const { chromium } = require('playwright');

const targetUrl = process.env.WEBGL_RUNTIME_URL || 'http://localhost:3001/';

async function main() {
    const browser = await chromium.launch({ headless: true });
    const page = await browser.newPage({ viewport: { width: 1920, height: 1080 } });
    const errors = [];

    page.on('console', (message) => {
        if (message.type() === 'error') errors.push(message.text());
    });
    page.on('pageerror', (error) => errors.push(error.message));

    await page.addInitScript(() => {
        localStorage.removeItem('ai-interactive-fiction-preferences');
    });
    await page.goto(targetUrl, { waitUntil: 'domcontentloaded', timeout: 60000 });
    await page.waitForFunction(() => window.BookTextureRenderer && window.BookLabDebug, null, { timeout: 180000 });

    const result = await page.evaluate(async () => {
        window.BookTextureRenderer.publishSpread();
        await new Promise(resolve => requestAnimationFrame(() => requestAnimationFrame(resolve)));

        const nav = document.getElementById('webgl_book_navigation');
        const slider = document.getElementById('webgl_book_nav_position');
        const minLabel = document.getElementById('webgl_book_nav_min_label');
        const maxLabel = document.getElementById('webgl_book_nav_max_label');
        const textureInfo = window.BookLabDebug.getTextureInfo();
        const initialBookState = window.BookLabDebug.getBookState();
        const initialSliderMax = slider?.max || null;
        const initialMinLabel = minLabel?.textContent || '';
        const initialMaxLabel = maxLabel?.textContent || '';
        const pageSpreadMap = [0, 1, 2, 3, 4, 5].map(page => [page, window.BookLabDebug.mapPageToSpread(page)]);
        const spreadPageMap = [0, 1, 2, 3].map(spread => [spread, window.BookLabDebug.mapSpreadToPage(spread)]);
        const pageCache = window.WebGLPageCache || window.moduleRegistry?.getModule?.('webgl-page-cache');
        const cacheProbeCanvas = document.createElement('canvas');
        cacheProbeCanvas.width = 8;
        cacheProbeCanvas.height = 8;
        const cacheProbeContext = cacheProbeCanvas.getContext('2d');
        cacheProbeContext.fillStyle = '#000';
        cacheProbeContext.fillRect(0, 0, 8, 8);
        const cacheProbeMeta = { pageIndex: 9999, width: 8, height: 8, cacheKey: 'runtime-probe' };
        const cacheStoreResult = await pageCache?.cachePageCanvas?.(cacheProbeMeta, cacheProbeCanvas);
        const cacheProbeResult = await pageCache?.getPageCanvas?.(cacheProbeMeta);

        window.BookLabDebug.setPaginationStateForTest({
            spreadIndex: 0,
            spreadCount: 126,
            writtenPageLimit: 250
        });
        const grownBookState = window.BookLabDebug.getBookState();

        window.BookLabDebug.setPaginationStateForTest({
            spreadIndex: 0,
            spreadCount: 8,
            writtenPageLimit: 10
        });
        slider.value = '100';
        slider.dispatchEvent(new Event('input', { bubbles: true }));
        await new Promise(resolve => {
            const startedAt = Date.now();
            const check = () => {
                if ((window.BookLabDebug?.activeFlips || 0) === 0 || Date.now() - startedAt > 2200) {
                    resolve();
                    return;
                }
                requestAnimationFrame(check);
            };
            requestAnimationFrame(check);
        });
        const clampedSliderValue = slider.value;

        document.dispatchEvent(new CustomEvent('webgl-book:page-reserve-directive', {
            detail: {
                value: 20,
                unit: 'percent'
            }
        }));
        const percentReserveState = window.BookLabDebug.getBookState();

