// Copyright (c) 2015 Mattermost, Inc. All Rights Reserved.
// See License.txt for license information.

const UserStore = require('../stores/user_store.jsx');
const Utils = require('../utils/utils.jsx');
const Post = require('./post.jsx');
const Constants = require('../utils/constants.jsx');

export default class PostsView extends React.Component {
    constructor(props) {
        super(props);

        this.handleScroll = this.handleScroll.bind(this);
        this.isAtBottom = this.isAtBottom.bind(this);
        this.loadMorePostsTop = this.loadMorePostsTop.bind(this);
        this.createPosts = this.createPosts.bind(this);
        this.updateScrolling = this.updateScrolling.bind(this);
        this.handleResize = this.handleResize.bind(this);

        this.jumpToPostNode = null;
        this.wasAtBottom = true;
        this.scrollHeight = 0;
    }
    static get SCROLL_TYPE_FREE() {
        return 1;
    }
    static get SCROLL_TYPE_BOTTOM() {
        return 2;
    }
    static get SIDEBAR_OPEN() {
        return 3;
    }
    static get SCROLL_TYPE_NEW_MESSAGE() {
        return 4;
    }
    isAtBottom() {
        return ((this.refs.postlist.scrollHeight - this.refs.postlist.scrollTop) === this.refs.postlist.clientHeight);
    }
    handleScroll() {
        // HACK FOR RHS -- REMOVE WHEN RHS DIES
        const childNodes = this.refs.postlistcontent.childNodes;
        for (let i = 0; i < childNodes.length; i++) {
            // If the node is 1/3 down the page
            if (childNodes[i].offsetTop > (this.refs.postlist.scrollTop + (this.refs.postlist.offsetHeight / 3))) {
                this.jumpToPostNode = childNodes[i];
                break;
            }
        }
        this.wasAtBottom = this.isAtBottom();

        // --- --------

        this.props.postViewScrolled(this.isAtBottom());
        this.prevScrollHeight = this.refs.postlist.scrollHeight;
    }
    loadMorePostsTop() {
        this.props.loadMorePostsTopClicked();
    }
    createPosts(posts, order) {
        const postCtls = [];
        let previousPostDay = new Date(0);
        const userId = UserStore.getCurrentId();

        let renderedLastViewed = false;

        let numToDisplay = this.props.numPostsToDisplay;
        if (order.length - 1 < numToDisplay) {
            numToDisplay = order.length - 1;
        }

        for (let i = numToDisplay; i >= 0; i--) {
            const post = posts[order[i]];
            const parentPost = posts[post.parent_id];
            const prevPost = posts[order[i + 1]];

            // If the post is a comment whose parent has been deleted, don't add it to the list.
            if (parentPost && parentPost.state === Constants.POST_DELETED) {
                continue;
            }

            let sameUser = false;
            let sameRoot = false;
            let hideProfilePic = false;

            if (prevPost) {
                const postIsComment = Utils.isComment(post);
                const prevPostIsComment = Utils.isComment(prevPost);
                const postFromWebhook = Boolean(post.props && post.props.from_webhook);
                const prevPostFromWebhook = Boolean(prevPost.props && prevPost.props.from_webhook);

                sameUser = prevPost.user_id === post.user_id && postFromWebhook === prevPostFromWebhook &&
                    post.create_at - prevPost.create_at <= 1000 * 60 * 5;
                sameRoot = (postIsComment && (prevPost.id === post.root_id || prevPost.root_id === post.root_id)) || (!postIsComment && !prevPostIsComment && sameUser);

                // hide the profile pic if:
                //     the previous post was made by the same user as the current post,
                //     the previous post is not a comment,
                //     the current post is not a comment,
                //     the current post is not from a webhook
                //     and the previous post is not from a webhook
                if ((prevPost.user_id === post.user_id) &&
                        !prevPostIsComment &&
                        !postIsComment &&
                        !postFromWebhook &&
                        !prevPostFromWebhook) {
                    hideProfilePic = true;
                }
            }

            // check if it's the last comment in a consecutive string of comments on the same post
            // it is the last comment if it is last post in the channel or the next post has a different root post
            const isLastComment = Utils.isComment(post) && (i === 0 || posts[order[i - 1]].root_id !== post.root_id);

            const keyPrefix = post.id ? post.id : i;

            const postCtl = (
                <Post
                    key={keyPrefix + 'postKey'}
                    ref={post.id}
                    sameUser={sameUser}
                    sameRoot={sameRoot}
                    post={post}
                    parentPost={parentPost}
                    posts={posts}
                    hideProfilePic={hideProfilePic}
                    isLastComment={isLastComment}
                />
            );

            const currentPostDay = Utils.getDateForUnixTicks(post.create_at);
            if (currentPostDay.toDateString() !== previousPostDay.toDateString()) {
                postCtls.push(
                    <div
                        key={currentPostDay.toDateString()}
                        className='date-separator'
                    >
                        <hr className='separator__hr' />
                        <div className='separator__text'>{currentPostDay.toDateString()}</div>
                    </div>
                );
            }

            if (post.user_id !== userId &&
                    this.props.messageSeparatorTime !== 0 &&
                    post.create_at > this.props.messageSeparatorTime &&
                    !renderedLastViewed) {
                renderedLastViewed = true;

