import type { Bookmark, BookmarkId, Tag, TaggedBookmark } from "@markone/core"
import type { User } from "@markone/core/user"
import { Readability } from "@mozilla/readability"
import { JSDOM } from "jsdom"
import { db } from "~/database.ts"
import { findTagsByNames, insertTags } from "~/tag/tag.js"
import { DEMO_BOOKMARKS } from "./demo-bookmarks.ts"

class LinkUnreachable {}
class UnsupportedLink {}

interface CachedContent {
	title: string
	mimeType: string
	data: Buffer | null
}

function insertDemoBookmarks(user: User) {
	const query = db.query(`
INSERT OR IGNORE INTO bookmarks (id, user_id, title, url, mime_type, content)
VALUES ${Array(DEMO_BOOKMARKS.length).fill("(?,?,?,?,NULL,NULL)").join(",")}
`)

	const args: Parameters<typeof query.run> = []
	for (const bookmark of DEMO_BOOKMARKS) {
		args.push(bookmark.id, user.id, bookmark.title, bookmark.url)
	}

	query.run(...args)
}

function insertBookmark(bookmark: Bookmark, cachedContent: CachedContent | null, user: User) {
	const query = db.query(`
INSERT INTO bookmarks (id, user_id, title, url, mime_type, content)
VALUES ($id, $userId, $title, $url, $mimeType, $content)
`)
	query.run({
		id: bookmark.id,
		userId: user.id,
		title: bookmark.title,
		url: bookmark.url,
		mimeType: cachedContent?.mimeType || null,
		content: cachedContent?.data ?? null,
	})
}

function findBookmarkCachedContent(id: string, user: User): Buffer | null {
	const query = db.query<{ content: Buffer | null }, { id: string; userId: string }>(
		"SELECT content FROM bookmarks WHERE id = $id AND user_id = $userId",
	)
	const row = query.get({ id, userId: user.id })
	return row?.content ?? null
}

function findBookmark(id: string, user: User): Bookmark | null {
	const bookmarkQuery = db.query<TaggedBookmark, { id: string; userId: string }>(
		"SELECT id, title, url FROM bookmarks WHERE id = $id AND user_id = $userId",
	)
	const bookmark = bookmarkQuery.get({ id, userId: user.id })
	if (!bookmark) {
		return null
	}

	const tagsQuery = db.query<Tag, { bookmarkId: string }>(`
		SELECT tags.id, tags.name FROM tags
		INNER JOIN bookmark_tags
		ON bookmark_tags.tag_id = tags.id AND bookmark_tags.bookmark_id = $bookmarkId
  `)
	const tags = tagsQuery.all({ bookmarkId: id })

	bookmark.tags = tags

	return bookmark
}

function updateBookmarkTitle(bookmark: Bookmark, newTitle: string, user: User) {
	const query = db.query("UPDATE bookmarks SET title = $title WHERE id = $id AND user_id = $userId")
	query.run({
		title: newTitle,
		id: bookmark.id,
		userId: user.id,
	})
}

function deleteBookmark(id: BookmarkId, user: User) {
	db.query("DELETE FROM bookmarks WHERE user_id = $userId AND id = $id").run({
		id,
		userId: user.id,
	})
	db.query("DELETE FROM bookmark_tags WHERE bookmark_id = ?").run(id)
}

async function cacheContent(url: string): Promise<CachedContent | null> {
	const res = await fetch(url).catch(() => {
		throw new LinkUnreachable()
	})

	let contentType = res.headers.get("Content-Type")
	if (!contentType) {
		contentType = "application/octet-stream"
	}

	if (contentType.startsWith("text/html")) {
		const matches = contentType.match(/charset=([^; ]+)/gi)
		let charset: string
		if (!matches || matches.length <= 2) {
			charset = "utf-8"
		} else {
			charset = matches[1] || "utf-8"
		}

		const websiteText = await res.text().catch(() => {
			throw new UnsupportedLink()
		})

		const dom = new JSDOM(websiteText, { url })
		const reader = new Readability(dom.window.document)
		const article = reader.parse()

		if (!article) {
			return null
		}

		if (article.content) {
			const newDom = new JSDOM(article.content, { url })
			const doc = newDom.window.document

			const lightStyleLink = doc.createElement("link")
			lightStyleLink.rel = "stylesheet"
			lightStyleLink.href = "/reader-styles/sakura.css"
			lightStyleLink.media = "screen"

			const darkStyleLink = doc.createElement("link")
			darkStyleLink.rel = "stylesheet"
			darkStyleLink.href = "/reader-styles/sakura-dark.css"
			darkStyleLink.media = "screen and (prefers-color-scheme: dark)"

			doc.head.appendChild(lightStyleLink)
			doc.head.appendChild(darkStyleLink)

			article.content = newDom.serialize()
		}

		return {
			title: article.title || "Untitled",
			mimeType: "text/html",
			data: article.content ? Buffer.from(article.content, charset as BufferEncoding) : null,
		}
	}

	throw new UnsupportedLink()
}

function assignTagsToBookmark(tags: Tag[], bookmark: Bookmark) {
	const query = db.query(`
		INSERT OR IGNORE INTO bookmark_tags (tag_id, bookmark_id)
		VALUES ${Array(tags.length).fill("(?,?)").join(",")}
	`)

	const args: Parameters<typeof query.run> = []
	for (const tag of tags) {
		args.push(tag.id)
		args.push(bookmark.id)
	}

	query.run(...args)
}

function findBookmarkTags(bookmark: Bookmark): Tag[] {
	const query = db.query<Tag, { bookmarkId: string }>(`
		SELECT tags.name as name, tags.id as id FROM bookmark_tags
		INNER JOIN tags
		ON tags.id = bookmark_tags.tag_id
		WHERE bookmark_tags.bookmark_id = $bookmarkId
	`)
	const tags = query.all({ bookmarkId: bookmark.id })
	return tags
}

function updateBookmarkTags(bookmark: Bookmark, tagNames: string[], user: User) {
	const tags = findTagsByNames(tagNames, user)
	const existingTagNames = new Set<string>()
	for (const tag of tags) {
		existingTagNames.add(tag.name)
	}

	const newTagNames: string[] = []
	for (const name of tagNames) {
		if (!existingTagNames.has(name)) {
			newTagNames.push(name)
		}
	}

	if (newTagNames.length > 0) {
		const newTags = insertTags(newTagNames, user)
		tags.push(...newTags)
	}

	assignTagsToBookmark(tags, bookmark)

	return tags
}

export {
	insertDemoBookmarks,
	insertBookmark,
	updateBookmarkTitle,
	deleteBookmark,
	findBookmark,
	findBookmarkCachedContent,
	cacheContent,
	assignTagsToBookmark,
	findBookmarkTags,
	updateBookmarkTags,
}
export { LinkUnreachable, UnsupportedLink }