use super::MainTui;
use super::input::{FilterEdit, edit_filter, jumped, list_jump, scroll_log};
use crate::models::{ChatFilter, RoomsView};
use ratatui::crossterm::event::{KeyCode, KeyEvent, KeyModifiers};

impl MainTui {
    /// Open the chat-rooms popup and refresh the room list. If rooms are
    /// already open, jump straight to the chat view; otherwise show the list.
    pub(super) fn start_rooms(&mut self) {
        let _ = self.client.request_room_list();
        self.state.show_rooms = true;
        if self.state.rooms.open.is_empty() {
            self.state.rooms.view = RoomsView::List;
        } else {
            self.state.rooms.view = RoomsView::Chat;
            self.state.rooms.mark_active_read();
        }
    }

    pub(super) fn handle_rooms_input(&mut self, key: KeyEvent) {
        // Composing a message captures typing.
        if self.state.rooms.composing {
            self.handle_room_compose_input(key);
            return;
        }
        // Filtering the room list captures typing.
        if self.state.rooms.view == RoomsView::List
            && self.state.rooms.list_is_filtering
        {
            self.handle_room_filter_input(key);
            return;
        }
        // So does typing a filter over the log or the member list; the
        // other keys still move around.
        if self.state.rooms.view == RoomsView::Chat
            && self.state.rooms.filtering.is_some()
            && self.handle_chat_filter_input(key)
        {
            return;
        }

        match self.state.rooms.view {
            RoomsView::List => self.handle_rooms_list_input(key),
            RoomsView::Chat => self.handle_rooms_chat_input(key),
        }
    }

    fn handle_rooms_list_input(&mut self, key: KeyEvent) {
        let len = self.state.rooms.filtered_rooms().len();
        if let Some(jump) = list_jump(key, self.popup_page(1)) {
            self.state.rooms.list_selected =
                jumped(self.state.rooms.list_selected, len, jump);
            return;
        }
        // Control combinations are only ever jumps; the letters below are
        // not theirs to trigger.
        if key.modifiers.contains(KeyModifiers::CONTROL) {
            return;
        }
        match key.code {
            // Esc peels back one level: clear a lingering filter first (as the
            // title's "Esc: clear" promises), otherwise close the popup.
            KeyCode::Esc if !self.state.rooms.list_filter.is_empty() => {
                self.state.rooms.list_filter.clear();
                self.state.rooms.list_selected = 0;
            }
            KeyCode::Esc | KeyCode::Char('q') => {
                self.state.show_rooms = false;
            }
            KeyCode::Char('/') => {
                self.state.rooms.list_is_filtering = true;
            }
            KeyCode::Up | KeyCode::Char('k') => {
                self.state.rooms.list_selected =
                    self.state.rooms.list_selected.saturating_sub(1);
            }
            KeyCode::Down | KeyCode::Char('j') if len > 0 => {
                self.state.rooms.list_selected =
                    (self.state.rooms.list_selected + 1).min(len - 1);
            }
            KeyCode::Enter => self.join_selected_room(),
            KeyCode::Tab if !self.state.rooms.open.is_empty() => {
                self.state.rooms.view = RoomsView::Chat;
                self.state.rooms.mark_active_read();
            }
            _ => {}
        }
    }

    fn handle_room_filter_input(&mut self, key: KeyEvent) {
        let Some(edit) = edit_filter(&mut self.state.rooms.list_filter, key)
        else {
            return self.handle_rooms_list_input(key);
        };
        match edit {
            FilterEdit::Changed | FilterEdit::Cleared => {
                self.state.rooms.list_selected = 0;
            }
            FilterEdit::Kept => self.join_selected_room(),
        }
        if edit != FilterEdit::Changed {
            self.state.rooms.list_is_filtering = false;
        }
    }

    fn handle_rooms_chat_input(&mut self, key: KeyEvent) {
        // Paging keys move through the room's history; the member list is a
        // row at a time.
        if let Some(view) = self.state.rooms.active_view_mut()
            && scroll_log(view, key)
        {
            return;
        }
        if key.modifiers.contains(KeyModifiers::CONTROL) {
            return;
        }
        let filtered = !self.state.rooms.log_filter.is_empty()
            || !self.state.rooms.user_filter.is_empty();
        match key.code {
            KeyCode::Char('q') => self.state.show_rooms = false,
            // Esc peels back one level: the filters first, then the list.
            KeyCode::Esc if filtered => {
                self.state.rooms.set_log_filter(String::new());
                self.state.rooms.set_user_filter(String::new());
            }
            KeyCode::Esc | KeyCode::Char('l') => {
                self.state.rooms.view = RoomsView::List;
            }
            KeyCode::Char('/') => {
                self.state.rooms.filtering = Some(ChatFilter::Log);
            }
            KeyCode::Char('u') => {
                self.state.rooms.filtering = Some(ChatFilter::Users);
            }
            KeyCode::Tab => self.state.rooms.next_tab(),
            KeyCode::BackTab => self.state.rooms.prev_tab(),
            KeyCode::Char('x') => self.leave_active_room(),
            KeyCode::Up | KeyCode::Char('k') => {
                self.state.rooms.select_user_up();
            }
            KeyCode::Down | KeyCode::Char('j') => {
                self.state.rooms.select_user_down();
            }
            // Act on the highlighted member of the room.
            KeyCode::Char('b') => self.browse_selected_room_user(),
            KeyCode::Char('m') => self.message_selected_room_user(),
            KeyCode::Enter if self.state.rooms.active_room().is_some() => {
                self.state.rooms.composing = true;
            }
            _ => {}
        }
    }

