/*
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 type SyntheticKeyboardEvent from 'react/lib/SyntheticKeyboardEvent';
import marked from 'marked';
marked.setOptions({
    renderer: new marked.Renderer(),
    gfm: true,
    tables: true,
    breaks: true,
    pedantic: false,
    sanitize: true,
    smartLists: true,
    smartypants: false,
});

import {Editor, EditorState, RichUtils, CompositeDecorator,
    convertFromRaw, convertToRaw, Modifier, EditorChangeType,
    getDefaultKeyBinding, KeyBindingUtil, ContentState, SelectionState} from 'draft-js';

import {stateToMarkdown} from 'draft-js-export-markdown';
import classNames from 'classnames';
import escape from 'lodash/escape';

import MatrixClientPeg from '../../../MatrixClientPeg';
import type {MatrixClient} from 'matrix-js-sdk/lib/matrix';
import SlashCommands from '../../../SlashCommands';
import Modal from '../../../Modal';
import sdk from '../../../index';

import dis from '../../../dispatcher';
import KeyCode from '../../../KeyCode';
import UserSettingsStore from '../../../UserSettingsStore';

import * as RichText from '../../../RichText';

const TYPING_USER_TIMEOUT = 10000, TYPING_SERVER_TIMEOUT = 30000;

const KEY_M = 77;

// FIXME Breaks markdown with multiple paragraphs, since it only strips first and last <p>
function mdownToHtml(mdown: string): string {
    let html = marked(mdown) || "";
    html = html.trim();
    // strip start and end <p> tags else you get 'orrible spacing
    if (html.indexOf("<p>") === 0) {
        html = html.substring("<p>".length);
    }
    if (html.lastIndexOf("</p>") === (html.length - "</p>".length)) {
        html = html.substring(0, html.length - "</p>".length);
    }
    return html;
}

/*
 * The textInput part of the MessageComposer
 */
export default class MessageComposerInput extends React.Component {
    static getKeyBinding(e: SyntheticKeyboardEvent): string {
        // C-m => Toggles between rich text and markdown modes
        if (e.keyCode === KEY_M && KeyBindingUtil.isCtrlKeyCommand(e)) {
            return 'toggle-mode';
        }

        return getDefaultKeyBinding(e);
    }

    client: MatrixClient;

    constructor(props, context) {
        super(props, context);
        this.onAction = this.onAction.bind(this);
        this.focus = this.focus.bind(this);
        this.handleReturn = this.handleReturn.bind(this);
        this.handleKeyCommand = this.handleKeyCommand.bind(this);
        this.setEditorState = this.setEditorState.bind(this);
        this.onUpArrow = this.onUpArrow.bind(this);
        this.onDownArrow = this.onDownArrow.bind(this);
        this.onTab = this.onTab.bind(this);
        this.onConfirmAutocompletion = this.onConfirmAutocompletion.bind(this);
        this.onMarkdownToggleClicked = this.onMarkdownToggleClicked.bind(this);

        const isRichtextEnabled = UserSettingsStore.getSyncedSetting('MessageComposerInput.isRichTextEnabled', true);

        this.state = {
            isRichtextEnabled,
            editorState: null,
        };

        // bit of a hack, but we need to do this here since createEditorState needs isRichtextEnabled
        this.state.editorState = this.createEditorState();

        this.client = MatrixClientPeg.get();
    }

    /**
     * "Does the right thing" to create an EditorState, based on:
     * - whether we've got rich text mode enabled
     * - contentState was passed in
     */
    createEditorState(richText: boolean, contentState: ?ContentState): EditorState {
        let decorators = richText ? RichText.getScopedRTDecorators(this.props) :
                                    RichText.getScopedMDDecorators(this.props),
            compositeDecorator = new CompositeDecorator(decorators);

        let editorState = null;
        if (contentState) {
            editorState = EditorState.createWithContent(contentState, compositeDecorator);
        } else {
            editorState = EditorState.createEmpty(compositeDecorator);
        }

        return EditorState.moveFocusToEnd(editorState);
    }

    componentWillMount() {
        const component = this;
        this.sentHistory = {
            // The list of typed messages. Index 0 is more recent
            data: [],
            // The position in data currently displayed
            position: -1,
            // The room the history is for.
            roomId: null,
            // The original text before they hit UP
            originalText: null,
            // The textarea element to set text to.
            element: null,

            init: function(element, roomId) {
                this.roomId = roomId;
                this.element = element;
                this.position = -1;
                var storedData = window.sessionStorage.getItem(
                    "mx_messagecomposer_history_" + roomId
                );
                if (storedData) {
                    this.data = JSON.parse(storedData);
                }
                if (this.roomId) {
                    this.setLastTextEntry();
                }
            },

            push: function(text) {
                // store a message in the sent history
                this.data.unshift(text);
                window.sessionStorage.setItem(
                    "mx_messagecomposer_history_" + this.roomId,
                    JSON.stringify(this.data)
                );
                // reset history position
                this.position = -1;
                this.originalText = null;
            },

