//! Design tokens. Every widget reads colours/sizes from [`Tokens`] so themes apply everywhere.
//!
//! The default theme follows the look of After Effects' dark UI (values estimated from public
//! documentation and product knowledge, tuned by eye; see `plan/aftereffects/README.md` §2). Fonts
//! are Inter + JetBrains Mono (OFL).

use std::sync::Arc;

use egui::{Color32, FontData, FontDefinitions, FontFamily, FontId, Stroke, TextStyle, Visuals};
use serde::{Deserialize, Serialize};

#[derive(Clone, Copy, Debug, Default, PartialEq, Eq, Serialize, Deserialize)]
pub enum ThemeKind {
    #[default]
    Dark,
    Darker,
    Light,
}

impl ThemeKind {
    pub fn from_name(s: &str) -> Option<ThemeKind> {
        match s.to_ascii_lowercase().as_str() {
            "dark" | "default" => Some(ThemeKind::Dark),
            "darker" | "darkest" => Some(ThemeKind::Darker),
            "light" => Some(ThemeKind::Light),
            _ => None,
        }
    }
}

#[derive(Clone, Copy, Debug, PartialEq)]
pub struct Tokens {
    pub kind: ThemeKind,
    pub app_bg: Color32,
    pub header_bg: Color32,
    pub panel_bg: Color32,
    pub tab_text: Color32,
    pub tab_text_active: Color32,
    pub focus: Color32,
    pub accent: Color32,
    pub accent_hover: Color32,
    pub text: Color32,
    pub text_dim: Color32,
    pub text_faint: Color32,
    pub icon: Color32,
    pub icon_active: Color32,
    pub hover: Color32,
    pub pressed: Color32,
    pub field_bg: Color32,
    pub field_border: Color32,
    pub separator: Color32,
    pub row: Color32,
    pub row_alt: Color32,
    pub row_selected: Color32,
    pub hot_text: Color32,
    pub tl_bg: Color32,
    pub tl_ruler_bg: Color32,
    pub tl_ruler_tick: Color32,
    pub tl_ruler_text: Color32,
    pub cti: Color32,
    pub work_area: Color32,
    pub cache_green: Color32,
    /// Timeline cache bar for frames held in the disk cache (not in RAM).
    pub cache_blue: Color32,
    pub keyframe: Color32,
    pub keyframe_selected: Color32,
    pub pasteboard: Color32,
    pub timecode: Color32,
    pub danger: Color32,
    pub warning: Color32,
    /// Label colours (`Label::ALL` order), from Settings ▸ Labels.
    pub labels: [Color32; 17],
    pub radius: f32,
    pub radius_sm: f32,
    pub gap: f32,
    pub tab_h: f32,
    pub row_h: f32,
}

