use matrix_sdk::{
    room::Room as MatrixRoom,
    ruma::{OwnedRoomId, RoomId},
};

use modalkit::tui::{buffer::Buffer, layout::Rect, widgets::StatefulWidget};

use modalkit::{
    widgets::textbox::{TextBox, TextBoxState},
    widgets::TerminalCursor,
    widgets::{PromptActions, WindowOps},
};

use modalkit::editing::{
    action::{
        EditError,
        EditInfo,
        EditResult,
        Editable,
        EditorAction,
        Jumpable,
        PromptAction,
        Promptable,
        Scrollable,
    },
    base::{CloseFlags, Count, MoveDir1D, PositionList, ScrollStyle, WordStyle},
    context::Resolve,
    history::{self, HistoryList},
    rope::EditRope,
};

use crate::base::{
    IambAction,
    IambBufferId,
    IambInfo,
    IambResult,
    ProgramAction,
    ProgramContext,
    ProgramStore,
    RoomFocus,
};

use super::scrollback::{Scrollback, ScrollbackState};

pub struct ChatState {
    room_id: OwnedRoomId,
    room: MatrixRoom,

    tbox: TextBoxState<IambInfo>,
    sent: HistoryList<EditRope>,
    sent_scrollback: history::ScrollbackState,

    scrollback: ScrollbackState,
    focus: RoomFocus,
}

impl ChatState {
    pub fn new(room: MatrixRoom, store: &mut ProgramStore) -> Self {
        let room_id = room.room_id().to_owned();
        let scrollback = ScrollbackState::new(room_id.clone());
        let id = IambBufferId::Room(room_id.clone(), RoomFocus::MessageBar);
        let ebuf = store.load_buffer(id);
        let tbox = TextBoxState::new(ebuf);

        ChatState {
            room_id,
            room,

            tbox,
            sent: HistoryList::new(EditRope::from(""), 100),
            sent_scrollback: history::ScrollbackState::Pending,

            scrollback,
            focus: RoomFocus::MessageBar,
        }
    }

    pub fn focus_toggle(&mut self) {
        self.focus = match self.focus {
            RoomFocus::Scrollback => RoomFocus::MessageBar,
            RoomFocus::MessageBar => RoomFocus::Scrollback,
        };
    }

    pub fn room(&self) -> &MatrixRoom {
        &self.room
    }

    pub fn id(&self) -> &RoomId {
        &self.room_id
    }

    pub fn typing_notice(
        &self,
        act: &EditorAction,
        ctx: &ProgramContext,
        store: &mut ProgramStore,
    ) {
        if !self.focus.is_msgbar() || act.is_readonly(ctx) {
            return;
        }

        if !store.application.settings.tunables.typing_notice {
            return;
        }

        store.application.worker.typing_notice(self.room_id.clone());
    }
}

macro_rules! delegate {
    ($s: expr, $id: ident => $e: expr) => {
        match $s.focus {
            RoomFocus::Scrollback => {
                match $s {
                    ChatState { scrollback: $id, .. } => $e,
                }
            },
            RoomFocus::MessageBar => {
                match $s {
                    ChatState { tbox: $id, .. } => $e,
                }
            },
        }
    };
}

impl WindowOps<IambInfo> for ChatState {
    fn draw(&mut self, area: Rect, buf: &mut Buffer, focused: bool, store: &mut ProgramStore) {
        Chat::new(store).focus(focused).render(area, buf, self)
    }

    fn dup(&self, store: &mut ProgramStore) -> Self {
        // XXX: I want each WindowSlot to have its own shared buffer, instead of each Room; need to
        // find a good way to pass that info here so that it can be part of the content id.
        let id = IambBufferId::Room(self.room_id.clone(), RoomFocus::MessageBar);
        let ebuf = store.load_buffer(id);
        let tbox = TextBoxState::new(ebuf);

        ChatState {
            room_id: self.room_id.clone(),
            room: self.room.clone(),

            tbox,
            sent: self.sent.clone(),
            sent_scrollback: history::ScrollbackState::Pending,

            scrollback: self.scrollback.dup(store),
            focus: self.focus,
        }
    }

    fn close(&mut self, _: CloseFlags, _: &mut ProgramStore) -> bool {
        // XXX: what's the right closing behaviour for a room?
        // Should write send a message?
        true
    }

    fn get_cursor_word(&self, style: &WordStyle) -> Option<String> {
        delegate!(self, w => w.get_cursor_word(style))
    }

    fn get_selected_word(&self) -> Option<String> {
        delegate!(self, w => w.get_selected_word())
    }
}

impl Editable<ProgramContext, ProgramStore, IambInfo> for ChatState {
    fn editor_command(
        &mut self,
        act: &EditorAction,
        ctx: &ProgramContext,
        store: &mut ProgramStore,
    ) -> EditResult<EditInfo, IambInfo> {
        self.typing_notice(act, ctx, store);

        match delegate!(self, w => w.editor_command(act, ctx, store)) {
            res @ Ok(_) => res,
            Err(EditError::WrongBuffer(IambBufferId::Room(room_id, focus)))
                if room_id == self.room_id && act.is_switchable(ctx) =>
            {
                // Switch focus.
                self.focus = focus;

