use std::collections::HashSet;

use abstutil::prettyprint_usize;
use geom::{ArrowCap, Circle, Distance, Duration, PolyLine, Pt2D, Time};
use map_gui::tools::{ChooseSomething, ColorLegend, Minimap, MinimapControls};
use map_model::BuildingID;
use widgetry::{
    Choice, Color, Drawable, EventCtx, GeomBatch, GfxCtx, HorizontalAlignment, Image, Key, Line,
    Outcome, Panel, State, Text, TextExt, UpdateType, VerticalAlignment, Widget,
};

use crate::after_level::{RecordPath, Results, Strategize};
use crate::animation::{Animator, Effect, SnowEffect};
use crate::buildings::{BldgState, Buildings};
use crate::levels::Level;
use crate::meters::{custom_bar, make_bar};
use crate::player::Player;
use crate::vehicles::Vehicle;
use crate::{App, Transition};

const MAX_BOOST: Duration = Duration::const_seconds(5.0);
const ACQUIRE_BOOST_RATE: f64 = 0.5;
const BOOST_SPEED_MULTIPLIER: f64 = 2.0;
const HANGRY_SPEED_MULTIPLIER: f64 = 0.3;

pub struct Game {
    status_panel: Panel,
    time_panel: Panel,
    pause_panel: Panel,
    minimap: Minimap<App, MinimapController>,

    animator: Animator,
    snow: SnowEffect,

    state: GameState,
    player: Player,
}

impl Game {
    pub fn new_state(
        ctx: &mut EventCtx,
        app: &mut App,
        level: Level,
        vehicle: Vehicle,
        upzones: HashSet<BuildingID>,
    ) -> Box<dyn State<App>> {
        app.session.current_vehicle = vehicle.name.clone();
        app.time = Time::START_OF_DAY;
        app.session.music.specify_volume(crate::music::IN_GAME);

        let status_panel = Panel::new_builder(Widget::col(vec![
            "15-min Santa".text_widget(ctx).centered_vert(),
            Widget::row(vec![
                // TODO The blur is messed up
                Image::from_path("system/assets/tools/map.svg")
                    .into_widget(ctx)
                    .centered_vert(),
                Line(&level.title).into_widget(ctx),
            ])
            .padding(10)
            .bg(Color::hex("#003046")),
            "Complete Deliveries".text_widget(ctx).named("score label"),
            GeomBatch::new().into_widget(ctx).named("score"),
            "Blood sugar".text_widget(ctx).named("energy label"),
            GeomBatch::new().into_widget(ctx).named("energy"),
        ]))
        .aligned(HorizontalAlignment::RightInset, VerticalAlignment::TopInset)
        .build(ctx);

        let time_panel = Panel::new_builder(Widget::row(vec![
            GeomBatch::new().into_widget(ctx).named("time circle"),
            "Time".text_widget(ctx).centered_vert().named("time label"),
        ]))
        .aligned(HorizontalAlignment::LeftInset, VerticalAlignment::TopInset)
        .build(ctx);

        let pause_panel = Panel::new_builder(
            ctx.style()
                .btn_plain
                .icon_text("system/assets/speed/pause.svg", "Pause")
                .hotkey(Key::Escape)
                .build_widget(ctx, "pause")
                .container(),
        )
        // TODO Very brittle layout to wind up to the right of the volume panel...
        .aligned(
            HorizontalAlignment::Percent(0.05),
            VerticalAlignment::BottomInset,
        )
        .build(ctx);

        let start = app
            .map
            .find_i_by_osm_id(level.start)
            .unwrap_or_else(|_| panic!("can't find {}", level.start));
        let player = Player::new(ctx, app, start);

        let bldgs = Buildings::new(ctx, app, upzones);
        let state = GameState::new(ctx, level, vehicle, bldgs);

        let mut game = Game {
            status_panel,
            time_panel,
            pause_panel,
            minimap: Minimap::new(ctx, app, MinimapController),

            animator: Animator::new(ctx),
            snow: SnowEffect::new(ctx),

            state,
            player,
        };
        game.update_time_panel(ctx, app);
        game.update_status_panel(ctx, app);
        game.minimap
            .set_zoom(ctx, app, game.state.level.minimap_zoom);
        game.update_boost_panel(ctx, app);
        Box::new(game)
    }

    fn update_time_panel(&mut self, ctx: &mut EventCtx, app: &App) {
        let pct = (app.time - Time::START_OF_DAY) / self.state.level.time_limit;

        let text_color = if pct < 0.75 { Color::WHITE } else { Color::RED };
        let label = Line(format!(
            "{}",
            self.state.level.time_limit - (app.time - Time::START_OF_DAY)
        ))
        .small_heading()
        .fg(text_color)
        .into_widget(ctx)
        .centered_vert();
        self.time_panel.replace(ctx, "time label", label);

