import { useCallback, useEffect, useRef, useState } from "react";
import { useMutation } from "@tanstack/react-query";
import { AlertTriangle, ChevronDown, Download, FolderOpen, RotateCcw } from "lucide-react";
import { Button } from "~/client/components/ui/button";
import { Tooltip, TooltipContent, TooltipTrigger } from "~/client/components/ui/tooltip";
import { Alert, AlertDescription, AlertTitle } from "~/client/components/ui/alert";
import { Card, CardContent, CardDescription, CardHeader, CardTitle } from "~/client/components/ui/card";
import { Input } from "~/client/components/ui/input";
import { Label } from "~/client/components/ui/label";
import { Select, SelectContent, SelectItem, SelectTrigger, SelectValue } from "~/client/components/ui/select";
import {
	AlertDialog,
	AlertDialogAction,
	AlertDialogContent,
	AlertDialogDescription,
	AlertDialogFooter,
	AlertDialogHeader,
	AlertDialogTitle,
} from "~/client/components/ui/alert-dialog";
import { PathSelector } from "~/client/components/path-selector";
import { SnapshotTreeBrowser } from "~/client/components/file-browsers/snapshot-tree-browser";
import { RestoreProgress } from "~/client/components/restore-progress";
import { restoreSnapshotMutation } from "~/client/api-client/@tanstack/react-query.gen";
import { type RestoreCompletedEvent, useServerEvents } from "~/client/hooks/use-server-events";
import { OVERWRITE_MODES, type OverwriteMode } from "@zerobyte/core/restic";
import { isPathWithin } from "@zerobyte/core/utils";
import type { Repository } from "~/client/lib/types";
import { handleRepositoryError } from "~/client/lib/errors";
import { useNavigate } from "@tanstack/react-router";
import { cn } from "~/client/lib/utils";

type RestoreLocation = "original" | "custom";

interface RestoreFormProps {
	repository: Repository;
	snapshotId: string;
	returnPath: string;
	queryBasePath?: string;
	displayBasePath?: string;
	hasNonPosixSnapshotPaths?: boolean;
}

export function RestoreForm({
	repository,
	snapshotId,
	returnPath,
	queryBasePath,
	displayBasePath,
	hasNonPosixSnapshotPaths = false,
}: RestoreFormProps) {
	const navigate = useNavigate();
	const { addEventListener } = useServerEvents();

	const snapshotBasePath = queryBasePath ?? "/";
	const hasMismatchedDisplayBasePath = displayBasePath && !isPathWithin(displayBasePath, snapshotBasePath);
	const restoreRequiresCustomTarget = hasNonPosixSnapshotPaths || hasMismatchedDisplayBasePath;

	const [restoreLocation, setRestoreLocation] = useState<RestoreLocation>(
		restoreRequiresCustomTarget ? "custom" : "original",
	);
	const [customTargetPath, setCustomTargetPath] = useState("");
	const [overwriteMode, setOverwriteMode] = useState<OverwriteMode>("always");
	const [showAdvanced, setShowAdvanced] = useState(false);
	const [excludeXattr, setExcludeXattr] = useState("");
	const [isRestoreActive, setIsRestoreActive] = useState(false);
	const [restoreResult, setRestoreResult] = useState<RestoreCompletedEvent | null>(null);
	const [showRestoreResultAlert, setShowRestoreResultAlert] = useState(false);
	const restoreCompletedRef = useRef(false);

	const [selectedPaths, setSelectedPaths] = useState<Set<string>>(new Set());
	const [selectedPathKind, setSelectedPathKind] = useState<"file" | "dir" | null>(null);
	const trimmedCustomTargetPath = customTargetPath.trim();
	const hasCustomTargetPath = trimmedCustomTargetPath !== "";
	const selectedPathCount = selectedPaths.size;

	useEffect(() => {
		if (restoreRequiresCustomTarget) {
			setRestoreLocation("custom");
		}
	}, [restoreRequiresCustomTarget]);

	useEffect(() => {
		const abortController = new AbortController();
		const signal = abortController.signal;

