satie/src/private_views_metadata.ts

A sheet music renderer for the web

/**
 * This file is part of Satie music engraver <https://github.com/jnetterf/satie>.
 * Copyright (C) Joshua Netterfield <joshua.ca> 2015 - present.
 * 
 * Satie is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as
 * published by the Free Software Foundation, either version 3 of the
 * License, or (at your option) any later version.
 * 
 * Satie is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Affero General Public License for more details.
 * 
 * You should have received a copy of the GNU Affero General Public License
 * along with Satie.  If not, see <http://www.gnu.org/licenses/>.
 */

import {Component, ComponentLifecycle} from "react";
import * as invariant from "invariant";
import {isEqual, sortedIndex, indexOf} from "lodash";

import {ILayout} from "./document";

export interface IBaseProps {
    layout: ILayout;
    originX: number;
}

export interface IMetaComponent<P, S> extends Component<P, S>, ComponentLifecycle<P, S> {
    context: {
        originYByPartAndStaff: {[key: string]: number[]};
    };
    _record?: IRecord;
}

export interface ILookup {
    x: number;
    y: number;
}

export interface IRecord {
    key: string;
    obj: any;
    x1: number;
    x2: number;
    y1: number;
    y2: number;
    originY: number;
}

/**
 * A decorator that records the position of a component.
 */
export function Targetable<P extends IBaseProps, S>() {
    return function decorator(component: {prototype: IMetaComponent<P, S>}) {
        function updateMeta(self: IMetaComponent<P, S>, props: P) {
            const layout = props.layout;

            let originX: number = props.originX;
            let originY = self.context.originYByPartAndStaff[
                layout.part][layout.model.staffIdx || 1] || 0;

            let newRecord: IRecord  = {
                key: props.layout.key,
                obj: self,
                x1: originX + props.layout.x - 2,
                x2: originX + props.layout.x + props.layout.renderedWidth,
                y1: originY - 60,
                y2: originY + 60,
                originY,
            };

            if (self._record) {
                if (isEqual(newRecord, self._record)) {
                    return;
                }

                clearMeta(self);
            }
            if (isNaN(props.layout.renderedWidth)) {
                console.warn("Missing rendered width in", props.layout.key);
                return;
            }

            self._record = {
                key: props.layout.key,
                obj: self,
                x1: originX + props.layout.x - 2,
                x2: originX + props.layout.x + props.layout.renderedWidth,
                y1: originY - 60,
                y2: originY + 60,
                originY,
            };

            set(self._record);
        }

        function clearMeta(self: IMetaComponent<P, S>) {
            clear(self._record);
            self._record = null;
        }

        // ---- //

        let originalComponentWillMount =
            component.prototype.componentWillMount;

        component.prototype.componentWillMount =
            function metaComponentWillMountWrapper() {
                let self = this as IMetaComponent<P, S>;
                updateMeta(self, self.props);

                if (originalComponentWillMount) {
                    originalComponentWillMount.call(self);
                }
            };

        // ---- //

        let originalComponentWillUnmount =
            component.prototype.componentWillUnmount;

        component.prototype.componentWillUnmount =
            function metaComponentWillUnmountWrapper() {
                let self = this as IMetaComponent<P, S>;
                clearMeta(self);

                if (originalComponentWillUnmount) {
                    originalComponentWillUnmount.call(self);
                }
            };

        // ---- //

        let originalComponentWillReceiveProps =
            component.prototype.componentWillReceiveProps;

        component.prototype.componentWillReceiveProps =
            function metaComponentWillReceiveProps(nextProps: P) {
                let self = this as IMetaComponent<P, S>;

                updateMeta(self, nextProps);

                if (originalComponentWillReceiveProps) {
                    originalComponentWillReceiveProps.call(self);
                }
            };
    };
}

let _sorted: IRecord[] = [];
let _weights: number[] = [];

function set(record: IRecord) {
    let weight = weightForRecord(record);
    let idx = sortedIndex(_weights, weight);
    _sorted.splice(idx, 0, record);
    _weights.splice(idx, 0, weight);
}

function clear(record: IRecord) {
    let weight = weightForRecord(record);
    let firstPossibleIdx = sortedIndex(_weights, weight);
    let idx = indexOf(_sorted, record, firstPossibleIdx);

    invariant(idx >= 0, `${record.key} not currently in array.`);
    _sorted.splice(idx, 1);
    _weights.splice(idx, 1);
}

export function get(lookup: ILookup): IRecord {
    let {x, y} = lookup;
    let weight = weightForLookup(lookup);
    let firstPossibleIdx = sortedIndex(_weights, weight);
    for (let i = firstPossibleIdx; i < _sorted.length; ++i) {
        let record = _sorted[i];
        if (_sorted[i].x1 <= x && _sorted[i].x2 >= x &&
                _sorted[i].y1 <= y && _sorted[i].y2 >= y) {
            return record;
        }
    }
    return null;
}

function weightForRecord(record: IRecord) {
    // In the future we should seperate by line.
    return record.x2;
}

function weightForLookup(lookup: ILookup) {
    return lookup.x;
}