/*
Copyright 2021 The Matrix.org Foundation C.I.C.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

import React, { ReactNode, useContext, useMemo, useRef, useState } from "react";
import classNames from "classnames";
import { Room } from "matrix-js-sdk/src/models/room";
import { sleep } from "matrix-js-sdk/src/utils";
import { EventType } from "matrix-js-sdk/src/@types/event";
import { logger } from "matrix-js-sdk/src/logger";

import { _t, _td } from '../../../languageHandler';
import BaseDialog from "./BaseDialog";
import Dropdown from "../elements/Dropdown";
import SearchBox from "../../structures/SearchBox";
import SpaceStore from "../../../stores/spaces/SpaceStore";
import RoomAvatar from "../avatars/RoomAvatar";
import { getDisplayAliasForRoom } from "../../../Rooms";
import AccessibleButton, { ButtonEvent } from "../elements/AccessibleButton";
import AutoHideScrollbar from "../../structures/AutoHideScrollbar";
import DMRoomMap from "../../../utils/DMRoomMap";
import { calculateRoomVia } from "../../../utils/permalinks/Permalinks";
import StyledCheckbox from "../elements/StyledCheckbox";
import MatrixClientContext from "../../../contexts/MatrixClientContext";
import { sortRooms } from "../../../stores/room-list/algorithms/tag-sorting/RecentAlgorithm";
import ProgressBar from "../elements/ProgressBar";
import DecoratedRoomAvatar from "../avatars/DecoratedRoomAvatar";
import QueryMatcher from "../../../autocomplete/QueryMatcher";
import LazyRenderList from "../elements/LazyRenderList";

// These values match CSS
const ROW_HEIGHT = 32 + 12;
const HEADER_HEIGHT = 15;
const GROUP_MARGIN = 24;

interface IProps {
    space: Room;
    onCreateRoomClick(ev: ButtonEvent): void;
    onAddSubspaceClick(): void;
    onFinished(added?: boolean): void;
}

export const Entry = ({ room, checked, onChange }) => {
    return <label className="mx_AddExistingToSpace_entry">
        { room?.isSpaceRoom()
            ? <RoomAvatar room={room} height={32} width={32} />
            : <DecoratedRoomAvatar room={room} avatarSize={32} />
        }
        <span className="mx_AddExistingToSpace_entry_name">{ room.name }</span>
        <StyledCheckbox
            onChange={onChange ? (e) => onChange(e.target.checked) : null}
            checked={checked}
            disabled={!onChange}
        />
    </label>;
};

type OnChangeFn = (checked: boolean, room: Room) => void;

type Renderer = (
    rooms: Room[],
    selectedToAdd: Set<Room>,
    scrollState: IScrollState,
    onChange: undefined | OnChangeFn,
) => ReactNode;

interface IAddExistingToSpaceProps {
    space: Room;
    footerPrompt?: ReactNode;
    filterPlaceholder: string;
    emptySelectionButton?: ReactNode;
    onFinished(added: boolean): void;
    roomsRenderer?: Renderer;
    spacesRenderer?: Renderer;
    dmsRenderer?: Renderer;
}

interface IScrollState {
    scrollTop: number;
    height: number;
}

const getScrollState = (
    { scrollTop, height }: IScrollState,
    numItems: number,
    ...prevGroupSizes: number[]
): IScrollState => {
    let heightBefore = 0;
    prevGroupSizes.forEach(size => {
        heightBefore += GROUP_MARGIN + HEADER_HEIGHT + (size * ROW_HEIGHT);
    });

    const viewportTop = scrollTop;
    const viewportBottom = viewportTop + height;
    const listTop = heightBefore + HEADER_HEIGHT;
    const listBottom = listTop + (numItems * ROW_HEIGHT);
    const top = Math.max(viewportTop, listTop);
    const bottom = Math.min(viewportBottom, listBottom);
    // the viewport height and scrollTop passed to the LazyRenderList
    // is capped at the intersection with the real viewport, so lists
    // out of view are passed height 0, so they won't render any items.
    return {
        scrollTop: Math.max(0, scrollTop - listTop),
        height: Math.max(0, bottom - top),
    };
};

