use std::collections::BTreeSet;

use maplit::btreeset;

use geom::{Distance, Duration};
use map_model::IntersectionID;
use sim::Scenario;
use widgetry::{
    Btn, Color, Drawable, EventCtx, GfxCtx, HorizontalAlignment, Key, Line, Outcome, Panel,
    RewriteColor, Spinner, State, Text, TextExt, VerticalAlignment, Widget,
};

use crate::app::App;
use crate::common::CommonState;
use crate::edit::traffic_signals::fade_irrelevant;
use crate::game::Transition;
use crate::helpers::ID;

pub struct ShowAbsolute {
    members: BTreeSet<IntersectionID>,
    panel: Panel,
    labels: Drawable,
}

impl ShowAbsolute {
    pub fn new(
        ctx: &mut EventCtx,
        app: &App,
        members: BTreeSet<IntersectionID>,
    ) -> Box<dyn State<App>> {
        let mut batch = fade_irrelevant(app, &members);
        for i in &members {
            batch.append(
                Text::from(Line(
                    app.primary
                        .map
                        .get_traffic_signal(*i)
                        .offset
                        .to_string(&app.opts.units),
                ))
                .bg(Color::PURPLE)
                .render_to_batch(ctx.prerender)
                .color(RewriteColor::ChangeAlpha(0.8))
                .scale(0.3)
                .centered_on(app.primary.map.get_i(*i).polygon.center()),
            );
        }

        Box::new(ShowAbsolute {
            panel: Panel::new(Widget::col(vec![
                Widget::row(vec![
                    Line(format!("Tuning offset for {} signals", members.len()))
                        .small_heading()
                        .draw(ctx),
                    Btn::close(ctx),
                ]),
                "Select an intersection as the base".draw_text(ctx),
            ]))
            .aligned(HorizontalAlignment::Center, VerticalAlignment::Top)
            .build(ctx),
            members,
            labels: ctx.upload(batch),
        })
    }
}

impl State<App> for ShowAbsolute {
    fn event(&mut self, ctx: &mut EventCtx, app: &mut App) -> Transition {
        ctx.canvas_movement();
        if ctx.redo_mouseover() {
            app.primary.current_selection = app.mouseover_unzoomed_roads_and_intersections(ctx);
        }
        if let Some(ID::Intersection(i)) = app.primary.current_selection {
            if self.members.contains(&i) {
                if app.per_obj.left_click(ctx, "select base intersection") {
                    return Transition::Replace(ShowRelative::new(
                        ctx,
                        app,
                        i,
                        self.members.clone(),
                    ));
                }
            } else {
                app.primary.current_selection = None;
            }
        } else {
            app.primary.current_selection = None;
        }

        match self.panel.event(ctx) {
            Outcome::Clicked(x) => match x.as_ref() {
                "close" => {
                    // TODO Bit confusing UX, because all the offset changes won't show up in the
                    // undo stack. Could maybe do ReplaceWithData.
                    return Transition::Pop;
                }
                _ => unreachable!(),
            },
            _ => {}
        }

        Transition::Keep
    }

    fn draw(&self, g: &mut GfxCtx, app: &App) {
        self.panel.draw(g);
        CommonState::draw_osd(g, app);

        g.redraw(&self.labels);
    }
}

struct ShowRelative {
    base: IntersectionID,
    members: BTreeSet<IntersectionID>,
    panel: Panel,
    labels: Drawable,
}

impl ShowRelative {
    pub fn new(
        ctx: &mut EventCtx,
        app: &App,
        base: IntersectionID,
        members: BTreeSet<IntersectionID>,
    ) -> Box<dyn State<App>> {
        let base_offset = app.primary.map.get_traffic_signal(base).offset;
        let mut batch = fade_irrelevant(app, &members);
        for i in &members {
            if *i == base {
                batch.push(
                    Color::BLUE.alpha(0.8),
                    app.primary.map.get_i(*i).polygon.clone(),
                );
            } else {
                let offset = app.primary.map.get_traffic_signal(*i).offset - base_offset;
                batch.append(
                    Text::from(Line(offset.to_string(&app.opts.units)))
                        .bg(Color::PURPLE)
                        .render_to_batch(ctx.prerender)
                        .color(RewriteColor::ChangeAlpha(0.8))
                        .scale(0.3)
                        .centered_on(app.primary.map.get_i(*i).polygon.center()),
                );
            }
        }

