export type DisplayMode = "list" | "grid";
export type FileItemType = "dir" | "file";

export interface ServerFile {
	name: string;
	extension?: string;
	absolutePath?: string;
	size?: number;
	modifiedAt?: number;
	type?: string;
	isFile?: boolean;
	isDirectory?: boolean;
	canPreview?: boolean;
	previewURI?: string;
}

export interface ExplorerItem {
	name: string;
	type: FileItemType;
	size?: string;
	updatedAt: string;
	icon: string;
	path: string;
	rawType?: string;
}

const fileIconMap: Record<string, string> = {
	TXT: "file-text",
	CODE: "code",
	SCRIPT: "code",
	ZIP: "file-zip",
	MICROSOFT: "file-excel",
	JAVA: "logo-android",
	VIDEO: "video",
	FONT: "font-size",
	AUDIO: "music",
	IMAGE: "image",
	SYSTEM: "setting",
	FILE: "file"
};

const dateTimeFormatter = new Intl.DateTimeFormat("zh-CN", {
	year: "numeric",
	month: "2-digit",
	day: "2-digit",
	hour: "2-digit",
	minute: "2-digit",
	hour12: false
});

export function mapServerFileToExplorerItem(file: ServerFile): ExplorerItem {
	const isDirectory = file.isDirectory || file.type === "DIRECTORY";
	const rawPath = typeof file.absolutePath === "string" ? file.absolutePath.trim() : "";

	return {
		name: file.name || "未命名",
		type: isDirectory ? "dir" : "file",
		size: isDirectory ? undefined : formatFileSize(file.size),
		updatedAt: formatModifiedAt(file.modifiedAt),
		icon: resolveFileIcon(file, isDirectory),
		path: rawPath || file.name || "",
		rawType: file.type
	};
}

export function sortExplorerItems(items: ExplorerItem[]): ExplorerItem[] {
	return [...items].sort((left, right) => {
		if (left.type !== right.type) {
			return left.type === "dir" ? -1 : 1;
		}

		return left.name.localeCompare(right.name, "zh-CN");
	});
}

export function formatItemDesc(item: ExplorerItem): string {
	if (item.type === "dir") {
		return `文件夹 | ${item.updatedAt}`;
	}

	return `${item.size || "--"} | ${item.updatedAt}`;
}

function resolveFileIcon(file: ServerFile, isDirectory: boolean): string {
	if (isDirectory) {
		return "folder";
	}

	const rawType = typeof file.type === "string" ? file.type.toUpperCase() : "FILE";
	return fileIconMap[rawType] || "file";
}

function formatModifiedAt(modifiedAt?: number): string {
	if (!modifiedAt) {
		return "未知时间";
	}

	return dateTimeFormatter.format(modifiedAt);
}

function formatFileSize(size?: number): string {
	if (typeof size !== "number" || Number.isNaN(size) || size < 0) {
		return "--";
	}

	if (size < 1024) {
		return `${size} B`;
	}

	const units = ["KB", "MB", "GB", "TB"];
	let nextSize = size / 1024;
	let unitIndex = 0;

	while (1024 <= nextSize && unitIndex < units.length - 1) {
		nextSize /= 1024;
		unitIndex += 1;
	}

	return `${trimDecimal(nextSize)} ${units[unitIndex]}`;
}

function trimDecimal(value: number): string {
	if (10 <= value || Number.isInteger(value)) {
		return value.toFixed(0);
	}

	if (1 <= value) {
		return value.toFixed(1);
	}

	return value.toFixed(2);
}