            // move in the history. Returns true if we managed to move.
            next: function(offset) {
                if (this.position === -1) {
                    // user is going into the history, save the current line.
                    this.originalText = this.element.value;
                }
                else {
                    // user may have modified this line in the history; remember it.
                    this.data[this.position] = this.element.value;
                }

                if (offset > 0 && this.position === (this.data.length - 1)) {
                    // we've run out of history
                    return false;
                }

                // retrieve the next item (bounded).
                var newPosition = this.position + offset;
                newPosition = Math.max(-1, newPosition);
                newPosition = Math.min(newPosition, this.data.length - 1);
                this.position = newPosition;

                if (this.position !== -1) {
                    // show the message
                    this.element.value = this.data[this.position];
                }
                else if (this.originalText !== undefined) {
                    // restore the original text the user was typing.
                    this.element.value = this.originalText;
                }

                return true;
            },

            saveLastTextEntry: function() {
                // save the currently entered text in order to restore it later.
                // NB: This isn't 'originalText' because we want to restore
                // sent history items too!
                let contentJSON = JSON.stringify(convertToRaw(component.state.editorState.getCurrentContent()));
                window.sessionStorage.setItem("mx_messagecomposer_input_" + this.roomId, contentJSON);
            },

            setLastTextEntry: function() {
                let contentJSON = window.sessionStorage.getItem("mx_messagecomposer_input_" + this.roomId);
                if (contentJSON) {
                    let content = convertFromRaw(JSON.parse(contentJSON));
                    component.setEditorState(component.createEditorState(component.state.isRichtextEnabled, content));
                }
            },
        };
    }

    componentDidMount() {
        this.dispatcherRef = dis.register(this.onAction);
        this.sentHistory.init(
            this.refs.editor,
            this.props.room.roomId
        );
        // this is disabled for now, since https://github.com/matrix-org/matrix-react-sdk/pull/296 will land soon
        // if (this.props.tabComplete) {
        //     this.props.tabComplete.setEditor(this.refs.editor);
        // }
    }

    componentWillUnmount() {
        dis.unregister(this.dispatcherRef);
        this.sentHistory.saveLastTextEntry();
    }

    componentWillUpdate(nextProps, nextState) {
        // this is dirty, but moving all this state to MessageComposer is dirtier
        if (this.props.onInputStateChanged && nextState !== this.state) {
            const state = this.getSelectionInfo(nextState.editorState);
            state.isRichtextEnabled = nextState.isRichtextEnabled;
            state.wordCount = nextState.editorState.getCurrentContent().getPlainText().split(' ').filter(w => !!w).length;
            this.props.onInputStateChanged(state);
        }
    }

    onAction(payload) {
        let editor = this.refs.editor;
        let contentState = this.state.editorState.getCurrentContent();

        switch (payload.action) {
            case 'focus_composer':
                editor.focus();
                break;

            // TODO change this so we insert a complete user alias

            case 'insert_displayname': {
                contentState = Modifier.replaceText(
                    contentState,
                    this.state.editorState.getSelection(),
                    `${payload.displayname}: `
                );
                let editorState = EditorState.push(this.state.editorState, contentState, 'insert-characters');
                editorState = EditorState.forceSelection(editorState, contentState.getSelectionAfter());
                this.setEditorState(editorState);
                editor.focus();
            }
            break;

            case 'quote': {
                let {event: {content: {body, formatted_body}}} = payload.event || {};
                formatted_body = formatted_body || escape(body);
                if (formatted_body) {
                    let content = RichText.HTMLtoContentState(`<blockquote>${formatted_body}</blockquote>`);
                    if (!this.state.isRichtextEnabled) {
                        content = ContentState.createFromText(stateToMarkdown(content));
                    }