        document.body.classList.add('webgl-mode');
        if (!document.getElementById('page_left')) {
            window.moduleRegistry?.getModule?.('ui-display-handler')?.initializeContainers?.();
        }
        window.moduleRegistry?.getModule?.('webgl-book-scene')?.moveBookToControlOverlay?.();
        const pageLeft = document.getElementById('page_left');
        let choicesPanel = document.getElementById('choices');
        if (!choicesPanel && pageLeft) {
            choicesPanel = document.createElement('div');
            choicesPanel.id = 'choices';
            choicesPanel.className = 'container';
            pageLeft.appendChild(choicesPanel);
        }
        const choicesGroup = document.createElement('div');
        choicesGroup.className = 'choices-group';
        const choiceButton = document.createElement('button');
        choiceButton.className = 'choice-button';
        choiceButton.textContent = 'A deliberately long choice label that must stay inside the WebGL overlay without creating horizontal scrolling';
        choicesGroup.appendChild(choiceButton);
        choicesPanel?.appendChild(choicesGroup);
        await new Promise(resolve => requestAnimationFrame(() => requestAnimationFrame(resolve)));
        const gameTitle = document.getElementById('game_title');
        const startPrompt = document.getElementById('start_prompt');
        const titleDisplay = gameTitle ? window.getComputedStyle(gameTitle).display : 'absent';
        const startPromptDisplay = startPrompt ? window.getComputedStyle(startPrompt).display : 'absent';
        const pageLeftStyle = pageLeft ? window.getComputedStyle(pageLeft) : null;
        const choicesStyle = choicesPanel ? window.getComputedStyle(choicesPanel) : null;
        const buttonStyle = window.getComputedStyle(choiceButton);
        const overlayLayout = {
            pageLeftExists: Boolean(pageLeft),
            choicesPanelExists: Boolean(choicesPanel),
            pageLeftNoHorizontalScrollbar: pageLeft ? pageLeft.scrollWidth <= pageLeft.clientWidth + 1 : false,
            choicesNoHorizontalScrollbar: choicesPanel ? choicesPanel.scrollWidth <= choicesPanel.clientWidth + 1 : false,
            pageLeftOverflowX: pageLeftStyle?.overflowX || null,
            choicesOverflowX: choicesStyle?.overflowX || null,
            titleDisplay,
            startPromptDisplay,
            buttonColor: buttonStyle.color,
            buttonBackground: buttonStyle.backgroundColor
        };

        window.BookLabDebug.setPaginationStateForTest({
            spreadIndex: 1,
            spreadCount: 8,
            writtenPageLimit: 10
        });
        if (window.BookPagination) {
            window.BookPagination.spreads = Array.from({ length: 8 }, (_, index) => ({
                index,
                left: [],
                right: [],
                pageMeta: {}
            }));
            window.BookPagination.currentSpreadIndex = 1;
        }
        let targetFlipEventDetail = null;
        const flipFinished = new Promise(resolve => {
            document.addEventListener('webgl-book:page-flip-finished', (event) => {
                targetFlipEventDetail = event.detail || null;
                resolve(true);
            }, { once: true });
        });
        const requestedFlip = await window.BookLabDebug.startPageFlipForTest(1, {
            force: true,
            targetSpread: 2
        });
        const activeFlipsAfterRequest = window.BookLabDebug.activeFlips;
        let postAdvanceState = null;
        if (requestedFlip && window.BookLabDebug.activeFlips > 0) {
            postAdvanceState = window.BookLabDebug.advancePageFlipForTest();
        }
        const activeFlipsAfterAdvance = window.BookLabDebug.activeFlips;
        const targetFlipFinished = targetFlipEventDetail
            ? true
            : await Promise.race([
                flipFinished,
                new Promise(resolve => window.setTimeout(() => resolve(false), 5000))
            ]);
        const postTargetFlipState = window.BookLabDebug.getBookState();

        return {
            navExists: Boolean(nav),
            initialSliderMax,
            initialMinLabel,
            initialMaxLabel,
            finalSliderMax: slider?.max || null,
            finalMaxLabel: maxLabel?.textContent || '',
            initialBookState,
            pageSpreadMap,
            spreadPageMap,
            pageCacheReady: pageCache?.cacheStatus === 'ready',
            pageCacheProbe: {
                stored: cacheStoreResult === true,
                width: cacheProbeResult?.width || 0,
                height: cacheProbeResult?.height || 0
            },
            grownBookState,
            clampedSliderValue,
            percentReserveState,
            overlayLayout,
            requestedFlip,
            activeFlipsAfterRequest,
            activeFlipsAfterAdvance,
            postAdvanceState,
            targetFlipFinished,
            targetFlipEventDetail,
            postTargetFlipState,
            textureInfo
        };
    });

    await browser.close();

