<script lang="ts">
	import { apiFetch } from '$lib/utils/api';
	import { toast } from 'svelte-sonner';
	import * as Modal from '$lib/components/ui/dialog';
	import { Button } from '$lib/components/ui/button';
	import * as AlertDialog from '$lib/components/ui/alert-dialog';
	import { formatUserName } from '$lib/utils/nameDisplay';
	import { parseWallClockDate } from '$lib/utils/timeSlots';

	interface ServiceItem {
		id: string;
		name: string;
		price: number;
		duration_minutes: number;
	}

	interface EditRequest {
		id: string;
		booking_id: string;
		notes: string | null;
		original: {
			start_time: string;
			services: ServiceItem[];
			notes: string;
		};
		proposed: {
			start_time: string | null;
			services: ServiceItem[];
			notes: string | null;
		};
		user: {
			full_name: string;
			email: string;
			phone: string;
			previous_first_name?: string | null;
			previous_last_name?: string | null;
		};
	}

	interface Props {
		open: boolean;
		editRequest: EditRequest;
		onApproved: () => void;
		onDenied: () => void;
	}

	let { open = $bindable(), editRequest, onApproved, onDenied }: Props = $props();

	let submitting = $state(false);
	let showDenyConfirm = $state(false);

	function formatDateLine1(dateTimeString: string): string {
		const d = parseWallClockDate(dateTimeString);
		const dateStr = d.toLocaleDateString('en-GB', {
			weekday: 'long',
			day: 'numeric',
			month: 'long',
			year: 'numeric'
		});
		const startTime = d.toLocaleTimeString('en-GB', {
			hour: 'numeric',
			minute: '2-digit',
			hour12: true
		});
		return `${dateStr} at ${startTime}`;
	}

	function formatDateLine2(dateTimeString: string, durationMinutes: number): string {
		const d = parseWallClockDate(dateTimeString);
		const endMinutes = d.getHours() * 60 + d.getMinutes() + durationMinutes;
		const endH = Math.floor(endMinutes / 60);
		const endM = endMinutes % 60;
		const endPeriod = endH >= 12 ? 'pm' : 'am';
		const endDisplayH = endH % 12 || 12;
		const endTime = `${endDisplayH}:${String(endM).padStart(2, '0')} ${endPeriod}`;
		return `${endTime}, ${durationMinutes} minutes`;
	}

	function getDuration(services: ServiceItem[]): number {
		return services.reduce((sum, s) => sum + s.duration_minutes, 0);
	}

	function isTimeChanged(): boolean {
		if (!editRequest.proposed.start_time) return false;
		return editRequest.proposed.start_time !== editRequest.original.start_time;
	}

	function areServicesChanged(): boolean {
		const origIds = new Set(editRequest.original.services.map((s) => s.id));
		const propIds = new Set(editRequest.proposed.services.map((s) => s.id));
		if (origIds.size !== propIds.size) return true;
		for (const id of origIds) {
			if (!propIds.has(id)) return true;
		}
		return false;
	}

	const serviceDiff = $derived.by(() => {
		const orig = editRequest.original.services;
		const prop = editRequest.proposed.services;
		const origIds = new Set(orig.map((s) => s.id));
		const propIds = new Set(prop.map((s) => s.id));
		return {
			removed: orig.filter((s) => !propIds.has(s.id)),
			added: prop.filter((s) => !origIds.has(s.id)),
			same: orig.filter((s) => propIds.has(s.id))
		};
	});

	async function handleApprove() {
		submitting = true;
		const loadingToast = toast.loading('Approving change request...');

		try {
			const response = await apiFetch(
				`/api/admin/bookings/${editRequest.booking_id}/edit-requests/${editRequest.id}/approve`,
				{
					method: 'POST',
					headers: {
						'Content-Type': 'application/json'
					}
				}
			);

			if (response.ok) {
				toast.success('Change request approved!', { id: loadingToast });
				open = false;
				onApproved();
			} else {
				const text = await response.text();
				toast.error('Failed to approve: ' + text, { id: loadingToast });
			}
		} catch (err) {
			console.error('Error approving edit request:', err);
			toast.error('Network error approving change request', { id: loadingToast });
		} finally {
			submitting = false;
		}
	}

	async function handleDeny() {
		submitting = true;
		const loadingToast = toast.loading('Denying change request...');

