use anyhow::Result;
use cursive::Cursive;
use cursive::Printer;
use cursive::Rect;
use cursive::View;
use cursive::XY;
use cursive::direction::Direction;
use cursive::event::Callback;
use cursive::event::Event;
use cursive::event::EventResult;
use cursive::view::Nameable;
use cursive::view::Selector;
use cursive::views::Dialog;
use cursive::views::EditView;
use cursive::views::NamedView;
use cursive::views::ResizedView;
use cursive::traits::Resizable;
use cursive_multiplex::Mux;
use cursive::view::SizeConstraint;
use cursive::event::Key;
use getset::{Getters, MutGetters};

use crate::configuration::Configuration;
use crate::maillist_view::MaillistView;
use crate::maillist_view::MailListingData;
use crate::bindings::Bindings;
use crate::bindings::BindingCaller;

pub const MAIN_VIEW_NAME: &'static str = "main_view";
pub const MAIN_MUX_NAME: &'static str = "main_mux";
pub const MAIN_MAIL_LIST_NAME: &'static str = "main_mail_list";

#[derive(Getters, MutGetters)]
pub struct MainView {
    config: Configuration,
    muxroot: cursive_multiplex::Id,

    #[getset(get = "pub", get_mut = "pub")]
    tabs: cursive_tabs::TabPanel<String>,

    bindings: Bindings,
    bindings_caller: Option<ResizedView<NamedView<BindingCaller>>>,
}

impl View for MainView {
    fn draw(&self, printer: &Printer) {
        self.tabs.draw(printer);
        if let Some(caller) = self.bindings_caller.as_ref() {
            caller.draw(printer);
        }
    }

    fn layout(&mut self, xy: XY<usize>) {
        self.tabs.layout(xy)
    }

    fn needs_relayout(&self) -> bool {
        self.tabs.needs_relayout()
    }

    fn required_size(&mut self, constraint: XY<usize>) -> XY<usize> {
        self.tabs.required_size(constraint)
    }

    fn on_event(&mut self, e: Event) -> EventResult {
        debug!("Received event: {:?}", e);
        match self.bindings_caller.as_mut() {
            Some(caller) => match e {
                Event::Key(Key::Esc) => {
                    self.bindings_caller = None;
                    debug!("Escape. Resetting bindings caller.");
                    EventResult::Consumed(None)
                },
                other => {
                    debug!("Forwarding event to bindings caller");
                    caller.on_event(other)
                },
            },
            None => match e {
                Event::Char(':') => {
                    debug!(": -> Constructing bindings caller.");
                    self.bindings_caller = Some({
                        self.bindings.caller()
                            .with_name(crate::bindings::BINDINGS_CALLER)
                            .resized(SizeConstraint::Full, SizeConstraint::AtLeast(5))
                    });
                    EventResult::Consumed(None)
                },
                other => {
                    debug!("Forwarding event to tabs");
                    self.tabs.on_event(other)
                },
            }
        }
    }

    fn call_on_any<'a>(&mut self, s: &Selector, tpl: &'a mut (dyn FnMut(&mut (dyn View + 'static)) + 'a)) {
        self.tabs.call_on_any(s, tpl);
    }

    fn focus_view(&mut self, s: &Selector) -> Result<(), ()> {
        self.tabs.focus_view(s)
    }

    fn take_focus(&mut self, source: Direction) -> bool {
        self.tabs.take_focus(source)
    }

    fn important_area(&self, view_size: XY<usize>) -> Rect {
        self.tabs.important_area(view_size)
    }

    fn type_name(&self) -> &'static str {
        self.tabs.type_name()
    }

}

impl MainView {
    pub fn new(config: Configuration) -> Result<NamedView<Self>> {
        let mut tab = cursive_multiplex::Mux::new();
        let muxroot = tab.root().build().unwrap();

        {
            let dbpath  = config.notmuch_database_path();
            let dbquery = config.notmuch_default_query();
            let mlname  = MAIN_MAIL_LIST_NAME.to_string();
            let view    = MaillistView::create_for(dbpath.to_path_buf(), dbquery, mlname)?;

            let _ = tab.add_right_of(view, muxroot);
        }

        let tabs = cursive_tabs::TabPanel::default()
            .with_bar_alignment(cursive_tabs::Align::Start)
            .with_bar_placement(cursive_tabs::Placement::HorizontalTop)
            .with_tab(config.notmuch_default_query().clone(), tab.with_name(MAIN_MUX_NAME));

        let bindings = crate::bindings::get_bindings();

        Ok(MainView { config, muxroot, tabs, bindings, bindings_caller: None }.with_name(MAIN_VIEW_NAME))
    }

    pub fn add_tab<T: View>(&mut self, id: String, view: T) {
        self.tabs.add_tab(id, view)
    }

    pub fn config(&self) -> &Configuration {
        &self.config
    }

    pub fn add_notmuch_query_layer(siv: &mut Cursive) {
        use crate::util::dialog_for;
        use crate::util::error_dialog_for;

        let edit_view = EditView::new()
            .on_submit(move |siv: &mut Cursive, query: &str| {
                siv.call_on_name(MAIN_VIEW_NAME, move |main_view: &mut MainView| {
                        main_view.config().notmuch_database_path().clone()
                    })
                    .map(|dbpath| {
                        let t = MaillistView::create_for(dbpath.to_path_buf(), query, query.to_string())?
                            .full_screen()
                            .with_name(format!("{}-view", query));

                        siv.call_on_name(MAIN_VIEW_NAME, move |main_view: &mut MainView| {
                            main_view.add_tab(query.to_string(), t);
                        });

                        siv.pop_layer();
                        Ok(())
                    })
                    .unwrap_or_else(|| {
                        siv.pop_layer();
                        siv.add_layer(dialog_for("Failed to get database connection set up"));
                        Ok(())
                    })
                    .unwrap_or_else(|e: anyhow::Error| {
                        siv.pop_layer();
                        siv.add_layer(error_dialog_for(e))
                    });
            })
            .with_name("query");

        siv.add_layer({
            Dialog::around(edit_view)
                .title("Query")
                .min_width(80)
        })
    }

    fn add_mailview(siv: &mut Cursive, muxroot: cursive_multiplex::Id) {
        debug!("Creating mailview");
        siv.call_on_name(MAIN_MAIL_LIST_NAME, |maillist_view: &mut MaillistView| {
                if let Some(ml_data) = maillist_view.item().and_then(move |idx| maillist_view.borrow_item(idx)) {
                    debug!("Found item");
                    Ok(ml_data.clone())
                } else {
                    unimplemented!()
                }
            })
            .map(|maillist_item: Result<MailListingData>| {
                if let Ok(mldata) = maillist_item {
                    let _ = siv.call_on_name(MAIN_MUX_NAME, |mux: &mut Mux| {
                        debug!("Adding mux pane");
                        let _ = mux.add_right_of(crate::mailview::MailView::create_for(mldata), muxroot); // TODO handle error
                    }); // TODO handle error.
                } else {
                    // do something
                }

                Ok(())
            })
            .unwrap_or_else(|| {
                siv.add_layer(crate::util::dialog_for("Failed to find View"));
                Ok(())
            })
            .unwrap_or_else(|e: anyhow::Error| {
                siv.add_layer(crate::util::error_dialog_for(e))
            });
    }

}