        // TODO I couldn't quite work out how to get the partial outline from Figma working
        let center = Pt2D::new(0.0, 0.0);
        let outer = Distance::meters(30.0);
        let draw = GeomBatch::from(vec![
            (Color::WHITE, Circle::new(center, outer).to_polygon()),
            (
                Color::hex("#5D92C2"),
                Circle::new(center, outer).to_partial_polygon(pct),
            ),
        ])
        .autocrop()
        .into_widget(ctx);
        self.time_panel.replace(ctx, "time circle", draw);
    }

    fn update_status_panel(&mut self, ctx: &mut EventCtx, app: &App) {
        let score_bar = make_bar(
            ctx,
            app.session.colors.score,
            self.state.score,
            if self.state.met_goal() {
                self.state.bldgs.total_housing_units
            } else {
                self.state.level.goal
            },
        );
        self.status_panel.replace(ctx, "score", score_bar);

        let energy_bar = make_bar(
            ctx,
            app.session.colors.energy,
            self.state.energy,
            self.state.vehicle.max_energy,
        );
        self.status_panel.replace(ctx, "energy", energy_bar);
    }

    fn update_boost_panel(&mut self, ctx: &mut EventCtx, app: &App) {
        let boost_bar = custom_bar(
            ctx,
            app.session.colors.boost,
            self.state.boost / MAX_BOOST,
            if self.state.boost == Duration::ZERO {
                Text::from("Find a bike or bus lane")
            } else {
                Text::from("Hold space to boost")
            },
        );
        self.minimap.mut_panel().replace(ctx, "boost", boost_bar);
    }

    fn update(&mut self, ctx: &mut EventCtx, app: &mut App, dt: Duration) {
        app.time += dt;

        let orig_boost = self.state.boost;
        let (orig_score, orig_energy) = (self.state.score, self.state.energy);
        let orig_pos = self.player.get_pos();

        self.update_time_panel(ctx, app);

        let base_speed = if self.state.has_energy() {
            self.state.vehicle.speed
        } else {
            HANGRY_SPEED_MULTIPLIER * self.state.vehicle.speed
        };
        let speed = if ctx.is_key_down(Key::Space) && self.state.boost > Duration::ZERO {
            if !self.player.on_good_road(app) {
                self.state.boost -= dt;
                self.state.boost = self.state.boost.max(Duration::ZERO);
            }
            base_speed * BOOST_SPEED_MULTIPLIER
        } else {
            base_speed
        };

        let met_goal = self.state.met_goal();
        for b in self.player.update_with_speed(ctx, app, speed) {
            match self.state.bldgs.buildings[&b] {
                BldgState::Undelivered(_) => {
                    if let Some(increase) = self.state.present_dropped(ctx, app, b) {
                        let path_speed = Duration::seconds(0.2);
                        self.animator.add(
                            app.time,
                            path_speed,
                            Effect::FollowPath {
                                color: app.session.colors.score,
                                width: map_model::NORMAL_LANE_THICKNESS,
                                pl: app.map.get_b(b).driveway_geom.reversed(),
                            },
                        );
                        self.animator.add(
                            app.time + path_speed,
                            Duration::seconds(0.5),
                            Effect::Scale {
                                lerp_scale: (1.0, 4.0),
                                center: app.map.get_b(b).label_center,
                                orig: Text::from(format!("+{}", prettyprint_usize(increase)))
                                    .bg(app.session.colors.score)
                                    .render_autocropped(ctx)
                                    .scale(0.1),
                            },
                        );
                    }
                }
                BldgState::Store => {
                    let refill = self.state.vehicle.max_energy - self.state.energy;
                    if refill > 0 {
                        self.state.energy += refill;
                        self.state.warned_low_energy = false;
                        let path_speed = Duration::seconds(0.2);
                        self.animator.add(
                            app.time,
                            path_speed,
                            Effect::FollowPath {
                                color: app.session.colors.energy,
                                width: map_model::NORMAL_LANE_THICKNESS,
                                pl: app.map.get_b(b).driveway_geom.clone(),
                            },
                        );
                        self.animator.add(
                            app.time + path_speed,
                            Duration::seconds(0.5),
                            Effect::Scale {
                                lerp_scale: (1.0, 4.0),
                                center: app.map.get_b(b).label_center,
                                orig: Text::from(format!("Refilled {}", prettyprint_usize(refill)))
                                    .bg(app.session.colors.energy)
                                    .render_autocropped(ctx)
                                    .scale(0.1),
                            },
                        );
                    }
                }
                BldgState::Done | BldgState::Ignore => {}
            }
        }
        if !met_goal && self.state.met_goal() {
            // TODO What should we say here? Should we add some kind of animation to call this
            // out?
            let label = "Goal met! Keep going".text_widget(ctx);
            self.status_panel.replace(ctx, "score label", label);
        }

