import {
	CANVAS_PANE_WIDTH,
	CanvasPane,
	DOT_GRID,
	useCanvasSeat,
} from '@agent/components/Canvas';
import { usePortal } from '@agent/hooks/usePortal';
import { DESKTOP_MIN_WIDTH, useGlobalStore } from '@agent/state/global';
import { createPortal, useEffect, useRef } from '@wordpress/element';
import { __ } from '@wordpress/i18n';
import { close, Icon } from '@wordpress/icons';
import { motion } from 'framer-motion';
import { OptionsPopover } from '../OptionsPopover';

const SIDEBAR_WIDTH = 384;
const CANVAS_WIDTH = SIDEBAR_WIDTH + CANVAS_PANE_WIDTH;
const FRAME_WIDTH = 8; // border-8
const ANIMATE_TIME = 300;

export const SidebarLayout = ({ children }) => {
	const mountNode = usePortal('extendify-agent-sidebar-mount');
	const frameNode = usePortal('extendify-agent-border-frame-mount');
	const { open, setOpen } = useGlobalStore();
	const seat = useCanvasSeat();
	const beside = seat === 'beside';
	useLayoutShift(open);

	const closeAgent = () => {
		setOpen(false);
		// External contract: no in-repo listener by design — notifies
		// host-page/analytics consumers the user dismissed the agent.
		window.dispatchEvent(new CustomEvent('extendify-agent:closed-button'));
	};

	useEffect(() => {
		if (open) return;
		if (!mountNode?.contains(document.activeElement)) return;
		document.activeElement?.blur();
	}, [open]);

	if (!mountNode) return null;

	// A border that sits around the entire browser to look like the sidebar is inside it
	const frameAnim = {
		open: {
			top: FRAME_WIDTH,
			right: FRAME_WIDTH,
			bottom: FRAME_WIDTH,
			left: SIDEBAR_WIDTH,
			boxShadow: '#e0e0e0 0px 0px 0px 9999px',
			borderRadius: '1rem',
		},
		closed: {
			inset: 0,
			boxShadow: '0 0 0 0 #fff',
			borderRadius: 0,
		},
	};

	// Unclipped, the 9999px shadow covers the notification bar.
	const frameBar = frameNode
		? createPortal(
				<div className="fixed top-0 left-0 right-0 bottom-(--extendify-notification-bar-height,0px) overflow-hidden pointer-events-none z-high">
					<motion.div
						className="absolute overflow-hidden"
						initial={false}
						animate={open ? 'open' : 'closed'}
						variants={frameAnim}
						transition={{ duration: ANIMATE_TIME / 1000, ease: 'easeInOut' }}
					/>
					<motion.div
						className="absolute rounded-2xl shadow-xl"
						style={{
							top: FRAME_WIDTH,
							right: FRAME_WIDTH,
							bottom: FRAME_WIDTH,
							left: SIDEBAR_WIDTH,
						}}
						initial={false}
						animate={{ opacity: open ? 1 : 0 }}
						transition={{
							duration: 0.15,
							delay: open ? ANIMATE_TIME / 1000 : 0,
						}}
					/>
				</div>,
				frameNode,
			)
		: null;

