use ashpd::desktop::settings::{ColorScheme, Contrast};
use ashpd::desktop::Color;
use iced::futures::{self, select, FutureExt, SinkExt, StreamExt};
use iced_futures::subscription;
use tracing::error;

#[derive(Debug, Clone)]
pub enum Desktop {
    Accent(Color),
    ColorScheme(ColorScheme),
    Contrast(Contrast),
}

pub fn desktop_settings() -> iced_futures::Subscription<Desktop> {
    subscription::channel(std::any::TypeId::of::<Desktop>(), 10, |mut tx| {
        async move {
            let mut attempts = 0;
            loop {
                let Ok(settings) = ashpd::desktop::settings::Settings::new().await else {
                    error!("Failed to create the settings proxy");
                    #[cfg(feature = "tokio")]
                    ::tokio::time::sleep(::tokio::time::Duration::from_secs(2_u64.pow(attempts)))
                        .await;
                    #[cfg(not(feature = "tokio"))]
                    {
                        pending::<()>().await;
                        unreachable!();
                    }
                    attempts += 1;
                    continue;
                };

                match settings.color_scheme().await {
                    Ok(color_scheme) => {
                        let _ = tx.send(Desktop::ColorScheme(color_scheme)).await;
                    }
                    Err(err) => error!("Failed to get the color scheme {err:?}"),
                };
                match settings.contrast().await {
                    Ok(contrast) => {
                        let _ = tx.send(Desktop::Contrast(contrast)).await;
                    }
                    Err(err) => error!("Failed to get the contrast {err:?}"),
                };

                let mut color_scheme_stream = settings.receive_color_scheme_changed().await.ok();
                if color_scheme_stream.is_none() {
                    error!("Failed to receive color scheme changes");
                }

                let mut contrast_stream = settings.receive_contrast_changed().await.ok();
                if contrast_stream.is_none() {
                    error!("Failed to receive contrast changes");
                }

                loop {
                    if color_scheme_stream.is_none() && contrast_stream.is_none() {
                        break;
                    }
                    let next_color_scheme = async {
                        if let Some(s) = color_scheme_stream.as_mut() {
                            return s.next().await;
                        }
                        futures::future::pending().await
                    };

                    let next_contrast = async {
                        if let Some(s) = contrast_stream.as_mut() {
                            return s.next().await;
                        }
                        futures::future::pending().await
                    };

                    select! {
                        s = next_color_scheme.fuse() => {
                            if let Some(s) = s {
                                _ = tx.send(Desktop::ColorScheme(s)).await;
                            } else {
                                color_scheme_stream = None;
                            }
                        },

                        c = next_contrast.fuse() => {
                            if let Some(c) = c {
                                _ = tx.send(Desktop::Contrast(c)).await;
                            } else {
                                contrast_stream = None;
                            }
                        }
                    };
                    // Reset the attempts counter if we successfully received a change
                    attempts = 0;
                }
            }
        }
    })
}