/*
ENSnano, a 3d graphical application for DNA nanostructures.
    Copyright (C) 2021  Nicolas Levy <nicolaspierrelevy@gmail.com> and Nicolas Schabanel <nicolas.schabanel@ens-lyon.fr>

    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <https://www.gnu.org/licenses/>.
*/
//! This module handles the 2D view

use crate::design::{Design, DesignNotification, DesignNotificationContent, Nucl};
use crate::mediator;
use crate::{DrawArea, Duration, PhySize, WindowEvent};
use iced_wgpu::wgpu;
use iced_winit::winit;
use mediator::{
    ActionMode, AppId, Application, CrossCut, Cut, Mediator, Notification, RawHelixCreation,
    RmStrand, Selection, StrandConstruction, Xover,
};
use std::cell::RefCell;
use std::collections::HashMap;
use std::rc::Rc;
use std::sync::{Arc, Mutex, RwLock};
use wgpu::{Device, Queue};
use winit::dpi::PhysicalPosition;

use crate::utils::camera2d as camera;
use crate::utils::PhantomElement;
mod controller;
mod data;
mod flattypes;
mod view;
use camera::{Camera, Globals};
use controller::Controller;
use data::Data;
use flattypes::*;
use std::time::Instant;
use view::View;

type ViewPtr = Rc<RefCell<View>>;
type DataPtr = Rc<RefCell<Data>>;
type CameraPtr = Rc<RefCell<Camera>>;

/// A Flatscene handles one design at a time
pub struct FlatScene {
    /// Handle the data to send to the GPU
    view: Vec<ViewPtr>,
    /// Handle the data representing the design
    data: Vec<DataPtr>,
    /// Handle the inputs
    controller: Vec<Controller>,
    /// The area on which the flatscene is displayed
    area: DrawArea,
    /// The size of the window on which the flatscene is displayed
    window_size: PhySize,
    /// The identifer of the design being drawn
    selected_design: usize,
    device: Rc<Device>,
    queue: Rc<Queue>,
    mediator: Arc<Mutex<Mediator>>,
    last_update: Instant,
    splited: bool,
}

impl FlatScene {
    pub fn new(
        device: Rc<Device>,
        queue: Rc<Queue>,
        window_size: PhySize,
        area: DrawArea,
        mediator: Arc<Mutex<Mediator>>,
    ) -> Self {
        Self {
            view: Vec::new(),
            data: Vec::new(),
            controller: Vec::new(),
            area,
            window_size,
            selected_design: 0,
            device,
            queue,
            mediator,
            last_update: Instant::now(),
            splited: false,
        }
    }

    /// Add a design to the scene. This creates a new `View`, a new `Data` and a new `Controller`
    fn add_design(&mut self, design: Arc<RwLock<Design>>) {
        let height = if self.splited {
            self.area.size.height as f32 / 2.
        } else {
            self.area.size.height as f32
        };
        let globals_top = Globals {
            resolution: [self.area.size.width as f32, height],
            scroll_offset: [-1., -1.],
            zoom: 80.,
            _padding: 0.,
        };
        let globals_bottom = Globals {
            resolution: [self.area.size.width as f32, height],
            scroll_offset: [-1., -1.],
            zoom: 80.,
            _padding: 0.,
        };
        let camera_top = Rc::new(RefCell::new(Camera::new(globals_top, false)));
        let camera_bottom = Rc::new(RefCell::new(Camera::new(globals_bottom, true)));
        let view = Rc::new(RefCell::new(View::new(
            self.device.clone(),
            self.queue.clone(),
            self.area,
            camera_top.clone(),
            camera_bottom.clone(),
            self.splited,
        )));
        let data = Rc::new(RefCell::new(Data::new(view.clone(), design, 0)));
        data.borrow_mut().perform_update();
        let controller = Controller::new(
            view.clone(),
            data.clone(),
            self.window_size,
            self.area.size,
            camera_top,
            camera_bottom,
            self.mediator.clone(),
            self.splited,
        );
        if self.view.len() > 0 {
            self.view[0] = view;
            self.data[0] = data;
            self.controller[0] = controller;
        } else {
            self.view.push(view);
            self.data.push(data);
            self.controller.push(controller);
        }
    }

