(() => {
    'use strict';

    // Set once before uploading this stable file to GetCourse. It must belong
    // to infrastructure independent from both Foxplan and Naverivo.
    const FAILURE_REPORT_URL = '';
    const LOAD_TIMEOUT_MS = 4000;

    // Stable bootstrap installed in GetCourse once. URL exclusions and the
    // Foxplan/Naverivo fallback stay here; product behavior stays in Pixel.

    const loader = document.currentScript;

    if (!(loader instanceof HTMLScriptElement)) {
        return;
    }

    const pixelKey = loader.dataset.pixel;

    if (!pixelKey || !/^[0-9a-f-]{36}$/i.test(pixelKey)) {
        return;
    }

    const normalizePath = value => value.replace(/\/+$/, '') || '/';
    const currentPage = new URL(window.location.href);
    let excludedUrls = [];

    try {
        excludedUrls = JSON.parse(loader.dataset.exclude || '[]');
    } catch {
        excludedUrls = [];
    }

    const excluded = excludedUrls.some(value => {
        try {
            const page = new URL(value, currentPage.origin);

            return page.hostname.toLowerCase() === currentPage.hostname.toLowerCase()
                && normalizePath(page.pathname) === normalizePath(currentPage.pathname)
                && [...page.searchParams].every(([name, expected]) =>
                    currentPage.searchParams.get(name) === expected
                );
        } catch {
            return false;
        }
    });

    if (excluded || window.__foxplanLoaderStarted) {
        return;
    }

    window.__foxplanLoaderStarted = true;

    const load = url => new Promise(resolve => {
        const started = performance.now();
        const script = document.createElement('script');
        let finished = false;

        const finish = error => {
            if (finished) {
                return;
            }

            finished = true;
            window.clearTimeout(timeout);
            script.onload = null;
            script.onerror = null;

            if (error) {
                script.remove();
            }

            resolve({
                error,
                duration_ms: Math.round(performance.now() - started),
            });
        };

        const timeout = window.setTimeout(() => finish('timeout'), LOAD_TIMEOUT_MS);

        script.src = url;
        script.async = true;
        script.onload = () => finish(null);
        script.onerror = () => finish('network_or_block');
        document.head.appendChild(script);
    });

    const showReportButton = tests => {
        if (currentPage.searchParams.get('foxplan_debug') !== '1') {
            return;
        }

        const button = document.createElement('button');
        let publicIp = null;
        let ipLookup = 'pending';

        const report = () => JSON.stringify({
            generated_at: new Date().toISOString(),
            page: currentPage.origin + currentPage.pathname,
            public_ip: publicIp,
            ip_lookup: ipLookup,
            online: navigator.onLine,
            user_agent: navigator.userAgent,
            language: navigator.language || null,
            timezone: Intl.DateTimeFormat().resolvedOptions().timeZone || null,
            tests,
        }, null, 2);

        button.type = 'button';
        button.disabled = true;
        button.textContent = 'Подготовка отчёта Foxplan…';
        button.style.cssText = 'position:fixed;right:16px;bottom:16px;z-index:2147483647;padding:10px 14px;border:0;border-radius:8px;background:#f59e0b;color:#111827;font:bold 14px Arial;cursor:pointer';
        button.onclick = () => {
            const contents = report();
            const copy = navigator.clipboard?.writeText(contents);

            if (!copy) {
                window.prompt('Скопируйте отчёт', contents);

                return;
            }

            copy
                .then(() => { button.textContent = 'Отчёт скопирован'; })
                .catch(() => window.prompt('Скопируйте отчёт', contents));
        };

        const mount = () => document.body.appendChild(button);

        if (document.body) {
            mount();
        } else {
            document.addEventListener('DOMContentLoaded', mount, {once: true});
        }

        const controller = new AbortController();
        const timeout = window.setTimeout(() => controller.abort(), 3000);

        fetch('https://api64.ipify.org?format=json', {
            cache: 'no-store',
            credentials: 'omit',
            referrerPolicy: 'no-referrer',
            signal: controller.signal,
        })
            .then(response => response.ok ? response.json() : Promise.reject(new Error('http')))
            .then(result => {
                const value = String(result.ip || '').trim();

                if (!/^[0-9a-f:.]{3,45}$/i.test(value)) {
                    throw new Error('invalid_ip');
                }

                publicIp = value;
                ipLookup = 'ok';
            })
            .catch(error => {
                ipLookup = error.name === 'AbortError' ? 'timeout' : 'unavailable';
            })
            .finally(() => {
                window.clearTimeout(timeout);
                button.disabled = false;
                button.textContent = 'Скопировать отчёт Foxplan';
            });
    };

    const reportTotalFailure = tests => {
        if (!/^https:\/\//i.test(FAILURE_REPORT_URL)) {
            return;
        }

        const connection = navigator.connection || navigator.mozConnection || navigator.webkitConnection || {};
        const userId = Number(window.accountUserId);
        const eventId = window.crypto?.randomUUID?.() || 'xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx'.replace(/[xy]/g, character => {
            const random = Math.random() * 16 | 0;
            return (character === 'x' ? random : (random & 3 | 8)).toString(16);
        });
        const body = JSON.stringify({
            event_id: eventId,
            site_key: pixelKey,
            observed_at: new Date().toISOString(),
            result: 'failed',
            reason: 'both_endpoints_unavailable',
            external_user_id: Number.isSafeInteger(userId) && userId > 0 ? userId : null,
            origin_host: currentPage.hostname,
            page_path: currentPage.pathname,
            online: navigator.onLine,
            language: navigator.language || null,
            timezone: Intl.DateTimeFormat().resolvedOptions().timeZone || null,
            platform: navigator.userAgentData?.platform || navigator.platform || null,
            connection: {
                type: connection.type || null,
                effective_type: connection.effectiveType || null,
                downlink: connection.downlink ?? null,
                rtt: connection.rtt ?? null,
                save_data: Boolean(connection.saveData),
            },
            tests: [
                {name: 'foxplan_direct', ok: false, duration_ms: tests.direct.duration_ms, error: tests.direct.error},
                {name: 'naverivo_proxy', ok: false, duration_ms: tests.fallback.duration_ms, error: tests.fallback.error},
            ],
            script_version: '3.0.0',
        });

        fetch(FAILURE_REPORT_URL, {
            method: 'POST',
            mode: 'no-cors',
            cache: 'no-store',
            credentials: 'omit',
            keepalive: true,
            headers: {'Content-Type': 'text/plain;charset=UTF-8'},
            body,
        }).catch(() => {});
    };

    const run = async () => {
        window.__foxplanDelivery = {mode: 'direct'};
        const direct = await load(`https://foxplan.online/assets/runtime/${pixelKey}.js`);

        if (!direct.error) {
            return;
        }

        window.__foxplanDelivery = {
            mode: 'fallback',
            directError: direct.error,
            directDuration: direct.duration_ms,
        };
        const fallback = await load(`https://naverivo.com/assets/runtime/${pixelKey}.js`);

        if (fallback.error) {
            reportTotalFailure({direct, fallback});
            showReportButton({direct, fallback});
        }
    };

    void run();
})();