/**
 * @file  zendesk-config.js
 * @desc  Zendesk Messenger - Central Configuration
 *
 * This script provides central configuration for the Zendesk Messenger widget,
 * defining visual themes and dynamic conversation tagging rules based on URL
 * parameters and hostnames.
 *
 * === WHAT THIS FILE DOES =====================================================
 *
 *  1. THEME: Defines all color tokens used by the Zendesk Messenger widget.
 *            Modifying values here automatically updates the widget's appearance.
 *
 *  2. TAG RULES: Determines which conversation tags are sent to Zendesk when a
 *                chat initiates. These tags are crucial for routing, reporting,
 *                and bot behavior.
 *
 * === HOW TO USE ==============================================================
 *
 *  Load this file once on every page, ensuring it executes before
 *  `zendesk-bootstrap.js`. Upon loading, the following are exposed globally:
 *
 *    `window.ZENDESK_CONFIG.theme`       A frozen object containing color tokens.
 *    `window.ZENDESK_CONFIG.getTags()`   A function that returns an array of active tags.
 *
 * === HOW TO ADD A NEW TAG RULE ===============================================
 *
 *  To add a new tag rule, append an object to the `TAG_RULES` array in Section 2.
 *  Each rule object must contain two functions:
 *
 *    `test(location)`: A function that returns a boolean, indicating whether
 *                      this rule should apply for the given URL.
 *    `tags(location)`: A function that returns an array of strings, representing
 *                      the tags to be added if the `test` function returns true.
 *
 *  No modifications to page templates are required; all tag logic is managed
 *  within this file. Refer to the commented examples within `TAG_RULES` for
 *  common patterns.
 *
 * === EVENTS ==================================================================
 *
 *  This script dispatches a `zendesk-config:ready` CustomEvent on `window` once
 *  fully initialized. Bootstrap scripts can listen for this event before
 *  accessing `window.ZENDESK_CONFIG`.
 *
 * === BROWSER SUPPORT =========================================================
 *
 *  Requires `URLSearchParams` and `Array.from`. Compatible with all modern
 *  browsers; Internet Explorer is not supported.
 *
 * =============================================================================
 */

(function bootstrap(global) {
    'use strict';

    // =========================================================================
    // SECTION 1 - VISUAL THEME
    //
    // Color tokens consumed directly by Zendesk Messenger.
    // Naming convention:
    //   `someElement`    →  the background or fill color of that element
    //   `onSomeElement`  →  the text / icon color drawn ON TOP of it
    //
    // Every token is a hex string. Adjust values here only - never inline
    // colors elsewhere.
    // =========================================================================

    const THEME = Object.freeze({
        // == Widget launcher & conversation header =================
        primary: '#8a2ce8', // header + launcher background
        onPrimary: '#ffffff', // header/launcher text & icons

        // == End-user (visitor) message bubbles ====================
        message: '#a456f6', // end-user message bubbles
        onMessage: '#ffffff', // end-user message text

        // == Agent / bot message bubbles ===========================
        businessMessage: '#f5f6f8', // bot/agent message bubbles
        onBusinessMessage: '#192642', // bot/agent message text

        // == Buttons & quick-reply chips ===========================
        action: '#1d2124', // button / quick-reply background
        onAction: '#ffffff', // button / quick-reply text

        // == Chat window background ================================
        background: '#ffffff', // chat window background
        onBackground: '#1d2124', // timestamps, names, meta text

        // == Error / failure states ================================
        error: '#cd3642', // error / failure states
        onError: '#ffffff', // error / failure text

        // == System / notification banners ========================
        notify: '#cce0f0', // system / notification banners
        onNotify: '#13456d', // system / notification text

        // == Secondary / disabled actions =========================
        onSecondaryAction: '#1d2124', // secondary / disabled action text
    });

    // =========================================================================
    // SECTION 2 - CONVERSATION TAG RULES
    //
    // `TAG_RULES` is the definitive list of routing decisions for this widget.
    //
    // How evaluation works:
    //   • Rules are processed sequentially from top to bottom on every chat open.
    //   • Any rule whose `test()` function returns `true` will contribute its tags.
    //   • Rules are additive; multiple rules can fire simultaneously.
    //   • Duplicate tags are automatically removed before being sent to Zendesk.
    //
    // The `location` parameter passed to `test()` and `tags()` is the standard
    // browser `Location` / `URL` object. For unit testing, a synthetic URL object
    // can be injected to decouple from the real browser address bar.
    //
    // Rule structure:
    //   `{
    //     test: (location) => boolean,
    //     tags: (location) => string[]
    //   }`
    //
    // Both `test()` and `tags()` functions are mandatory for each rule.
    // =========================================================================

    /**
     * Detects the recruiting feature-flag in the URL query string.
     * This function supports two formats for backward compatibility:
     *
     *   1. Standard (new links): `?recruiting_page=universal-testing`
     *   2. Legacy (old links): `?parameter1+recruiting_page=universal-testing`
     *      (The browser decodes `+` in a key as a space, so the key becomes
     *      `"parameter1 recruiting_page"` - its suffix is still `"recruiting_page"`.)
     *
     * The parameter's value is not checked; its mere presence is sufficient.
     *
     * @param {URLSearchParams} params - An already-parsed `URLSearchParams` object.
     * @returns {boolean} - True if the recruiting page flag is present, false otherwise.
     */
    const isRecruitingPageFlagSet = (params) => {
        // Fast path: check for the standard key directly.
        if (params.has('recruiting_page')) {
            return true;
        }

        // Slow path: iterate through all keys to find the legacy format.
        // This is acceptable as real URLs typically have a small number of parameters.
        for (const key of params.keys()) {
            if (key.endsWith('recruiting_page')) {
                return true;
            }
        }

        return false;
    };