		try {
			const response = await apiFetch(
				`/api/admin/bookings/${editRequest.booking_id}/edit-requests/${editRequest.id}/deny`,
				{
					method: 'POST',
					headers: {
						'Content-Type': 'application/json'
					}
				}
			);

			if (response.ok) {
				toast.success('Change request denied', { id: loadingToast });
				showDenyConfirm = false;
				open = false;
				onDenied();
			} else {
				const text = await response.text();
				toast.error('Failed to deny: ' + text, { id: loadingToast });
			}
		} catch (err) {
			console.error('Error denying edit request:', err);
			toast.error('Network error denying change request', { id: loadingToast });
		} finally {
			submitting = false;
			showDenyConfirm = false;
		}
	}
</script>

<Modal.Root bind:open>
	<Modal.Content class="max-h-[90vh] max-w-2xl overflow-y-auto">
		<Modal.Header>
			<Modal.Title class="text-lg font-semibold">Booking Change Request</Modal.Title>
			<Modal.Description>
				Review the requested changes to {formatUserName(
					editRequest.user.full_name,
					editRequest.user.previous_first_name,
					editRequest.user.previous_last_name
				)}'s booking.
			</Modal.Description>
		</Modal.Header>

		<div class="space-y-6 px-4 pb-4">
			<!-- Customer Contact Info -->
			<div class="rounded-lg border border-gray-200 bg-gray-50 p-4">
				<h3 class="mb-3 text-sm font-semibold tracking-wide text-gray-600 uppercase">
					Customer Contact
				</h3>
				<div class="space-y-2">
					<div>
						<div class="text-xs text-gray-500">Name</div>
						<div class="font-medium">
							{formatUserName(
								editRequest.user.full_name,
								editRequest.user.previous_first_name,
								editRequest.user.previous_last_name
							)}
						</div>
					</div>
					<div class="grid gap-3 md:grid-cols-2">
						<div>
							<div class="text-xs text-gray-500">Phone</div>
							<div class="font-medium">
								{#if editRequest.user.phone}
									<a href="tel:{editRequest.user.phone}" class="text-blue-600 hover:underline"
										>{editRequest.user.phone}</a
									>
								{:else}—{/if}
							</div>
						</div>
						<div>
							<div class="text-xs text-gray-500">Email</div>
							<div class="font-medium break-all">
								{#if editRequest.user.email}
									<a href="mailto:{editRequest.user.email}" class="text-blue-600 hover:underline"
										>{editRequest.user.email}</a
									>
								{:else}—{/if}
							</div>
						</div>
					</div>
				</div>
			</div>

			{#if isTimeChanged()}
				<div class="rounded-lg border border-gray-200 bg-gray-50 p-4">
					<h3 class="mb-3 text-sm font-semibold tracking-wide text-gray-600 uppercase">
						Date & Time Change
					</h3>
					<div class="space-y-3">
						<div>
							<div class="mb-1 text-xs text-gray-500">Before</div>
							<div class="font-medium">
								{formatDateLine1(editRequest.original.start_time)}
							</div>
							<div class="text-sm text-gray-600">
								{formatDateLine2(
									editRequest.original.start_time,
									getDuration(editRequest.original.services)
								)}
							</div>
						</div>
						<div>
							<div class="mb-1 text-xs text-gray-500">After</div>
							<div class="font-medium text-emerald-700">
								{formatDateLine1(editRequest.proposed.start_time!)}
							</div>
							<div class="text-sm text-gray-600">
								{formatDateLine2(
									editRequest.proposed.start_time!,
									getDuration(editRequest.proposed.services)
								)}
							</div>
						</div>
					</div>
				</div>
			{/if}