export const AddExistingToSpace: React.FC<IAddExistingToSpaceProps> = ({
    space,
    footerPrompt,
    emptySelectionButton,
    filterPlaceholder,
    roomsRenderer,
    dmsRenderer,
    spacesRenderer,
    onFinished,
}) => {
    const cli = useContext(MatrixClientContext);
    const visibleRooms = useMemo(() => cli.getVisibleRooms().filter(r => r.getMyMembership() === "join"), [cli]);

    const scrollRef = useRef<AutoHideScrollbar>();
    const [scrollState, setScrollState] = useState<IScrollState>({
        // these are estimates which update as soon as it mounts
        scrollTop: 0,
        height: 600,
    });

    const [selectedToAdd, setSelectedToAdd] = useState(new Set<Room>());
    const [progress, setProgress] = useState<number>(null);
    const [error, setError] = useState<Error>(null);
    const [query, setQuery] = useState("");
    const lcQuery = query.toLowerCase().trim();

    const existingSubspacesSet = useMemo(() => new Set(SpaceStore.instance.getChildSpaces(space.roomId)), [space]);
    const existingRoomsSet = useMemo(() => new Set(SpaceStore.instance.getChildRooms(space.roomId)), [space]);

    const [spaces, rooms, dms] = useMemo(() => {
        let rooms = visibleRooms;

        if (lcQuery) {
            const matcher = new QueryMatcher<Room>(visibleRooms, {
                keys: ["name"],
                funcs: [r => [r.getCanonicalAlias(), ...r.getAltAliases()].filter(Boolean)],
                shouldMatchWordsOnly: false,
            });

            rooms = matcher.match(lcQuery);
        }

        const joinRule = space.getJoinRule();
        return sortRooms(rooms).reduce((arr, room) => {
            if (room.isSpaceRoom()) {
                if (room !== space && !existingSubspacesSet.has(room)) {
                    arr[0].push(room);
                }
            } else if (!existingRoomsSet.has(room)) {
                if (!DMRoomMap.shared().getUserIdForRoomId(room.roomId)) {
                    arr[1].push(room);
                } else if (joinRule !== "public") {
                    // Only show DMs for non-public spaces as they make very little sense in spaces other than "Just Me" ones.
                    arr[2].push(room);
                }
            }
            return arr;
        }, [[], [], []]);
    }, [visibleRooms, space, lcQuery, existingRoomsSet, existingSubspacesSet]);

    const addRooms = async () => {
        setError(null);
        setProgress(0);

        let error;

        for (const room of selectedToAdd) {
            const via = calculateRoomVia(room);
            try {
                await SpaceStore.instance.addRoomToSpace(space, room.roomId, via).catch(async e => {
                    if (e.errcode === "M_LIMIT_EXCEEDED") {
                        await sleep(e.data.retry_after_ms);
                        return SpaceStore.instance.addRoomToSpace(space, room.roomId, via); // retry
                    }

                    throw e;
                });
                setProgress(i => i + 1);
            } catch (e) {
                logger.error("Failed to add rooms to space", e);
                setError(error = e);
                break;
            }
        }

        if (!error) {
            onFinished(true);
        }
    };

    const busy = progress !== null;

    let footer;
    if (error) {
        footer = <>
            <img
                src={require("../../../../res/img/element-icons/warning-badge.svg").default}
                height="24"
                width="24"
                alt=""
            />

            <span className="mx_AddExistingToSpaceDialog_error">
                <div className="mx_AddExistingToSpaceDialog_errorHeading">{ _t("Not all selected were added") }</div>
                <div className="mx_AddExistingToSpaceDialog_errorCaption">{ _t("Try again") }</div>
            </span>

