element-portable/src/components/views/elements/PowerSelector.tsx

/*
Copyright 2015, 2016 OpenMarket Ltd

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 from "react";

import * as Roles from "../../../Roles";
import { _t } from "../../../languageHandler";
import Field from "./Field";
import { KeyBindingAction } from "../../../accessibility/KeyboardShortcuts";
import { getKeyBindingsManager } from "../../../KeyBindingsManager";
import { objectHasDiff } from "../../../utils/objects";

const CUSTOM_VALUE = "SELECT_VALUE_CUSTOM";

interface Props<K extends undefined | string> {
    value: number;
    // The maximum value that can be set with the power selector
    maxValue: number;

    // Default user power level for the room
    usersDefault: number;

    // should the user be able to change the value? false by default.
    disabled?: boolean;

    // The name to annotate the selector with
    label?: string;

    onChange(value: number, powerLevelKey: K extends undefined ? void : K): void | Promise<void>;

    // Optional key to pass as the second argument to `onChange`
    powerLevelKey: K extends undefined ? void : K;
}

interface IState {
    levelRoleMap: Partial<Record<number | "undefined", string>>;
    // List of power levels to show in the drop-down
    options: number[];

    customValue: number;
    selectValue: number | string;
    custom?: boolean;
}

export default class PowerSelector<K extends undefined | string> extends React.Component<Props<K>, IState> {
    public static defaultProps: Partial<Props<any>> = {
        maxValue: Infinity,
        usersDefault: 0,
    };
    private unmounted = false;

    public constructor(props: Props<K>) {
        super(props);

        this.state = {
            levelRoleMap: {},
            // List of power levels to show in the drop-down
            options: [],

            customValue: this.props.value,
            selectValue: 0,
        };
    }

    public componentDidMount(): void {
        this.initStateFromProps();
    }

    public componentDidUpdate(prevProps: Readonly<Props<K>>): void {
        if (objectHasDiff(this.props, prevProps)) {
            this.initStateFromProps();
        }
    }

    public componentWillUnmount(): void {
        this.unmounted = true;
    }

    private initStateFromProps(): void {
        // This needs to be done now because levelRoleMap has translated strings
        const levelRoleMap = Roles.levelRoleMap(this.props.usersDefault);
        const options = Object.keys(levelRoleMap)
            .filter((level) => {
                return (
                    level === undefined || parseInt(level) <= this.props.maxValue || parseInt(level) == this.props.value
                );
            })
            .map((level) => parseInt(level));

        const isCustom = levelRoleMap[this.props.value] === undefined;

        this.setState({
            levelRoleMap,
            options,
            custom: isCustom,
            customValue: this.props.value,
            selectValue: isCustom ? CUSTOM_VALUE : this.props.value,
        });
    }

    private onSelectChange = async (event: React.ChangeEvent<HTMLSelectElement>): Promise<void> => {
        const isCustom = event.target.value === CUSTOM_VALUE;
        if (isCustom) {
            this.setState({ custom: true });
        } else {
            const powerLevel = parseInt(event.target.value);
            this.setState({ selectValue: powerLevel });
            try {
                await this.props.onChange(powerLevel, this.props.powerLevelKey);
            } catch {
                if (this.unmounted) return;
                // If the request failed, roll back the state of the selector.
                this.initStateFromProps();
            }
        }
    };

    private onCustomChange = (event: React.ChangeEvent<HTMLInputElement>): void => {
        this.setState({ customValue: parseInt(event.target.value) });
    };

    private onCustomBlur = async (event: React.FocusEvent): Promise<void> => {
        event.preventDefault();
        event.stopPropagation();

        if (Number.isFinite(this.state.customValue)) {
            try {
                await this.props.onChange(this.state.customValue, this.props.powerLevelKey);
            } catch {
                if (this.unmounted) return;
                // If the request failed, roll back the state of the selector.
                this.initStateFromProps();
            }
        } else {
            this.initStateFromProps(); // reset, invalid input
        }
    };

    private onCustomKeyDown = (event: React.KeyboardEvent<HTMLInputElement>): void => {
        const action = getKeyBindingsManager().getAccessibilityAction(event);
        switch (action) {
            case KeyBindingAction.Enter:
                event.preventDefault();
                event.stopPropagation();

                // Do not call the onChange handler directly here - it can cause an infinite loop.
                // Long story short, a user hits Enter to submit the value which onChange handles as
                // raising a dialog which causes a blur which causes a dialog which causes a blur and
                // so on. By not causing the onChange to be called here, we avoid the loop because we
                // handle the onBlur safely.
                (event.target as HTMLInputElement).blur();
                break;
        }
    };

    public render(): React.ReactNode {
        let picker;
        const label = typeof this.props.label === "undefined" ? _t("power_level|label") : this.props.label;
        if (this.state.custom) {
            picker = (
                <Field
                    type="number"
                    label={label}
                    max={this.props.maxValue}
                    onBlur={this.onCustomBlur}
                    onKeyDown={this.onCustomKeyDown}
                    onChange={this.onCustomChange}
                    value={String(this.state.customValue)}
                    disabled={this.props.disabled}
                />
            );
        } else {
            // Each level must have a definition in this.state.levelRoleMap
            const options = this.state.options.map((level) => {
                return {
                    value: String(level),
                    text: Roles.textualPowerLevel(level, this.props.usersDefault),
                };
            });
            options.push({ value: CUSTOM_VALUE, text: _t("power_level|custom_level") });
            const optionsElements = options.map((op) => {
                return (
                    <option value={op.value} key={op.value} data-testid={`power-level-option-${op.value}`}>
                        {op.text}
                    </option>
                );
            });

            picker = (
                <Field
                    element="select"
                    label={label}
                    onChange={this.onSelectChange}
                    value={String(this.state.selectValue)}
                    disabled={this.props.disabled}
                    data-testid="power-level-select-element"
                >
                    {optionsElements}
                </Field>
            );
        }

        return <div className="mx_PowerSelector">{picker}</div>;
    }
}