import React, { createRef } from "react";
import { Link, withRouter } from "react-router-dom";

import { Files } from "../../model/";
import { sort } from "../../pages/filespage.helper.js";
import { Icon, NgIf, EventReceiver, EventEmitter } from "../../components/";
import {
    dirname, basename, settings_get, getMimeType, debounce, appendShareToUrl,
} from "../../helpers/";
import "./pager.scss";

class PagerComponent extends React.Component {
    constructor(props) {
        super(props);
        this.state = {
            files: [],
            n: 0,
        };
        this.$page = createRef();
        this.onKeyPress = this.onKeyPress.bind(this);
        this.onSubmitDebounced = debounce(this.onFormSubmit.bind(this), 1000);
    }

    componentDidMount() {
        this.setNavigation(this.props);
        window.addEventListener("keyup", this.onKeyPress);
        this.props.subscribe("media::next", () => {
            this.navigatePage(this.calculateNextPageNumber(this.state.n));
        });
        this.props.subscribe("media::previous", () => {
            this.navigatePage(this.calculatePrevPageNumber(this.state.n));
        });
    }

    UNSAFE_componentWillReceiveProps(props) {
        if (props.path !== this.props.path) {
            this.setNavigation(props);
        }
    }

    componentWillUnmount() {
        window.removeEventListener("keyup", this.onKeyPress);
        this.props.unsubscribe("media::next");
        this.props.unsubscribe("media::previous");
        this.hasUnmounted = true;
    }

    navigatePage(n) {
        if (this.state.files[n]) {
            const url = appendShareToUrl(this.state.files[n].link);
            if (this.$page && this.$page.current) this.$page.current.blur();
            const preload_index = (
                n >= this.state.n ||
                    (this.state.n === this.state.files.length - 1 && n === 0)
            ) ? this.calculateNextPageNumber(n) : this.calculatePrevPageNumber(n);
            Files.url(this.state.files[preload_index].path)
                .then((url) => this.props.emit("media::preload", url))
                .then(() => setTimeout(() => this.props.history.push(url), 0))
                .catch(() => {});
        }
    }
    calculateNextPageNumber(n) {
        if (n + 1 >= this.state.files.length) return 0;
        return n + 1;
    }
    calculatePrevPageNumber(n) {
        if (n <= 0) return this.state.files.length - 1;
        return n - 1;
    }

    setNavigation(props) {
        Files._ls_from_cache(dirname(props.path))
            .then((f) => {
                if (f === null) return Promise.reject({ code: "NO_DATA" });
                return Promise.resolve(f);
            })
            .then((f) => f.results.filter((file) => {
                if (file.type !== "file") return false;
                const mType = getMimeType(file.name);
                switch(mType.split("/")[0]) {
                case "video": return true;
                case "image": return true;
                }
                return false;
            }))
            .then((f) => sort(f, settings_get("filespage_sort") || "type"))
            .then((f) => findPosition(f, basename(props.path)))
            .then((res) => {
                if (this.hasUnmounted === true) return;
                if (this.props.pageChange) this.props.pageChange(res[0]);
                this.setState({
                    files: res[0],
                    n: res[1],
                });
            })
            .catch(() => {});

        const findPosition = (files, filename) => {
            let i;
            for (i=0; i < files.length; i++) {
                if (files[i].name === filename) {
                    break;
                }
            }
            return [files, i];
        };
    }

    onFormInputChange(e) {
        let n = parseInt(e.target.value);
        if (Number.isNaN(n)) n = undefined;
        else if (n < 1) n = 0;
        else if (n > this.state.files.length) n = this.state.files.length - 1;
        else n = n - 1;

        this.setState({ n: n });
        if (n >= 0) {
            this.onSubmitDebounced();
        }
    }

    onFormSubmit(e) {
        if (e) e.preventDefault();
        this.navigatePage(this.state.n);
    }

    onKeyPress(e) {
        e.preventDefault();
        e.stopPropagation();
        if (e.target.classList.contains("prevent")) return;
        if (e.keyCode === 39) {
            this.navigatePage(this.calculateNextPageNumber(this.state.n));
        } else if (e.keyCode === 37) {
            this.navigatePage(this.calculatePrevPageNumber(this.state.n));
        }
    }

    render() {
        const inputWidth = this.state.n === undefined ?
            12 : ((this.state.n + 1).toString().length) * 12;
        const nextLink = () => {
            const l = this.state.files[this.calculateNextPageNumber(this.state.n)];
            return (((l && l.link) || "") + window.location.search) || "#";
        };
        const prevLink = () => {
            const l = this.state.files[this.calculatePrevPageNumber(this.state.n)];
            return (((l && l.link) || "") + window.location.search) || "#";
        };
        const current_page_number = this.state.n === undefined ? "" : this.state.n + 1;
        return (
            <div className="component_pager">
                <div className="wrapper no-select">
                    <NgIf cond={this.state.files.length > 0} type="inline">
                        <Link to={prevLink()}><Icon name="arrow_left_white"/></Link>
                        <label className="pager">
                            <form onSubmit={this.onFormSubmit.bind(this)}>
                                <input
                                    ref={this.$page} className="prevent" type="number"
                                    style={{ width: inputWidth+"px" }}
                                    onChange={this.onFormInputChange.bind(this)}
                                    value={current_page_number} />
                            </form>
                            <span className="separator">/</span>
                            <span>{this.state.files.length}</span>
                        </label>
                        <Link to={nextLink()}><Icon name="arrow_right_white"/></Link>
                    </NgIf>
                </div>
            </div>
        );
    }
}

export const Pager = EventEmitter(EventReceiver(withRouter(PagerComponent)));