	// app/Agent/Skeleton.php mirrors this markup for the deferred mount; edit both.
	const sidebar = mountNode
		? createPortal(
				<motion.div
					className={`fixed top-0 bottom-[var(--extendify-notification-bar-height,0px)] left-0 border-transparent border-8 ${
						// An emptied panel belongs under the scrim with the rest of the page.
						seat === 'modal' ? 'z-high' : 'z-higher'
					}`}
					id="extendify-agent-sidebar"
					data-extendify-agent-panel
					data-extendify-agent-emptied={seat === 'modal' ? '' : undefined}
					initial={false}
					inert={open ? undefined : ''}
					animate={{
						x: open ? 0 : -SIDEBAR_WIDTH,
						width: beside ? CANVAS_WIDTH : SIDEBAR_WIDTH,
					}}
					transition={{ duration: ANIMATE_TIME / 1000, ease: 'easeInOut' }}
				>
					<div
						className={`relative h-full flex shadow-lg rounded-2xl overflow-hidden ${beside ? 'bg-gray-50' : 'bg-white'}`}
						style={beside ? DOT_GRID : undefined}
					>
						<div
							className="relative z-10 h-full flex shrink-0 flex-col rounded-2xl overflow-hidden bg-white shadow-lg"
							style={{ width: SIDEBAR_WIDTH - FRAME_WIDTH * 2 }}
						>
							<div className="group flex shrink-0 items-center justify-between overflow-hidden bg-banner-main text-banner-text">
								<div className="flex h-full grow items-center justify-between gap-1 p-0 py-2.5">
									<div className="flex h-5 px-4 max-w-36 overflow-hidden">
										<img
											className="max-h-full max-w-full object-contain"
											src={window.extSharedData.partnerLogo}
											alt={window.extSharedData.partnerName}
										/>
									</div>
								</div>
								<div className="flex gap-1 h-full items-center p-2">
									{seat ? null : (
										<>
											<OptionsPopover />
											<button
												type="button"
												className="relative z-10 flex justify-center h-6 w-6 items-center border-0 bg-banner-main text-banner-text outline-hidden ring-design-main focus:shadow-none focus:outline-hidden focus-visible:outline-design-main focus:ring-2 hover:opacity-80 rounded-sm"
												onClick={closeAgent}
											>
												<Icon
													className="pointer-events-none fill-current leading-none"
													icon={close}
													size={18}
												/>
												<span className="sr-only">
													{__('Close window', 'extendify-local')}
												</span>
											</button>
										</>
									)}
								</div>
							</div>
							{open ? children : null}
						</div>
						<CanvasPane seat="beside" />
					</div>
				</motion.div>,
				mountNode,
			)
		: null;

	return (
		<>
			{frameBar}
			{sidebar}
		</>
	);
};

// Survives save-triggered reloads (modal saves, undo) — the page can
// reload while the agent is open and we want to land at the same scroll.
const SCROLL_STASH_KEY = 'extendify-agent-wsb-scroll-stash';

const urlKey = () => window.location.pathname + window.location.search;

const stashScroll = (scroll) => {
	try {
		window.sessionStorage.setItem(
			SCROLL_STASH_KEY,
			JSON.stringify({ key: urlKey(), scroll }),
		);
	} catch (_) {
		/* no-op */
	}
};

const consumeStashedScroll = () => {
	try {
		const raw = window.sessionStorage.getItem(SCROLL_STASH_KEY);
		window.sessionStorage.removeItem(SCROLL_STASH_KEY);
		if (!raw) return 0;
		const data = JSON.parse(raw);
		if (!data || data.key !== urlKey()) return 0;
		const n = Number(data.scroll);
		return Number.isFinite(n) && n > 0 ? n : 0;
	} catch (_) {
		return 0;
	}
};

export const useLayoutShift = (open) => {
	const ease = 'ease-in-out';
	const t = (props) =>
		props.map((p) => `${p} ${ANIMATE_TIME}ms ${ease}`).join(', ');
	const firstRun = useRef(true);
	const savedScroll = useRef(0);

	useEffect(() => {
		const onBeforeUnload = () => {
			const wsb = document.querySelector('.wp-site-blocks');
			const scroll = wsb?.scrollTop || window.scrollY || 0;
			if (scroll > 0) stashScroll(scroll);
		};
		window.addEventListener('beforeunload', onBeforeUnload);
		return () => window.removeEventListener('beforeunload', onBeforeUnload);
	}, []);

	useEffect(() => {
		const siteBlocks = document.querySelector('.wp-site-blocks');
		const wpadminbar = document.querySelector('#wpadminbar');
		const stickyHeader = document.querySelector(
			'header.is-position-sticky, header.wp-block-template-part:has(.ext-header-sticky)',
		);

		// firstRun.current flips below before applyScaling runs in rAF.
		const isFirstApply = firstRun.current;

		const applyScaling = () => {
			if (!siteBlocks) return;

