import { createFileRoute, Link } from "@tanstack/react-router";
import { Reorder } from "framer-motion";
import { useEffect, useState } from "react";
import { CandidateCard } from "../../components/CandidateCard";
import { CandidateListItem } from "../../components/CandidateListItem";
import {
	useReorderCandidates,
	useUpdateCandidate,
} from "../../hooks/useCandidates";
import { useThread } from "../../hooks/useThreads";
import { LucideIcon } from "../../lib/iconData";
import { useUIStore } from "../../stores/uiStore";

export const Route = createFileRoute("/threads/$threadId")({
	component: ThreadDetailPage,
});

function ThreadDetailPage() {
	const { threadId: threadIdParam } = Route.useParams();
	const threadId = Number(threadIdParam);
	const { data: thread, isLoading, isError } = useThread(threadId);
	const openCandidateAddPanel = useUIStore((s) => s.openCandidateAddPanel);
	const candidateViewMode = useUIStore((s) => s.candidateViewMode);
	const setCandidateViewMode = useUIStore((s) => s.setCandidateViewMode);
	const updateCandidate = useUpdateCandidate(threadId);
	const reorderMutation = useReorderCandidates(threadId);

	const [tempItems, setTempItems] =
		useState<typeof thread extends { candidates: infer C } ? C : never | null>(
			null,
		);

	// Clear tempItems when server data changes (biome-ignore: thread?.candidates is intentional dep)
	// biome-ignore lint/correctness/useExhaustiveDependencies: thread?.candidates is the intended trigger
	useEffect(() => {
		setTempItems(null);
	}, [thread?.candidates]);

	if (isLoading) {
		return (
			<div className="max-w-7xl mx-auto px-4 sm:px-6 lg:px-8 py-8">
				<div className="animate-pulse space-y-6">
					<div className="h-6 bg-gray-200 rounded w-48" />
					<div className="grid grid-cols-1 md:grid-cols-2 lg:grid-cols-3 gap-4">
						{[1, 2, 3].map((i) => (
							<div key={i} className="h-40 bg-gray-200 rounded-xl" />
						))}
					</div>
				</div>
			</div>
		);
	}

	if (isError || !thread) {
		return (
			<div className="max-w-7xl mx-auto px-4 sm:px-6 lg:px-8 py-16 text-center">
				<h2 className="text-xl font-semibold text-gray-900 mb-2">
					Thread not found
				</h2>
				<Link
					to="/"
					search={{ tab: "planning" }}
					className="text-sm text-gray-600 hover:text-gray-700"
				>
					Back to planning
				</Link>
			</div>
		);
	}

	const isActive = thread.status === "active";
	const winningCandidate = thread.resolvedCandidateId
		? thread.candidates.find((c) => c.id === thread.resolvedCandidateId)
		: null;

	const displayItems = tempItems ?? thread.candidates;

	function handleDragEnd() {
		if (!tempItems) return;
		reorderMutation.mutate(
			{ orderedIds: tempItems.map((c) => c.id) },
			{ onSettled: () => setTempItems(null) },
		);
	}

	return (
		<div className="max-w-7xl mx-auto px-4 sm:px-6 lg:px-8 py-6">
			{/* Header */}
			<div className="mb-6">
				<Link
					to="/"
					search={{ tab: "planning" }}
					className="text-sm text-gray-500 hover:text-gray-700 mb-2 inline-block"
				>
					&larr; Back to planning
				</Link>
				<div className="flex items-center gap-3">
					<h1 className="text-xl font-semibold text-gray-900">{thread.name}</h1>
					<span
						className={`inline-flex items-center px-2 py-0.5 rounded-full text-xs font-medium ${
							isActive
								? "bg-gray-100 text-gray-600"
								: "bg-gray-100 text-gray-500"
						}`}
					>
						{isActive ? "Active" : "Resolved"}
					</span>
				</div>
			</div>

			{/* Resolution banner */}
			{!isActive && winningCandidate && (
				<div className="mb-6 p-4 bg-amber-50 border border-amber-200 rounded-xl">
					<p className="text-sm text-amber-800">
						<span className="font-medium">{winningCandidate.name}</span> was
						picked as the winner and added to your collection.
					</p>
				</div>
			)}