    /// Draw the view of the currently selected design
    fn draw_view(&mut self, encoder: &mut wgpu::CommandEncoder, target: &wgpu::TextureView) {
        if let Some(view) = self.view.get(self.selected_design) {
            self.data[self.selected_design]
                .borrow_mut()
                .perform_update();
            view.borrow_mut().draw(encoder, target, self.area);
        }
    }

    /// This function must be called when the drawing area of the flatscene is modified
    fn resize(&mut self, window_size: PhySize, area: DrawArea) {
        self.window_size = window_size;
        self.area = area;
        for view in self.view.iter() {
            view.borrow_mut().resize(area);
        }
        for controller in self.controller.iter_mut() {
            controller.resize(window_size, area.size);
        }
    }

    /// Change the action beign performed by the user
    fn change_action_mode(&mut self, action_mode: ActionMode) {
        if let Some(controller) = self.controller.get_mut(self.selected_design) {
            controller.set_action_mode(action_mode)
        }
    }

    /// Handle an input that happend while the cursor was on the flatscene drawing area
    fn input(&mut self, event: &WindowEvent, cursor_position: PhysicalPosition<f64>) {
        if let Some(controller) = self.controller.get_mut(self.selected_design) {
            let consequence = controller.input(event, cursor_position);
            self.read_consequence(consequence);
        }
    }

