/** @file a stand-in for webapp's `WebAppFactory`, serving diigo-shaped pages to tests. */
import { RpcTarget, WorkerEntrypoint } from "cloudflare:workers";

const KNOWN_WEBAPP = "fake-webapp-id";
const TOTAL = 250;
/** the plain account, capped below PAGE_SIZE (as diigo caps at 100) */
const CAPPED_WEBAPP = "fake-capped-webapp";
const CAP = 64;
/** the plain account, but its `total` claims 60 more items than it has
 * (hypothetical: what looked like this on 2026-10-07 was the 0-based
 * page_num, but the guard stays) */
const OVERSTATED_WEBAPP = "fake-overstated-webapp";
const OVERSTATEMENT = 60;

/** a second account, for date filters (goal 1d): 60 bookmarks, item n
 * updated n-1 days + 1 hour before the call, in diigo's updated-desc
 * order; tagged ocap, plus weekly every 7th; every 10th private; every
 * 5th an old bookmark edited recently (created 100 days before updated) */
const DATED_WEBAPP = "fake-dated-webapp";
const DATED_TOTAL = 60;
/** the same shape, 300 deep (3 pages of 100): for paging matches */
const DEEP_WEBAPP = "fake-deep-webapp";
const DEEP_TOTAL = 300;
const HOUR = 60 * 60 * 1000;

function datedItem(n, now, user = "dated_dan") {
	return {
		link_id: 5000 + n,
		url: `https://dated.example/${n}`,
		title: `dated ${n}`,
		description: n % 7 === 0 ? "a week of fragments" : "",
		private: n % 10 === 0,
		u_name: user,
		user_id: 777,
		tags: n % 7 === 0 ? "ocap,weekly" : "ocap",
		created_at: Math.floor((now - (n - 1) * 24 * HOUR - HOUR - (n % 5 === 0 ? 100 * 24 * HOUR : 0)) / 1000),
		updated_at: Math.floor((now - (n - 1) * 24 * HOUR - HOUR) / 1000),
	};
}

/** item n (1-based, in diigo's order): diigo's field names, made-up
 * values. link_id and updated_at are scrambled (distinct; 7 and 11 are
 * coprime to 307, a prime above TOTAL), so neither column sorts back
 * into diigo's order — a
 * cache that replays by column rather than by fetch order is caught. */
function item(n) {
	return {
		link_id: 1000 + ((n * 7) % 307),
		url: `https://example.com/${n}`,
		title: `bookmark ${n}`,
		description: "",
		private: n % 3 === 0,
		u_name: "alice_99",
		first_by: "someone-else",
		user_id: 4242,
		tags: "",
		created_at: 1700000000,
		updated_at: 1700001000 + ((n * 11) % 307),
	};
}

let calls = 0;

class FakeGet extends RpcTarget {
	#path;
	#params;
	/** null (the plain account), "capped", "overstated", "dated", or "deep" */
	#dated;
	constructor(path, params, dated) {
		super();
		this.#path = path;
		this.#params = params;
		this.#dated = dated;
	}
	pathjoin(ref) {
		return new FakeGet(ref, this.#params, this.#dated);
	}
	query(params) {
		return new FakeGet(this.#path, { ...this.#params, ...params }, this.#dated);
	}
	async get() {
		calls += 1;
		if (this.#path !== "load_user_items") throw new Error(`fake webapp: no route ${this.#path}`);
		const count = Math.min(Number(this.#params.count), this.#dated === "capped" ? CAP : Infinity);
		const page = Number(this.#params.page_num);
		const dated = this.#dated === "dated" || this.#dated === "deep";
		const total = this.#dated === "deep" ? DEEP_TOTAL : dated ? DATED_TOTAL : TOTAL;
		const now = Date.now();
		const items = [];
		// diigo's page_num counts from 0 (observed 2026-10-07: page_num=1
		// skipped the newest page)
		for (let n = page * count + 1; n <= Math.min((page + 1) * count, total); n += 1) {
			items.push(dated ? datedItem(n, now, this.#dated === "deep" ? "deep_dee" : "dated_dan") : item(n));
		}
		// past the end, diigo answers no items and a total of 0 (observed
		// 2026-10-07: the page after the last reported total ≤ 100)
		if (items.length === 0) return JSON.stringify({ total: 0, items });
		return JSON.stringify({ total: this.#dated === "overstated" ? total + OVERSTATEMENT : total, items });
	}
}

/**
 * webapp's `WebAppFactory` entrypoint, faked: an auxiliary worker (plain
 * JS; the vitest pool doesn't transform aux workers) serving
 * `load_user_items` pages for a few known webapp ids. Counts its diigo
 * calls, so tests can tell a cache hit (no call) from a miss.
 */
export class WebAppFactory extends WorkerEntrypoint {
	async at(id) {
		const kind = {
			[KNOWN_WEBAPP]: null,
			[CAPPED_WEBAPP]: "capped",
			[OVERSTATED_WEBAPP]: "overstated",
			[DATED_WEBAPP]: "dated",
			[DEEP_WEBAPP]: "deep",
		}[id];
		if (kind === undefined) throw new Error("fake webapp: unknown id");
		return new FakeGet("", {}, kind);
	}
	/** how many diigo calls so far (test hook) */
	async calls() {
		return calls;
	}
}

export default {
	fetch() {
		return new Response("fake webapp", { status: 404 });
	},
};