            <AccessibleButton className="mx_AddExistingToSpaceDialog_retryButton" onClick={addRooms}>
                { _t("Retry") }
            </AccessibleButton>
        </>;
    } else if (busy) {
        footer = <span>
            <ProgressBar value={progress} max={selectedToAdd.size} />
            <div className="mx_AddExistingToSpaceDialog_progressText">
                { _t("Adding rooms... (%(progress)s out of %(count)s)", {
                    count: selectedToAdd.size,
                    progress,
                }) }
            </div>
        </span>;
    } else {
        let button = emptySelectionButton;
        if (!button || selectedToAdd.size > 0) {
            button = <AccessibleButton kind="primary" disabled={selectedToAdd.size < 1} onClick={addRooms}>
                { _t("Add") }
            </AccessibleButton>;
        }

        footer = <>
            <span>
                { footerPrompt }
            </span>

            { button }
        </>;
    }

    const onChange = !busy && !error ? (checked: boolean, room: Room) => {
        if (checked) {
            selectedToAdd.add(room);
        } else {
            selectedToAdd.delete(room);
        }
        setSelectedToAdd(new Set(selectedToAdd));
    } : null;

    // only count spaces when alone as they're shown on a separate modal all on their own
    const numSpaces = (spacesRenderer && !dmsRenderer && !roomsRenderer) ? spaces.length : 0;
    const numRooms = roomsRenderer ? rooms.length : 0;
    const numDms = dmsRenderer ? dms.length : 0;

    let noResults = true;
    if (numSpaces > 0 || numRooms > 0 || numDms > 0) {
        noResults = false;
    }

    const onScroll = () => {
        const body = scrollRef.current?.containerRef.current;
        setScrollState({
            scrollTop: body.scrollTop,
            height: body.clientHeight,
        });
    };

    const wrappedRef = (body: HTMLDivElement) => {
        setScrollState({
            scrollTop: body.scrollTop,
            height: body.clientHeight,
        });
    };

    const roomsScrollState = getScrollState(scrollState, numRooms);
    const spacesScrollState = getScrollState(scrollState, numSpaces, numRooms);
    const dmsScrollState = getScrollState(scrollState, numDms, numSpaces, numRooms);

    return <div className="mx_AddExistingToSpace">
        <SearchBox
            className="mx_textinput_icon mx_textinput_search"
            placeholder={filterPlaceholder}
            onSearch={setQuery}
            autoFocus={true}
        />
        <AutoHideScrollbar
            className="mx_AddExistingToSpace_content"
            onScroll={onScroll}
            wrappedRef={wrappedRef}
            ref={scrollRef}
        >
            { rooms.length > 0 && roomsRenderer ? (
                roomsRenderer(rooms, selectedToAdd, roomsScrollState, onChange)
            ) : undefined }

            { spaces.length > 0 && spacesRenderer ? (
                spacesRenderer(spaces, selectedToAdd, spacesScrollState, onChange)
            ) : null }

            { dms.length > 0 && dmsRenderer ? (
                dmsRenderer(dms, selectedToAdd, dmsScrollState, onChange)
            ) : null }

            { noResults ? <span className="mx_AddExistingToSpace_noResults">
                { _t("No results") }
            </span> : undefined }
        </AutoHideScrollbar>

