// ==UserScript==
// @name        ycombinator-keys
// @namespace   https://gitea.amine-bouabdallaoui.fr/AmineB/ycombinator-keys
// @license     gpl-3.0-only
// @match       http*://news.ycombinator.com/*
// @icon        https://gitea.amine-bouabdallaoui.fr/AmineB/ycombinator-keys/raw/branch/main/icons/48.png
// @grant       none
// @version     4
// @author      AmineB
// @description Ycombinator keyboard nav.
// @downloadURL https://gitea.amine-bouabdallaoui.fr/brian6932/ycombinator-keys/raw/branch/main/keyboard-watcher.user.js
// @updateURL   https://gitea.amine-bouabdallaoui.fr/brian6932/ycombinator-keys/raw/branch/main/keyboard-watcher.user.js
// ==/UserScript==
// jshint esversion: 11

globalThis.document.styleSheets[0].insertRule('tbody tr.athing>td.title>span.titleline>a:focus,tbody tr.athing.comtr a.togg.clicky:focus{outline: none}')

const requery = () => globalThis.document.querySelectorAll('tbody tr.athing')
let
	query = requery(),
	selected = -1
const
	// This is a Firefox only option. For some reason older versions of Firefox can't set outline: none.
	focusInvisible = { __proto__: null, focusVisible: false },
	isComment = () => query[selected].classList.contains('comtr'),
	highlightSelected = () => {
		query[selected].style.boxShadow = '0px 0px 10px 4px rgba(0,0,0,0.73)'

		isComment() ?
			// Drawing the boxShadow on this selector isn't visible enough.
			query[selected].querySelector('a.togg.clicky')?.focus(focusInvisible)
			:
			// Focuses link without re-query.
			query[selected].lastChild.firstChild.firstChild.focus(focusInvisible)
	},
	keydown = event => {
		switch (event.key) {
			case 'j':
				if (selected + 1 === query.length)
					return

				if (selected !== -1)
					query[selected].style.boxShadow = ''

				while (selected < query.length && query[++selected].classList.contains('noshow'));
				highlightSelected()
				return
			case 'k':
				if (selected <= 0)
					return

				query[selected].style.boxShadow = ''
				while (selected >= 0 && query[--selected].classList.contains('noshow'));
				highlightSelected()
				return
			case 'h':
				if (globalThis.location.pathname === '/hidden')
					for (const selector of query[selected].nextSibling.querySelectorAll('a'))
						if (selector.innerText === 'un-hide') {
							selector.click()
							break
						}
						else
							query[selected].nextSibling.querySelector('a.clicky.hider')?.click()
				if (selected + 1 <= query.length)
					highlightSelected()
				return
			case 'c':
				globalThis.open('https://news.ycombinator.com/item?id=' + query[selected].id, '_self')
				return
			case 'C':
				globalThis.open('https://news.ycombinator.com/item?id=' + query[selected].id)
				return
			case 'r':
				if (!isComment())
					return
				globalThis.open(query[selected].querySelector('div.reply a').href, '_self')
				return
			case 'R':
				if (!isComment())
					return
				globalThis.open(query[selected].querySelector('div.reply a').href)
				return
			case 'u':
				globalThis.open((isComment() ? query[selected] : query[selected].nextSibling).querySelector('a.hnuser').href, '_self')
				return
			case 'U':
				globalThis.open((isComment() ? query[selected] : query[selected].nextSibling).querySelector('a.hnuser').href)
		}
	},
	listen = () => globalThis.document.addEventListener('keydown', keydown)

listen()

// This allows for compatibility with automatic pagination scripts.
new globalThis.MutationObserver(mutations => {
	for (const mutation of mutations)
		if (mutation.type === 'childList') {
			globalThis.document.removeEventListener('keydown', keydown)
			query = requery()
			return listen()
		}
}).observe(globalThis.document.body, { __proto__: null, childList: true, subtree: true })