                // Temporary fix to solve ie11 rendering issue
                let newSeparatorId = '';
                if (!Utils.isBrowserIE()) {
                    newSeparatorId = 'new_message_' + post.id;
                }
                postCtls.push(
                    <div
                        id={newSeparatorId}
                        key='unviewed'
                        ref='newMessageSeparator'
                        className='new-separator'
                    >
                        <hr
                            className='separator__hr'
                        />
                        <div className='separator__text'>{'New Messages'}</div>
                    </div>
                );
            }
            postCtls.push(postCtl);
            previousPostDay = currentPostDay;
        }

        return postCtls;
    }
    updateScrolling() {
        if (this.props.scrollType === PostsView.SCROLL_TYPE_BOTTOM) {
            window.requestAnimationFrame(() => {
                this.refs.postlist.scrollTop = this.refs.postlist.scrollHeight;
            });
        } else if (this.props.scrollType === PostsView.SCROLL_TYPE_NEW_MESSAGE) {
            window.requestAnimationFrame(() => {
                // If separator exists scroll to it. Otherwise scroll to bottom.
                if (this.refs.newMessageSeparator) {
                    this.refs.newMessageSeparator.scrollIntoView();
                } else {
                    this.refs.postlist.scrollTop = this.refs.postlist.scrollHeight;
                }
            });
        } else if (this.props.scrollType === PostsView.SCROLL_TYPE_POST && this.props.scrollPost) {
            window.requestAnimationFrame(() => {
                const postNode = ReactDOM.findDOMNode(this.refs[this.props.scrollPost]);
                postNode.scrollIntoView();
                if (this.refs.postlist.scrollTop === postNode.offsetTop) {
                    this.refs.postlist.scrollTop -= (this.refs.postlist.offsetHeight / 3);
                } else {
                    this.refs.postlist.scrollTop -= (this.refs.postlist.offsetHeight / 3) + (this.refs.postlist.scrollTop - postNode.offsetTop);
                }
            });
        } else if (this.props.scrollType === PostsView.SIDEBAR_OPEN) {
            // If we are at the bottom then stay there
            if (this.wasAtBottom) {
                this.refs.postlist.scrollTop = this.refs.postlist.scrollHeight;
            } else {
                window.requestAnimationFrame(() => {
                    this.jumpToPostNode.scrollIntoView();
                    if (this.refs.postlist.scrollTop === this.jumpToPostNode.offsetTop) {
                        this.refs.postlist.scrollTop -= (this.refs.postlist.offsetHeight / 3);
                    } else {
                        this.refs.postlist.scrollTop -= (this.refs.postlist.offsetHeight / 3) + (this.refs.postlist.scrollTop - this.jumpToPostNode.offsetTop);
                    }
                });
            }
        } else if (this.refs.postlist.scrollHeight !== this.prevScrollHeight) {
            window.requestAnimationFrame(() => {
                this.refs.postlist.scrollTop += (this.refs.postlist.scrollHeight - this.prevScrollHeight);
            });
        }
    }
    handleResize() {
        this.updateScrolling();
    }
    componentDidMount() {
        this.updateScrolling();
        window.addEventListener('resize', this.handleResize);
    }
    componentWillUnmount() {
        window.removeEventListener('resize', this.handleResize);
    }
    componentDidUpdate() {
        this.updateScrolling();
    }
    shouldComponentUpdate(nextProps) {
        if (this.props.isActive !== nextProps.isActive) {
            return true;
        }
        if (this.props.postList !== nextProps.postList) {
            return true;
        }
        if (this.props.scrollPost !== nextProps.scrollPost) {
            return true;
        }
        if (this.props.scrollType !== nextProps.scrollType && nextProps.scrollType !== PostsView.SCROLL_TYPE_FREE) {
            return true;
        }
        if (this.props.numPostsToDisplay !== nextProps.numPostsToDisplay) {
            return true;
        }
        if (this.props.messageSeparatorTime !== nextProps.messageSeparatorTime) {
            return true;
        }
        if (!Utils.areObjectsEqual(this.props.postList, nextProps.postList)) {
            return true;
        }

        return false;
    }
    render() {
        let posts = [];
        let order = [];
        let moreMessages;
        let postElements;
        let activeClass = 'inactive';
        if (this.props.postList != null) {
            posts = this.props.postList.posts;
            order = this.props.postList.order;

            // Create intro message or top loadmore link
            if (order.length >= this.props.numPostsToDisplay) {
                moreMessages = (
                    <a
                        ref='loadmore'
                        className='more-messages-text theme'
                        href='#'
                        onClick={this.loadMorePostsTop}
                    >
                        {'Load more messages'}
                    </a>
                );
            } else {
                moreMessages = this.props.introText;
            }

            // Create post elements
            postElements = this.createPosts(posts, order);

            // Show ourselves if we are marked active
            if (this.props.isActive) {
                activeClass = '';
            }
        }

        return (
            <div
                ref='postlist'
                className={'post-list-holder-by-time ' + activeClass}
                onScroll={this.handleScroll}
            >
                <div className='post-list__table'>
                    <div
                        ref='postlistcontent'
                        className='post-list__content'
                    >
                        {moreMessages}
                        {postElements}
                    </div>
                </div>
            </div>
        );
    }
}
PostsView.defaultProps = {
};

PostsView.propTypes = {
    isActive: React.PropTypes.bool,
    postList: React.PropTypes.object,
    scrollPost: React.PropTypes.string,
    scrollType: React.PropTypes.number,
    postViewScrolled: React.PropTypes.func.isRequired,
    loadMorePostsTopClicked: React.PropTypes.func.isRequired,
    numPostsToDisplay: React.PropTypes.number,
    introText: React.PropTypes.element,
    messageSeparatorTime: React.PropTypes.number
};