                    const blockMap = content.getBlockMap();
                    let startSelection = SelectionState.createEmpty(contentState.getFirstBlock().getKey());
                    contentState = Modifier.splitBlock(contentState, startSelection);
                    startSelection = SelectionState.createEmpty(contentState.getFirstBlock().getKey());
                    contentState = Modifier.replaceWithFragment(contentState,
                        startSelection,
                        blockMap);
                    startSelection = SelectionState.createEmpty(contentState.getFirstBlock().getKey());
                    if (this.state.isRichtextEnabled)
                        contentState = Modifier.setBlockType(contentState, startSelection, 'blockquote');
                    let editorState = EditorState.push(this.state.editorState, contentState, 'insert-characters');
                    this.setEditorState(editorState);
                    editor.focus();
                }
            }
            break;
        }
    }

    onKeyDown(ev) {
        if (ev.keyCode === KeyCode.UP || ev.keyCode === KeyCode.DOWN) {
            var oldSelectionStart = this.refs.textarea.selectionStart;
            // Remember the keyCode because React will recycle the synthetic event
            var keyCode = ev.keyCode;
            // set a callback so we can see if the cursor position changes as
            // a result of this event. If it doesn't, we cycle history.
            setTimeout(() => {
                if (this.refs.textarea.selectionStart == oldSelectionStart) {
                    this.sentHistory.next(keyCode === KeyCode.UP ? 1 : -1);
                }
            }, 0);
        }
    }

    onTypingActivity() {
        this.isTyping = true;
        if (!this.userTypingTimer) {
            this.sendTyping(true);
        }
        this.startUserTypingTimer();
        this.startServerTypingTimer();
    }

    onFinishedTyping() {
        this.isTyping = false;
        this.sendTyping(false);
        this.stopUserTypingTimer();
        this.stopServerTypingTimer();
    }

    startUserTypingTimer() {
        this.stopUserTypingTimer();
        var self = this;
        this.userTypingTimer = setTimeout(function() {
            self.isTyping = false;
            self.sendTyping(self.isTyping);
            self.userTypingTimer = null;
        }, TYPING_USER_TIMEOUT);
    }

    stopUserTypingTimer() {
        if (this.userTypingTimer) {
            clearTimeout(this.userTypingTimer);
            this.userTypingTimer = null;
        }
    }

    startServerTypingTimer() {
        if (!this.serverTypingTimer) {
            var self = this;
            this.serverTypingTimer = setTimeout(function() {
                if (self.isTyping) {
                    self.sendTyping(self.isTyping);
                    self.startServerTypingTimer();
                }
            }, TYPING_SERVER_TIMEOUT / 2);
        }
    }

    stopServerTypingTimer() {
        if (this.serverTypingTimer) {
            clearTimeout(this.servrTypingTimer);
            this.serverTypingTimer = null;
        }
    }

    sendTyping(isTyping) {
        MatrixClientPeg.get().sendTyping(
            this.props.room.roomId,
            this.isTyping, TYPING_SERVER_TIMEOUT
        ).done();
    }

    refreshTyping() {
        if (this.typingTimeout) {
            clearTimeout(this.typingTimeout);
            this.typingTimeout = null;
        }
    }

    focus(ev) {
        this.refs.editor.focus();
    }

    setEditorState(editorState: EditorState) {
        editorState = RichText.attachImmutableEntitiesToEmoji(editorState);
        this.setState({editorState});

        if (editorState.getCurrentContent().hasText()) {
            this.onTypingActivity();
        } else {
            this.onFinishedTyping();
        }

        if (this.props.onContentChanged) {
            const textContent = editorState.getCurrentContent().getPlainText();
            const selection = RichText.selectionStateToTextOffsets(editorState.getSelection(),
                editorState.getCurrentContent().getBlocksAsArray());

            this.props.onContentChanged(textContent, selection);
        }
    }

    enableRichtext(enabled: boolean) {
        if (enabled) {
            let html = mdownToHtml(this.state.editorState.getCurrentContent().getPlainText());
            this.setEditorState(this.createEditorState(enabled, RichText.HTMLtoContentState(html)));
        } else {
            let markdown = stateToMarkdown(this.state.editorState.getCurrentContent()),
                contentState = ContentState.createFromText(markdown);
            this.setEditorState(this.createEditorState(enabled, contentState));
        }

        this.setState({
            isRichtextEnabled: enabled,
        });

