duat-base 0.10.0

//! A widget that shows general information, usually about a
//! [`Buffer`]
//!
//! The [`StatusLine`] is a very convenient widget when the user
//! simply wants to show some informatioon. The information, when
//! relevant, can automatically be tied to the active buffer, saving
//! some keystrokes for the user's configuration.
//!
//! There is also the [`status!`] macro, which is an extremely
//! convenient way to modify the text of the status line, letting you
//! place form, in the same way that [`text!`] does, and
//! automatically recognizing a ton of different types of functions,
//! that can read from the buffer, from other places, from [data]
//! types, etc.
//!
//! [data]: crate::data
//! [`Buffer`]: duat_core::buffer::Buffer
use std::sync::{Arc, LazyLock, mpsc};

use duat_core::{
    context::{self, DynBuffer, Handle},
    data::Pass,
    hook::{self, BufferClosed, BufferUpdated},
    text::{Builder, Spacer, Text, TextMut},
    ui::{PushSpecs, PushTarget, Side, Widget},
};

pub use self::state::State;
use crate::state::{main_txt, mode_txt, name_txt, sels_txt};

mod state;
#[macro_use]
mod macros;
#[doc(inline)]
pub use crate::__status__ as status;

/// A widget to show information, usually about a [`Buffer`]
///
/// This widget is updated whenever any of its parts needs to be
/// updated, and it also automatically adjusts to where it was pushed.
/// For example, if you push it to a buffer (via
/// `hook::add::<BufferOpened>`, for example), it's information will
/// point to the [`Buffer`] to which it was pushed. However, if you
/// push it with [`WindowOpened`], it will always point to the
/// currently active [`Buffer`]:
///
/// ```rust
/// # duat_core::doc_duat!(duat);
/// # use duat_base::widgets::status;
/// setup_duat!(setup);
/// use duat::prelude::*;
///
/// fn setup() {
///     opts::set(|opts| opts.one_line_footer = true);
///     opts::fmt_status(|pa| status!("{Spacer}{} {sels_txt} {main_txt}", mode_txt()));
///
///     hook::add::<BufferOpened>(|pa, handle| {
///         status!("{Spacer}{name_txt}{Spacer}")
///             .above()
///             .push_on(pa, handle);
///     });
/// }
/// ```
///
/// In the code above, I'm modifying the "global" `StatusLine` through
/// [`opts::set_status`] (this can be done with [hooks] as well, but
/// this method is added for convenience's sake). This is in
/// conjunction with [`opts::one_line_footer`], which will place
/// the [`PromptLine`] and `StatusLine` on the same line.
///
/// After that, I'm _also_ pushing a new `StatusLine` above every
/// opened [`Buffer`], showing that `Buffer`]'s name, centered.
///
/// You will usually want to create `StatusLine`s via the
/// [`status!`] macro, since that is how you can customize it.
/// Although, if you want the regular status line, you can call
/// [`StatusLine::builder`]:
///
/// ```rust
/// # duat_core::doc_duat!(duat);
/// # use duat_base::widgets::StatusLine;
/// setup_duat!(setup);
/// use duat::prelude::*;
///
/// fn setup() {
///     hook::add::<BufferOpened>(|pa, handle| {
///         StatusLine::builder().above().push_on(pa, handle);
///     });
/// }
/// ```
///
/// [`Buffer`]: duat_core::buffer::Buffer
/// [`WindowOpened`]: duat_core::hook::WindowOpened
/// [`PromptLine`]: super::PromptLine
/// [`Notifications`]: super::Notifications
/// [`FooterWidgets`]: super::FooterWidgets
/// [`opts::set_status`]: https://docs.rs/duat/latest/duat/opts/fn.set_status.html
/// [`opts::one_line_footer`]: https://docs.rs/duat/latest/duat/opts/fn.one_line_footer.html
/// [hooks]: duat_core::hook
pub struct StatusLine {
    buffer_handle: BufferHandle,
    text_fn: TextFn,
    text: Text,
    checker: CheckerFn,
}

impl StatusLine {
    fn new(builder: StatusLineFmt, buffer_handle: BufferHandle) -> Self {
        let (builder_fn, checker) = if let Some((builder, checker)) = builder.fns {
            (builder, checker)
        } else {
            let mode_txt = mode_txt();

            let opts = match builder.specs.side {
                Side::Above | Side::Below => {
                    status!("{mode_txt}{Spacer}{name_txt} {sels_txt} {main_txt}")
                }
                Side::Right => {
                    status!("{Spacer}{name_txt} {mode_txt} {sels_txt} {main_txt}",)
                }
                Side::Left => unreachable!(),
            };

            opts.fns.unwrap()
        };

        Self {
            buffer_handle,
            text_fn: Box::new(move |pa, fh| {
                let builder = Text::builder();
                builder_fn(pa, builder, fh)
            }),
            text: Text::new(),
            checker,
        }
    }

    /// Replaces this `StatusLine` with a new one
    pub fn fmt(&mut self, new: StatusLineFmt) {
        let handle = self.buffer_handle.clone();
        *self = StatusLine::new(new, handle);
    }

    /// Returns a [`StatusLineFmt`], which can be used to push
    /// around `StatusLine`s
    ///
    /// The same can be done more conveniently with the [`status!`]
    /// macro, which is imported by default in the configuration
    /// crate.
    pub fn builder() -> StatusLineFmt {
        StatusLineFmt { fns: None, ..Default::default() }
    }

    fn update(pa: &mut Pass, handle: &Handle<Self>) {
        if let BufferHandle::Dynamic(dyn_file) = &mut handle.write(pa).buffer_handle {
            dyn_file.swap_to_current();
        }

        let sl = handle.read(pa);

        handle.write(pa).text = match &sl.buffer_handle {
            BufferHandle::Fixed(buffer) => (sl.text_fn)(pa, buffer),
            BufferHandle::Dynamic(dyn_file) => (sl.text_fn)(pa, dyn_file.handle()),
        };

