//! Ballast editor, shared by the CLAP wrapper and the headless renderer.
use ballast_core::{
    AnalyzerFrame, Grid, Segment, Settings, Source, FROM_MAX, FROM_MIN, HISTORY, RANGE_MAX,
    TARGET_MAX, TARGET_MIN,
};
use common_ui::*;
use egui::{self, Color32, FontId, Pos2, Rect, RichText, Sense, Stroke, Vec2};

pub use common_ui::style;
pub const WIDTH: u32 = 980;
pub const HEIGHT: u32 = 660;

pub struct State {
    pub analyzer: AnalyzerFrame,
    /// Set by the Learn button; the wrapper passes it to the engine and clears it.
    pub learn_request: bool,
    /// The last Learn result already applied. None until the first frame arrives, so an old
    /// result is not applied again when the editor opens.
    learn_seen: Option<u32>,
    learned: Option<f32>,
    /// True while a pointer button is held, so knob drags become one host gesture.
    pub gesture_active: bool,
    pub help: String,
}
impl Default for State {
    fn default() -> Self {
        Self {
            analyzer: AnalyzerFrame::default(),
            learn_request: false,
            learn_seen: None,
            learned: None,
            gesture_active: false,
            help: DEFAULT_HELP.into(),
        }
    }
}
const DEFAULT_HELP: &str = "Put Ballast on the bass after its sound design. Press LEARN on the \
                            switch-up that sits right, or set Target.";
impl State {
    pub fn accept_frame(&mut self, frame: AnalyzerFrame) {
        match self.learn_seen {
            Some(id) if id != frame.learn_id && frame.learned.is_finite() => {
                self.learned = Some(frame.learned);
            }
            _ => {}
        }
        self.learn_seen = Some(frame.learn_id);
        self.analyzer = frame;
    }
}
fn hint(r: &egui::Response, state: &mut State, text: &str) {
    if r.hovered() || r.has_focus() {
        state.help = text.into();
    }
}
#[allow(clippy::too_many_arguments)]
fn knob(
    ui: &mut egui::Ui,
    state: &mut State,
    name: &str,
    value: &mut f32,
    range: std::ops::RangeInclusive<f32>,
    default: f32,
    unit: &str,
    help: &str,
) {
    ui.vertical_centered(|ui| {
        let r = rotary(ui, name, value, range, default, unit, 72., ACCENT);
        hint(&r, state, help);
    });
}

const LOW: f32 = -42.;
const HIGH: f32 = 0.;