		addEventListener(
			"restore:started",
			(startedData) => {
				if (startedData.repositoryId === repository.shortId && startedData.snapshotId === snapshotId) {
					restoreCompletedRef.current = false;
					setIsRestoreActive(true);
					setRestoreResult(null);
					setShowRestoreResultAlert(false);
				}
			},
			{ signal },
		);

		addEventListener(
			"restore:progress",
			(progressData) => {
				if (progressData.repositoryId === repository.shortId && progressData.snapshotId === snapshotId) {
					if (restoreCompletedRef.current) {
						return;
					}
					setIsRestoreActive(true);
				}
			},
			{ signal },
		);

		addEventListener(
			"restore:completed",
			(completedData) => {
				if (completedData.repositoryId === repository.shortId && completedData.snapshotId === snapshotId) {
					restoreCompletedRef.current = true;
					setIsRestoreActive(false);
					setRestoreResult(completedData);
					setShowRestoreResultAlert(true);
				}
			},
			{ signal },
		);

		return () => {
			abortController.abort();
		};
	}, [addEventListener, repository.shortId, snapshotId]);

	const { mutate: restoreSnapshot, isPending: isRestoring } = useMutation({
		...restoreSnapshotMutation(),
		onError: (error) => {
			restoreCompletedRef.current = true;
			setIsRestoreActive(false);
			handleRepositoryError("Restore failed", error, repository.shortId);
		},
	});

	const handleRestore = useCallback(() => {
		const excludeXattrValues = excludeXattr
			.split(",")
			.map((value) => value.trim())
			.filter(Boolean);

		const isCustomLocation = restoreLocation === "custom";
		const targetPath = isCustomLocation && hasCustomTargetPath ? trimmedCustomTargetPath : undefined;

		const includePaths = Array.from(selectedPaths);

		restoreCompletedRef.current = false;
		setIsRestoreActive(true);
		setRestoreResult(null);
		setShowRestoreResultAlert(false);

		restoreSnapshot({
			path: { shortId: repository.shortId },
			body: {
				snapshotId,
				include: includePaths.length > 0 ? includePaths : undefined,
				selectedItemKind: includePaths.length === 1 ? (selectedPathKind ?? undefined) : undefined,
				excludeXattr: excludeXattrValues.length > 0 ? excludeXattrValues : undefined,
				targetPath,
				overwrite: overwriteMode,
			},
		});
	}, [
		repository.shortId,
		snapshotId,
		excludeXattr,
		hasCustomTargetPath,
		restoreLocation,
		trimmedCustomTargetPath,
		selectedPaths,
		selectedPathKind,
		overwriteMode,
		restoreSnapshot,
	]);

	const handleDownload = useCallback(() => {
		if (selectedPaths.size > 1) return;

		const url = new URL(
			`/api/v1/repositories/${repository.shortId}/snapshots/${snapshotId}/dump`,
			window.location.origin,
		);

		const [selectedPath] = selectedPaths;
		if (selectedPath) {
			url.searchParams.set("path", selectedPath);
			if (selectedPathKind) {
				url.searchParams.set("kind", selectedPathKind);
			}
		}

		window.location.assign(url.toString());
	}, [repository.shortId, snapshotId, selectedPathKind, selectedPaths]);

	const acknowledgeRestoreResult = useCallback(() => {
		setShowRestoreResultAlert(false);
		setRestoreResult(null);
	}, []);

	const handleResultAlertOpenChange = useCallback((open: boolean) => {
		if (open) {
			setShowRestoreResultAlert(true);
		}
	}, []);

	const canRestore = restoreRequiresCustomTarget
		? hasCustomTargetPath
		: restoreLocation === "original" || hasCustomTargetPath;
	const canDownload = selectedPathCount <= 1;
	const isRestoreRunning = isRestoring || isRestoreActive;

	function getDownloadButtonText(): string {
		if (selectedPathCount > 0) {
			return `Download ${selectedPathCount} ${selectedPathCount === 1 ? "item" : "items"}`;
		}
		return "Download All";
	}