impl Tokens {
    pub fn for_kind(kind: ThemeKind) -> Self {
        let dark = Tokens {
            kind,
            app_bg: Color32::from_rgb(0x12, 0x12, 0x12),
            header_bg: Color32::from_rgb(0x1f, 0x1f, 0x1f),
            panel_bg: Color32::from_rgb(0x23, 0x23, 0x23),
            tab_text: Color32::from_rgb(0x9a, 0x9a, 0x9a),
            tab_text_active: Color32::from_rgb(0xe3, 0xe3, 0xe3),
            focus: Color32::from_rgb(0x2d, 0x8c, 0xeb),
            accent: Color32::from_rgb(0x2d, 0x8c, 0xeb),
            accent_hover: Color32::from_rgb(0x4a, 0xa0, 0xf5),
            text: Color32::from_rgb(0xc8, 0xc8, 0xc8),
            text_dim: Color32::from_rgb(0x9a, 0x9a, 0x9a),
            text_faint: Color32::from_rgb(0x66, 0x66, 0x66),
            icon: Color32::from_rgb(0xb4, 0xb4, 0xb4),
            icon_active: Color32::from_rgb(0xf0, 0xf0, 0xf0),
            hover: Color32::from_rgb(0x30, 0x30, 0x30),
            pressed: Color32::from_rgb(0x45, 0x45, 0x45),
            field_bg: Color32::from_rgb(0x17, 0x17, 0x17),
            field_border: Color32::from_rgb(0x3a, 0x3a, 0x3a),
            separator: Color32::from_rgb(0x34, 0x34, 0x34),
            row: Color32::from_rgb(0x23, 0x23, 0x23),
            row_alt: Color32::from_rgb(0x27, 0x27, 0x27),
            row_selected: Color32::from_rgb(0x3a, 0x3a, 0x3a),
            hot_text: Color32::from_rgb(0x3d, 0x8f, 0xf5),
            tl_bg: Color32::from_rgb(0x1b, 0x1b, 0x1b),
            tl_ruler_bg: Color32::from_rgb(0x23, 0x23, 0x23),
            tl_ruler_tick: Color32::from_rgb(0x70, 0x70, 0x70),
            tl_ruler_text: Color32::from_rgb(0x9a, 0x9a, 0x9a),
            cti: Color32::from_rgb(0x2d, 0x8c, 0xeb),
            work_area: Color32::from_rgb(0x4a, 0x4a, 0x4a),
            cache_green: Color32::from_rgb(0x3c, 0xa6, 0x4c),
            cache_blue: Color32::from_rgb(0x3a, 0x6f, 0xd8),
            keyframe: Color32::from_rgb(0xa8, 0xa8, 0xa8),
            keyframe_selected: Color32::from_rgb(0x3d, 0x8f, 0xf5),
            pasteboard: Color32::from_rgb(0x1a, 0x1a, 0x1a),
            timecode: Color32::from_rgb(0x3d, 0x8f, 0xf5),
            danger: Color32::from_rgb(0xe0, 0x4a, 0x3c),
            warning: Color32::from_rgb(0xe8, 0x9a, 0x2c),
            labels: default_labels(),
            radius: 6.0,
            radius_sm: 3.0,
            gap: 4.0,
            tab_h: 30.0,
            row_h: 22.0,
        };
        match kind {
            ThemeKind::Dark => dark,
            ThemeKind::Darker => Tokens {
                app_bg: Color32::from_rgb(0x08, 0x08, 0x08),
                header_bg: Color32::from_rgb(0x16, 0x16, 0x16),
                panel_bg: Color32::from_rgb(0x19, 0x19, 0x19),
                row: Color32::from_rgb(0x19, 0x19, 0x19),
                row_alt: Color32::from_rgb(0x1d, 0x1d, 0x1d),
                tl_bg: Color32::from_rgb(0x12, 0x12, 0x12),
                tl_ruler_bg: Color32::from_rgb(0x19, 0x19, 0x19),
                field_bg: Color32::from_rgb(0x0e, 0x0e, 0x0e),
                pasteboard: Color32::from_rgb(0x11, 0x11, 0x11),
                ..dark
            },
            ThemeKind::Light => Tokens {
                app_bg: Color32::from_rgb(0xb4, 0xb4, 0xb4),
                header_bg: Color32::from_rgb(0xd6, 0xd6, 0xd6),
                panel_bg: Color32::from_rgb(0xe6, 0xe6, 0xe6),
                tab_text: Color32::from_rgb(0x5a, 0x5a, 0x5a),
                tab_text_active: Color32::from_rgb(0x14, 0x14, 0x14),
                text: Color32::from_rgb(0x22, 0x22, 0x22),
                text_dim: Color32::from_rgb(0x5a, 0x5a, 0x5a),
                text_faint: Color32::from_rgb(0x8c, 0x8c, 0x8c),
                icon: Color32::from_rgb(0x3c, 0x3c, 0x3c),
                icon_active: Color32::from_rgb(0x10, 0x10, 0x10),
                hover: Color32::from_rgb(0xd0, 0xd0, 0xd0),
                pressed: Color32::from_rgb(0xc0, 0xc0, 0xc0),
                field_bg: Color32::from_rgb(0xfa, 0xfa, 0xfa),
                field_border: Color32::from_rgb(0xaa, 0xaa, 0xaa),
                separator: Color32::from_rgb(0xc8, 0xc8, 0xc8),
                row: Color32::from_rgb(0xe6, 0xe6, 0xe6),
                row_alt: Color32::from_rgb(0xde, 0xde, 0xde),
                row_selected: Color32::from_rgb(0xaa, 0xc8, 0xf0),
                tl_bg: Color32::from_rgb(0xd2, 0xd2, 0xd2),
                tl_ruler_bg: Color32::from_rgb(0xe2, 0xe2, 0xe2),
                tl_ruler_text: Color32::from_rgb(0x50, 0x50, 0x50),
                pasteboard: Color32::from_rgb(0xa8, 0xa8, 0xa8),
                ..dark
            },
        }
    }