        Box::new(ShowRelative {
            panel: Panel::new(Widget::col(vec![
                Widget::row(vec![
                    Line(format!("Tuning offset for {} signals", members.len()))
                        .small_heading()
                        .draw(ctx),
                    Btn::close(ctx),
                ]),
                "Select a second intersection to tune offset between the two".draw_text(ctx),
            ]))
            .aligned(HorizontalAlignment::Center, VerticalAlignment::Top)
            .build(ctx),
            base,
            members,
            labels: ctx.upload(batch),
        })
    }
}

impl State<App> for ShowRelative {
    fn event(&mut self, ctx: &mut EventCtx, app: &mut App) -> Transition {
        ctx.canvas_movement();
        if ctx.redo_mouseover() {
            app.primary.current_selection = app.mouseover_unzoomed_roads_and_intersections(ctx);
        }
        if let Some(ID::Intersection(i)) = app.primary.current_selection {
            if self.members.contains(&i) && i != self.base {
                if app.per_obj.left_click(ctx, "select second intersection") {
                    return Transition::Push(TuneRelative::new(
                        ctx,
                        app,
                        self.base,
                        i,
                        self.members.clone(),
                    ));
                }
            } else {
                app.primary.current_selection = None;
            }
        } else {
            app.primary.current_selection = None;
        }

        match self.panel.event(ctx) {
            Outcome::Clicked(x) => match x.as_ref() {
                "close" => {
                    return Transition::Replace(ShowAbsolute::new(ctx, app, self.members.clone()));
                }
                _ => unreachable!(),
            },
            _ => {}
        }

        Transition::Keep
    }

    fn draw(&self, g: &mut GfxCtx, app: &App) {
        self.panel.draw(g);
        CommonState::draw_osd(g, app);

        g.redraw(&self.labels);
    }
}

struct TuneRelative {
    i1: IntersectionID,
    i2: IntersectionID,
    members: BTreeSet<IntersectionID>,
    panel: Panel,
    labels: Drawable,
}

impl TuneRelative {
    pub fn new(
        ctx: &mut EventCtx,
        app: &App,
        i1: IntersectionID,
        i2: IntersectionID,
        members: BTreeSet<IntersectionID>,
    ) -> Box<dyn State<App>> {
        let mut batch = fade_irrelevant(app, &btreeset! {i1, i2});
        let map = &app.primary.map;
        // TODO Colors aren't clear. Show directionality.
        batch.push(Color::BLUE.alpha(0.8), map.get_i(i1).polygon.clone());
        batch.push(Color::RED.alpha(0.8), map.get_i(i2).polygon.clone());
        let path = map.simple_path_btwn(i1, i2).unwrap_or_else(Vec::new);
        let mut dist_btwn = Distance::ZERO;
        let mut car_dt = Duration::ZERO;
        for r in path {
            let r = map.get_r(r);
            // TODO Glue polylines together and do dashed_lines
            batch.push(app.cs.route, r.get_thick_polygon(map));
            dist_btwn += r.center_pts.length();
            car_dt += r.center_pts.length() / r.speed_limit;
        }

        let offset1 = map.get_traffic_signal(i1).offset;
        let offset2 = map.get_traffic_signal(i2).offset;
        Box::new(TuneRelative {
            panel: Panel::new(Widget::col(vec![
                Widget::row(vec![
                    Line(format!("Tuning offset between {} and {}", i1, i2))
                        .small_heading()
                        .draw(ctx),
                    Btn::close(ctx),
                ]),
                Text::from_multiline(vec![
                    Line(format!("Distance: {}", dist_btwn)),
                    Line(format!(
                        "  about {} for a car if there's no congestion",
                        car_dt
                    )),
                    Line(format!(
                        "  about {} for a bike",
                        dist_btwn / Scenario::max_bike_speed()
                    )),
                    Line(format!(
                        "  about {} for a pedestrian",
                        dist_btwn / Scenario::max_ped_speed()
                    )),
                ])
                .draw(ctx),
                Widget::row(vec![
                    "Offset (seconds):".draw_text(ctx),
                    Spinner::new(ctx, (0, 90), (offset2 - offset1).inner_seconds() as isize)
                        .named("offset"),
                ]),
                Btn::text_bg2("Update offset").build_def(ctx, Key::Enter),
            ]))
            .build(ctx),
            i1,
            i2,
            members,
            labels: ctx.upload(batch),
        })
    }
}

impl State<App> for TuneRelative {
    fn event(&mut self, ctx: &mut EventCtx, app: &mut App) -> Transition {
        ctx.canvas_movement();
        match self.panel.event(ctx) {
            Outcome::Clicked(x) => match x.as_ref() {
                "close" => {
                    return Transition::Pop;
                }
                "Update offset" => {
                    let mut ts = app.primary.map.get_traffic_signal(self.i2).clone();
                    let relative = Duration::seconds(self.panel.spinner("offset") as f64);
                    let offset1 = app.primary.map.get_traffic_signal(self.i1).offset;
                    ts.offset = offset1 + relative;
                    app.primary.map.incremental_edit_traffic_signal(ts);
                    return Transition::Multi(vec![
                        Transition::Pop,
                        Transition::Replace(ShowRelative::new(
                            ctx,
                            app,
                            self.i1,
                            self.members.clone(),
                        )),
                    ]);
                }
                _ => unreachable!(),
            },
            _ => {}
        }

        Transition::Keep
    }

    fn draw(&self, g: &mut GfxCtx, _: &App) {
        self.panel.draw(g);
        g.redraw(&self.labels);
    }
}