<script lang="ts">
	import { browser } from '$app/environment';
	import { privacyNote } from '$lib/privacy-note-store';
	import { themePreference, type ThemePreference } from '$lib/theme-store';
	import { focusTrap } from '$lib/actions/focus-trap';
	import { scrollLock } from '$lib/actions/scroll-lock';
	import { vibrate } from '$lib/haptics';
	import { hasSeenGuide, markGuideSeen } from '$lib/onboarding';

	type Step =
		| { kind: 'text'; icon: string; title: string; body: string }
		| { kind: 'theme'; icon: string; title: string };

	let visible = $state(false);
	let step = $state(0);

	// The PIN step gets an extra line when the admin has set a Datenschutzhinweis. Done
	// reactively so the nudge appears as soon as the note loads from `/me/context`,
	// even if the user opens the onboarding before the request returns.
	let hasPrivacyNote = $derived($privacyNote.trim().length > 0);

	let steps: Step[] = $derived([
		{
			kind: 'text',
			icon: '📸',
			title: 'Willkommen bei EventSnap!',
			body: 'Hier kannst du Fotos und Videos mit allen Gästen teilen — in Echtzeit, ganz ohne App-Store.'
		},
		{
			kind: 'text',
			icon: '⬆️',
			title: 'Fotos & Videos hochladen',
			body: 'Tippe auf den Kamera-Button unten in der Mitte, um Fotos aus deiner Galerie zu wählen oder direkt mit der Kamera aufzunehmen. Mehrere Dateien auf einmal sind kein Problem!'
		},
		{
			kind: 'text',
			icon: '#️⃣',
			title: 'Hashtags nutzen',
			body: 'Füge in deiner Bildunterschrift #hashtags ein, um Fotos zu gruppieren — z.B. #tanz, #buffet oder #reden. Du kannst danach filtern.'
		},
		{
			kind: 'text',
			icon: '👆',
			title: 'Lange tippen für mehr',
			body: 'Tippe lange auf ein Bild im Feed, um zusätzliche Aktionen zu öffnen — zum Beispiel das Original anzeigen oder eigene Beiträge löschen.'
		},
		{
			kind: 'theme',
			icon: '🌗',
			title: 'Helles oder dunkles Design?'
		},
		{
			kind: 'text',
			icon: '🔑',
			title: 'Deinen PIN merken!',
			body:
				'Du hast beim Registrieren einen 4-stelligen PIN erhalten. Speichere ihn — du brauchst ihn, um dein Konto auf einem anderen Gerät wiederherzustellen. Er ist immer unter „Mein Konto“ zu finden.' +
				(hasPrivacyNote ? ' Den Datenschutzhinweis findest du ebenfalls unter „Mein Konto“.' : '')
		}
	]);

	// Derived in the script so TypeScript can narrow on `.kind` inside the template.
	let currentStep = $derived(steps[step]);

	const THEME_OPTIONS: Array<{
		value: ThemePreference;
		label: string;
		hint: string;
		icon: string;
	}> = [
		{ value: 'system', label: 'System', hint: 'Folgt der Geräteeinstellung', icon: '🖥️' },
		{ value: 'light', label: 'Hell', hint: 'Heller Hintergrund', icon: '☀️' },
		{ value: 'dark', label: 'Dunkel', hint: 'Dunkler Hintergrund', icon: '🌙' }
	];

	if (browser && !hasSeenGuide()) {
		visible = true;
	}

	function next() {
		if (step < steps.length - 1) {
			step++;
		} else {
			dismiss();
		}
	}

	function dismiss() {
		markGuideSeen();
		vibrate([0, 8, 60, 8]);
		visible = false;
	}

	function goToStep(i: number) {
		if (i >= 0 && i < steps.length) step = i;
	}
</script>