			// Unmount leaves these styles, so scaling below the breakpoint is permanent.
			if (open && window.innerWidth >= DESKTOP_MIN_WIDTH) {
				// Capture before `position: fixed` zeroes window.scrollY.
				// Fall through to savedScroll.current so resize / strict-mode
				// re-runs don't clobber it with the now-pinned scrollY (0).
				const stashed = isFirstApply ? consumeStashedScroll() : 0;
				savedScroll.current = stashed || window.scrollY || savedScroll.current;

				const viewportWidth = window.innerWidth;
				const scale = (viewportWidth - SIDEBAR_WIDTH) / viewportWidth;

				// Subtract 40 because translateY(40px) below pushes the element down.
				const scaledHeight = (window.innerHeight - 40) / scale;
				// Divided by the scale because this height is in pre-scale units.
				const height =
					`calc(${scaledHeight}px - ` +
					`var(--extendify-notification-bar-height, 0px) / ${scale})`;

				Object.assign(siteBlocks.style, {
					transformOrigin: 'top left',
					transform: `translateX(${SIDEBAR_WIDTH}px) translateY(40px) scale(${scale})`,
					height,
					overflowY: 'auto',
					// `auto` so the scrollTop below is instant; `smooth` would animate from 0.
					scrollBehavior: 'auto',
				});
				// Force layout so scrollTop respects the new height/overflow.
				void siteBlocks.scrollHeight;
				siteBlocks.scrollTop = savedScroll.current;
				if (stickyHeader) {
					stickyHeader.style.setProperty(
						'--wp-admin--admin-bar--position-offset',
						'0px',
					);
				}
				document.body.style.overflow = 'hidden';
				document.body.style.position = 'fixed';
				document.body.style.top = '0';
				document.body.style.left = '0';
				document.body.style.width = '100vw';
			} else {
				const stashed = isFirstApply ? consumeStashedScroll() : 0;
				const wsbScroll =
					siteBlocks.scrollTop || stashed || savedScroll.current;
				Object.assign(siteBlocks.style, {
					transformOrigin: 'top left',
					transform: 'translateX(0) translateY(0) scale(1)',
					height: '',
					overflowY: '',
					maxWidth: '100vw',
					scrollBehavior: '',
				});
				if (stickyHeader) {
					stickyHeader.style.removeProperty(
						'--wp-admin--admin-bar--position-offset',
						'32px',
					);
				}
				document.body.style.overflow = '';
				document.body.style.position = '';
				document.body.style.top = '';
				document.body.style.left = '';
				document.body.style.width = '';
				// `instant` overrides themes that set html { scroll-behavior: smooth }.
				void document.documentElement.scrollHeight;
				window.scrollTo({ top: wsbScroll, left: 0, behavior: 'instant' });
				savedScroll.current = 0;
			}
		};

		if (!firstRun.current) {
			if (siteBlocks) {
				siteBlocks.style.transition = t(['transform']);
			}
			if (wpadminbar) {
				wpadminbar.style.transition = t([
					'margin-left',
					'margin-top',
					'margin-right',
					'border-radius',
					'max-width',
				]);
			}
		} else {
			firstRun.current = false;
		}

		const raf = requestAnimationFrame(() => {
			applyScaling();

			// External contract: no in-repo listener by design — lets host-page
			// consumers react to the agent reflowing the viewport.
			window.dispatchEvent(
				new CustomEvent('extendify-agent:layout-shift', {
					detail: { open },
				}),
			);

			// agent.css carries the bar offsets, so they drop with the
			// breakpoint rather than with this component.
			document.documentElement.classList.toggle('extendify-agent-docked', open);
		});

		window.addEventListener('resize', applyScaling);

		return () => {
			if (siteBlocks?.scrollTop) {
				savedScroll.current = siteBlocks.scrollTop;
			}
			cancelAnimationFrame(raf);
			window.removeEventListener('resize', applyScaling);
			document.body.style.overflowX = '';
			// Don't clear wsb / wpadminbar styles here. Cleanup is sync,
			// but the next effect's close branch animates them in rAF —
			// wiping them now collapses the un-zoom to a no-op jump.
		};
	}, [open]);
};