use crate::*;
use crate::ratatui::style::Style;

pub struct Column<G, S, U> {
    pub title:     Arc<str>,
    pub width:     usize,
    pub collapsed: bool,
    pub getter:    G,
    pub setter:    Option<S>,
    pub styler:    Option<U>,
}

type Getter<T> = fn(&T)->Option<Arc<str>>;
type Setter<T> = fn(&mut T, usize, &str);
type Styler<T> = fn(&T)->Option<Style>;

impl<G, S, U> Column<Getter<G>, Setter<S>, Styler<U>> {
    pub fn new (
        title: &impl AsRef<str>,
        width: usize,
        getter: Getter<G>,
    ) -> Self {
        Self {
            width,
            title: title.as_ref().into(),
            getter,
            setter: None,
            styler: None,
            collapsed: false,
        }
    }
    fn setter (mut self, setter: Setter<S>) -> Self {
        self.setter = Some(setter);
        self
    }
    fn styler (mut self, styler: Styler<U>) -> Self {
        self.styler = Some(styler);
        self
    }
}

pub(crate) fn entries_under (
    entries: &mut [Entry],
    index:   usize
) -> Option<Vec<(Arc<PathBuf>, Arc<RwLock<Metadata>>)>> {
    let path = if let Some(Entry { path, info, .. }) = entries.get(index)
        && let Metadata::Directory { .. } = &*info.read().unwrap()
    {
        Some(path.clone())
    } else {
        None
    };
    if let Some(path) = path {
        let mut others = vec![];
        for other in entries.iter_mut() {
            if other.path.starts_with(path.as_ref()) && !other.is_directory() {
                others.push((other.path.clone(), other.info.clone()));
            }
        }
        Some(others)
    } else {
        None
    }
}

pub struct Columns<G, S, U>(pub Vec<Column<G, S, U>>);

macro_rules! setter {
    ($set:ident) => {{
        fn $set (state: &mut Taggart, index: usize, value: &str) {
            if let Some(entries) = entries_under(&mut state.entries, index) {
                for (_path, entry) in entries.into_iter() {
                    if entry.write().unwrap().$set(&value) {
                        state.count_changes();
                        //state.tasks.retain(|t|{(t.path != p) || (t.item.key() != item.key())});
                        //state.tasks.push(Task { path: p, item, });
                    };
                }
            } else if let Some(entry) = state.entries.get_mut(index) {
                //let p = entry.path.clone();
                if entry.$set(&value) {
                    state.count_changes();
                    //state.tasks.retain(|t|{(t.path != p) || (t.item.key() != item.key())});
                    //state.tasks.push(Task { path: p, item, });
                };
            }
        }
        $set
    }}
}

impl Default for Columns<
    fn(&Entry)->Option<Arc<str>>,
    fn(&mut Taggart, usize, &str),
    fn(&Entry)->Option<Style>,
> {
    fn default () -> Self {
        Self(vec![
            // Computed file hash
            Column::new(&"Hash",     8, |entry: &Entry|entry.hash()),
            // File size
            Column::new(&"Size",     8, |entry: &Entry|entry.size()),
            // Selected?
            Column::new(&"∗",        1, |entry: &Entry|Some(" ".into())),
            // File name
            Column::new(&"File",    40, |entry: &Entry|entry.name()),
            // Modified tags?
            Column::new(&"~",        1, |entry: &Entry|if entry.is_modified() {
                Some("~".into())
            } else {
                None
            }),
            Column::new(&"Artist",  15, |entry: &Entry|entry.artist()).setter(setter!(set_artist)),
            Column::new(&"Year",     4, |entry: &Entry|entry.year()).setter(setter!(set_year)),
            Column::new(&"Release", 15, |entry: &Entry|entry.album()).setter(setter!(set_album)),
            Column::new(&"Track",    5, |entry: &Entry|entry.track()).setter(setter!(set_track)),
            Column::new(&"Title",   40, |entry: &Entry|entry.title()).setter(setter!(set_title)),
        ])
    }
}