        if self.player.on_good_road(app) && !ctx.is_key_down(Key::Space) {
            self.state.boost += dt * ACQUIRE_BOOST_RATE;
            self.state.boost = self.state.boost.min(MAX_BOOST);
        }

        self.animator.event(ctx, app.time);
        self.snow.event(ctx, app.time);
        if self.state.has_energy() {
            if self.state.energyless_arrow.is_some() {
                self.state.energyless_arrow = None;
                let label = "Blood sugar".text_widget(ctx);
                self.status_panel.replace(ctx, "energy label", label);
            }
        } else {
            if self.state.energyless_arrow.is_none() {
                self.state.energyless_arrow = Some(EnergylessArrow::new(
                    ctx,
                    app.time,
                    self.state.bldgs.all_stores(),
                ));
                let label = Text::from(
                    Line("SANTA'S HANGRY - grab some cookies from a store!").fg(Color::RED),
                )
                .into_widget(ctx);
                self.status_panel.replace(ctx, "energy label", label);
            }
            self.state
                .energyless_arrow
                .as_mut()
                .unwrap()
                .update(ctx, app, self.player.get_pos());
        }

        if self.state.boost != orig_boost {
            self.update_boost_panel(ctx, app);
        }
        if self.state.score != orig_score || self.state.energy != orig_energy {
            self.update_status_panel(ctx, app);
        }
        if self.player.get_pos() == orig_pos {
            self.state.idle_time += dt;
        }

        self.state.record_path.add_pt(self.player.get_pos());
    }
}

impl State<App> for Game {
    fn event(&mut self, ctx: &mut EventCtx, app: &mut App) -> Transition {
        if self.state.game_over {
            if let Some(dt) = ctx.input.nonblocking_is_update_event() {
                app.time += dt;
                self.animator.event(ctx, app.time);
                self.snow.event(ctx, app.time);
                self.player.override_pos(self.player.get_pos().project_away(
                    dt * self.state.vehicle.speed,
                    self.player.get_angle().opposite(),
                ));
            }

            if self.animator.is_done() {
                return Transition::Multi(vec![
                    Transition::Replace(Strategize::new_state(
                        ctx,
                        app,
                        self.state.score,
                        &self.state.level,
                        &self.state.bldgs,
                        std::mem::replace(&mut self.state.record_path, RecordPath::new()),
                    )),
                    Transition::Push(Results::new_state(
                        ctx,
                        app,
                        self.state.score,
                        &self.state.level,
                    )),
                ]);
            }

            ctx.request_update(UpdateType::Game);
            return Transition::Keep;
        }

        // Most things depend on time passing and don't care about other events
        if let Some(dt) = ctx.input.nonblocking_is_update_event() {
            self.update(ctx, app, dt);

            if app.time - Time::START_OF_DAY >= self.state.level.time_limit {
                self.state.game_over = true;
                self.animator.add(
                    app.time,
                    Duration::seconds(3.0),
                    Effect::Scale {
                        lerp_scale: (1.0, 4.0),
                        center: self.player.get_pos(),
                        orig: Text::from("Time's up!")
                            .bg(Color::RED)
                            .render_autocropped(ctx)
                            .scale(0.1),
                    },
                );
            }

            if !self.state.warned_low_time
                && self.state.level.time_limit - (app.time - Time::START_OF_DAY)
                    <= Duration::seconds(20.0)
            {
                self.state.warned_low_time = true;
                self.animator.add(
                    app.time,
                    Duration::seconds(2.0),
                    Effect::Flash {
                        alpha_scale: (0.1, 0.5),
                        cycles: 2,
                        orig: GeomBatch::from(vec![(
                            Color::RED,
                            app.map.get_boundary_polygon().clone(),
                        )]),
                    },
                );
                self.animator.add_screenspace(
                    app.time,
                    Duration::seconds(2.0),
                    Effect::Scale {
                        lerp_scale: (1.0, 4.0),
                        center: {
                            let pt = ctx.canvas.center_to_screen_pt();
                            Pt2D::new(pt.x, pt.y / 2.0)
                        },
                        orig: Text::from("Almost out of time!")
                            .bg(Color::RED)
                            .render_autocropped(ctx),
                    },
                );
            }