{#if visible}
	<!-- Backdrop -->
	<div class="fixed inset-0 z-50 flex items-end justify-center bg-black/60 sm:items-center">
		<!-- Same viewport guard as Modal/ConfirmSheet: the theme step (three option rows) is the
		     tallest thing a first-time guest sees, and this dialog's only exits are its own
		     "Weiter"/"Überspringen" buttons at the very bottom. Clipping them strands the guest
		     on step one of a modal they cannot dismiss. -->
		<div
			class="max-h-[90dvh] w-full max-w-sm overflow-y-auto overscroll-contain rounded-t-3xl bg-white p-6 shadow-2xl dark:bg-gray-900 sm:rounded-2xl"
			role="dialog"
			aria-modal="true"
			aria-labelledby="onboarding-title"
			use:focusTrap={{ onclose: dismiss }}
			use:scrollLock
		>
			<!-- Step indicator — tap a pip to jump back. The visible dot is small but
			     the touch target is padded to ~44 px so it remains tappable on mobile. -->
			<div class="mb-3 flex justify-center">
				{#each steps as _, i (i)}
					<button
						type="button"
						onclick={() => goToStep(i)}
						aria-label={`Schritt ${i + 1}`}
						aria-current={i === step ? 'step' : undefined}
						class="flex items-center justify-center p-2.5"
					>
						<span
							class="block rounded-full transition-all {i === step
								? 'h-1.5 w-6 bg-blue-600 dark:bg-blue-500'
								: 'h-1.5 w-1.5 bg-gray-200 dark:bg-gray-700'}"
						></span>
					</button>
				{/each}
			</div>

			<!-- Content -->
			<div class="mb-6 text-center">
				<div class="mb-4 flex justify-center">
					<div
						class="flex h-16 w-16 items-center justify-center rounded-2xl bg-primary-50 text-3xl dark:bg-primary-900/30"
					>
						{currentStep.icon}
					</div>
				</div>
				<h2
					id="onboarding-title"
					class="mb-2 text-xl font-semibold text-gray-900 dark:text-gray-100"
				>
					{currentStep.title}
				</h2>

				{#if currentStep.kind === 'text'}
					<p class="text-sm leading-relaxed text-gray-600 dark:text-gray-300">
						{currentStep.body}
					</p>
				{:else}
					<p class="mb-4 text-sm text-gray-600 dark:text-gray-300">
						Du kannst die Wahl jederzeit unter „Mein Konto“ ändern.
					</p>
					<div class="space-y-2 text-left" role="radiogroup" aria-label="Design">
						{#each THEME_OPTIONS as opt (opt.value)}
							{@const selected = $themePreference === opt.value}
							<button
								type="button"
								role="radio"
								aria-checked={selected}
								onclick={() => themePreference.set(opt.value)}
								class="flex w-full cursor-pointer items-center gap-3 rounded-xl border-2 p-3 transition focus:outline-none focus-visible:ring-2 focus-visible:ring-blue-200
									{selected
									? 'border-blue-600 bg-blue-50 dark:border-blue-500 dark:bg-blue-950/40'
									: 'border-gray-200 hover:bg-gray-50 dark:border-gray-700 dark:hover:bg-gray-800'}"
							>
								<span class="text-2xl leading-none">{opt.icon}</span>
								<div class="flex-1">
									<p class="text-sm font-semibold text-gray-900 dark:text-gray-100">{opt.label}</p>
									<p class="text-xs text-gray-500 dark:text-gray-400">{opt.hint}</p>
								</div>
								<span
									class="flex h-5 w-5 shrink-0 items-center justify-center rounded-full border-2
										{selected
										? 'border-blue-600 bg-blue-600 dark:border-blue-500 dark:bg-blue-500'
										: 'border-gray-300 dark:border-gray-600'}"
								>
									{#if selected}
										<svg
											class="h-3 w-3 text-white"
											fill="none"
											viewBox="0 0 24 24"
											stroke="currentColor"
											stroke-width="3"
										>
											<path stroke-linecap="round" stroke-linejoin="round" d="M5 13l4 4L19 7" />
										</svg>
									{/if}
								</span>
							</button>
						{/each}
					</div>
				{/if}
			</div>

			<!-- Buttons -->
			<div class="flex gap-2">
				<button
					onclick={dismiss}
					class="flex-1 rounded-xl border border-gray-200 py-3 text-sm text-gray-600 hover:bg-gray-50 active:bg-gray-100 dark:border-gray-700 dark:text-gray-300 dark:hover:bg-gray-800 dark:active:bg-gray-800"
				>
					Überspringen
				</button>
				<button onclick={next} class="btn btn-primary flex-1">
					{step < steps.length - 1 ? 'Weiter' : "Los geht's!"}
				</button>
			</div>
		</div>
	</div>
{/if}