                // Run command again.
                delegate!(self, w => w.editor_command(act, ctx, store))
            },
            res @ Err(_) => res,
        }
    }
}

impl TerminalCursor for ChatState {
    fn get_term_cursor(&self) -> Option<(u16, u16)> {
        delegate!(self, w => w.get_term_cursor())
    }
}

impl Jumpable<ProgramContext, IambInfo> for ChatState {
    fn jump(
        &mut self,
        list: PositionList,
        dir: MoveDir1D,
        count: usize,
        ctx: &ProgramContext,
    ) -> IambResult<usize> {
        delegate!(self, w => w.jump(list, dir, count, ctx))
    }
}

impl Scrollable<ProgramContext, ProgramStore, IambInfo> for ChatState {
    fn scroll(
        &mut self,
        style: &ScrollStyle,
        ctx: &ProgramContext,
        store: &mut ProgramStore,
    ) -> EditResult<EditInfo, IambInfo> {
        // Send all scroll commands to the scrollback.
        //
        // If there's enough message text for scrolling to be necessary,
        // navigating with movement keys should be enough to do the job.
        self.scrollback.scroll(style, ctx, store)
    }
}

impl PromptActions<ProgramContext, ProgramStore, IambInfo> for ChatState {
    fn submit(
        &mut self,
        ctx: &ProgramContext,
        _: &mut ProgramStore,
    ) -> EditResult<Vec<(ProgramAction, ProgramContext)>, IambInfo> {
        let txt = self.tbox.reset_text();

        let act = if txt.is_empty() {
            vec![]
        } else {
            let act = IambAction::SendMessage(self.room_id.clone(), txt).into();

            vec![(act, ctx.clone())]
        };

        Ok(act)
    }

    fn abort(
        &mut self,
        empty: bool,
        _: &ProgramContext,
        _: &mut ProgramStore,
    ) -> EditResult<Vec<(ProgramAction, ProgramContext)>, IambInfo> {
        let text = self.tbox.get();

        if empty && text.is_blank() {
            return Ok(vec![]);
        }

        let text = self.tbox.reset().trim();

        if text.is_empty() {
            let _ = self.sent.end();
        } else {
            self.sent.select(text);
        }

        return Ok(vec![]);
    }

    fn recall(
        &mut self,
        dir: &MoveDir1D,
        count: &Count,
        ctx: &ProgramContext,
        _: &mut ProgramStore,
    ) -> EditResult<Vec<(ProgramAction, ProgramContext)>, IambInfo> {
        let count = ctx.resolve(count);
        let rope = self.tbox.get();

        let text = self.sent.recall(&rope, &mut self.sent_scrollback, *dir, count);

        if let Some(text) = text {
            self.tbox.set_text(text);
        }

        Ok(vec![])
    }
}

impl Promptable<ProgramContext, ProgramStore, IambInfo> for ChatState {
    fn prompt(
        &mut self,
        act: &PromptAction,
        ctx: &ProgramContext,
        store: &mut ProgramStore,
    ) -> EditResult<Vec<(ProgramAction, ProgramContext)>, IambInfo> {
        if let RoomFocus::Scrollback = self.focus {
            return Ok(vec![]);
        }

        match act {
            PromptAction::Submit => self.submit(ctx, store),
            PromptAction::Abort(empty) => self.abort(*empty, ctx, store),
            PromptAction::Recall(dir, count) => self.recall(dir, count, ctx, store),
            _ => Err(EditError::Unimplemented("unknown prompt action".to_string())),
        }
    }
}

pub struct Chat<'a> {
    store: &'a mut ProgramStore,
    focused: bool,
}

impl<'a> Chat<'a> {
    pub fn new(store: &'a mut ProgramStore) -> Chat<'a> {
        Chat { store, focused: false }
    }

    pub fn focus(mut self, focused: bool) -> Self {
        self.focused = focused;
        self
    }
}

impl<'a> StatefulWidget for Chat<'a> {
    type State = ChatState;

    fn render(self, area: Rect, buf: &mut Buffer, state: &mut Self::State) {
        let lines = state.tbox.has_lines(5).max(1) as u16;
        let drawh = area.height;
        let texth = lines.min(drawh).clamp(1, 5);
        let scrollh = drawh.saturating_sub(texth);

        let scrollarea = Rect::new(area.x, area.y, area.width, scrollh);
        let textarea = Rect::new(scrollarea.x, scrollarea.y + scrollh, scrollarea.width, texth);

        let scrollback_focused = state.focus.is_scrollback() && self.focused;
        let scrollback = Scrollback::new(self.store).focus(scrollback_focused);
        scrollback.render(scrollarea, buf, &mut state.scrollback);

        let prompt = if self.focused { "> " } else { "  " };

        let tbox = TextBox::new().prompt(prompt);
        tbox.render(textarea, buf, &mut state.tbox);
    }
}