window.ilc = window.ilc || {};

/**
 * Upon clicking the icon at `target`, copies the string `[[${link}]]` to the clipboard and temporarily replaces the
 * clipboard icon with a checkmark.
 *
 * @param target the icon that is clicked on
 * @param link {String} the link to copy to the clipboard
 */
window.ilc.onClickCopy = function(target, link) {
    // noinspection JSIgnoredPromiseFromCall
    navigator.clipboard.writeText(`[[${link}]]`);
    target.classList.replace("fa-clipboard", "fa-check");
    setTimeout(() => target.classList.replace("fa-check", "fa-clipboard"), 1000);
}


/**
 * An input that can be validated.
 *
 * @property input {HTMLElement} the input that is validatable
 */
export class ValidatableInput {
    /**
     * Constructs a new validatable input.
     *
     * @param input {HTMLInputElement} the input that is validatable
     * @param isValid {function(string): string} returns an empty string if the given input string is valid, and a
     * string explaining why it is is invalid otherwise
     */
    constructor(input, isValid) {
        this.input = input;
        this._isValid = isValid;
    }


    /**
     * Returns the value of the underlying input element.
     *
     * @return {String} the value of the underlying input element
     */
    getValue() {
        return this.input.value;
    }

    /**
     * Sets the value of the underlying input element.
     *
     * @param value {string} the value to set
     */
    setValue(value) {
        this.input.value = value;
    }

    /**
     * Validates the input.
     *
     * @return {String} an empty string if the input string is valid, and a string explaining why it is is invalid
     * otherwise
     */
    validate() {
        const validity = this._isValid(this.input.value);

        if (validity.length === 0) this.showSuccess();
        else this.showError();

        return validity;
    }

    /**
     * Marks the input as neither valid nor invalid.
     */
    showBlank() {
        this.input.dataset["entered"] = "false";
        this.input.setCustomValidity("");
    }

    /**
     * Marks the input as invalid and moves focus to it.
     */
    showError() {
        this.input.dataset["entered"] = "true";
        this.input.setCustomValidity("Incorrect");
        this.input.focus();
    }

    /**
     * Marks the input as valid.
     */
    showSuccess() {
        this.input.dataset["entered"] = "true";
        this.input.setCustomValidity("");
    }
}

/**
 * Interacts with the DOM to delegate messages to the user.
 */
export class MessageHandler {
    /**
     * Constructs a new `MessageHandler`, inserting relevant new elements into the DOM to interact with.
     *
     * @param parent {HTMLElement} the element to insert elements into
     * @param [id] {string} the id of the div containing the message
     */
    constructor(parent, id) {
        this._mainDiv = document.createElement("div");
        this._mainDiv.style.display = "none";
        this._mainDiv.classList.add("messageInner");
        parent.appendChild(this._mainDiv);

        this._loadingIcon = document.createElement("i");
        this._loadingIcon.classList.add("fa", "fa-spinner", "fa-spin");
        this._mainDiv.appendChild(this._loadingIcon);

        this._spacing = document.createElement("span");
        this._spacing.innerHTML = " ";
        this._mainDiv.appendChild(this._spacing);

        this._textSpan = document.createElement("span");
        if (id !== undefined)
            this._textSpan.id = id;
        this._mainDiv.appendChild(this._textSpan);

        this._currentLevel = undefined;
        this._callback = undefined;
    }


    /**
     * Handles the displaying of the given message.
     *
     * If no message is given, the current message and the loading icon are hidden. To display an empty message next to
     * the loading icon, give an empty string.
     *
     * @param [level] {"complete"|"progress"|"warning"|"error"|"neutral"} the level of message to display, or
     * `undefined` if the entire message handler should be hidden
     * @param [message] {*} the message to display
     * @returns {MessageHandler} this `MessageHandler`
     */
    handle(level, message) {
        this._displayLevel(level);
        if (level === undefined) return this; // No need to handle the rest

        if (this._callback !== undefined) this._callback(level, message);
        this._textSpan.innerHTML = message;
        return this;
    }

    /**
     * Calls `#handle` without any arguments.
     *
     * @returns {MessageHandler} this `MessageHandler`
     */
    clear() {
        return this.handle();
    }

    /**
     * Sets the callback to be executed whenever a message is handler by this handler.
     *
     * @param callback {function("complete"|"progress"|"warning"|"error"|"neutral", [*]): *} the function to execute
     * whenever a message is handled
     * @returns {MessageHandler} this `MessageHandler`
     */
    setCallback(callback) {
        this._callback = callback;
        return this;
    }


    /**
     * Changes the appearance of the message handler to that of the given level.
     *
     * @param level {"complete"|"progress"|"warning"|"error"|"neutral"} the level to change appearance to
     * @private
     */
    _displayLevel(level) {
        if (level === this._currentLevel) return;
        this._currentLevel = level;

        this._mainDiv.style.display = null;
        this._mainDiv.classList.remove("success", "warning", "error");

        switch (level) {
            case "complete":
                this._mainDiv.classList.add("success");
                this._toggleLoadingIcon(false);
                break;
            case "progress":
                this._toggleLoadingIcon(true);
                break;
            case "warning":
                this._mainDiv.classList.add("warning");
                this._toggleLoadingIcon(false);
                break;
            case "error":
                this._mainDiv.classList.add("error");
                this._toggleLoadingIcon(false);
                break;
            case "neutral":
                this._toggleLoadingIcon(false);
                break;
            default:
                this._mainDiv.style.display = "none";
                return this; // No further handling necessary
        }
    }