	function getRestoreButtonText(): string {
		if (isRestoreRunning) {
			return "Restoring...";
		}
		if (selectedPathCount > 0) {
			return `Restore ${selectedPathCount} ${selectedPathCount === 1 ? "item" : "items"}`;
		}
		return "Restore All";
	}

	return (
		<div className="space-y-6">
			<div className="flex flex-col gap-4 lg:flex-row lg:items-center lg:justify-between">
				<div>
					<h1 className="text-2xl font-bold">Restore Snapshot</h1>
					<p className="text-sm text-muted-foreground">
						{repository.name} / {snapshotId}
					</p>
				</div>
				<div className="flex flex-wrap gap-2">
					<Button variant="outline" onClick={() => navigate({ to: returnPath })}>
						Cancel
					</Button>
					<Tooltip>
						<TooltipTrigger asChild>
							<span className="inline-flex">
								<Button variant="outline" onClick={handleDownload} disabled={!canDownload}>
									<Download className="h-4 w-4 mr-2" />
									{getDownloadButtonText()}
								</Button>
							</span>
						</TooltipTrigger>
						<TooltipContent className={cn({ hidden: canDownload })}>
							<p>Download is available only for one selected item, or with no selection to download everything.</p>
						</TooltipContent>
					</Tooltip>
					<Button variant="primary" onClick={handleRestore} disabled={isRestoreRunning || !canRestore}>
						<RotateCcw className="h-4 w-4 mr-2" />
						{getRestoreButtonText()}
					</Button>
				</div>
			</div>

			<div className="grid grid-cols-1 lg:grid-cols-3 gap-6">
				<div className="space-y-6">
					{isRestoreRunning && <RestoreProgress repositoryId={repository.shortId} snapshotId={snapshotId} />}

					{restoreRequiresCustomTarget && (
						<Alert variant="warning">
							<AlertTriangle className="size-4" />
							<AlertTitle>Source paths do not match</AlertTitle>
							<AlertDescription>
								This snapshot was created from source paths that do not match this Zerobyte server or the current linked
								volume. Restoring to the original location is unavailable. Restore it to a custom location, or download
								it instead.
							</AlertDescription>
						</Alert>
					)}

					<Card>
						<CardHeader>
							<CardTitle>Restore Location</CardTitle>
							<CardDescription>Choose where to restore the files</CardDescription>
						</CardHeader>
						<CardContent className="space-y-4">
							<div className="grid grid-cols-1 gap-2">
								<Button
									type="button"
									variant={restoreLocation === "original" ? "secondary" : "outline"}
									size="sm"
									className="flex justify-start gap-2"
									onClick={() => setRestoreLocation("original")}
									disabled={!!restoreRequiresCustomTarget}
								>
									<RotateCcw size={16} className="mr-1" />
									Original location
								</Button>
								<Button
									type="button"
									variant={restoreLocation === "custom" ? "secondary" : "outline"}
									size="sm"
									className="justify-start gap-2"
									onClick={() => setRestoreLocation("custom")}
								>
									<FolderOpen size={16} className="mr-1" />
									Custom location
								</Button>
							</div>
							{restoreLocation === "custom" && (
								<div className="space-y-2">
									<PathSelector value={customTargetPath || "/"} onChange={setCustomTargetPath} />
									<p className="text-xs text-muted-foreground">Files will be restored directly to this path</p>
								</div>
							)}
						</CardContent>
					</Card>