/// The last parts: their loudness in (bars), after Ballast (marks) and the target.
fn parts(ui: &mut egui::Ui, settings: &Settings, frame: &AnalyzerFrame, height: f32) {
    let (rect, _) = ui.allocate_exact_size(Vec2::new(ui.available_width(), height), Sense::hover());
    let p = ui.painter_at(rect);
    p.rect_filled(rect, 2., SCREEN);
    p.text(
        rect.left_top() + Vec2::new(10., 8.),
        egui::Align2::LEFT_TOP,
        format!("LAST {HISTORY} PARTS · LOUDNESS OF THE FIRST 100 MS"),
        FontId::proportional(11.),
        MUTED,
    );
    p.text(
        rect.right_top() + Vec2::new(-12., 8.),
        egui::Align2::RIGHT_TOP,
        "bar: in · mark: out",
        FontId::proportional(11.),
        MUTED,
    );
    let area = Rect::from_min_max(
        rect.left_top() + Vec2::new(44., 30.),
        rect.right_bottom() - Vec2::new(12., 12.),
    );
    let y = |lufs: f32| {
        let t = ((lufs - LOW) / (HIGH - LOW)).clamp(0., 1.);
        area.bottom() - t * area.height()
    };
    for db in [-36., -24., -12., 0.] {
        p.line_segment(
            [
                Pos2::new(area.left(), y(db)),
                Pos2::new(area.right(), y(db)),
            ],
            Stroke::new(1.0_f32, Color32::from_rgb(32, 35, 40)),
        );
        p.text(
            Pos2::new(area.left() - 6., y(db)),
            egui::Align2::RIGHT_CENTER,
            format!("{db:.0}"),
            FontId::monospace(10.),
            DIM,
        );
    }
    let column = area.width() / HISTORY as f32;
    // Newest part on the right.
    let offset = HISTORY - frame.count;
    for i in 0..frame.count {
        let part = frame.history[i];
        let x = area.left() + column * (offset + i) as f32;
        let bar = Rect::from_min_max(
            Pos2::new(x + column * 0.2, y(part.loudness)),
            Pos2::new(x + column * 0.8, area.bottom()),
        );
        let color = if part.gated {
            DIM.gamma_multiply(0.6)
        } else {
            STEEL.gamma_multiply(0.45)
        };
        p.rect_filled(bar, 1., color);
        if !part.gated {
            let out = y(part.loudness + part.gain);
            p.line_segment(
                [
                    Pos2::new(x + column * 0.1, out),
                    Pos2::new(x + column * 0.9, out),
                ],
                Stroke::new(3.0_f32, ACCENT),
            );
        }
    }
    let t = y(settings.target);
    p.line_segment(
        [Pos2::new(area.left(), t), Pos2::new(area.right(), t)],
        Stroke::new(1.0_f32, ACCENT.gamma_multiply(0.5)),
    );
    p.text(
        Pos2::new(area.left() + 4., t - 3.),
        egui::Align2::LEFT_BOTTOM,
        format!("TARGET {:.1} LUFS", settings.target),
        FontId::proportional(10.),
        ACCENT,
    );
    p.rect_stroke(
        rect,
        2.,
        Stroke::new(1.0_f32, EDGE),
        egui::StrokeKind::Inside,
    );
}

pub fn show(ui: &mut egui::Ui, settings: &mut Settings, state: &mut State) {
    backdrop(ui);
    state.help = DEFAULT_HELP.into();
    state.gesture_active = ui.input(|i| i.pointer.any_down());
    if let Some(l) = state.learned.take() {
        settings.target = l.clamp(TARGET_MIN, TARGET_MAX);
    }
    ui.add_space(2.);
    header(ui, "BALLAST", "SWITCH-UP LEVELLER", |ui| {
        let r = ui
            .selectable_label(settings.bypass, RichText::new("BYPASS").size(13.))
            .on_hover_text("Crossfade to the delayed dry signal.");
        if r.clicked() {
            settings.bypass = !settings.bypass;
        }
        ui.separator();
        if settings.segment == Segment::Notes {
            for (source, label) in [(Source::Midi, "MIDI"), (Source::Audio, "AUDIO")] {
                let r =
                    ui.selectable_label(settings.source == source, RichText::new(label).size(13.));
                if r.clicked() {
                    settings.source = source;
                }
            }
            caption(ui, "NOTES FROM");
            ui.separator();
        }
        for (segment, label) in [(Segment::Grid, "GRID"), (Segment::Notes, "NOTES")] {
            let r =
                ui.selectable_label(settings.segment == segment, RichText::new(label).size(13.));
            if r.clicked() {
                settings.segment = segment;
            }
        }
        caption(ui, "PARTS FROM");
    });
    ui.add_space(6.);
    let frame = state.analyzer;
    ui.horizontal_top(|ui| {
        panel(ui, |ui| {
            ui.set_width(250.);
            ui.set_min_height(TOP);
            ui.vertical(|ui| readings(ui, settings, state, &frame));
        });
        ui.add_space(4.);
        panel(ui, |ui| {
            ui.set_width(ui.available_width());
            parts(ui, settings, &frame, TOP);
        });
    });
    ui.add_space(6.);
    panel(ui, |ui| {
        ui.set_width(ui.available_width());
        ui.vertical(|ui| controls(ui, settings, state));
    });
    ui.separator();
    ui.label(RichText::new(&state.help).color(MUTED));
}
const TOP: f32 = 300.;