        UserSettingsStore.setSyncedSetting('MessageComposerInput.isRichTextEnabled', enabled);
    }

    handleKeyCommand(command: string): boolean {
        if (command === 'toggle-mode') {
            this.enableRichtext(!this.state.isRichtextEnabled);
            return true;
        }

        let newState: ?EditorState = null;

        // Draft handles rich text mode commands by default but we need to do it ourselves for Markdown.
        if (this.state.isRichtextEnabled) {
            // These are block types, not handled by RichUtils by default.
            const blockCommands = ['code-block', 'blockquote', 'unordered-list-item', 'ordered-list-item'];

            if (blockCommands.includes(command)) {
                this.setEditorState(RichUtils.toggleBlockType(this.state.editorState, command));
            } else if (command === 'strike') {
                // this is the only inline style not handled by Draft by default
                this.setEditorState(RichUtils.toggleInlineStyle(this.state.editorState, 'STRIKETHROUGH'));
            }
        } else {
            let contentState = this.state.editorState.getCurrentContent(),
                selection = this.state.editorState.getSelection();

            let modifyFn = {
                bold: text => `**${text}**`,
                italic: text => `*${text}*`,
                underline: text => `_${text}_`, // there's actually no valid underline in Markdown, but *shrug*
                code: text => `\`${text}\``,
                blockquote: text => text.split('\n').map(line => `> ${line}\n`).join(''),
                'unordered-list-item': text => text.split('\n').map(line => `- ${line}\n`).join(''),
                'ordered-list-item': text => text.split('\n').map((line, i) => `${i+1}. ${line}\n`).join(''),
            }[command];

            if (modifyFn) {
                newState = EditorState.push(
                    this.state.editorState,
                    RichText.modifyText(contentState, selection, modifyFn),
                    'insert-characters'
                );
            }
        }

        if (newState == null)
            newState = RichUtils.handleKeyCommand(this.state.editorState, command);

        if (newState != null) {
            this.setEditorState(newState);
            return true;
        }

        return false;
    }

    handleReturn(ev) {
        if (ev.shiftKey) {
            this.setEditorState(RichUtils.insertSoftNewline(this.state.editorState));
            return true;
        }

        const contentState = this.state.editorState.getCurrentContent();
        if (!contentState.hasText()) {
            return true;
        }
            

        let contentText = contentState.getPlainText(), contentHTML;

        var cmd = SlashCommands.processInput(this.props.room.roomId, contentText);
        if (cmd) {
            if (!cmd.error) {
                this.setState({
                    editorState: this.createEditorState()
                });
            }
            if (cmd.promise) {
                cmd.promise.done(function() {
                    console.log("Command success.");
                }, function(err) {
                    console.error("Command failure: %s", err);
                    var ErrorDialog = sdk.getComponent("dialogs.ErrorDialog");
                    Modal.createDialog(ErrorDialog, {
                        title: "Server error",
                        description: err.message
                    });
                });
            }
            else if (cmd.error) {
                console.error(cmd.error);
                var ErrorDialog = sdk.getComponent("dialogs.ErrorDialog");
                Modal.createDialog(ErrorDialog, {
                    title: "Command error",
                    description: cmd.error
                });
            }
            return true;
        }

        if (this.state.isRichtextEnabled) {
            contentHTML = RichText.contentStateToHTML(contentState);
        } else {
            contentHTML = mdownToHtml(contentText);
        }

        let sendFn = this.client.sendHtmlMessage;

        if (contentText.startsWith('/me')) {
            contentText = contentText.replace('/me', '');
            // bit of a hack, but the alternative would be quite complicated
            contentHTML = contentHTML.replace('/me', '');
            sendFn = this.client.sendHtmlEmote;
        }

        this.sentHistory.push(contentHTML);
        let sendMessagePromise = sendFn.call(this.client, this.props.room.roomId, contentText, contentHTML);

        sendMessagePromise.done(() => {
            dis.dispatch({
                action: 'message_sent'
            });
        }, () => {
            dis.dispatch({
                action: 'message_send_failed'
            });
        });

        this.setState({
            editorState: this.createEditorState()
        });

        return true;
    }

    onUpArrow(e) {
        if (this.props.onUpArrow && this.props.onUpArrow()) {
            e.preventDefault();
        }
    }

    onDownArrow(e) {
        if (this.props.onDownArrow && this.props.onDownArrow()) {
            e.preventDefault();
        }
    }