					<Card>
						<CardHeader>
							<CardTitle>Overwrite Mode</CardTitle>
							<CardDescription>How to handle existing files</CardDescription>
						</CardHeader>
						<CardContent className="space-y-3">
							<Select value={overwriteMode} onValueChange={(value) => setOverwriteMode(value as OverwriteMode)}>
								<SelectTrigger className="w-full">
									<SelectValue placeholder="Select overwrite behavior" />
								</SelectTrigger>
								<SelectContent>
									<SelectItem value={OVERWRITE_MODES.always}>Always overwrite</SelectItem>
									<SelectItem value={OVERWRITE_MODES.ifChanged}>Only if content changed</SelectItem>
									<SelectItem value={OVERWRITE_MODES.ifNewer}>Only if snapshot is newer</SelectItem>
									<SelectItem value={OVERWRITE_MODES.never}>Never overwrite</SelectItem>
								</SelectContent>
							</Select>
							<p className="text-xs text-muted-foreground">
								{overwriteMode === OVERWRITE_MODES.always &&
									"Existing files will always be replaced with the snapshot version."}
								{overwriteMode === OVERWRITE_MODES.ifChanged &&
									"Files are only replaced if their content differs from the snapshot."}
								{overwriteMode === OVERWRITE_MODES.ifNewer &&
									"Files are only replaced if the snapshot version has a newer modification time."}
								{overwriteMode === OVERWRITE_MODES.never &&
									"Existing files will never be replaced, only missing files are restored."}
							</p>
						</CardContent>
					</Card>

					<Card>
						<CardHeader className="cursor-pointer" onClick={() => setShowAdvanced(!showAdvanced)}>
							<div className="flex items-center justify-between">
								<CardTitle className="text-base">Advanced options</CardTitle>
								<ChevronDown size={16} className={`transition-transform ${showAdvanced ? "rotate-180" : ""}`} />
							</div>
						</CardHeader>
						{showAdvanced && (
							<CardContent className="space-y-4">
								<div className="space-y-2">
									<Label htmlFor="exclude-xattr" className="text-sm">
										Exclude extended attributes
									</Label>
									<Input
										id="exclude-xattr"
										placeholder="com.apple.metadata,user.*,nfs4.*"
										value={excludeXattr}
										onChange={(e) => setExcludeXattr(e.target.value)}
									/>
									<p className="text-xs text-muted-foreground">
										Exclude specific extended attributes during restore (comma-separated)
									</p>
								</div>
							</CardContent>
						)}
					</Card>
				</div>
				<Card className="lg:col-span-2 flex flex-col">
					<CardHeader>
						<CardTitle>Select Files to Restore</CardTitle>
						<CardDescription>
							{selectedPaths.size > 0
								? `${selectedPaths.size} ${selectedPaths.size === 1 ? "item" : "items"} selected`
								: "Select specific files or folders, or leave empty to restore everything"}
						</CardDescription>
					</CardHeader>
					<CardContent className="flex-1 overflow-hidden flex flex-col p-0">
						<SnapshotTreeBrowser
							repositoryId={repository.shortId}
							snapshotId={snapshotId}
							queryBasePath={snapshotBasePath}
							displayBasePath={displayBasePath}
							pageSize={500}
							className="flex flex-1 min-h-0 flex-col"
							treeContainerClassName="overflow-auto flex-1 min-h-0 border border-border rounded-md bg-card m-4"
							treeClassName="px-2 py-2"
							loadingMessage="Loading files..."
							emptyMessage="No files in this snapshot"
							withCheckboxes
							selectedPaths={selectedPaths}
							onSelectionChange={setSelectedPaths}
							onSingleSelectionKindChange={setSelectedPathKind}
							stateClassName="flex-1 min-h-0"
						/>
					</CardContent>
				</Card>
			</div>

			<AlertDialog open={showRestoreResultAlert} onOpenChange={handleResultAlertOpenChange}>
				<AlertDialogContent>
					<AlertDialogHeader>
						<AlertDialogTitle>
							{restoreResult?.status === "success" ? "Restore completed" : "Restore failed"}
						</AlertDialogTitle>
						<AlertDialogDescription>
							{restoreResult?.status === "success"
								? `Snapshot ${snapshotId} was restored successfully.`
								: restoreResult?.error || `Snapshot ${snapshotId} could not be restored.`}
						</AlertDialogDescription>
					</AlertDialogHeader>
					<AlertDialogFooter>
						<AlertDialogAction onClick={acknowledgeRestoreResult}>OK</AlertDialogAction>
					</AlertDialogFooter>
				</AlertDialogContent>
			</AlertDialog>
		</div>
	);
}