// @flow

import {
    getParticipantCountWithFake,
    getPinnedParticipant
} from '../base/participants';
import { toState } from '../base/redux';

import { TILE_ASPECT_RATIO } from './constants';

declare var interfaceConfig: Object;

/**
 * Returns true if the filmstrip on mobile is visible, false otherwise.
 *
 * NOTE: Filmstrip on web behaves differently to mobile, much simpler, but so
 * function lies here only for the sake of consistency and to avoid flow errors
 * on import.
 *
 * @param {Object | Function} stateful - The Object or Function that can be
 * resolved to a Redux state object with the toState function.
 * @returns {boolean}
 */
export function isFilmstripVisible(stateful: Object | Function) {
    return toState(stateful)['features/filmstrip'].visible;
}

/**
 * Determines whether the remote video thumbnails should be displayed/visible in
 * the filmstrip.
 *
 * @param {Object} state - The full redux state.
 * @returns {boolean} - If remote video thumbnails should be displayed/visible
 * in the filmstrip, then {@code true}; otherwise, {@code false}.
 */
export function shouldRemoteVideosBeVisible(state: Object) {
    if (state['features/invite'].calleeInfoVisible) {
        return false;
    }

    // Include fake participants to derive how many thumbnails are dispalyed,
    // as it is assumed all participants, including fake, will be displayed
    // in the filmstrip.
    const participantCount = getParticipantCountWithFake(state);
    let pinnedParticipant;

    return Boolean(
        participantCount > 2

            // Always show the filmstrip when there is another participant to
            // show and the filmstrip is hovered, or local video is pinned, or
            // the toolbar is displayed.
            || (participantCount > 1
                && (state['features/filmstrip'].hovered
                    || state['features/toolbox'].visible
                    || ((pinnedParticipant = getPinnedParticipant(state))
                        && pinnedParticipant.local)))

            || state['features/base/config'].disable1On1Mode);
}

/**
 * Calculates the size for thumbnails when in horizontal view layout.
 *
 * @param {number} clientHeight - The height of the app window.
 * @returns {{local: {height, width}, remote: {height, width}}}
 */
export function calculateThumbnailSizeForHorizontalView(clientHeight: number = 0) {
    const topBottomMargin = 15;
    const availableHeight = Math.min(clientHeight, (interfaceConfig.FILM_STRIP_MAX_HEIGHT || 120) + topBottomMargin);
    const height = availableHeight - topBottomMargin;

    return {
        local: {
            height,
            width: Math.floor(interfaceConfig.LOCAL_THUMBNAIL_RATIO * height)
        },
        remote: {
            height,
            width: Math.floor(interfaceConfig.REMOTE_THUMBNAIL_RATIO * height)
        }
    };
}

/**
 * Calculates the size for thumbnails when in tile view layout.
 *
 * @param {Object} dimensions - The desired dimensions of the tile view grid.
 * @returns {{height, width}}
 */
export function calculateThumbnailSizeForTileView({
    columns,
    visibleRows,
    clientWidth,
    clientHeight
}: Object) {
    // Minimum space to keep between the sides of the tiles and the sides
    // of the window.
    const sideMargins = 30 * 2;

    const verticalMargins = visibleRows * 10;
    const viewWidth = clientWidth - sideMargins;
    const viewHeight = clientHeight - verticalMargins;
    const initialWidth = viewWidth / columns;
    const aspectRatioHeight = initialWidth / TILE_ASPECT_RATIO;
    const height = Math.floor(Math.min(aspectRatioHeight, viewHeight / visibleRows));
    const width = Math.floor(TILE_ASPECT_RATIO * height);

    return {
        height,
        width
    };
}

/**
 * Returns the width of the visible area (doesn't include the left margin/padding) of the the vertical filmstrip.
 *
 * @returns {number} - The width of the vertical filmstrip.
 */
export function getVerticalFilmstripVisibleAreaWidth() {
    // Adding 11px for the 2px right margin, 2px borders on the left and right and 5px right padding.
    // Also adding 7px for the scrollbar. Note that we are not counting the left margins and paddings because this
    // function is used for calculating the available space and they are invisible.
    // TODO: Check if we can remove the left margins and paddings from the CSS.
    // FIXME: This function is used to calculate the size of the large video, etherpad or shared video. Once everything
    // is reactified this calculation will need to move to the corresponding components.
    const filmstripMaxWidth = (interfaceConfig.FILM_STRIP_MAX_HEIGHT || 120) + 18;

    return Math.min(filmstripMaxWidth, window.innerWidth);
}