use crate::app::App;
use crate::common::{ColorLegend, ColorNetwork, ColorScale, DivergingScale};
use crate::layer::{Layer, LayerOutcome};
use abstutil::Counter;
use geom::{Distance, Duration, Polygon, Time};
use map_model::{IntersectionID, Map, Traversable};
use maplit::btreeset;
use std::collections::BTreeSet;
use widgetry::{
    hotkey, Btn, Checkbox, Color, Drawable, EventCtx, GeomBatch, GfxCtx, HorizontalAlignment, Key,
    Line, Outcome, Panel, Text, TextExt, VerticalAlignment, Widget,
};

pub struct Backpressure {
    time: Time,
    unzoomed: Drawable,
    zoomed: Drawable,
    panel: Panel,
}

impl Layer for Backpressure {
    fn name(&self) -> Option<&'static str> {
        Some("backpressure")
    }
    fn event(
        &mut self,
        ctx: &mut EventCtx,
        app: &mut App,
        minimap: &Panel,
    ) -> Option<LayerOutcome> {
        if app.primary.sim.time() != self.time {
            *self = Backpressure::new(ctx, app);
        }

        Layer::simple_event(ctx, minimap, &mut self.panel)
    }
    fn draw(&self, g: &mut GfxCtx, app: &App) {
        self.panel.draw(g);
        if g.canvas.cam_zoom < app.opts.min_zoom_for_detail {
            g.redraw(&self.unzoomed);
        } else {
            g.redraw(&self.zoomed);
        }
    }
    fn draw_minimap(&self, g: &mut GfxCtx) {
        g.redraw(&self.unzoomed);
    }
}

impl Backpressure {
    pub fn new(ctx: &mut EventCtx, app: &App) -> Backpressure {
        let mut cnt_per_r = Counter::new();
        let mut cnt_per_i = Counter::new();
        for path in app.primary.sim.get_all_driving_paths() {
            for step in path.get_steps() {
                match step.as_traversable() {
                    Traversable::Lane(l) => {
                        cnt_per_r.inc(app.primary.map.get_l(l).parent);
                    }
                    Traversable::Turn(t) => {
                        cnt_per_i.inc(t.parent);
                    }
                }
            }
        }

        let panel = Panel::new(Widget::col(vec![
            Widget::row(vec![
                Widget::draw_svg(ctx, "system/assets/tools/layers.svg"),
                "Backpressure".draw_text(ctx),
                Btn::plaintext("X")
                    .build(ctx, "close", hotkey(Key::Escape))
                    .align_right(),
            ]),
            Text::from(
                Line("This counts all active trips passing through a road in the future")
                    .secondary(),
            )
            .wrap_to_pct(ctx, 15)
            .draw(ctx),
            ColorLegend::gradient(
                ctx,
                &app.cs.good_to_bad_red,
                vec!["lowest count", "highest"],
            ),
        ]))
        .aligned(HorizontalAlignment::Right, VerticalAlignment::Center)
        .build(ctx);

        let mut colorer = ColorNetwork::new(app);
        colorer.ranked_roads(cnt_per_r, &app.cs.good_to_bad_red);
        colorer.ranked_intersections(cnt_per_i, &app.cs.good_to_bad_red);
        let (unzoomed, zoomed) = colorer.build(ctx);

        Backpressure {
            time: app.primary.sim.time(),
            unzoomed,
            zoomed,
            panel,
        }
    }
}

// TODO Filter by mode
pub struct Throughput {
    time: Time,
    compare: bool,
    unzoomed: Drawable,
    zoomed: Drawable,
    panel: Panel,
}

impl Layer for Throughput {
    fn name(&self) -> Option<&'static str> {
        Some("throughput")
    }
    fn event(
        &mut self,
        ctx: &mut EventCtx,
        app: &mut App,
        minimap: &Panel,
    ) -> Option<LayerOutcome> {
        if app.primary.sim.time() != self.time {
            *self = Throughput::new(ctx, app, self.compare);
        }

        self.panel.align_above(ctx, minimap);
        match self.panel.event(ctx) {
            Outcome::Clicked(x) => match x.as_ref() {
                "close" => {
                    return Some(LayerOutcome::Close);
                }
                _ => unreachable!(),
            },
            Outcome::Changed => {
                *self = Throughput::new(
                    ctx,
                    app,
                    self.panel
                        .maybe_is_checked("Compare before proposal")
                        .unwrap_or(false),
                );
                self.panel.align_above(ctx, minimap);
            }
            _ => {}
        }
        None
    }
    fn draw(&self, g: &mut GfxCtx, app: &App) {
        self.panel.draw(g);
        if g.canvas.cam_zoom < app.opts.min_zoom_for_detail {
            g.redraw(&self.unzoomed);
        } else {
            g.redraw(&self.zoomed);
        }
    }
    fn draw_minimap(&self, g: &mut GfxCtx) {
        g.redraw(&self.unzoomed);
    }
}