        <div className="mx_AddExistingToSpace_footer">
            { footer }
        </div>
    </div>;
};

const defaultRendererFactory = (title: string): Renderer => (
    rooms,
    selectedToAdd,
    { scrollTop, height },
    onChange,
) => (
    <div className="mx_AddExistingToSpace_section">
        <h3>{ _t(title) }</h3>
        <LazyRenderList
            itemHeight={ROW_HEIGHT}
            items={rooms}
            scrollTop={scrollTop}
            height={height}
            renderItem={room => (
                <Entry
                    key={room.roomId}
                    room={room}
                    checked={selectedToAdd.has(room)}
                    onChange={onChange ? (checked: boolean) => {
                        onChange(checked, room);
                    } : null}
                />
            )}
        />
    </div>
);

export const defaultRoomsRenderer = defaultRendererFactory(_td("Rooms"));
export const defaultSpacesRenderer = defaultRendererFactory(_td("Spaces"));
export const defaultDmsRenderer = defaultRendererFactory(_td("Direct Messages"));

interface ISubspaceSelectorProps {
    title: string;
    space: Room;
    value: Room;
    onChange(space: Room): void;
}

export const SubspaceSelector = ({ title, space, value, onChange }: ISubspaceSelectorProps) => {
    const options = useMemo(() => {
        return [space, ...SpaceStore.instance.getChildSpaces(space.roomId).filter(space => {
            return space.currentState.maySendStateEvent(EventType.SpaceChild, space.client.credentials.userId);
        })];
    }, [space]);

    let body;
    if (options.length > 1) {
        body = (
            <Dropdown
                id="mx_SpaceSelectDropdown"
                className="mx_SpaceSelectDropdown"
                onOptionChange={(key: string) => {
                    onChange(options.find(space => space.roomId === key) || space);
                }}
                value={value.roomId}
                label={_t("Space selection")}
            >
                { options.map((space) => {
                    const classes = classNames({
                        mx_SubspaceSelector_dropdownOptionActive: space === value,
                    });
                    return <div key={space.roomId} className={classes}>
                        <RoomAvatar room={space} width={24} height={24} />
                        { space.name || getDisplayAliasForRoom(space) || space.roomId }
                    </div>;
                }) }
            </Dropdown>
        );
    } else {
        body = (
            <div className="mx_SubspaceSelector_onlySpace">
                { space.name || getDisplayAliasForRoom(space) || space.roomId }
            </div>
        );
    }

    return <div className="mx_SubspaceSelector">
        <RoomAvatar room={value} height={40} width={40} />
        <div>
            <h1>{ title }</h1>
            { body }
        </div>
    </div>;
};

const AddExistingToSpaceDialog: React.FC<IProps> = ({ space, onCreateRoomClick, onAddSubspaceClick, onFinished }) => {
    const [selectedSpace, setSelectedSpace] = useState(space);

    return <BaseDialog
        title={(
            <SubspaceSelector
                title={_t("Add existing rooms")}
                space={space}
                value={selectedSpace}
                onChange={setSelectedSpace}
            />
        )}
        className="mx_AddExistingToSpaceDialog"
        contentId="mx_AddExistingToSpace"
        onFinished={onFinished}
        fixedWidth={false}
    >
        <MatrixClientContext.Provider value={space.client}>
            <AddExistingToSpace
                space={space}
                onFinished={onFinished}
                footerPrompt={<>
                    <div>{ _t("Want to add a new room instead?") }</div>
                    <AccessibleButton
                        kind="link"
                        onClick={(ev: ButtonEvent) => {
                            onCreateRoomClick(ev);
                            onFinished();
                        }}
                    >
                        { _t("Create a new room") }
                    </AccessibleButton>
                </>}
                filterPlaceholder={_t("Search for rooms")}
                roomsRenderer={defaultRoomsRenderer}
                spacesRenderer={() => (
                    <div className="mx_AddExistingToSpace_section">
                        <h3>{ _t("Spaces") }</h3>
                        <AccessibleButton
                            kind="link"
                            onClick={() => {
                                onAddSubspaceClick();
                                onFinished();
                            }}
                        >
                            { _t("Adding spaces has moved.") }
                        </AccessibleButton>
                    </div>
                )}
                dmsRenderer={defaultDmsRenderer}
            />
        </MatrixClientContext.Provider>
    </BaseDialog>;
};

export default AddExistingToSpaceDialog;