    pub fn mono(size: f32) -> FontId {
        FontId::new(size, FontFamily::Monospace)
    }
    pub fn ui(size: f32) -> FontId {
        FontId::new(size, FontFamily::Proportional)
    }
    pub fn semibold(size: f32) -> FontId {
        FontId::new(size, FontFamily::Name("semibold".into()))
    }
    pub fn medium(size: f32) -> FontId {
        FontId::new(size, FontFamily::Name("medium".into()))
    }
    /// sRGB colour of an item/layer label (Settings ▸ Labels).
    pub fn label(&self, l: effectcraft_color::Label) -> Color32 {
        let i = effectcraft_color::Label::ALL.iter().position(|x| *x == l).unwrap_or(0);
        self.labels[i]
    }

    /// Theme tokens for the current settings: theme, UI brightness and label colours.
    pub fn from_prefs(p: &effectcraft_engine::prefs::Prefs) -> Tokens {
        let kind = ThemeKind::from_name(&p.appearance.theme).unwrap_or_default();
        let mut t = Tokens::for_kind(kind).with_brightness(p.appearance.brightness as f32);
        for (i, l) in effectcraft_color::Label::ALL.iter().enumerate() {
            let [r, g, b] = p.label_rgb(*l);
            t.labels[i] = Color32::from_rgb(r, g, b);
        }
        t
    }

    /// Lighten (b > 0) or darken (b < 0) the interface greys, like After Effects' brightness
    /// slider. Accent colours, labels and keyframe colours are kept.
    pub fn with_brightness(mut self, b: f32) -> Tokens {
        let b = b.clamp(-1.0, 1.0);
        if b.abs() < 1e-3 {
            return self;
        }
        let adj = |c: &mut Color32| {
            let f = |v: u8| -> u8 {
                let v = v as f32;
                (if b > 0.0 { v + (110.0 - v).max(0.0) * b * 0.8 + 10.0 * b } else { v * (1.0 + b * 0.6) }).round().clamp(0.0, 255.0) as u8
            };
            *c = Color32::from_rgb(f(c.r()), f(c.g()), f(c.b()));
        };
        for c in [
            &mut self.app_bg,
            &mut self.header_bg,
            &mut self.panel_bg,
            &mut self.hover,
            &mut self.pressed,
            &mut self.field_bg,
            &mut self.field_border,
            &mut self.separator,
            &mut self.row,
            &mut self.row_alt,
            &mut self.row_selected,
            &mut self.tl_bg,
            &mut self.tl_ruler_bg,
            &mut self.pasteboard,
            &mut self.work_area,
        ] {
            adj(c);
        }
        self
    }
}

fn default_labels() -> [Color32; 17] {
    effectcraft_color::Label::ALL.map(|l| {
        let [r, g, b] = l.rgb();
        Color32::from_rgb(r, g, b)
    })
}

static INTER_REGULAR: &[u8] = include_bytes!("../../../assets/fonts/Inter-Regular.ttf");
static INTER_MEDIUM: &[u8] = include_bytes!("../../../assets/fonts/Inter-Medium.ttf");
static INTER_SEMIBOLD: &[u8] = include_bytes!("../../../assets/fonts/Inter-SemiBold.ttf");
static JETBRAINS_MONO: &[u8] = include_bytes!("../../../assets/fonts/JetBrainsMono-Regular.ttf");