    const failures = [];
    const relevantErrors = errors.filter((error) => !/^Failed to load resource: the server responded with a status of 400/.test(error));
    if (relevantErrors.length) failures.push(`browser errors: ${relevantErrors.join(' | ')}`);
    if (!result.navExists) failures.push('bottom navigation missing');
    if (result.initialSliderMax !== '300') failures.push(`expected initial slider max 300, got ${result.initialSliderMax}`);
    if (result.initialMinLabel !== '0') failures.push(`expected min label 0, got ${result.initialMinLabel}`);
    if (result.initialMaxLabel !== '300') failures.push(`expected initial max label 300, got ${result.initialMaxLabel}`);
    if (result.initialBookState?.pageCount !== 300) failures.push(`expected initial pageCount 300, got ${result.initialBookState?.pageCount}`);
    if (result.initialBookState?.pageReserve !== 50) failures.push(`expected initial pageReserve 50, got ${result.initialBookState?.pageReserve}`);
    if (result.initialBookState?.progress !== 0) failures.push(`expected initial progress 0, got ${result.initialBookState?.progress}`);
    if (JSON.stringify(result.pageSpreadMap) !== JSON.stringify([[0, 0], [1, 1], [2, 2], [3, 2], [4, 3], [5, 3]])) {
        failures.push(`unexpected page-to-spread map ${JSON.stringify(result.pageSpreadMap)}`);
    }
    if (JSON.stringify(result.spreadPageMap) !== JSON.stringify([[0, 0], [1, 1], [2, 2], [3, 4]])) {
        failures.push(`unexpected spread-to-page map ${JSON.stringify(result.spreadPageMap)}`);
    }
    if (!result.pageCacheReady) failures.push('WebGL page cache is not ready');
    if (!result.pageCacheProbe?.stored || result.pageCacheProbe?.width !== 8 || result.pageCacheProbe?.height !== 8) {
        failures.push(`WebGL page cache probe failed: ${JSON.stringify(result.pageCacheProbe)}`);
    }
    if (result.grownBookState?.pageCount !== 310) failures.push(`expected page count to grow to 310 at writable limit, got ${result.grownBookState?.pageCount}`);
    if (result.finalSliderMax !== '310') failures.push(`expected final slider max 310, got ${result.finalSliderMax}`);
    if (result.finalMaxLabel !== '310') failures.push(`expected final max label 310, got ${result.finalMaxLabel}`);
    if (result.clampedSliderValue !== '10') failures.push(`expected slider clamp to written page 10, got ${result.clampedSliderValue}`);
    if (result.percentReserveState?.pageReserve !== 62) failures.push(`expected 20% reserve of 310 pages to be 62, got ${result.percentReserveState?.pageReserve}`);
    if (!result.overlayLayout?.pageLeftNoHorizontalScrollbar) failures.push('WebGL overlay page_left has a horizontal scrollbar');
    if (!result.overlayLayout?.choicesNoHorizontalScrollbar) failures.push('WebGL choices panel has a horizontal scrollbar');
    if (result.overlayLayout?.pageLeftOverflowX !== 'hidden') failures.push(`expected page_left overflow-x hidden, got ${result.overlayLayout?.pageLeftOverflowX}`);
    if (result.overlayLayout?.choicesOverflowX !== 'hidden') failures.push(`expected choices overflow-x hidden, got ${result.overlayLayout?.choicesOverflowX}`);
    if (!['none', 'absent'].includes(result.overlayLayout?.titleDisplay)) failures.push(`expected title hidden in WebGL overlay, got ${result.overlayLayout?.titleDisplay}`);
    if (!['none', 'absent'].includes(result.overlayLayout?.startPromptDisplay)) failures.push(`expected start prompt hidden in WebGL overlay, got ${result.overlayLayout?.startPromptDisplay}`);
    if (/^rgb\(0,\s*0,\s*0\)$/.test(result.overlayLayout?.buttonColor || '')) failures.push('choice button text is still black in WebGL overlay');
    if (!result.requestedFlip) failures.push('targeted page flip request was rejected');
    if (!result.targetFlipFinished) failures.push(`targeted page flip did not finish: ${JSON.stringify({
        requestedFlip: result.requestedFlip,
        activeFlipsAfterRequest: result.activeFlipsAfterRequest,
        activeFlipsAfterAdvance: result.activeFlipsAfterAdvance,
        postAdvanceState: result.postAdvanceState,
        eventDetail: result.targetFlipEventDetail
    })}`);
    if (result.postTargetFlipState?.spreadIndex !== 2) failures.push(`targeted page flip should commit spread 2, got ${result.postTargetFlipState?.spreadIndex}`);
    if (!result.textureInfo?.debug?.left?.painted || !result.textureInfo?.debug?.right?.painted) failures.push('page texture publish did not paint both pages');

    if (failures.length) {
        console.error('WebGL runtime regression checks failed:');
        failures.forEach(failure => console.error(`- ${failure}`));
        process.exit(1);
    }

    console.log('WebGL runtime regression checks passed.');
}

main().catch((error) => {
    console.error(error);
    process.exit(1);
});