import { readFileSync, readdirSync, statSync } from "node:fs";
import path from "node:path";
import matter from "gray-matter";
import {
	adConfig1,
	adConfig2,
	announcementConfig,
	backgroundWallpaper,
	commentConfig,
	coverImageConfig,
	fontConfig,
	footerConfig,
	friendsConfig,
	friendsPageConfig,
	licenseConfig,
	live2dModelConfig,
	musicPlayerConfig,
	navBarConfig,
	profileConfig,
	sakuraConfig,
	sidebarLayoutConfig,
	siteConfig,
	sponsorConfig,
	spineModelConfig,
} from "@/config";
import type {
	AdminConfigBundle,
	AdminImageRecord,
	AdminPostRecord,
	AdminSnapshot,
	AdminSpecPageRecord,
} from "./types";

const PROJECT_ROOT = process.cwd();
const POSTS_DIR = path.join(PROJECT_ROOT, "src", "content", "posts");
const SPEC_DIR = path.join(PROJECT_ROOT, "src", "content", "spec");
const PUBLIC_DIR = path.join(PROJECT_ROOT, "public");

const IMAGE_EXTENSIONS = new Set([
	".png",
	".jpg",
	".jpeg",
	".webp",
	".gif",
	".svg",
	".avif",
]);

const MARKDOWN_EXTENSIONS = new Set([".md", ".mdx"]);

function toUnixPath(value: string): string {
	return value.replace(/\\/g, "/");
}

function readUtf8(filePath: string): string {
	return readFileSync(filePath, "utf8");
}

function statSafe(filePath: string) {
	try {
		return statSync(filePath);
	} catch {
		return null;
	}
}

function walkFiles(rootDir: string, matcher: (filePath: string) => boolean): string[] {
	if (!statSafe(rootDir)?.isDirectory()) {
		return [];
	}

	const results: string[] = [];
	const stack = [rootDir];

	while (stack.length > 0) {
		const currentDir = stack.pop();
		if (!currentDir) continue;

		for (const entry of readdirSync(currentDir, { withFileTypes: true })) {
			const absolutePath = path.join(currentDir, entry.name);
			if (entry.isDirectory()) {
				stack.push(absolutePath);
				continue;
			}
			if (matcher(absolutePath)) {
				results.push(absolutePath);
			}
		}
	}

	return results.sort((left, right) => left.localeCompare(right));
}

function toPreviewUrl(origin: AdminImageRecord["origin"], relativeToRoot: string): string {
	const encodedPath = relativeToRoot
		.split("/")
		.map((segment) => encodeURIComponent(segment))
		.join("/");
	return `/_admin/files/${origin}/${encodedPath}`;
}

function getPostRecords(): AdminPostRecord[] {
	const markdownFiles = walkFiles(POSTS_DIR, (filePath) =>
		MARKDOWN_EXTENSIONS.has(path.extname(filePath).toLowerCase()),
	);

	return markdownFiles
		.map((filePath) => {
			const raw = readUtf8(filePath);
			const parsed = matter(raw);
			const stats = statSync(filePath);
			const relativePath = toUnixPath(path.relative(PROJECT_ROOT, filePath));
			const relativeToPosts = toUnixPath(path.relative(POSTS_DIR, filePath));
			const slug = relativeToPosts.replace(/\.(md|mdx)$/i, "");
			const data = parsed.data as Record<string, unknown>;

			return {
				slug,
				filePath: relativePath,
				title: String(data.title ?? slug),
				published: String(data.published ?? ""),
				updated: String(data.updated ?? ""),
				description: String(data.description ?? ""),
				image: String(data.image ?? ""),
				tags: Array.isArray(data.tags) ? data.tags.map((item) => String(item)) : [],
				category: String(data.category ?? ""),
				lang: String(data.lang ?? ""),
				draft: Boolean(data.draft ?? false),
				pinned: Boolean(data.pinned ?? false),
				comment: Boolean(data.comment ?? true),
				author: String(data.author ?? ""),
				sourceLink: String(data.sourceLink ?? ""),
				licenseName: String(data.licenseName ?? ""),
				licenseUrl: String(data.licenseUrl ?? ""),
				body: parsed.content,
				extension: path.extname(filePath).toLowerCase() === ".mdx" ? "mdx" : "md",
				excerpt: parsed.content.trim().slice(0, 180),
				modifiedAt: stats.mtime.toISOString(),
			};
		})
		.sort((left, right) => {
			const pinnedDiff = Number(right.pinned) - Number(left.pinned);
			if (pinnedDiff !== 0) return pinnedDiff;
			return right.published.localeCompare(left.published);
		});
}

function getSpecPageRecords(): AdminSpecPageRecord[] {
	const markdownFiles = walkFiles(SPEC_DIR, (filePath) =>
		MARKDOWN_EXTENSIONS.has(path.extname(filePath).toLowerCase()),
	);

	return markdownFiles.map((filePath) => ({
		slug: path.basename(filePath).replace(/\.(md|mdx)$/i, ""),
		filePath: toUnixPath(path.relative(PROJECT_ROOT, filePath)),
		body: readUtf8(filePath),
		extension: path.extname(filePath).toLowerCase() === ".mdx" ? "mdx" : "md",
		modifiedAt: statSync(filePath).mtime.toISOString(),
	}));
}

function getImageRecords(): AdminImageRecord[] {
	const imageRoots: Array<{
		dir: string;
		origin: AdminImageRecord["origin"];
	}> = [
		{ dir: PUBLIC_DIR, origin: "public" },
		{ dir: POSTS_DIR, origin: "content" },
	];

	return imageRoots.flatMap(({ dir, origin }) => {
		return walkFiles(dir, (filePath) =>
			IMAGE_EXTENSIONS.has(path.extname(filePath).toLowerCase()),
		).map((filePath) => {
			const stats = statSync(filePath);
			const relativePath = toUnixPath(path.relative(PROJECT_ROOT, filePath));
			const relativeToRoot = toUnixPath(path.relative(dir, filePath));

			return {
				id: relativePath,
				name: path.basename(filePath),
				path: relativePath,
				url: toPreviewUrl(origin, relativeToRoot),
				directory: toUnixPath(path.dirname(relativePath)),
				origin,
				size: stats.size,
				updatedAt: stats.mtime.toISOString(),
				sitePath: origin === "public" ? `/${relativeToRoot}` : relativeToRoot,
			};
		});
	});
}

function getConfigBundle(): AdminConfigBundle {
	return {
		siteConfig,
		profileConfig,
		navBarConfig,
		sidebarConfig: sidebarLayoutConfig,
		backgroundWallpaper,
		announcementConfig,
		footerConfig,
		adConfig: {
			adConfig1,
			adConfig2,
		},
		commentConfig,
		musicConfig: musicPlayerConfig,
		pioConfig: {
			spineModelConfig,
			live2dModelConfig,
		},
		sponsorConfig,
		friendsConfig: {
			friendsPageConfig,
			friendsConfig,
		},
		licenseConfig,
		coverImageConfig,
		sakuraConfig,
		fontConfig,
	};
}

export function getAdminSnapshot(): AdminSnapshot {
	return {
		generatedAt: new Date().toISOString(),
		configs: getConfigBundle(),
		posts: getPostRecords(),
		specPages: getSpecPageRecords(),
		images: getImageRecords(),
	};
}