			{/* Toolbar: Add candidate + view toggle */}
			<div className="mb-6 flex items-center gap-3">
				{isActive && (
					<button
						type="button"
						onClick={openCandidateAddPanel}
						className="inline-flex items-center gap-2 px-4 py-2 bg-gray-700 hover:bg-gray-800 text-white text-sm font-medium rounded-lg transition-colors"
					>
						<svg
							className="w-4 h-4"
							fill="none"
							stroke="currentColor"
							viewBox="0 0 24 24"
						>
							<path
								strokeLinecap="round"
								strokeLinejoin="round"
								strokeWidth={2}
								d="M12 4v16m8-8H4"
							/>
						</svg>
						Add Candidate
					</button>
				)}
				{thread.candidates.length > 0 && (
					<div className="flex items-center gap-1 bg-gray-100 rounded-lg p-0.5">
						<button
							type="button"
							onClick={() => setCandidateViewMode("list")}
							className={`p-1.5 rounded-md transition-colors ${
								candidateViewMode === "list"
									? "bg-gray-200 text-gray-900"
									: "text-gray-400 hover:text-gray-600"
							}`}
							title="List view"
						>
							<LucideIcon name="layout-list" size={16} />
						</button>
						<button
							type="button"
							onClick={() => setCandidateViewMode("grid")}
							className={`p-1.5 rounded-md transition-colors ${
								candidateViewMode === "grid"
									? "bg-gray-200 text-gray-900"
									: "text-gray-400 hover:text-gray-600"
							}`}
							title="Grid view"
						>
							<LucideIcon name="layout-grid" size={16} />
						</button>
					</div>
				)}
			</div>

			{/* Candidates */}
			{thread.candidates.length === 0 ? (
				<div className="py-12 text-center">
					<div className="mb-3">
						<LucideIcon
							name="tag"
							size={48}
							className="text-gray-400 mx-auto"
						/>
					</div>
					<h3 className="text-lg font-semibold text-gray-900 mb-1">
						No candidates yet
					</h3>
					<p className="text-sm text-gray-500">
						Add your first candidate to start comparing.
					</p>
				</div>
			) : candidateViewMode === "list" ? (
				isActive ? (
					<Reorder.Group
						axis="y"
						values={displayItems}
						onReorder={setTempItems}
						onPointerUp={handleDragEnd}
						className="flex flex-col gap-2"
					>
						{displayItems.map((candidate, index) => (
							<CandidateListItem
								key={candidate.id}
								candidate={candidate}
								rank={index + 1}
								isActive={isActive}
								onStatusChange={(newStatus) =>
									updateCandidate.mutate({
										candidateId: candidate.id,
										status: newStatus,
									})
								}
							/>
						))}
					</Reorder.Group>
				) : (
					<div className="flex flex-col gap-2">
						{displayItems.map((candidate, index) => (
							<CandidateListItem
								key={candidate.id}
								candidate={candidate}
								rank={index + 1}
								isActive={isActive}
								onStatusChange={(newStatus) =>
									updateCandidate.mutate({
										candidateId: candidate.id,
										status: newStatus,
									})
								}
							/>
						))}
					</div>
				)
			) : (
				<div className="grid grid-cols-1 md:grid-cols-2 lg:grid-cols-3 gap-4">
					{thread.candidates.map((candidate, index) => (
						<CandidateCard
							key={candidate.id}
							id={candidate.id}
							name={candidate.name}
							weightGrams={candidate.weightGrams}
							priceCents={candidate.priceCents}
							categoryName={candidate.categoryName}
							categoryIcon={candidate.categoryIcon}
							imageFilename={candidate.imageFilename}
							productUrl={candidate.productUrl}
							threadId={threadId}
							isActive={isActive}
							status={candidate.status}
							onStatusChange={(newStatus) =>
								updateCandidate.mutate({
									candidateId: candidate.id,
									status: newStatus,
								})
							}
							pros={candidate.pros}
							cons={candidate.cons}
							rank={index + 1}
						/>
					))}
				</div>
			)}
		</div>
	);
}