impl Throughput {
    pub fn new(ctx: &mut EventCtx, app: &App, compare: bool) -> Throughput {
        if compare {
            return Throughput::compare_throughput(ctx, app);
        }
        let panel = Panel::new(Widget::col(vec![
            Widget::row(vec![
                Widget::draw_svg(ctx, "system/assets/tools/layers.svg"),
                "Throughput".draw_text(ctx),
                Btn::plaintext("X")
                    .build(ctx, "close", hotkey(Key::Escape))
                    .align_right(),
            ]),
            Text::from(Line("This counts all people crossing since midnight").secondary())
                .wrap_to_pct(ctx, 15)
                .draw(ctx),
            if app.has_prebaked().is_some() {
                Checkbox::switch(ctx, "Compare before proposal", None, false)
            } else {
                Widget::nothing()
            },
            ColorLegend::gradient(
                ctx,
                &app.cs.good_to_bad_red,
                vec!["lowest count", "highest"],
            ),
        ]))
        .aligned(HorizontalAlignment::Right, VerticalAlignment::Center)
        .build(ctx);

        let mut colorer = ColorNetwork::new(app);
        let stats = &app.primary.sim.get_analytics();
        colorer.ranked_roads(
            stats.road_thruput.all_total_counts(),
            &app.cs.good_to_bad_red,
        );
        colorer.ranked_intersections(
            stats.intersection_thruput.all_total_counts(),
            &app.cs.good_to_bad_red,
        );
        let (unzoomed, zoomed) = colorer.build(ctx);

        Throughput {
            time: app.primary.sim.time(),
            compare: false,
            unzoomed,
            zoomed,
            panel,
        }
    }

    fn compare_throughput(ctx: &mut EventCtx, app: &App) -> Throughput {
        let after = app.primary.sim.get_analytics();
        let before = app.prebaked();
        let hour = app.primary.sim.time().get_hours();

        let mut after_road = Counter::new();
        let mut before_road = Counter::new();
        {
            for ((r, _, _), count) in &after.road_thruput.counts {
                after_road.add(*r, *count);
            }
            // TODO ew. lerp?
            for ((r, _, hr), count) in &before.road_thruput.counts {
                if *hr <= hour {
                    before_road.add(*r, *count);
                }
            }
        }
        let mut after_intersection = Counter::new();
        let mut before_intersection = Counter::new();
        {
            for ((i, _, _), count) in &after.intersection_thruput.counts {
                after_intersection.add(*i, *count);
            }
            // TODO ew. lerp?
            for ((i, _, hr), count) in &before.intersection_thruput.counts {
                if *hr <= hour {
                    before_intersection.add(*i, *count);
                }
            }
        }

        let mut colorer = ColorNetwork::new(app);

        let scale = DivergingScale::new(Color::hex("#5D9630"), Color::WHITE, Color::hex("#A32015"))
            .range(0.0, 2.0)
            .ignore(0.7, 1.3);

        for (r, before, after) in before_road.compare(after_road) {
            if let Some(c) = scale.eval((after as f64) / (before as f64)) {
                colorer.add_r(r, c);
            }
        }
        for (i, before, after) in before_intersection.compare(after_intersection) {
            if let Some(c) = scale.eval((after as f64) / (before as f64)) {
                colorer.add_i(i, c);
            }
        }

        let panel = Panel::new(Widget::col(vec![
            Widget::row(vec![
                Widget::draw_svg(ctx, "system/assets/tools/layers.svg"),
                "Relative Throughput".draw_text(ctx),
                Btn::plaintext("X")
                    .build(ctx, "close", hotkey(Key::Escape))
                    .align_right(),
            ]),
            Checkbox::switch(ctx, "Compare before proposal", None, true),
            scale.make_legend(ctx, vec!["less traffic", "same", "more"]),
        ]))
        .aligned(HorizontalAlignment::Right, VerticalAlignment::Center)
        .build(ctx);
        let (unzoomed, zoomed) = colorer.build(ctx);