    fn read_consequence(&mut self, consequence: controller::Consequence) {
        use controller::Consequence;
        match consequence {
            Consequence::Xover(nucl1, nucl2) => {
                let (prime5_id, prime3_id) =
                    self.data[self.selected_design].borrow().xover(nucl1, nucl2);
                let strand_5prime = self.data[self.selected_design]
                    .borrow()
                    .get_strand(prime5_id)
                    .unwrap();
                let strand_3prime = self.data[self.selected_design]
                    .borrow()
                    .get_strand(prime3_id)
                    .unwrap();
                self.mediator
                    .lock()
                    .unwrap()
                    .update_opperation(Arc::new(Xover {
                        strand_3prime,
                        strand_5prime,
                        prime3_id,
                        prime5_id,
                        undo: false,
                        design_id: self.selected_design,
                    }))
            }
            Consequence::Cut(nucl) => {
                let strand_id = self.data[self.selected_design].borrow().get_strand_id(nucl);
                if let Some(strand_id) = strand_id {
                    println!("cutting");
                    let strand = self.data[self.selected_design]
                        .borrow()
                        .get_strand(strand_id)
                        .unwrap();
                    let nucl = nucl.to_real();
                    self.mediator
                        .lock()
                        .unwrap()
                        .update_opperation(Arc::new(Cut {
                            nucl,
                            strand_id,
                            strand,
                            undo: false,
                            design_id: self.selected_design,
                        }))
                }
            }
            Consequence::FreeEnd(free_end) => self.data[self.selected_design]
                .borrow_mut()
                .set_free_end(free_end),
            Consequence::CutFreeEnd(nucl, free_end) => {
                let strand_id = self.data[self.selected_design].borrow().get_strand_id(nucl);
                if let Some(strand_id) = strand_id {
                    println!("cutting");
                    let strand = self.data[self.selected_design]
                        .borrow()
                        .get_strand(strand_id)
                        .unwrap();
                    let nucl = nucl.to_real();
                    self.mediator
                        .lock()
                        .unwrap()
                        .update_opperation(Arc::new(Cut {
                            nucl,
                            strand_id,
                            strand,
                            undo: false,
                            design_id: self.selected_design,
                        }))
                }
                self.data[self.selected_design]
                    .borrow_mut()
                    .set_free_end(free_end);
            }
            Consequence::CutCross(from, to) => {
                if from.helix != to.helix {
                    // CrossCut with source and target on the same helix are forbidden
                    let op_var = self.data[self.selected_design].borrow().cut_cross(from, to);
                    if let Some((source_id, target_id, target_3prime)) = op_var {
                        let source_strand = self.data[self.selected_design]
                            .borrow()
                            .get_strand(source_id)
                            .unwrap();
                        let target_strand = self.data[self.selected_design]
                            .borrow()
                            .get_strand(target_id)
                            .unwrap();
                        self.mediator
                            .lock()
                            .unwrap()
                            .update_opperation(Arc::new(CrossCut {
                                source_strand,
                                target_strand,
                                source_id,
                                target_id,
                                target_3prime,
                                nucl: to.to_real(),
                                undo: false,
                                design_id: self.selected_design,
                            }))
                    }
                }
            }
            Consequence::NewCandidate(candidate) => {
                let phantom = candidate.map(|n| PhantomElement {
                    position: n.position as i32,
                    helix_id: n.helix.real as u32,
                    forward: n.forward,
                    bound: false,
                    design_id: self.selected_design as u32,
                });
                let mut other = candidate.and_then(|candidate| {
                    self.data[self.selected_design]
                        .borrow()
                        .get_best_suggestion(candidate)
                });
                other = other.or(candidate.and_then(|n| {
                    self.data[self.selected_design]
                        .borrow()
                        .can_make_auto_xover(n)
                }));
                self.view[self.selected_design]
                    .borrow_mut()
                    .set_candidate_suggestion(candidate, other);
                let candidate = if let Some(selection) = phantom.and_then(|p| {
                    self.data[self.selected_design]
                        .borrow()
                        .phantom_to_selection(p)
                }) {
                    Some(selection)
                } else {
                    phantom.map(|p| Selection::Phantom(p))
                };
                self.mediator.lock().unwrap().set_candidate(
                    phantom,
                    candidate.iter().cloned().collect(),
                    AppId::FlatScene,
                )
            }
            Consequence::RmStrand(nucl) => {
                let strand_id = self.data[self.selected_design].borrow().get_strand_id(nucl);
                if let Some(strand_id) = strand_id {
                    println!("removing strand");
                    let strand = self.data[self.selected_design]
                        .borrow()
                        .get_strand(strand_id)
                        .unwrap();
                    self.mediator
                        .lock()
                        .unwrap()
                        .update_opperation(Arc::new(RmStrand {
                            strand,
                            strand_id,
                            undo: false,
                            design_id: self.selected_design,
                        }))
                }
            }
            Consequence::RmHelix(h_id) => {
                let helix = self.data[self.selected_design]
                    .borrow_mut()
                    .can_delete_helix(h_id);
                if let Some((helix, helix_id)) = helix {
                    self.mediator
                        .lock()
                        .unwrap()
                        .update_opperation(Arc::new(RawHelixCreation {
                            helix,
                            helix_id,
                            design_id: self.selected_design,
                            delete: true,
                        }))
                }
            }
            Consequence::Built(builder) => {
                let color = builder.get_strand_color();
                self.mediator
                    .lock()
                    .unwrap()
                    .update_opperation(Arc::new(StrandConstruction {
                        redo: Some(color),
                        color,
                        builder,
                    }));
            }
            Consequence::FlipVisibility(helix, apply_to_other) => self.data[self.selected_design]
                .borrow_mut()
                .flip_visibility(helix, apply_to_other),
            Consequence::FlipGroup(helix) => self.data[self.selected_design]
                .borrow_mut()
                .flip_group(helix),
            Consequence::FollowingSuggestion(nucl, double) => {
                let nucl2 = self.data[self.selected_design]
                    .borrow()
                    .get_best_suggestion(nucl)
                    .or(self.data[self.selected_design]
                        .borrow()
                        .can_make_auto_xover(nucl));
                if let Some(nucl2) = nucl2 {
                    self.attempt_xover(nucl, nucl2);
                    if double {
                        self.attempt_xover(nucl.prime3(), nucl2.prime5());
                    }
                }
            }
            Consequence::Centering(nucl, bottom) => {
                self.view[self.selected_design]
                    .borrow_mut()
                    .center_nucl(nucl, bottom);
                let nucl = nucl.to_real();
                self.mediator
                    .lock()
                    .unwrap()
                    .request_centering(nucl, self.selected_design)
            }
            Consequence::DrawingSelection(c1, c2) => self.view[self.selected_design]
                .borrow_mut()
                .update_rectangle(c1, c2),
            Consequence::ReleasedSelection(_, _) => {
                self.view[self.selected_design]
                    .borrow_mut()
                    .clear_rectangle();
                //self.data[self.selected_design].borrow().get_helices_in_rect(c1, c2, camera);
                self.mediator.lock().unwrap().notify_multiple_selection(
                    self.data[self.selected_design].borrow().selection.clone(),
                    AppId::FlatScene,
                );
            }
            Consequence::PasteRequest(nucl) => {
                self.mediator
                    .lock()
                    .unwrap()
                    .attempt_paste(nucl.map(|n| n.to_real()));
            }
            Consequence::AddClick(click, add) => {
                self.data[self.selected_design]
                    .borrow_mut()
                    .add_selection(click, add);
                self.mediator.lock().unwrap().notify_multiple_selection(
                    self.data[self.selected_design].borrow().selection.clone(),
                    AppId::FlatScene,
                );
            }
            Consequence::SelectionChanged => {
                self.mediator.lock().unwrap().notify_multiple_selection(
                    self.data[self.selected_design].borrow().selection.clone(),
                    AppId::FlatScene,
                );
            }
            Consequence::ClearSelection => {
                self.data[self.selected_design]
                    .borrow_mut()
                    .set_selection(vec![]);
                self.mediator.lock().unwrap().notify_multiple_selection(
                    self.data[self.selected_design].borrow().selection.clone(),
                    AppId::FlatScene,
                );
            }
            Consequence::DoubleClick(click) => {
                let selection = self.data[self.selected_design]
                    .borrow()
                    .double_click_to_selection(click);
                if let Some(selection) = selection {
                    self.mediator
                        .lock()
                        .unwrap()
                        .request_center_selection(selection, AppId::FlatScene)
                }
            }
            _ => (),
        }
    }