/// Install fonts (Inter, Inter Medium/SemiBold, JetBrains Mono) and egui visuals.
pub fn install(ctx: &egui::Context, t: &Tokens) {
    let mut fonts = FontDefinitions::default();
    fonts.font_data.insert("inter".into(), Arc::new(FontData::from_static(INTER_REGULAR)));
    fonts.font_data.insert("inter-medium".into(), Arc::new(FontData::from_static(INTER_MEDIUM)));
    fonts.font_data.insert("inter-semibold".into(), Arc::new(FontData::from_static(INTER_SEMIBOLD)));
    fonts.font_data.insert("jbmono".into(), Arc::new(FontData::from_static(JETBRAINS_MONO)));
    fonts.families.entry(FontFamily::Proportional).or_default().insert(0, "inter".into());
    fonts.families.entry(FontFamily::Monospace).or_default().insert(0, "jbmono".into());
    fonts.families.insert(FontFamily::Name("semibold".into()), vec!["inter-semibold".into(), "inter".into()]);
    fonts.families.insert(FontFamily::Name("medium".into()), vec!["inter-medium".into(), "inter".into()]);
    ctx.set_fonts(fonts);
    apply_visuals(ctx, t);
}

pub fn apply_visuals(ctx: &egui::Context, t: &Tokens) {
    let mut v = if t.kind == ThemeKind::Light { Visuals::light() } else { Visuals::dark() };
    v.panel_fill = t.panel_bg;
    v.window_fill = t.panel_bg;
    v.extreme_bg_color = t.field_bg;
    v.faint_bg_color = t.row_alt;
    v.override_text_color = Some(t.text);
    v.selection.bg_fill = t.accent;
    v.selection.stroke = Stroke::new(1.0, Color32::WHITE);
    v.hyperlink_color = t.accent;
    v.window_stroke = Stroke::new(1.0, t.field_border);
    v.window_corner_radius = egui::CornerRadius::same(8);
    v.menu_corner_radius = egui::CornerRadius::same(6);
    v.popup_shadow = egui::epaint::Shadow { offset: [0, 6], blur: 20, spread: 0, color: Color32::from_black_alpha(150) };
    v.window_shadow = egui::epaint::Shadow { offset: [0, 10], blur: 36, spread: 0, color: Color32::from_black_alpha(170) };
    for w in [&mut v.widgets.noninteractive, &mut v.widgets.inactive, &mut v.widgets.hovered, &mut v.widgets.active, &mut v.widgets.open] {
        w.corner_radius = egui::CornerRadius::same(t.radius_sm as u8);
    }
    v.widgets.noninteractive.bg_fill = t.panel_bg;
    v.widgets.noninteractive.weak_bg_fill = t.panel_bg;
    v.widgets.noninteractive.bg_stroke = Stroke::new(1.0, t.separator);
    v.widgets.noninteractive.fg_stroke = Stroke::new(1.0, t.text);
    v.widgets.inactive.bg_fill = t.field_bg;
    v.widgets.inactive.weak_bg_fill = Color32::from_rgb(0x2e, 0x2e, 0x2e);
    v.widgets.inactive.bg_stroke = Stroke::new(1.0, t.field_border);
    v.widgets.inactive.fg_stroke = Stroke::new(1.0, t.text);
    v.widgets.hovered.bg_fill = t.hover;
    v.widgets.hovered.weak_bg_fill = Color32::from_rgb(0x3a, 0x3a, 0x3a);
    v.widgets.hovered.bg_stroke = Stroke::new(1.0, t.field_border);
    v.widgets.hovered.fg_stroke = Stroke::new(1.0, t.tab_text_active);
    v.widgets.active.bg_fill = t.pressed;
    v.widgets.active.weak_bg_fill = t.pressed;
    v.widgets.active.fg_stroke = Stroke::new(1.0, t.tab_text_active);
    v.widgets.open.bg_fill = t.hover;
    v.widgets.open.weak_bg_fill = t.hover;
    ctx.set_visuals(v);
    ctx.global_style_mut(|s| {
        s.spacing.item_spacing = egui::vec2(6.0, 4.0);
        s.spacing.button_padding = egui::vec2(8.0, 3.0);
        s.spacing.interact_size.y = 22.0;
        s.spacing.menu_margin = egui::Margin::same(5);
        s.text_styles.insert(TextStyle::Body, FontId::new(12.0, FontFamily::Proportional));
        s.text_styles.insert(TextStyle::Button, FontId::new(12.0, FontFamily::Proportional));
        s.text_styles.insert(TextStyle::Small, FontId::new(11.0, FontFamily::Proportional));
        s.text_styles.insert(TextStyle::Heading, FontId::new(15.0, FontFamily::Name("semibold".into())));
        s.text_styles.insert(TextStyle::Monospace, FontId::new(12.0, FontFamily::Monospace));
        s.animation_time = 0.1;
    });
}