    /// The keys that edit whichever filter is being typed, the log's or the
    /// member list's. Says whether `key` was one of them.
    fn handle_chat_filter_input(&mut self, key: KeyEvent) -> bool {
        let rooms = &mut self.state.rooms;
        let over_log = rooms.filtering == Some(ChatFilter::Log);
        let mut filter = if over_log {
            rooms.log_filter.clone()
        } else {
            rooms.user_filter.clone()
        };
        let Some(edit) = edit_filter(&mut filter, key) else {
            return false;
        };
        if edit != FilterEdit::Changed {
            rooms.filtering = None;
        }
        // Keeping a filter leaves the view where it is.
        if edit != FilterEdit::Kept {
            if over_log {
                rooms.set_log_filter(filter);
            } else {
                rooms.set_user_filter(filter);
            }
        }
        true
    }

    /// Browse the shares of the member highlighted in the active room. Closes
    /// the rooms popup so the browse tree is the sole overlay.
    fn browse_selected_room_user(&mut self) {
        if let Some(user) = self.state.rooms.selected_user() {
            self.state.show_rooms = false;
            self.start_browse(user);
        }
    }

    /// Compose a private message to the member highlighted in the active room.
    /// Closes the rooms popup and opens the chat box on that conversation.
    fn message_selected_room_user(&mut self) {
        if let Some(user) = self.state.rooms.selected_user() {
            self.state.show_rooms = false;
            self.state.open_chat(user);
        }
    }

    fn handle_room_compose_input(&mut self, key: KeyEvent) {
        match key.code {
            KeyCode::Enter => self.send_room_message(),
            KeyCode::Esc => {
                self.state.rooms.composing = false;
                if let Some(room) =
                    self.state.rooms.open.get_mut(self.state.rooms.active)
                {
                    room.input.clear();
                }
            }
            KeyCode::Backspace => {
                if let Some(room) =
                    self.state.rooms.open.get_mut(self.state.rooms.active)
                {
                    room.input.pop();
                }
            }
            KeyCode::Char(c)
                if !key
                    .modifiers
                    .intersects(KeyModifiers::CONTROL | KeyModifiers::ALT) =>
            {
                if let Some(room) =
                    self.state.rooms.open.get_mut(self.state.rooms.active)
                {
                    room.input.push(c);
                }
            }
            _ => {}
        }
    }

    /// Join (or focus) the room highlighted in the list view.
    fn join_selected_room(&mut self) {
        if let Some(name) = self.state.rooms.selected_room_name() {
            let newly_opened = self.state.rooms.focus_or_open(&name);
            if newly_opened && let Err(e) = self.client.join_room(&name) {
                soulseek_rs::warn!("Failed to join {name}: {e}");
            }
        }
    }

    /// Leave the active room and close its tab.
    fn leave_active_room(&mut self) {
        if let Some(name) = self.state.rooms.close_active()
            && let Err(e) = self.client.leave_room(&name)
        {
            soulseek_rs::warn!("Failed to leave {name}: {e}");
        }
    }

    /// Send the active room's compose buffer. The server echoes the message
    /// back as a RoomEvent, which is what actually renders it in the log.
    fn send_room_message(&mut self) {
        let active = self.state.rooms.active;
        let (room, text) = match self.state.rooms.open.get(active) {
            Some(room) if !room.input.trim().is_empty() => {
                (room.name.clone(), room.input.trim().to_string())
            }
            _ => {
                self.state.rooms.composing = false;
                return;
            }
        };
        if let Err(e) = self.client.say_in_room(&room, &text) {
            soulseek_rs::warn!("Failed to say in {room}: {e}");
        }
        if let Some(room) = self.state.rooms.open.get_mut(active) {
            room.input.clear();
        }
        self.state.rooms.composing = false;
    }

    /// The room whose newest messages are on screen, if any: the active one
    /// in the chat view, unless the reader is held back in its history, when
    /// what arrives still counts as unread.
    pub(super) fn viewed_room(&self) -> Option<String> {
        if !self.state.show_rooms || self.state.rooms.view != RoomsView::Chat {
            return None;
        }
        self.state
            .rooms
            .active_room()
            .filter(|room| room.view.following())
            .map(|room| room.name.clone())
    }

    /// Drain chat-room events into the rooms state, tracking unread badges.
    pub(super) fn poll_room_events(&mut self) {
        let viewing = self.viewed_room();
        for event in self.client.take_room_events() {
            self.state.rooms.apply_event(event, viewing.as_deref());
        }
    }
}