        // Do this in case the Buffer is never read during Text construction
        match &handle.read(pa).buffer_handle {
            BufferHandle::Fixed(handle) => handle.declare_as_read(),
            BufferHandle::Dynamic(dyn_file) => dyn_file.declare_as_read(),
        }
    }
}

impl Widget for StatusLine {
    fn text(&self) -> &Text {
        &self.text
    }

    fn text_mut(&mut self) -> TextMut<'_> {
        self.text.as_mut()
    }
}

/// A builder for [`StatusLine`]s
///
/// This struct is created by the [`status!`] macro, and its purpose
/// is mainly to allow formatting of the `StatusLine`.
///
/// There is also the [`StatusLineFmt::above`] method, which places
/// the `StatusLine` above, rather than below.
pub struct StatusLineFmt {
    fns: Option<(BuilderFn, CheckerFn)>,
    specs: PushSpecs,
}

impl StatusLineFmt {
    /// Push the [`StatusLine`]
    ///
    /// If the handle's [`Widget`] is a [`Buffer`], then this
    /// `StatusLine` will refer to it when printing information about
    /// `Buffer`s. Otherwise, the `StatusLine` will print information
    /// about the currently active `Buffer`.
    ///
    /// [`Buffer`]: duat_core::buffer::Buffer
    pub fn push_on(self, pa: &mut Pass, push_target: &impl PushTarget) -> Handle<StatusLine> {
        static SENDER: LazyLock<mpsc::Sender<StatusLineEvent>> = LazyLock::new(|| {
            hook::add::<BufferUpdated>(|pa, buffer| {
                let handles = buffer.get_related::<StatusLine>(pa);
                for (statusline, _) in &handles {
                    StatusLine::update(pa, statusline);
                }

                let handles: Vec<Handle<StatusLine>> = context::current_window(pa)
                    .handles(pa)
                    .filter_map(Handle::try_downcast)
                    .filter(|statusline| !handles.iter().any(|(other, _)| other == statusline))
                    .collect();

                for statusline in handles {
                    let sl = statusline.read(pa);
                    let buffer_changed = match &sl.buffer_handle {
                        BufferHandle::Fixed(handle) => handle.has_changed(pa),
                        BufferHandle::Dynamic(dyn_buf) => dyn_buf.has_changed(pa),
                    };

                    if buffer_changed || (sl.checker)() {
                        StatusLine::update(pa, &statusline);
                    }
                }
            });

            hook::add::<BufferClosed>(|pa, buffer| {
                for (statusline, _) in buffer.get_related::<StatusLine>(pa) {
                    SENDER.send(StatusLineEvent::Closed(statusline)).unwrap();
                }
            });

            let (tx, rx) = mpsc::channel();

            std::thread::spawn(move || {
                let mut entries = Vec::new();
                loop {
                    match rx.recv_timeout(std::time::Duration::from_millis(50)) {
                        Ok(StatusLineEvent::Opened(statusline, checker)) => {
                            entries.push((statusline, checker));
                        }
                        Ok(StatusLineEvent::Closed(rm_statusline)) => {
                            entries.retain(|(statusline, ..)| *statusline != rm_statusline);
                        }
                        Err(_) => {}
                    }

                    for (statusline, checker) in &entries {
                        if checker() {
                            let statusline = statusline.clone();
                            context::queue(move |pa| StatusLine::update(pa, &statusline))
                        }
                    }
                }
            });

            tx
        });

        let specs = self.specs;
        let statusline = StatusLine::new(self, match push_target.try_downcast() {
            Some(handle) => BufferHandle::Fixed(handle),
            None => BufferHandle::Dynamic(context::dynamic_buffer(pa)),
        });

        let checker = statusline.checker.clone();
        let statusline = push_target.push_outer(pa, statusline, specs);

        SENDER
            .send(StatusLineEvent::Opened(statusline.clone(), checker))
            .unwrap();

        statusline
    }

    /// Returns a new `StatusLineFmt`, meant to be called only be the
    /// [`status!`] macro
    #[doc(hidden)]
    pub fn new_with(fns: (BuilderFn, CheckerFn)) -> Self {
        Self { fns: Some(fns), ..Default::default() }
    }

    /// Puts the [`StatusLine`] above, as opposed to below
    pub fn above(self) -> Self {
        Self {
            specs: PushSpecs { side: Side::Above, ..self.specs },
            ..self
        }
    }

    /// Puts the [`StatusLine`] below, this is the default
    pub fn below(self) -> Self {
        Self {
            specs: PushSpecs { side: Side::Below, ..self.specs },
            ..self
        }
    }

    /// Puts the [`StatusLine`] on the right
    pub(crate) fn right(self) -> Self {
        Self {
            specs: PushSpecs { side: Side::Right, ..self.specs },
            ..self
        }
    }
}

impl Default for StatusLineFmt {
    fn default() -> Self {
        Self {
            fns: None,
            specs: PushSpecs {
                side: Side::Below,
                height: Some(1.0),
                ..Default::default()
            },
        }
    }
}

#[derive(Clone)]
enum BufferHandle {
    Fixed(Handle),
    Dynamic(DynBuffer),
}

enum StatusLineEvent {
    Opened(Handle<StatusLine>, CheckerFn),
    Closed(Handle<StatusLine>),
}

type TextFn = Box<dyn Fn(&Pass, &Handle) -> Text + Send>;
type BuilderFn = Box<dyn Fn(&Pass, Builder, &Handle) -> Text + Send>;
type CheckerFn = Arc<dyn Fn() -> bool + Send + Sync>;