    onTab(e) {
        if (this.props.tryComplete) {
            if (this.props.tryComplete()) {
                e.preventDefault();
            }
        }
    }

    onConfirmAutocompletion(range, content: string) {
        let contentState = Modifier.replaceText(
            this.state.editorState.getCurrentContent(),
            RichText.textOffsetsToSelectionState(range, this.state.editorState.getCurrentContent().getBlocksAsArray()),
            content
        );

        let editorState = EditorState.push(this.state.editorState, contentState, 'insert-characters');

        editorState = EditorState.forceSelection(editorState, contentState.getSelectionAfter());

        this.setEditorState(editorState);

        // for some reason, doing this right away does not update the editor :(
        setTimeout(() => this.refs.editor.focus(), 50);
    }

    onFormatButtonClicked(name: "bold" | "italic" | "strike" | "code" | "underline" | "quote" | "bullet" | "numbullet", e) {
        const command = {
            code: 'code-block',
            quote: 'blockquote',
            bullet: 'unordered-list-item',
            numbullet: 'ordered-list-item',
        }[name] || name;
        this.handleKeyCommand(command);
    }

    /* returns inline style and block type of current SelectionState so MessageComposer can render formatting
    buttons. */
    getSelectionInfo(editorState: EditorState) {
        const styleName = {
            BOLD: 'bold',
            ITALIC: 'italic',
            STRIKETHROUGH: 'strike',
            UNDERLINE: 'underline',
        };

        const originalStyle = editorState.getCurrentInlineStyle().toArray();
        const style = originalStyle
                .map(style => styleName[style] || null)
                .filter(styleName => !!styleName);

        const blockName = {
            'code-block': 'code',
            blockquote: 'quote',
            'unordered-list-item': 'bullet',
            'ordered-list-item': 'numbullet',
        };
        const originalBlockType = editorState.getCurrentContent()
            .getBlockForKey(editorState.getSelection().getStartKey())
            .getType();
        const blockType = blockName[originalBlockType] || null;

        return {
            style,
            blockType,
        };
    }

    onMarkdownToggleClicked() {
        this.enableRichtext(!this.state.isRichtextEnabled);
    }

    render() {
        const {editorState} = this.state;

        // From https://github.com/facebook/draft-js/blob/master/examples/rich/rich.html#L92
        // If the user changes block type before entering any text, we can
        // either style the placeholder or hide it.
        let hidePlaceholder = false;
        const contentState = editorState.getCurrentContent();
        if (!contentState.hasText()) {
            if (contentState.getBlockMap().first().getType() !== 'unstyled') {
                hidePlaceholder = true;
            }
        }

        const className = classNames('mx_MessageComposer_input', {
            mx_MessageComposer_input_empty: hidePlaceholder,
        });

        return (
            <div className={className}
                 onClick={ this.focus }>
                <img className="mx_MessageComposer_input_markdownIndicator"
                     onClick={this.onMarkdownToggleClicked}
                     title={`Markdown is ${this.state.isRichtextEnabled ? 'disabled' : 'enabled'}`}
                     src={`img/button-md-${!this.state.isRichtextEnabled}.png`} />
                <Editor ref="editor"
                        placeholder="Type a message…"
                        editorState={this.state.editorState}
                        onChange={this.setEditorState}
                        keyBindingFn={MessageComposerInput.getKeyBinding}
                        handleKeyCommand={this.handleKeyCommand}
                        handleReturn={this.handleReturn}
                        stripPastedStyles={!this.state.isRichtextEnabled}
                        onTab={this.onTab}
                        onUpArrow={this.onUpArrow}
                        onDownArrow={this.onDownArrow}
                        spellCheck={true} />
            </div>
        );
    }
};

MessageComposerInput.propTypes = {
    tabComplete: React.PropTypes.any,

    // a callback which is called when the height of the composer is
    // changed due to a change in content.
    onResize: React.PropTypes.func,

    // js-sdk Room object
    room: React.PropTypes.object.isRequired,

    // called with current plaintext content (as a string) whenever it changes
    onContentChanged: React.PropTypes.func,

    onUpArrow: React.PropTypes.func,

    onDownArrow: React.PropTypes.func,

    // attempts to confirm currently selected completion, returns whether actually confirmed
    tryComplete: React.PropTypes.func,

    onInputStateChanged: React.PropTypes.func.isRequired,
};