            if !self.state.warned_low_energy && self.state.energy < 30 {
                self.state.warned_low_energy = true;
                self.animator.add(
                    app.time,
                    Duration::seconds(2.0),
                    Effect::Flash {
                        alpha_scale: (0.1, 0.5),
                        cycles: 2,
                        orig: GeomBatch::from(vec![(
                            Color::RED,
                            app.map.get_boundary_polygon().clone(),
                        )]),
                    },
                );
                self.animator.add_screenspace(
                    app.time,
                    Duration::seconds(2.0),
                    Effect::Scale {
                        lerp_scale: (1.0, 4.0),
                        center: {
                            let pt = ctx.canvas.center_to_screen_pt();
                            Pt2D::new(pt.x, pt.y / 2.0)
                        },
                        orig: Text::from("Low on blood sugar, refill soon!")
                            .bg(Color::RED)
                            .render_autocropped(ctx),
                    },
                );
            }

            ctx.request_update(UpdateType::Game);
            return Transition::Keep;
        }

        if let Some(t) = self.minimap.event(ctx, app) {
            return t;
        }

        if let Outcome::Clicked(x) = self.pause_panel.event(ctx) {
            match x.as_ref() {
                "pause" => {
                    app.session.music.specify_volume(crate::music::OUT_OF_GAME);
                    return Transition::Push(ChooseSomething::new_state(
                        ctx,
                        "Game Paused",
                        vec![
                            Choice::string("Resume").key(Key::Escape),
                            Choice::string("Quit"),
                        ],
                        Box::new(|resp, _, app| match resp.as_ref() {
                            "Resume" => {
                                app.session.music.specify_volume(crate::music::IN_GAME);
                                Transition::Pop
                            }
                            "Quit" => Transition::Multi(vec![Transition::Pop, Transition::Pop]),
                            _ => unreachable!(),
                        }),
                    ));
                }
                _ => unreachable!(),
            }
        }

        if let Some((_, dy)) = ctx.input.get_mouse_scroll() {
            ctx.canvas.cam_zoom = 1.1_f64
                .powf(ctx.canvas.cam_zoom.log(1.1) + dy)
                .max(app.opts.min_zoom_for_detail)
                .min(50.0);
            ctx.canvas.center_on_map_pt(self.player.get_pos());
        }

        app.session.update_music(ctx);

        ctx.request_update(UpdateType::Game);
        Transition::Keep
    }

    fn draw(&self, g: &mut GfxCtx, app: &App) {
        self.status_panel.draw(g);
        self.time_panel.draw(g);
        self.pause_panel.draw(g);
        app.session.music.draw(g);

        let santa_tracker = g.upload(GeomBatch::from(vec![(
            Color::RED,
            Circle::new(self.player.get_pos(), Distance::meters(20.0)).to_polygon(),
        )]));
        self.minimap.draw_with_extra_layers(
            g,
            app,
            vec![
                &self.state.bldgs.draw_all,
                &self.state.draw_done_houses,
                &santa_tracker,
            ],
        );

        g.redraw(&self.state.bldgs.draw_all);
        g.redraw(&self.state.draw_done_houses);

        if true {
            self.state
                .vehicle
                .animate(g.prerender, app.time - self.state.idle_time)
                .centered_on(self.player.get_pos())
                .rotate_around_batch_center(self.player.get_angle())
                .draw(g);
        } else {
            // Debug
            g.draw_polygon(
                Color::RED,
                Circle::new(self.player.get_pos(), Distance::meters(2.0)).to_polygon(),
            );
        }

        self.snow.draw(g);
        self.animator.draw(g);
        if let Some(ref arrow) = self.state.energyless_arrow {
            g.redraw(&arrow.draw);
        }
    }

    fn on_destroy(&mut self, _: &mut EventCtx, app: &mut App) {
        app.session.music.specify_volume(crate::music::OUT_OF_GAME);
    }
}

struct GameState {
    level: Level,
    vehicle: Vehicle,
    bldgs: Buildings,

    // Number of deliveries
    score: usize,
    energy: usize,
    boost: Duration,