    /**
     * Turns the loading icon on or off.
     *
     * @param state {boolean} `true` if and only if the loading icon should be on
     * @returns {MessageHandler} this `MessageHandler`
     * @private
     */
    _toggleLoadingIcon(state) {
        this._loadingIcon.style.display = state ? null : "none";
        this._spacing.style.display = state ? null : "none";

        return this;
    }
}

/**
 * A network of interlanguage links.
 *
 * @property pages {Page[]} the pages in the network
 */
export class InterlangTable {
    /**
     * Generates an icon element with the given title and additional classes.
     *
     * @param icon {string} the name of the icon to display
     * @param title {string} the title of the icon, used for the `title` attribute
     * @param [classes] {string[]} the additional classes to apply to the icon
     * @return {String} an icon element with the given title and additional classes
     * @private
     */
    _createIcon(icon, title, classes) {
        return `<i class="fa fa-${icon} ${(classes || []).join(" ")}" title="${title}"></i>`;
    }

    /**
     * Returns an appropriate label for the given page.
     *
     * The label contains a link to the page and a few buttons to help the user interact with that page. The label's
     * appearance and contents depend both on the properties of the page (e.g. whether it exists and whether it's a
     * redirect page) and on the other pages in this network (e.g. whether it's the only page in its language).
     *
     * @param pages {Page[]} a list of all pages
     * @param page {Page} the page to generate a label of
     * @return {String} an appropriate label with icons for the given page
     * @private
     */
    _generateLabel(pages, page) {
        const labelText = pages.some(it => it.link.lang === page.link.lang && !it.link.equals(page.link))
            ? page.link.toString()
            : page.link.lang;

        return "" +
            `<span class="${page.exists ? "" : "redLink"}">` +
            /**/`<a href="${page.url}" target="_blank" title="${page.link}">${labelText}</a>` +
            /**/`<span> </span>` +
            /**/`<a href="${page.url}?action=edit" target="_blank" title="Edit"><i class="fa fa-pencil"></i></a>` +
            /**/`<span> </span>` +
            /**/`<a title="Copy"><i class="fa fa-clipboard" onclick="window.ilc.onClickCopy(this, '${page.link}')"></i></a>` +
            `</span>`;
    }

    /**
     * Generates the head of the table generated by `#toTable`.
     *
     * @param network {InterlangNetwork} the network to generate the head for
     * @return {String} the head of the table generated by `#toTable`
     * @private
     */
    _generateTableHead(network) {
        return "" +
            `<thead>` +
            /**/`<tr>` +
            /****/`<th rowspan="2"></th>` +
            /****/`<th class="sourceLabel" rowspan="2">Source</th>` +
            /****/`<th colspan="${network.pages.length}">Destination</th>` +
            /**/`</tr>` +
            /**/`<tr>${network.pages.map(page => `<th>${this._generateLabel(network.pages, page)}</th>`)}</tr>` +
            `</thead>`;
    }

    /**
     * Generates the body of the table generated by `#toTable`.
     *
     * @param network {InterlangNetwork} the network to generate the body for
     * @return {String} the body of the table generated by `#toTable`
     * @private
     */
    _generateTableBody(network) {
        const rows = network.pages.map(srcPage => {
            const verdict = network.getPageVerdict(srcPage);

            const icons = verdict.self
                .map(state => {
                    switch (state) {
                        case "perfect":
                            return this._createIcon("check", "Perfect 🙂", ["success"]);
                        case "not-found":
                            return this._createIcon("search", "Article does not exist 😕", ["error"]);
                        case "wrongly-ordered":
                            return this._createIcon("sort-alpha-asc", "Links are in the wrong order 😕", ["warning"]);
                        case "doubly-linked":
                            return this._createIcon("clone", "Links to the same wiki multiple times 😕", ["warning"]);
                        case "self-linked":
                            return this._createIcon("rotate-left", "Links to its own wiki 😕", ["warning"]);
                        case "unlinked":
                            return this._createIcon("chain-broken", "Misses one or more links 😕", ["error"]);
                    }
                })
                .map(it => `${it}<span> </span>`);
            const label = this._generateLabel(network.pages, srcPage);
            const cells = network.pages.map(dstPage => {
                const linkState = verdict.pages.find(it => it.page.link.equals(dstPage.link)).verdict;
                switch (linkState) {
                    case "linked":
                        return this._createIcon("check", "Linked 🙂", ["success"]);
                    case "self-linked":
                        return this._createIcon("rotate-left", "Links to its own wiki 😕", ["warning"]);
                    case "unlinked":
                        return this._createIcon("times", "Link is missing 😕", ["error"]);
                    case "self-unlinked":
                        return `<span></span>`;
                    case "redirected":
                        return this._createIcon("mail-forward", "Links to a redirect 😕", ["warning"]);
                    default:
                        throw new Error(`Invalid link state '${linkState}'`);
                }
            });

            return "" +
                `<tr>` +
                /**/`<th>${icons}</th>` +
                /**/`<th class="sourceLabel">${label}</th>` +
                /**/cells.map(it => `<td>${it}</td>`) +
                `</tr>`;
        });

        return `<tbody>${rows}</tbody>`;
    }

    /**
     * Renders the the table describing the interlanguage network.
     *
     * @param id {String} the ID to assign to the table element
     * @param network {InterlangNetwork} the network of pages to render
     * @return {String} the generated table
     */
    render(id, network) {
        return "" +
            `<table id="${id}">` +
            /**/this._generateTableHead(network) +
            /**/this._generateTableBody(network) +
            `</table>`;
    }
}