use crate::{
    strutil::StringType,
    time::Instant,
    ui::{
        component::{Component, Event, EventCtx, Marquee, Never},
        display,
        geometry::{Alignment, Offset, Rect},
        shape,
        shape::Renderer,
    },
};

use super::super::theme;

pub struct Title<T>
where
    T: StringType,
{
    area: Rect,
    title: T,
    marquee: Marquee<T>,
    needs_marquee: bool,
    centered: bool,
}

impl<T> Title<T>
where
    T: StringType + Clone,
{
    pub fn new(title: T) -> Self {
        Self {
            title: title.clone(),
            marquee: Marquee::new(title, theme::FONT_HEADER, theme::FG, theme::BG),
            needs_marquee: false,
            area: Rect::zero(),
            centered: false,
        }
    }

    pub fn with_centered(mut self) -> Self {
        self.centered = true;
        self
    }

    pub fn get_text(&self) -> &str {
        self.title.as_ref()
    }

    pub fn set_text(&mut self, ctx: &mut EventCtx, new_text: T) {
        self.title = new_text.clone();
        self.marquee.set_text(new_text.clone());
        let text_width = theme::FONT_HEADER.text_width(new_text.as_ref());
        self.needs_marquee = text_width > self.area.width();
        // Resetting the marquee to the beginning and starting it when necessary.
        self.marquee.reset();
        if self.needs_marquee {
            self.marquee.start(ctx, Instant::now());
        }
    }

    /// Display title/header at the top left of the given area.
    pub fn paint_header_left(title: &T, area: Rect) {
        let text_height = theme::FONT_HEADER.text_height();
        let title_baseline = area.top_left() + Offset::y(text_height - 1);
        display::text_left(
            title_baseline,
            title.as_ref(),
            theme::FONT_HEADER,
            theme::FG,
            theme::BG,
        );
    }

    /// Display title/header at the top left of the given area.
    pub fn render_header_left<'s>(target: &mut impl Renderer<'s>, title: &T, area: Rect) {
        let text_height = theme::FONT_HEADER.text_height();
        let title_baseline = area.top_left() + Offset::y(text_height - 1);
        shape::Text::new(title_baseline, title.as_ref())
            .with_font(theme::FONT_HEADER)
            .with_fg(theme::FG)
            .render(target);
    }

    /// Display title/header centered at the top of the given area.
    pub fn paint_header_centered(title: &T, area: Rect) {
        let text_height = theme::FONT_HEADER.text_height();
        let title_baseline = area.top_center() + Offset::y(text_height - 1);
        display::text_center(
            title_baseline,
            title.as_ref(),
            theme::FONT_HEADER,
            theme::FG,
            theme::BG,
        );
    }

    /// Display title/header centered at the top of the given area.
    pub fn render_header_centered<'s>(target: &mut impl Renderer<'s>, title: &T, area: Rect) {
        let text_height = theme::FONT_HEADER.text_height();
        let title_baseline = area.top_center() + Offset::y(text_height - 1);
        shape::Text::new(title_baseline, title.as_ref())
            .with_align(Alignment::Center)
            .with_font(theme::FONT_HEADER)
            .with_fg(theme::FG)
            .render(target);
    }
}

impl<T> Component for Title<T>
where
    T: StringType + Clone,
{
    type Msg = Never;

    fn place(&mut self, bounds: Rect) -> Rect {
        self.area = bounds;
        self.marquee.place(bounds);
        let width = theme::FONT_HEADER.text_width(self.title.as_ref());
        self.needs_marquee = width > self.area.width();
        bounds
    }

    fn event(&mut self, ctx: &mut EventCtx, event: Event) -> Option<Self::Msg> {
        if self.needs_marquee {
            if !self.marquee.is_animating() {
                self.marquee.start(ctx, Instant::now());
            }
            return self.marquee.event(ctx, event);
        }
        None
    }

    fn paint(&mut self) {
        if self.needs_marquee {
            self.marquee.paint();
        } else if self.centered {
            Self::paint_header_centered(&self.title, self.area);
        } else {
            Self::paint_header_left(&self.title, self.area);
        }
    }

    fn render<'s>(&'s self, target: &mut impl Renderer<'s>) {
        if self.needs_marquee {
            self.marquee.render(target);
        } else if self.centered {
            Self::render_header_centered(target, &self.title, self.area);
        } else {
            Self::render_header_left(target, &self.title, self.area);
        }
    }
}

// DEBUG-ONLY SECTION BELOW

#[cfg(feature = "ui_debug")]
impl<T> crate::trace::Trace for Title<T>
where
    T: StringType + Clone,
{
    fn trace(&self, t: &mut dyn crate::trace::Tracer) {
        t.component("Title");
        t.string("text", self.title.as_ref().into());
    }
}