// @flow

import React, { Component } from 'react';
import TextareaAutosize from 'react-textarea-autosize';
import type { Dispatch } from 'redux';

import { isMobileBrowser } from '../../../base/environment/utils';
import { translate } from '../../../base/i18n';
import { Icon, IconPlane, IconSmile } from '../../../base/icons';
import { connect } from '../../../base/redux';
import { areSmileysDisabled } from '../../functions';

import SmileysPanel from './SmileysPanel';

/**
 * The type of the React {@code Component} props of {@link ChatInput}.
 */
type Props = {

    /**
     * Invoked to send chat messages.
     */
    dispatch: Dispatch<any>,

    /**
     * Optional callback to invoke when the chat textarea has auto-resized to
     * fit overflowing text.
     */
    onResize: ?Function,

    /**
     * Callback to invoke on message send.
     */
    onSend: Function,

    /**
     * Invoked to obtain translated strings.
     */
    t: Function,

    /**
     * Whether chat emoticons are disabled.
     */
    _areSmileysDisabled: boolean

};

/**
 * The type of the React {@code Component} state of {@link ChatInput}.
 */
type State = {

    /**
     * User provided nickname when the input text is provided in the view.
     */
    message: string,

    /**
     * Whether or not the smiley selector is visible.
     */
    showSmileysPanel: boolean
};

/**
 * Implements a React Component for drafting and submitting a chat message.
 *
 * @extends Component
 */
class ChatInput extends Component<Props, State> {
    _textArea: ?HTMLTextAreaElement;

    state = {
        message: '',
        showSmileysPanel: false
    };

    /**
     * Initializes a new {@code ChatInput} instance.
     *
     * @param {Object} props - The read-only properties with which the new
     * instance is to be initialized.
     */
    constructor(props: Props) {
        super(props);

        this._textArea = null;

        // Bind event handlers so they are only bound once for every instance.
        this._onDetectSubmit = this._onDetectSubmit.bind(this);
        this._onMessageChange = this._onMessageChange.bind(this);
        this._onSmileySelect = this._onSmileySelect.bind(this);
        this._onSubmitMessage = this._onSubmitMessage.bind(this);
        this._onToggleSmileysPanel = this._onToggleSmileysPanel.bind(this);
        this._onEscHandler = this._onEscHandler.bind(this);
        this._onToggleSmileysPanelKeyPress = this._onToggleSmileysPanelKeyPress.bind(this);
        this._onSubmitMessageKeyPress = this._onSubmitMessageKeyPress.bind(this);
        this._setTextAreaRef = this._setTextAreaRef.bind(this);
    }

    /**
     * Implements React's {@link Component#componentDidMount()}.
     *
     * @inheritdoc
     */
    componentDidMount() {
        if (isMobileBrowser()) {
            // Ensure textarea is not focused when opening chat on mobile browser.
            this._textArea && this._textArea.blur();
        }
    }

    /**
     * Implements React's {@link Component#render()}.
     *
     * @inheritdoc
     * @returns {ReactElement}
     */
    render() {
        const smileysPanelClassName = `${this.state.showSmileysPanel
            ? 'show-smileys' : 'hide-smileys'} smileys-panel`;

        return (
            <div className = { `chat-input-container${this.state.message.trim().length ? ' populated' : ''}` }>
                <div id = 'chat-input' >
                    { this.props._areSmileysDisabled ? null : (
                        <div className = 'smiley-input'>
                            <div id = 'smileysarea'>
                                <div id = 'smileys'>
                                    <div
                                        aria-expanded = { this.state.showSmileysPanel }
                                        aria-haspopup = 'smileysContainer'
                                        aria-label = { this.props.t('chat.smileysPanel') }
                                        className = 'smiley-button'
                                        onClick = { this._onToggleSmileysPanel }
                                        onKeyDown = { this._onEscHandler }
                                        onKeyPress = { this._onToggleSmileysPanelKeyPress }
                                        role = 'button'
                                        tabIndex = { 0 }>
                                        <Icon src = { IconSmile } />
                                    </div>
                                </div>
                            </div>
                            <div
                                className = { smileysPanelClassName } >
                                <SmileysPanel
                                    onSmileySelect = { this._onSmileySelect } />
                            </div>
                        </div>
                    ) }
                    <div className = 'usrmsg-form'>
                        <TextareaAutosize
                            autoComplete = 'off'
                            autoFocus = { true }
                            id = 'usermsg'
                            maxRows = { 5 }
                            onChange = { this._onMessageChange }
                            onHeightChange = { this.props.onResize }
                            onKeyDown = { this._onDetectSubmit }
                            placeholder = { this.props.t('chat.messagebox') }
                            ref = { this._setTextAreaRef }
                            tabIndex = { 0 }
                            value = { this.state.message } />
                    </div>
                    <div className = 'send-button-container'>
                        <div
                            aria-label = { this.props.t('chat.sendButton') }
                            className = 'send-button'
                            onClick = { this._onSubmitMessage }
                            onKeyPress = { this._onSubmitMessageKeyPress }
                            role = 'button'
                            tabIndex = { this.state.message.trim() ? 0 : -1 } >
                            <Icon src = { IconPlane } />
                        </div>
                    </div>
                </div>
            </div>
        );
    }