    fn check_timers(&mut self) {
        let consequence = self.controller[self.selected_design].check_timers();
        self.read_consequence(consequence);
    }

    fn attempt_xover(&self, nucl1: FlatNucl, nucl2: FlatNucl) {
        let source = nucl1.to_real();
        let target = nucl2.to_real();
        self.mediator
            .lock()
            .unwrap()
            .xover_request(source, target, self.selected_design);
    }

    /// Ask the view if it has been modified since the last drawing
    fn needs_redraw_(&mut self) -> bool {
        self.check_timers();
        if let Some(view) = self.view.get(self.selected_design) {
            self.data[self.selected_design]
                .borrow_mut()
                .perform_update();
            view.borrow().needs_redraw()
        } else {
            false
        }
    }

    fn toggle_split(&mut self) {
        self.splited ^= true;
        for v in self.view.iter_mut() {
            v.borrow_mut().set_splited(self.splited);
        }
        for c in self.controller.iter_mut() {
            c.set_splited(self.splited);
        }
    }

    fn split_and_center(&mut self, n1: FlatNucl, n2: FlatNucl) {
        self.splited = true;
        for v in self.view.iter_mut() {
            v.borrow_mut().set_splited(self.splited);
        }
        for c in self.controller.iter_mut() {
            c.set_splited(self.splited);
        }
        self.view[self.selected_design]
            .borrow_mut()
            .center_split(n1, n2);
    }
}

