//! Keys and the mouse, routed: to the command line while it's open, to the
//! text being edited, to an open popup, or through the key engine to the
//! focused view and then the shared commands.

use ratatui::layout::Position;

use super::action::{Action, AppAction, DocumentChoice, Message};
use super::mode::Mode;
use super::{App, calls, commands, connect, visual};
use crate::command::parse::{Sources, parse};
use crate::config::settings::Setting;
use crate::config::theme_file;
use crate::input::command::{Bound, Command, help_for};
use crate::input::engine::{Outcome, Typed};
use crate::input::key::Key;
use crate::input::mouse::{Cell, Gesture};
use crate::ui::command_line::LineOutcome;
use crate::ui::document_bar::DocumentBar;

impl App {
    /// A key, as typed.
    pub fn key(&mut self, key: Key) {
        self.message = None;
        self.record(key);
        match self.shared.mode {
            Mode::Command(_) => self.command_line_key(key),
            Mode::Text(_) => self.text_key(key),
            Mode::Popup(_) => self.popup_key(key),
            Mode::Normal | Mode::Visual(_) | Mode::Move(_) | Mode::Connect(_) => {
                match self.keys.press(key, &self.keymap.tables(self.contexts())) {
                    Outcome::Run(typed) => self.run_typed(typed),
                    Outcome::Unknown(keys) => {
                        self.message = Some(Message::info(format!("{keys} does nothing here")));
                    }
                    Outcome::Waiting | Outcome::Cancelled => {}
                }
            }
        }
        self.end_recording();
        // Portals show the documents they lead to as they are now.
        self.refresh_portals(false);
    }

    /// A command: the focused view has the first say, then visual or
    /// connect mode's commands (in those modes), then the shared commands.
    pub(super) fn dispatch(&mut self, typed: Typed) {
        let selected = self.selection().unwrap_or_default();
        let pane = self.panes.current_mut();
        let kind = pane.view.kind();
        let ctx = self.shared.ctx(pane.buffer);
        let actions = pane
            .view
            .command(&typed, &ctx)
            .or_else(|| match &self.shared.mode {
                Mode::Visual(visual) => visual::command(&typed, visual, &selected, kind, &ctx),
                Mode::Connect(connect) => connect::command(&typed, connect, &ctx),
                _ => None,
            })
            .or_else(|| commands::shared(&typed, &ctx));
        let actions = actions.unwrap_or_else(|| {
            let later = format!("\"{}\" comes in a later part of the build", describe(typed.command));
            vec![Action::say(Message::info(later))]
        });
        self.update(actions);
    }

    /// Runs a command as if its keys were typed (the help and the menu).
    pub(super) fn run_command(&mut self, command: Command) {
        self.dispatch(Typed { command, count: None, register: None });
    }

    /// A key while a text is edited in a view: typed into it, or a vim key
    /// inside it.
    fn text_key(&mut self, key: Key) {
        let tables = self.keymap.tables(self.contexts());
        // The edit comes out of the mode while it works, so it can look at
        // the document; it goes back in before its actions run.
        let Mode::Text(mut edit) = std::mem::take(&mut self.shared.mode) else { return };
        let ctx = self.shared.ctx(self.buffer());
        let actions = if edit.editor.is_typing() {
            // Typing: a key the table doesn't bind types itself.
            edit.typing(key, tables.bound(&[key]), &ctx)
        } else {
            match self.keys.press(key, &tables) {
                Outcome::Run(typed) => edit.vim(&typed, &mut self.registers, &ctx),
                Outcome::Unknown(keys) => {
                    vec![Action::say(Message::info(format!("{keys} does nothing here")))]
                }
                Outcome::Waiting | Outcome::Cancelled => Vec::new(),
            }
        };
        self.shared.mode = Mode::Text(edit);
        self.update(actions);
    }

    /// A key while a popup is open: typed into its search (or the card's
    /// body), or one of its keys.
    fn popup_key(&mut self, key: Key) {
        let tables = self.keymap.tables(self.contexts());
        let Mode::Popup(mut popup) = std::mem::take(&mut self.shared.mode) else { return };
        let ctx = self.shared.ctx(self.buffer());
        let actions = if popup.takes_typing() {
            popup.typing(key, &self.keymap, &ctx)
        } else {
            match self.keys.press(key, &tables) {
                Outcome::Run(typed) => popup.command(&typed, &mut self.registers, &ctx),
                Outcome::Unknown(keys) => {
                    vec![Action::say(Message::info(format!("{keys} does nothing here")))]
                }
                Outcome::Waiting | Outcome::Cancelled => Vec::new(),
            }
        };
        self.shared.mode = Mode::Popup(popup);
        self.update(actions);
    }

    /// A key while the command line is open.
    fn command_line_key(&mut self, key: Key) {
        let sources = self.sources();
        let Mode::Command(line) = &mut self.shared.mode else { return };
        match line.key(key, &sources, &self.command_history) {
            LineOutcome::Typing => {}
            LineOutcome::Close => self.shared.mode = Mode::Normal,
            LineOutcome::Run(text) => {
                self.shared.mode = Mode::Normal;
                if text.trim().is_empty() {
                    return;
                }
                self.command_history.add(&text);
                self.run_line(&text);
            }
        }
    }