    /**
     * Defines the structure for a tag rule.
     * @typedef {Object} TagRule
     * @property {(location: Location | URL) => boolean} test - Function to test if the rule applies.
     * @property {(location: Location | URL) => string[]} tags - Function to return tags if the rule applies.
     */

    /**
     * The list of conversation tag rules.
     * @type {TagRule[]}
     */
    const TAG_RULES = [
        // == Rule 1: Recruiting pages =========================================
        //
        // This rule fires under two conditions:
        //   1. The current hostname matches a known recruiting domain (production or staging).
        //   2. The URL contains the `recruiting_page` feature-flag query parameter.
        //
        // The query-parameter path is intentionally unrestricted by hostname,
        // allowing testers and QA to activate recruiting behavior from any environment.
        //
        //   Standard flag:  `?recruiting_page=universal-testing`
        //   Legacy flag:    `?oldparam+recruiting_page=universal-testing`
        //
        // Result tag: `'recruiting_page'`
        {
            test: (location) => {
                const host = location.hostname;
                const params = new URLSearchParams(location.search);

                const isKnownRecruitingHost =
                    host === 'recruiting.xing.com' ||
                    host === 'staging.recruiting.xing.com';

                return isKnownRecruitingHost || isRecruitingPageFlagSet(params);
            },
            tags: () => ['recruiting_page'],
        },

        // == Rule 2: Audience segment =========================================
        //
        // This rule reads the `?segment=` query parameter and maps it to a routing tag.
        // Only the values `'b2b'` and `'b2c'` are recognized; any other value is
        // ignored (no tag added, no error).
        //
        // This rule works on any path, and additional query parameters do not interfere.
        //
        // Matching examples:
        //   `https://help.xing.com/hc/en-us?segment=b2b`
        //   `https://help.xing.com/hc/de/categories/123?utm_source=nl&segment=b2c`
        //
        // Result tags: `'segment_b2b'` or `'segment_b2c'`
        {
            test: (location) => {
                const params = new URLSearchParams(location.search);
                const segment = params.get('segment');
                return segment === 'b2b' || segment === 'b2c';
            },
            tags: (location) => {
                const params = new URLSearchParams(location.search);
                const segment = params.get('segment');
                return [`segment_${segment}`]; // e.g., 'segment_b2b' or 'segment_b2c'
            },
        },

        // == Add new rules here ===============================================
        //
        // Append new rule objects below. Avoid modifying page templates.
        // Each rule MUST define both `test()` and `tags()`. A missing `tags()`
        // will result in a console warning and the rule being skipped, preventing
        // a crash of the entire widget.
        //
        // Pattern examples:
        //
        //   Country routing (URL path prefix)
        //   `{ test: (l) => l.pathname.startsWith('/de'),
        //     tags: ()  => ['country_de'] }`
        //
        //   A/B experiment (50 / 50 random split)
        //   `{ test: () => Math.random() < 0.5,
        //     tags: ()  => ['ab_variant_b'] }`
        //
        //   Authenticated users (session storage flag)
        //   `{ test: () => !!sessionStorage.getItem('uid'),
        //     tags: ()  => ['authenticated'] }`
        //
        //   Product line (URL path segment)
        //   `{ test: (l) => l.pathname.includes('/pro'),
        //     tags: ()  => ['product_pro'] }`
        //
        //   Multi-brand (second hostname)
        //   `{ test: (l) => l.hostname === 'brand2.xing.com',
        //     tags: ()  => ['brand_2'] }`
        //
    ];

    // =========================================================================
    // SECTION 3 - getTags( [location] )
    //
    // Public function. Executes every rule in `TAG_RULES` against the provided
    // (or current) URL and returns a flat, deduplicated array of tag strings.
    //
    // Rules with a missing `tags()` function are gracefully skipped with a
    // console warning, ensuring that a misconfigured rule does not break the
    // entire widget.
    //
    // @param {Location|URL} [location=global.location] - The URL object to test against.
    //                                                    Defaults to `window.location`.
    //                                                    Inject a synthetic URL object for unit tests.
    // @returns {string[]} - An array of deduplicated tags, preserving their original
    //                       collection order.
    // =========================================================================

    const getTags = (location = global.location) => {
        let activeTags = [];

        for (let i = 0; i < TAG_RULES.length; i++) {
            const rule = TAG_RULES[i];

            // Safety guard: Ensure `tags()` function exists to prevent runtime errors.
            if (typeof rule.tags !== 'function') {
                console.warn(
                    `[ZENDESK_CONFIG] TAG_RULES[${i}] is missing a tags() function and will be skipped. ` +
                        `Every rule must define both test() and tags().`,
                );
                continue;
            }

            if (rule.test(location)) {
                activeTags = activeTags.concat(rule.tags(location));
            }
        }

        // Remove duplicates while preserving insertion order.
        // Using `Array.filter` for consistency with the original code's ES5 approach.
        return activeTags.filter(
            (tag, index) => activeTags.indexOf(tag) === index,
        );
    };

    // =========================================================================
    // SECTION 4 - PUBLIC API
    //
    // Exposed as a frozen object to prevent accidental runtime modification of
    // theme tokens or the `getTags` reference from outside this file.
    //
    // Accessible via: `window.ZENDESK_CONFIG`
    // =========================================================================

    global.ZENDESK_CONFIG = Object.freeze({
        theme: THEME,
        getTags: getTags,
    });

    // Notify any bootstrap scripts that are waiting for this file to finish.
    // Listen with: `window.addEventListener('zendesk-config:ready', fn)`
    global.dispatchEvent(new CustomEvent('zendesk-config:ready'));
})(window);