impl Application for FlatScene {
    fn on_notify(&mut self, notification: Notification) {
        match notification {
            Notification::NewDesign(design) => self.add_design(design),
            Notification::NewActionMode(am) => self.change_action_mode(am),
            Notification::DesignNotification(DesignNotification { design_id, content }) => {
                self.data[design_id].borrow_mut().notify_update();
                if let DesignNotificationContent::ViewNeedReset = content {
                    self.data[design_id].borrow_mut().notify_reset();
                }
            }
            Notification::FitRequest => self.controller[self.selected_design].fit(),
            Notification::Selection3D(selection, app_id) => match app_id {
                AppId::FlatScene => (),
                _ => {
                    self.needs_redraw(Duration::from_nanos(1));
                    self.data[self.selected_design]
                        .borrow_mut()
                        .set_selection(selection);
                    self.data[self.selected_design].borrow_mut().notify_update();
                    let pivots = self.data[self.selected_design]
                        .borrow_mut()
                        .get_pivot_of_selected_helices(
                            &self.controller[self.selected_design].get_camera(0f64),
                        );
                    if let Some((translation_pivots, rotation_pivots)) = pivots {
                        self.controller[self.selected_design]
                            .select_pivots(translation_pivots, rotation_pivots);
                    }
                }
            },
            Notification::Save(d_id) => self.data[d_id].borrow_mut().save_isometry(),
            Notification::ToggleText(b) => {
                self.view[self.selected_design].borrow_mut().set_show_sec(b)
            }
            Notification::ShowTorsion(b) => {
                for v in self.view.iter() {
                    v.borrow_mut().set_show_torsion(b);
                }
            }
            Notification::Pasting(b) => {
                for c in self.controller.iter_mut() {
                    c.set_pasting(b)
                }
            }
            Notification::CameraTarget(_) => (),
            Notification::NewSelectionMode(selection_mode) => {
                for data in self.data.iter() {
                    data.borrow_mut().change_selection_mode(selection_mode);
                }
            }
            Notification::AppNotification(_) => (),
            Notification::NewSensitivity(_) => (),
            Notification::ClearDesigns => (),
            Notification::NewCandidate(candidates, app_id) => match app_id {
                AppId::FlatScene => (),
                _ => self.data[self.selected_design]
                    .borrow_mut()
                    .set_candidate(candidates),
            },
            Notification::Centering(_, _) => (),
            Notification::CenterSelection(selection, app_id) => {
                if app_id != AppId::FlatScene {
                    self.data[self.selected_design]
                        .borrow_mut()
                        .set_selection(vec![selection]);
                    let xover = self.view[self.selected_design]
                        .borrow_mut()
                        .center_selection();
                    if let Some((n1, n2)) = xover {
                        self.split_and_center(n1, n2);
                    }
                }
            }
            Notification::CameraRotation(_, _, _) => (),
            Notification::ModifersChanged(modifiers) => {
                for c in self.controller.iter_mut() {
                    c.update_modifiers(modifiers.clone())
                }
            }
            Notification::Split2d => self.toggle_split(),
            Notification::Redim2dHelices(b) => self.data[self.selected_design]
                .borrow_mut()
                .redim_helices(b),
            Notification::ToggleWidget(_) => (),
            Notification::RenderingMode(_) => (),
            Notification::Background3D(_) => (),
        }
    }

    fn on_resize(&mut self, window_size: PhySize, area: DrawArea) {
        self.resize(window_size, area)
    }

    fn on_event(&mut self, event: &WindowEvent, cursor_position: PhysicalPosition<f64>) {
        self.input(event, cursor_position)
    }

    fn on_redraw_request(
        &mut self,
        encoder: &mut wgpu::CommandEncoder,
        target: &wgpu::TextureView,
        _dt: Duration,
    ) {
        //println!("draw flatscene");
        self.draw_view(encoder, target)
    }

    fn needs_redraw(&mut self, _: Duration) -> bool {
        let now = Instant::now();
        if (now - self.last_update).as_millis() < 25 {
            false
        } else {
            self.last_update = now;
            self.needs_redraw_()
        }
    }
}