			{#if areServicesChanged()}
				<div class="rounded-lg border border-gray-200 bg-gray-50 p-4">
					<h3 class="mb-3 text-sm font-semibold tracking-wide text-gray-600 uppercase">
						Services Change
					</h3>
					<div class="grid gap-4 md:grid-cols-2">
						<div>
							<div class="mb-1 text-xs text-gray-500">Original</div>
							<div class="space-y-2">
								{#each editRequest.original.services as service (service.id)}
									{#if serviceDiff.removed.some((s) => s.id === service.id)}
										<div class="flex items-start gap-2 rounded border border-red-200 bg-red-50 p-2">
											<span class="mt-0.5 font-mono text-sm text-red-600">−</span>
											<div class="flex-1">
												<div class="text-sm font-medium text-red-700 line-through">
													{service.name}
												</div>
												<div class="text-xs text-red-600">
													£{service.price.toFixed(2)} &middot; {service.duration_minutes} min
												</div>
											</div>
										</div>
									{:else}
										<div class="flex items-start gap-2 rounded border border-gray-200 bg-white p-2">
											<span class="mt-0.5 font-mono text-sm text-gray-400"> </span>
											<div class="flex-1">
												<div class="text-sm font-medium">{service.name}</div>
												<div class="text-xs text-gray-600">
													£{service.price.toFixed(2)} &middot; {service.duration_minutes} min
												</div>
											</div>
										</div>
									{/if}
								{/each}
							</div>
						</div>
						<div>
							<div class="mb-1 text-xs text-gray-500">Proposed</div>
							<div class="space-y-2">
								{#each editRequest.proposed.services as service (service.id)}
									{#if serviceDiff.added.some((s) => s.id === service.id)}
										<div
											class="flex items-start gap-2 rounded border border-emerald-200 bg-emerald-50 p-2"
										>
											<span class="mt-0.5 font-mono text-sm text-emerald-600">+</span>
											<div class="flex-1">
												<div class="text-sm font-medium text-emerald-700">{service.name}</div>
												<div class="text-xs text-emerald-600">
													£{service.price.toFixed(2)} &middot; {service.duration_minutes} min
												</div>
											</div>
										</div>
									{:else}
										<div class="flex items-start gap-2 rounded border border-gray-200 bg-white p-2">
											<span class="mt-0.5 font-mono text-sm text-gray-400"> </span>
											<div class="flex-1">
												<div class="text-sm font-medium">{service.name}</div>
												<div class="text-xs text-gray-600">
													£{service.price.toFixed(2)} &middot; {service.duration_minutes} min
												</div>
											</div>
										</div>
									{/if}
								{/each}
							</div>
						</div>
					</div>
				</div>
			{/if}

			{#if editRequest.proposed.notes !== editRequest.original.notes}
				<div class="rounded-lg border border-gray-200 bg-gray-50 p-4">
					<h3 class="mb-3 text-sm font-semibold tracking-wide text-gray-600 uppercase">
						Booking Notes Change
					</h3>
					<div class="grid gap-4 md:grid-cols-2">
						<div>
							<div class="mb-1 text-xs text-gray-500">Original</div>
							<div class="text-sm">{editRequest.original.notes || '—'}</div>
						</div>
						<div>
							<div class="mb-1 text-xs text-gray-500">Proposed</div>
							<div class="text-sm">{editRequest.proposed.notes}</div>
						</div>
					</div>
				</div>
			{/if}

			<!-- Request Notes -->
			{#if editRequest.notes}
				<div class="rounded-lg border border-gray-200 bg-gray-50 p-4">
					<h3 class="mb-3 text-sm font-semibold tracking-wide text-gray-600 uppercase">
						Reason for Change
					</h3>
					<p class="text-sm text-gray-700">{editRequest.notes}</p>
				</div>
			{/if}
		</div>

		<Modal.Footer class="flex items-center justify-end gap-2">
			<Button variant="destructive" onclick={() => (showDenyConfirm = true)} disabled={submitting}>
				Deny
			</Button>
			<Button
				onclick={handleApprove}
				disabled={submitting}
				class="bg-emerald-600 hover:bg-emerald-700"
			>
				{submitting ? 'Approving...' : 'Approve'}
			</Button>
		</Modal.Footer>
	</Modal.Content>
</Modal.Root>

<!-- Deny Confirmation Dialog -->
<AlertDialog.Root bind:open={showDenyConfirm}>
	<AlertDialog.Content class="z-60">
		<AlertDialog.Header>
			<AlertDialog.Title>Deny this change request?</AlertDialog.Title>
			<AlertDialog.Description>
				This will reject the requested changes and notify the customer. This action cannot be
				undone.
			</AlertDialog.Description>
		</AlertDialog.Header>
		<AlertDialog.Footer>
			<AlertDialog.Cancel>Cancel</AlertDialog.Cancel>
			<AlertDialog.Action onclick={handleDeny} class="bg-red-600 hover:bg-red-700">
				Deny Request
			</AlertDialog.Action>
		</AlertDialog.Footer>
	</AlertDialog.Content>
</AlertDialog.Root>