    draw_done_houses: Drawable,
    energyless_arrow: Option<EnergylessArrow>,

    // For animation
    idle_time: Duration,

    game_over: bool,
    warned_low_time: bool,
    warned_low_energy: bool,

    record_path: RecordPath,
}

impl GameState {
    fn new(ctx: &mut EventCtx, level: Level, vehicle: Vehicle, bldgs: Buildings) -> GameState {
        let energy = vehicle.max_energy;
        GameState {
            level,
            vehicle,
            bldgs,

            score: 0,
            energy,
            boost: Duration::ZERO,

            draw_done_houses: Drawable::empty(ctx),
            energyless_arrow: None,

            idle_time: Duration::ZERO,

            game_over: false,
            warned_low_time: false,
            warned_low_energy: false,

            record_path: RecordPath::new(),
        }
    }

    // If something changed, return the update to the score
    fn present_dropped(&mut self, ctx: &mut EventCtx, app: &App, id: BuildingID) -> Option<usize> {
        if !self.has_energy() {
            return None;
        }
        if let BldgState::Undelivered(num_housing_units) = self.bldgs.buildings[&id] {
            self.score += num_housing_units;
            self.bldgs.buildings.insert(id, BldgState::Done);
            self.energy -= 1;
            self.draw_done_houses = self.bldgs.draw_done_houses(ctx, app);
            return Some(num_housing_units);
        }
        None
    }

    fn has_energy(&self) -> bool {
        self.energy > 0
    }

    fn met_goal(&self) -> bool {
        self.score >= self.level.goal
    }
}

struct EnergylessArrow {
    draw: Drawable,
    started: Time,
    last_update: Time,
    all_stores: Vec<BuildingID>,
}

impl EnergylessArrow {
    fn new(ctx: &EventCtx, started: Time, all_stores: Vec<BuildingID>) -> EnergylessArrow {
        EnergylessArrow {
            draw: Drawable::empty(ctx),
            started,
            last_update: Time::START_OF_DAY,
            all_stores,
        }
    }

    fn update(&mut self, ctx: &mut EventCtx, app: &App, sleigh: Pt2D) {
        if self.last_update == app.time {
            return;
        }
        self.last_update = app.time;
        // Find the closest store as the crow -- or Santa -- flies. Point to the end of the
        // driveway, since sometimes it's hard to quickly spot which road a building is connected
        // to.
        // TODO Or pathfind and show them that?
        let store = app.map.get_b(
            *self
                .all_stores
                .iter()
                .min_by_key(|b| app.map.get_b(**b).driveway_geom.last_pt().fast_dist(sleigh))
                .unwrap(),
        );

        // Vibrate in size slightly
        let period = Duration::seconds(0.5);
        let pct = ((app.time - self.started) % period) / period;
        // -1 to 1
        let shift = (pct * std::f64::consts::PI).sin();
        let thickness = Distance::meters(5.0 + shift);

        let goto = store.driveway_geom.last_pt();
        let angle = sleigh.angle_to(goto);
        // TODO When we're too close, we get an awkward arrowcap; the intention was for it to
        // disappear...
        if let Some(arrow) = PolyLine::new(vec![
            sleigh.project_away(Distance::meters(20.0), angle),
            goto,
        ])
        .and_then(|pl| {
            pl.maybe_exact_slice(Distance::ZERO, Distance::meters(20.0).min(pl.length()))
        })
        .ok()
        .and_then(|slice| slice.maybe_make_arrow(thickness, ArrowCap::Triangle))
        {
            self.draw = ctx.upload(GeomBatch::from(vec![(Color::RED.alpha(0.8), arrow)]));
        }
    }
}

struct MinimapController;

impl MinimapControls<App> for MinimapController {
    fn has_zorder(&self, _: &App) -> bool {
        false
    }

    fn make_legend(&self, ctx: &mut EventCtx, app: &App) -> Widget {
        Widget::col(vec![
            Widget::row(vec![
                ColorLegend::row(ctx, app.session.colors.house, "house"),
                ColorLegend::row(ctx, app.session.colors.apartment, "apartment"),
                ColorLegend::row(ctx, app.session.colors.store, "store"),
            ])
            .evenly_spaced(),
            // TODO If the player messes with the minimap, the panel gets recreated, and we'll
            // clobber the boost bar. No easy way to plumb everything we need for
            // update_boost_panel here. It's not super common to actually mess with those controls,
            // so fine with this for now.
            Widget::row(vec![
                "Boost".text_widget(ctx),
                GeomBatch::new()
                    .into_widget(ctx)
                    .named("boost")
                    .align_right(),
            ]),
        ])
    }
}