target, true);
        shade_workspace(target_ws, false);
    }

    /**
     * shade all but the selected workspace instantly (without animation)
     */
    void highlight_active_workspace()
    {
        auto dim = output->wset()->get_workspace_grid_size();
        for (int x = 0; x < dim.width; x++)
        {
            for (int y = 0; y < dim.height; y++)
            {
                if ((x == target_ws.x) && (y == target_ws.y))
                {
                    wall->set_ws_dim({x, y}, 1.0);
                } else
                {
                    wall->set_ws_dim({x, y}, inactive_brightness);
                }
            }
        }
    }

    /**
     * start an animation for shading the given workspace
     */
    void shade_workspace(const wf::point_t& ws, bool shaded)
    {
        double target = shaded ? inactive_brightness : 1.0;
        auto& anim    = ws_fade.at(ws.x).at(ws.y);

        if (anim.running())
        {
            anim.animate(target);
        } else
        {
            anim.animate(shaded ? 1.0 : inactive_brightness, target);
        }

        output->render->schedule_redraw();
    }

    wf::point_t move_started_ws = offscreen_point;

    /**
     * Find the coordinate of the given point from output-local coordinates
     * to coordinates relative to the first workspace (i.e (0,0))
     */
    void input_coordinates_to_global_coordinates(int & sx, int & sy)
    {
        auto og = output->get_layout_geometry();

        auto wsize = output->wset()->get_workspace_grid_size();
        float max  = std::max(wsize.width, wsize.height);

        float grid_start_x = og.width * (max - wsize.width) / float(max) / 2;
        float grid_start_y = og.height * (max - wsize.height) / float(max) / 2;

        sx -= grid_start_x;
        sy -= grid_start_y;

        sx *= max;
        sy *= max;
    }

    /**
     * Find the coordinate of the given point from output-local coordinates
     * to output-workspace-local coordinates
     */
    wf::point_t input_coordinates_to_output_local_coordinates(wf::point_t ip)
    {
        input_coordinates_to_global_coordinates(ip.x, ip.y);

        auto cws = output->wset()->get_current_workspace();
        auto og  = output->get_relative_geometry();

        /* Translate coordinates into output-local coordinate system,
         * relative to the current workspace */
        return {
            ip.x - cws.x * og.width,
            ip.y - cws.y * og.height,
        };
    }

    wayfire_toplevel_view find_view_at_coordinates(int gx, int gy)
    {
        auto local = input_coordinates_to_output_local_coordinates({gx, gy});
        wf::pointf_t localf = {1.0 * local.x, 1.0 * local.y};
        auto view = wf::find_output_view_at(output, localf);
        if (view && view->is_mapped())
        {
            return view;
        } else
        {
            return nullptr;
        }
    }

    std::optional<wf::point_t> find_workspace_at(int x, int y)
    {
        wlr_box box = {x, y, 1, 1};
        auto og     = output->get_relative_geometry();
        auto in_grid = wf::origin(wf::scale_box(og, wall->get_viewport(), box));

        auto grid = output->wset()->get_workspace_grid_size();
        for (int i = 0; i < grid.width; i++)
        {
            for (int j = 0; j < grid.height; j++)
            {
                if (wall->get_workspace_rectangle({i, j}) & in_grid)
                {
                    return wf::point_t{i, j};
                }
            }
        }

        return std::nullopt;
    }

    bool update_target_workspace(int x, int y)
    {
        auto tmp = find_workspace_at(x, y);
        if (tmp.has_value() && (tmp != target_ws))
        {
            shade_workspace(target_ws, true);
            target_ws = tmp.value();
            shade_workspace(target_ws, false);
            return true;
        }

        return false;
    }

    wf::effect_hook_t pre_frame = [=] ()
    {
        if (zoom_animation.running())
        {
            wall->set_viewport(zoom_animation);
        } else if (!state.zoom_in)
        {
            finalize_and_exit();
            return;
        }

        auto size = this->output->wset()->get_workspace_grid_size();
        for (int x = 0; x < size.width; x++)
        {
            for (int y = 0; y < size.height; y++)
            {
                auto& anim = ws_fade.at(x).at(y);
                if (anim.running())
                {
                    wall->set_ws_dim({x, y}, anim);
                }
            }
        }
    };

    void resize_ws_fade()
    {
        auto size = this->output->wset()->get_workspace_grid_size();
        ws_fade.resize(size.width);
        for (auto& v : ws_fade)
        {
            size_t h = size.height;
            if (v.size() > h)
            {
                v.resize(h);
            } else
            {
                while (v.size() < h)
                {
                    v.emplace_back(transition_length);
                }
            }
        }
    }

    wf::signal::connection_t<wf::workspace_grid_changed_signal> on_workspace_grid_changed = [=] (auto)
    {
        resize_ws_fade();

        // check that the target and initial workspaces are still in the grid
        auto size = this->output->wset()->get_workspace_grid_size();
        initial_ws.x = std::min(initial_ws.x, size.width - 1);
        initial_ws.y = std::min(initial_ws.y, size.height - 1);

        if ((target_ws.x >= size.width) || (target_ws.y >= size.height))
        {
            target_ws.x = std::min(target_ws.x, size.width - 1);
            target_ws.y = std::min(target_ws.y, size.height - 1);
            highlight_active_workspace();
        }
    };

    void finalize_and_exit()
    {
        state.active = false;
        if (drag_helper->view)
        {
            drag_helper->handle_input_released();
        }

        output->deactivate_plugin(&grab_interface);
        input_grab->ungrab_input();
        wall->stop_output_renderer(true);
        output->render->rem_effect(&pre_frame);
        key_repeat.disconnect();
        key_pressed = 0;

        on_workspace_grid_changed.disconnect();
    }

    void fini() override
    {
        if (state.active)
        {
            finalize_and_exit();
        }
    }
};

class wayfire_expo_global : public wf::plugin_interface_t,
    public wf::per_output_tracker_mixin_t<wayfire_expo>
{
    wf::ipc_activator_t toggle_binding{"expo/toggle"};

  public:
    void init() override
    {
        this->init_output_tracking();
        toggle_binding.set_handler(toggle_cb);
    }

    void fini() override
    {
        this->fini_output_tracking();
    }

    wf::ipc_activator_t::handler_t toggle_cb = [=] (wf::output_t *output, wayfire_view)
    {
        return this->output_instance[output]->handle_toggle();
    };
};

DECLARE_WAYFIRE_PLUGIN(wayfire_expo_global);