        Throughput {
            time: app.primary.sim.time(),
            compare: true,
            unzoomed,
            zoomed,
            panel,
        }
    }
}

pub struct Delay {
    time: Time,
    compare: bool,
    unzoomed: Drawable,
    zoomed: Drawable,
    panel: Panel,
}

impl Layer for Delay {
    fn name(&self) -> Option<&'static str> {
        Some("delay")
    }
    fn event(
        &mut self,
        ctx: &mut EventCtx,
        app: &mut App,
        minimap: &Panel,
    ) -> Option<LayerOutcome> {
        if app.primary.sim.time() != self.time {
            *self = Delay::new(ctx, app, self.compare);
        }

        self.panel.align_above(ctx, minimap);
        match self.panel.event(ctx) {
            Outcome::Clicked(x) => match x.as_ref() {
                "close" => {
                    return Some(LayerOutcome::Close);
                }
                _ => unreachable!(),
            },
            Outcome::Changed => {
                *self = Delay::new(
                    ctx,
                    app,
                    self.panel
                        .maybe_is_checked("Compare before proposal")
                        .unwrap_or(false),
                );
                self.panel.align_above(ctx, minimap);
            }
            _ => {}
        }
        None
    }
    fn draw(&self, g: &mut GfxCtx, app: &App) {
        self.panel.draw(g);
        if g.canvas.cam_zoom < app.opts.min_zoom_for_detail {
            g.redraw(&self.unzoomed);
        } else {
            g.redraw(&self.zoomed);
        }
    }
    fn draw_minimap(&self, g: &mut GfxCtx) {
        g.redraw(&self.unzoomed);
    }
}

impl Delay {
    pub fn new(ctx: &mut EventCtx, app: &App, compare: bool) -> Delay {
        if compare {
            return Delay::compare_delay(ctx, app);
        }

        let mut colorer = ColorNetwork::new(app);

        let (per_road, per_intersection) = app.primary.sim.worst_delay(&app.primary.map);
        for (r, d) in per_road {
            if d < Duration::minutes(1) {
                continue;
            }
            let color = app
                .cs
                .good_to_bad_red
                .eval(((d - Duration::minutes(1)) / Duration::minutes(15)).min(1.0));
            colorer.add_r(r, color);
        }
        for (i, d) in per_intersection {
            if d < Duration::minutes(1) {
                continue;
            }
            let color = app
                .cs
                .good_to_bad_red
                .eval(((d - Duration::minutes(1)) / Duration::minutes(15)).min(1.0));
            colorer.add_i(i, color);
        }

        let panel = Panel::new(Widget::col(vec![
            Widget::row(vec![
                Widget::draw_svg(ctx, "system/assets/tools/layers.svg"),
                "Delay (minutes)".draw_text(ctx),
                Btn::plaintext("X")
                    .build(ctx, "close", hotkey(Key::Escape))
                    .align_right(),
            ]),
            if app.has_prebaked().is_some() {
                Checkbox::switch(ctx, "Compare before proposal", None, false)
            } else {
                Widget::nothing()
            },
            ColorLegend::gradient(ctx, &app.cs.good_to_bad_red, vec!["1", "5", "10", "15+"]),
        ]))
        .aligned(HorizontalAlignment::Right, VerticalAlignment::Center)
        .build(ctx);
        let (unzoomed, zoomed) = colorer.build(ctx);

        Delay {
            time: app.primary.sim.time(),
            compare: false,
            unzoomed,
            zoomed,
            panel,
        }
    }

    // TODO Needs work.
    fn compare_delay(ctx: &mut EventCtx, app: &App) -> Delay {
        let mut colorer = ColorNetwork::new(app);
        let red = Color::hex("#A32015");
        let green = Color::hex("#5D9630");

        let results = app
            .primary
            .sim
            .get_analytics()
            .compare_delay(app.primary.sim.time(), app.prebaked());
        if !results.is_empty() {
            let fastest = results.iter().min_by_key(|(_, dt)| *dt).unwrap().1;
            let slowest = results.iter().max_by_key(|(_, dt)| *dt).unwrap().1;

            for (i, dt) in results {
                let color = if dt < Duration::ZERO {
                    green.lerp(Color::WHITE, 1.0 - (dt / fastest))
                } else {
                    Color::WHITE.lerp(red, dt / slowest)
                };
                colorer.add_i(i, color);
            }
        }

        let panel = Panel::new(Widget::col(vec![
            Widget::row(vec![
                Widget::draw_svg(ctx, "system/assets/tools/layers.svg"),
                "Delay".draw_text(ctx),
                Btn::plaintext("X")
                    .build(ctx, "close", hotkey(Key::Escape))
                    .align_right(),
            ]),
            Checkbox::switch(ctx, "Compare before proposal", None, true),
            ColorLegend::gradient(
                ctx,
                &ColorScale(vec![green, Color::WHITE, red]),
                vec!["faster", "same", "slower"],
            ),
        ]))
        .aligned(HorizontalAlignment::Right, VerticalAlignment::Center)
        .build(ctx);
        let (unzoomed, zoomed) = colorer.build(ctx);