    /// Runs a command line (without its `:`).
    pub(super) fn run_line(&mut self, text: &str) {
        let sources = self.sources();
        let actions = match parse(text, &sources) {
            Ok(call) => calls::actions_for(call, &self.shared.ctx(self.buffer())),
            Err(error) => vec![Action::say(Message::problem(error.to_string()))],
        };
        self.update(actions);
    }

    /// What the command line can name: the open documents, the focused
    /// document's nodes and tags, the palette's colors, the settings.
    pub(super) fn sources(&self) -> Sources {
        let doc = self.current().doc();
        let nodes = doc.outline().into_iter().filter_map(|id| Some((id, doc.node(id)?.title().to_string())));
        let mut tags: Vec<String> = doc
            .outline()
            .into_iter()
            .filter_map(|id| doc.node(id))
            .flat_map(|node| node.tags.iter().map(|tag| tag.name().to_string()).collect::<Vec<_>>())
            .collect();
        tags.sort();
        tags.dedup();
        let theme = &self.shared.theme;
        Sources {
            documents: self.shared.names(),
            nodes: nodes.collect(),
            colors: theme.palette.keys().map(ToString::to_string).collect(),
            styles: theme.node_styles.keys().map(ToString::to_string).collect(),
            themes: theme_file::names(&self.paths),
            settings: Setting::ALL.iter().map(|setting| setting.name().to_string()).collect(),
            tags,
            folder: self.folder(),
        }
    }

    /// A mouse gesture: a popup has the mouse while it's open; otherwise it
    /// goes to the document bar or to the pane under it (a drag stays with
    /// the pane it started in), which takes the focus.
    pub fn gesture(&mut self, gesture: Gesture) {
        self.route_gesture(gesture);
        self.refresh_portals(false);
    }

    fn route_gesture(&mut self, gesture: Gesture) {
        let at = |cell: Cell| Position::new(cell.col, cell.row);
        // In connect mode a click only aims: no editing, no menu, no
        // selecting.
        let gesture = match (&self.shared.mode, gesture) {
            (Mode::Connect(_), Gesture::RightPress { .. }) => return,
            (Mode::Connect(_), Gesture::Press { at, .. } | Gesture::DoublePress { at }) => {
                Gesture::Press { at, ctrl: false }
            }
            _ => gesture,
        };
        // A click drops a half-typed key sequence: a `d` typed before
        // clicking somewhere else mustn't wait to delete what comes next.
        if matches!(gesture, Gesture::Press { .. } | Gesture::DoublePress { .. } | Gesture::RightPress { .. })
        {
            self.keys.reset();
            if let Mode::Command(_) = self.shared.mode {
                self.shared.mode = Mode::Normal;
            }
        }
        // A click without Ctrl ends a selection, as in most apps.
        if let (Mode::Visual(_), Gesture::Press { ctrl: false, .. } | Gesture::DoublePress { .. }) =
            (&self.shared.mode, gesture)
        {
            self.shared.mode = Mode::Normal;
        }
        if let Mode::Popup(_) = self.shared.mode {
            let Mode::Popup(mut popup) = std::mem::take(&mut self.shared.mode) else { return };
            let actions = popup.mouse(gesture, &self.shared.ctx(self.buffer()));
            self.shared.mode = Mode::Popup(popup);
            return self.update(actions);
        }
        if let Gesture::Press { at: cell, .. } = gesture
            && cell.row == self.screen.bar.y
        {
            let names = self.bar_names();
            let current = self.shared.docs.index_of(self.buffer());
            let bar = DocumentBar { names: &names, current, theme: &self.shared.theme };
            if let Some(index) = bar.at(cell.col.saturating_sub(self.screen.bar.x)) {
                self.update(vec![Action::App(AppAction::SwitchDocument(DocumentChoice::At(index)))]);
            }
            return;
        }
        let target = match gesture {
            Gesture::Press { at: cell, .. }
            | Gesture::DoublePress { at: cell }
            | Gesture::RightPress { at: cell }
            | Gesture::Scroll { at: cell, .. } => self.panes.at(self.screen.panes, at(cell)),
            Gesture::Drag { .. } | Gesture::Release { .. } => self.dragging,
        };
        let Some(target) = target else { return };
        if let Gesture::Press { .. } = gesture {
            self.dragging = Some(target);
        }
        if target != self.panes.focused() {
            // Another pane: a text edited in this one is done first, move or
            // visual mode ends, and connect mode is cancelled.
            let ctx = self.shared.ctx(self.buffer());
            let mut actions = self.shared.mode.edit().map(|edit| edit.finish(&ctx)).unwrap_or_default();
            match &self.shared.mode {
                Mode::Move(_) | Mode::Visual(_) => actions.push(Action::App(AppAction::LeaveMode)),
                Mode::Connect(connecting) => actions.extend(connect::cancel(connecting)),
                _ => {}
            }
            self.update(actions);
            self.panes.focus(target);
        }
        let pane = self.panes.current_mut();
        let actions = pane.view.mouse(gesture, &self.shared.ctx(pane.buffer));
        if let Gesture::Release { .. } = gesture {
            self.dragging = None;
        }
        self.update(actions);
    }
}

/// What a command does, in words: its own help, or its operator's.
fn describe(command: Command) -> &'static str {
    match (help_for(Bound::Command(command)), command) {
        ("", Command::Operate(operator, _)) => help_for(Bound::Operator(operator)),
        (help, _) => help,
    }
}