    /**
     * Place cursor focus on this component's text area.
     *
     * @private
     * @returns {void}
     */
    _focus() {
        this._textArea && this._textArea.focus();
    }


    _onSubmitMessage: () => void;

    /**
     * Submits the message to the chat window.
     *
     * @returns {void}
     */
    _onSubmitMessage() {
        const trimmed = this.state.message.trim();

        if (trimmed) {
            this.props.onSend(trimmed);

            this.setState({ message: '' });

            // Keep the textarea in focus when sending messages via submit button.
            this._focus();
        }

    }
    _onDetectSubmit: (Object) => void;

    /**
     * Detects if enter has been pressed. If so, submit the message in the chat
     * window.
     *
     * @param {string} event - Keyboard event.
     * @private
     * @returns {void}
     */
    _onDetectSubmit(event) {
        if (event.key === 'Enter'
            && event.shiftKey === false
            && event.ctrlKey === false) {
            event.preventDefault();
            event.stopPropagation();

            this._onSubmitMessage();
        }
    }

    _onSubmitMessageKeyPress: (Object) => void;

    /**
     * KeyPress handler for accessibility.
     *
     * @param {Object} e - The key event to handle.
     *
     * @returns {void}
     */
    _onSubmitMessageKeyPress(e) {
        if (e.key === ' ' || e.key === 'Enter') {
            e.preventDefault();
            this._onSubmitMessage();
        }
    }

    _onMessageChange: (Object) => void;

    /**
     * Updates the known message the user is drafting.
     *
     * @param {string} event - Keyboard event.
     * @private
     * @returns {void}
     */
    _onMessageChange(event) {
        this.setState({ message: event.target.value });
    }

    _onSmileySelect: (string) => void;

    /**
     * Appends a selected smileys to the chat message draft.
     *
     * @param {string} smileyText - The value of the smiley to append to the
     * chat message.
     * @private
     * @returns {void}
     */
    _onSmileySelect(smileyText) {
        if (smileyText) {
            this.setState({
                message: `${this.state.message} ${smileyText}`,
                showSmileysPanel: false
            });
        } else {
            this.setState({
                showSmileysPanel: false
            });
        }

        this._focus();
    }

    _onToggleSmileysPanel: () => void;

    /**
     * Callback invoked to hide or show the smileys selector.
     *
     * @private
     * @returns {void}
     */
    _onToggleSmileysPanel() {
        if (this.state.showSmileysPanel) {
            this._focus();
        }
        this.setState({ showSmileysPanel: !this.state.showSmileysPanel });
    }

    _onEscHandler: (Object) => void;

    /**
     * KeyPress handler for accessibility.
     *
     * @param {Object} e - The key event to handle.
     *
     * @returns {void}
     */
    _onEscHandler(e) {
        // Escape handling does not work in onKeyPress
        if (this.state.showSmileysPanel && e.key === 'Escape') {
            e.preventDefault();
            e.stopPropagation();
            this._onToggleSmileysPanel();
        }
    }

    _onToggleSmileysPanelKeyPress: (Object) => void;

    /**
     * KeyPress handler for accessibility.
     *
     * @param {Object} e - The key event to handle.
     *
     * @returns {void}
     */
    _onToggleSmileysPanelKeyPress(e) {
        if (e.key === ' ' || e.key === 'Enter') {
            e.preventDefault();
            this._onToggleSmileysPanel();
        }
    }

    _setTextAreaRef: (?HTMLTextAreaElement) => void;

    /**
     * Sets the reference to the HTML TextArea.
     *
     * @param {HTMLAudioElement} textAreaElement - The HTML text area element.
     * @private
     * @returns {void}
     */
    _setTextAreaRef(textAreaElement: ?HTMLTextAreaElement) {
        this._textArea = textAreaElement;
    }
}

/**
 * Function that maps parts of Redux state tree into component props.
 *
 * @param {Object} state - Redux state.
 * @private
 * @returns {{
 *     _areSmileysDisabled: boolean
 * }}
 */
const mapStateToProps = state => {
    return {
        _areSmileysDisabled: areSmileysDisabled(state)
    };
};

export default translate(connect(mapStateToProps)(ChatInput));