fn readings(ui: &mut egui::Ui, settings: &Settings, state: &mut State, frame: &AnalyzerFrame) {
    caption(ui, "SPREAD OF THE LAST PARTS");
    let known = frame.spread_in.is_finite();
    ui.label(
        RichText::new(if known {
            format!("{:.1} · {:.1} dB", frame.spread_in, frame.spread_out)
        } else {
            "—".into()
        })
        .font(FontId::new(34., egui::FontFamily::Name("medium".into())))
        .color(if known { TEXT } else { DIM }),
    );
    ui.label(
        RichText::new("in · out, standard deviation")
            .size(12.)
            .color(MUTED),
    );
    ui.add_space(12.);
    readout(ui, "GAIN NOW", format!("{:+.1} dB", frame.gain), ACCENT);
    readout(ui, "TARGET", format!("{:.1} LUFS", settings.target), TEXT);
    let label = if frame.learning || state.learn_request {
        "LISTENING"
    } else {
        "LEARN"
    };
    let r = ui.selectable_label(
        frame.learning || state.learn_request,
        RichText::new(label).size(13.),
    );
    if r.clicked() {
        state.learn_request = true;
    }
    hint(
        &r,
        state,
        "Takes the loudness of the next part over the gate as the target. Press it just \
         before the switch-up that sits right in the mix.",
    );
    ui.add_space(10.);
    ui.label(
        RichText::new(format!(
            "{:.0} ms lookahead · {}",
            frame.latency as f32 / frame.sample_rate.max(1.) * 1000.,
            match settings.segment {
                Segment::Notes => match settings.source {
                    Source::Audio => "parts at detected notes".to_string(),
                    Source::Midi => "parts at MIDI notes".to_string(),
                },
                Segment::Grid => format!(
                    "grid at {:.1} BPM, {}",
                    frame.tempo,
                    if frame.synced {
                        "host transport"
                    } else {
                        "free running"
                    }
                ),
            }
        ))
        .size(12.)
        .color(MUTED),
    );
}

fn controls(ui: &mut egui::Ui, settings: &mut Settings, state: &mut State) {
    let d = Settings::default();
    if settings.segment == Segment::Grid {
        ui.horizontal(|ui| {
            caption(ui, "ONE PART EVERY");
            ui.add_space(6.);
            for grid in Grid::ALL {
                let r = ui
                    .selectable_label(settings.grid == grid, RichText::new(grid.label()).size(13.));
                if r.clicked() {
                    settings.grid = grid;
                }
                hint(
                    &r,
                    state,
                    "A new part starts on every line of this grid, also when the note does not \
                     change.",
                );
            }
        });
        ui.add_space(8.);
        ui.separator();
    }
    ui.columns(6, |c| {
        knob(
            &mut c[0],
            state,
            "Target",
            &mut settings.target,
            TARGET_MIN..=TARGET_MAX,
            d.target,
            " LUFS",
            "Loudness every part lands at, over its first 100 ms.",
        );
        knob(
            &mut c[1],
            state,
            "Amount",
            &mut settings.amount,
            0. ..=100.,
            d.amount,
            " %",
            "Share of the correction. 50 % halves the differences between parts.",
        );
        knob(
            &mut c[2],
            state,
            "Range",
            &mut settings.range,
            0. ..=RANGE_MAX,
            d.range,
            " dB",
            "Most boost or cut a part gets.",
        );
        knob(
            &mut c[3],
            state,
            "Measure from",
            &mut settings.from,
            FROM_MIN..=FROM_MAX,
            d.from,
            " Hz",
            "The measurement hears only what is above this. Set it to Anvil's Split when \
             Anvil makes the sub; the gain still applies to the whole signal.",
        );
        knob(
            &mut c[4],
            state,
            "Gate",
            &mut settings.gate,
            -60. ..=-20.,
            d.gate,
            " dB",
            "Note-start threshold, and the loudness under which a part keeps the last gain.",
        );
        knob(
            &mut c[5],
            state,
            "Output",
            &mut settings.output,
            -12. ..=12.,
            d.output,
            " dB",
            "Output trim.",
        );
    });
}