        Delay {
            time: app.primary.sim.time(),
            compare: true,
            unzoomed,
            zoomed,
            panel,
        }
    }
}

pub struct TrafficJams {
    time: Time,
    unzoomed: Drawable,
    zoomed: Drawable,
    panel: Panel,
}

impl Layer for TrafficJams {
    fn name(&self) -> Option<&'static str> {
        Some("traffic jams")
    }
    fn event(
        &mut self,
        ctx: &mut EventCtx,
        app: &mut App,
        minimap: &Panel,
    ) -> Option<LayerOutcome> {
        if app.primary.sim.time() != self.time {
            *self = TrafficJams::new(ctx, app);
        }

        Layer::simple_event(ctx, minimap, &mut self.panel)
    }
    fn draw(&self, g: &mut GfxCtx, app: &App) {
        self.panel.draw(g);
        if g.canvas.cam_zoom < app.opts.min_zoom_for_detail {
            g.redraw(&self.unzoomed);
        } else {
            g.redraw(&self.zoomed);
        }
    }
    fn draw_minimap(&self, g: &mut GfxCtx) {
        g.redraw(&self.unzoomed);
    }
}

impl TrafficJams {
    pub fn new(ctx: &mut EventCtx, app: &App) -> TrafficJams {
        // TODO Use cached delayed_intersections?
        let mut unzoomed = GeomBatch::new();
        unzoomed.push(
            app.cs.fade_map_dark,
            app.primary.map.get_boundary_polygon().clone(),
        );
        let mut zoomed = GeomBatch::new();
        let mut cnt = 0;
        for (epicenter, boundary) in cluster_jams(
            &app.primary.map,
            app.primary.sim.delayed_intersections(Duration::minutes(5)),
        ) {
            cnt += 1;
            unzoomed.push(
                Color::RED,
                boundary.to_outline(Distance::meters(5.0)).unwrap(),
            );
            unzoomed.push(Color::RED.alpha(0.5), boundary.clone());
            unzoomed.push(Color::WHITE, epicenter.clone());

            zoomed.push(
                Color::RED.alpha(0.4),
                boundary.to_outline(Distance::meters(5.0)).unwrap(),
            );
            zoomed.push(Color::RED.alpha(0.3), boundary);
            zoomed.push(Color::WHITE.alpha(0.4), epicenter);
        }

        let panel = Panel::new(Widget::col(vec![
            Widget::row(vec![
                Widget::draw_svg(ctx, "system/assets/tools/layers.svg"),
                "Traffic jams".draw_text(ctx),
                Btn::plaintext("X")
                    .build(ctx, "close", hotkey(Key::Escape))
                    .align_right(),
            ]),
            Text::from(
                Line("A jam starts when delay exceeds 5 mins, then spreads out").secondary(),
            )
            .wrap_to_pct(ctx, 15)
            .draw(ctx),
            format!("{} jams detected", cnt).draw_text(ctx),
        ]))
        .aligned(HorizontalAlignment::Right, VerticalAlignment::Center)
        .build(ctx);

        TrafficJams {
            time: app.primary.sim.time(),
            unzoomed: ctx.upload(unzoomed),
            zoomed: ctx.upload(zoomed),
            panel,
        }
    }
}

struct Jam {
    epicenter: IntersectionID,
    members: BTreeSet<IntersectionID>,
}

// (Epicenter, entire shape)
fn cluster_jams(map: &Map, problems: Vec<(IntersectionID, Time)>) -> Vec<(Polygon, Polygon)> {
    let mut jams: Vec<Jam> = Vec::new();
    // The delay itself doesn't matter, as long as they're sorted.
    for (i, _) in problems {
        // Is this connected to an existing problem?
        if let Some(ref mut jam) = jams.iter_mut().find(|j| j.adjacent_to(map, i)) {
            jam.members.insert(i);
        } else {
            jams.push(Jam {
                epicenter: i,
                members: btreeset! { i },
            });
        }
    }

    jams.into_iter()
        .map(|jam| {
            (
                map.get_i(jam.epicenter).polygon.clone(),
                Polygon::convex_hull(jam.all_polygons(map)),
            )
        })
        .collect()
}

impl Jam {
    fn adjacent_to(&self, map: &Map, i: IntersectionID) -> bool {
        for r in &map.get_i(i).roads {
            let r = map.get_r(*r);
            if self.members.contains(&r.src_i) || self.members.contains(&r.dst_i) {
                return true;
            }
        }
        false
    }

    fn all_polygons(self, map: &Map) -> Vec<Polygon> {
        let mut polygons = Vec::new();
        for i in self.members {
            polygons.push(map.get_i(i).polygon.clone());
        }
        polygons
    }
}