/*
Copyright 2019 The Matrix.org Foundation C.I.C.

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 PropTypes from 'prop-types';
import MatrixClientPeg from "../../../MatrixClientPeg";
import { _t } from '../../../languageHandler';
import sdk from "../../../index";
import {wantsDateSeparator} from '../../../DateUtils';
import SettingsStore from '../../../settings/SettingsStore';

export default class MessageEditHistoryDialog extends React.PureComponent {
    static propTypes = {
        mxEvent: PropTypes.object.isRequired,
    };

    constructor(props) {
        super(props);
        this.state = {
            error: null,
            events: [],
            nextBatch: null,
            isLoading: true,
            isTwelveHour: SettingsStore.getValue("showTwelveHourTimestamps"),
        };
    }

    loadMoreEdits = async (backwards) => {
        if (backwards || (!this.state.nextBatch && !this.state.isLoading)) {
            // bail out on backwards as we only paginate in one direction
            return false;
        }
        const opts = {from: this.state.nextBatch};
        const roomId = this.props.mxEvent.getRoomId();
        const eventId = this.props.mxEvent.getId();
        let result;
        let resolve;
        let reject;
        const promise = new Promise((_resolve, _reject) => {resolve = _resolve; reject = _reject;});
        try {
            result = await MatrixClientPeg.get().relations(
                roomId, eventId, "m.replace", "m.room.message", opts);
        } catch (error) {
            this.setState({error}, () => reject(error));
            return promise;
        }
        this.setState({
            events: this.state.events.concat(result.events),
            nextBatch: result.nextBatch,
            isLoading: false,
        }, () => {
            const hasMoreResults = !!this.state.nextBatch;
            resolve(hasMoreResults);
        });
        return promise;
    }

    componentDidMount() {
        this.loadMoreEdits();
    }

    _renderEdits() {
        const EditHistoryMessage = sdk.getComponent('messages.EditHistoryMessage');
        const DateSeparator = sdk.getComponent('messages.DateSeparator');
        const nodes = [];
        let lastEvent;
        this.state.events.forEach(e => {
            if (!lastEvent || wantsDateSeparator(lastEvent.getDate(), e.getDate())) {
                nodes.push(<li key={e.getTs() + "~"}><DateSeparator ts={e.getTs()} /></li>);
            }
            nodes.push(<EditHistoryMessage key={e.getId()} mxEvent={e} isTwelveHour={this.state.isTwelveHour} />);
            lastEvent = e;
        });
        return nodes;
    }

    render() {
        let content;
        if (this.state.error) {
            const {error} = this.state;
            if (error.errcode === "M_UNRECOGNIZED") {
                content = (<p className="mx_MessageEditHistoryDialog_error">
                    {_t("Your homeserver doesn't seem to support this feature.")}
                </p>);
            } else if (error.errcode) {
                // some kind of error from the homeserver
                content = (<p className="mx_MessageEditHistoryDialog_error">
                    {_t("Something went wrong!")}
                </p>);
            } else {
                content = (<p className="mx_MessageEditHistoryDialog_error">
                    {_t("Could not reach your homeserver to fetch the edit history.")}
                    <br />
                    {_t("Verify your internet connection or try again later.")}
                </p>);
            }
        } else if (this.state.isLoading) {
            const Spinner = sdk.getComponent("elements.Spinner");
            content = <Spinner />;
        } else {
            const ScrollPanel = sdk.getComponent("structures.ScrollPanel");
            content = (<ScrollPanel
                className="mx_MessageEditHistoryDialog_scrollPanel"
                onFillRequest={ this.loadMoreEdits }
                stickyBottom={false}
                startAtBottom={false}
            >
                <ul className="mx_MessageEditHistoryDialog_edits mx_MessagePanel_alwaysShowTimestamps">{this._renderEdits()}</ul>
            </ScrollPanel>);
        }
        const BaseDialog = sdk.getComponent('views.dialogs.BaseDialog');
        return (
            <BaseDialog className='mx_MessageEditHistoryDialog' hasCancel={true}
                        onFinished={this.props.onFinished} title={_t("Message edits")}>
                {content}
            </BaseDialog>
        );
    }
}