// gomuks - A Matrix client written in Go.
// Copyright (C) 2024 Tulir Asokan
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program.  If not, see <https://www.gnu.org/licenses/>.
import { CSSProperties, JSX, use, useCallback, useState } from "react"
import { getMediaURL } from "@/api/media.ts"
import { RoomStateStore, useCustomEmojis } from "@/api/statestore"
import { CATEGORY_FREQUENTLY_USED, Emoji, PartialEmoji, categories, useFilteredEmojis } from "@/util/emoji"
import useEvent from "@/util/useEvent.ts"
import { ClientContext } from "../ClientContext.ts"
import { ModalCloseContext } from "../modal/Modal.tsx"
import FallbackPackIcon from "@/icons/category.svg?react"
import CloseIcon from "@/icons/close.svg?react"
import ActivitiesIcon from "@/icons/emoji-categories/activities.svg?react"
import AnimalsNatureIcon from "@/icons/emoji-categories/animals-nature.svg?react"
import FlagsIcon from "@/icons/emoji-categories/flags.svg?react"
import FoodBeverageIcon from "@/icons/emoji-categories/food-beverage.svg?react"
import ObjectsIcon from "@/icons/emoji-categories/objects.svg?react"
import PeopleBodyIcon from "@/icons/emoji-categories/people-body.svg?react"
import SmileysEmotionIcon from "@/icons/emoji-categories/smileys-emotion.svg?react"
import SymbolsIcon from "@/icons/emoji-categories/symbols.svg?react"
import TravelPlacesIcon from "@/icons/emoji-categories/travel-places.svg?react"
import RecentIcon from "@/icons/schedule.svg?react"
import SearchIcon from "@/icons/search.svg?react"
import "./EmojiPicker.css"

interface EmojiCategory {
	index: number
	name?: string
	icon: JSX.Element
}

const sortedEmojiCategories: EmojiCategory[] = [
	{ index: 7, icon: <SmileysEmotionIcon/> },
	{ index: 6, icon: <PeopleBodyIcon/> },
	{ index: 1, icon: <AnimalsNatureIcon/> },
	{ index: 4, icon: <FoodBeverageIcon/> },
	{ index: 9, icon: <TravelPlacesIcon/> },
	{ index: 0, icon: <ActivitiesIcon/> },
	{ index: 5, icon: <ObjectsIcon/> },
	{ index: 8, icon: <SymbolsIcon/> },
	{ index: 3, icon: <FlagsIcon/> },
]

function renderEmoji(emoji: Emoji): JSX.Element | string {
	if (emoji.u.startsWith("mxc://")) {
		return <img loading="lazy" src={getMediaURL(emoji.u)} alt={`:${emoji.n}:`}/>
	}
	return emoji.u
}

interface EmojiPickerProps {
	style: CSSProperties
	onSelect: (emoji: PartialEmoji, isSelected?: boolean) => void
	room: RoomStateStore
	allowFreeform?: boolean
	closeOnSelect?: boolean
	selected?: string[]
}

export const EmojiPicker = ({ style, selected, onSelect, room, allowFreeform, closeOnSelect }: EmojiPickerProps) => {
	const client = use(ClientContext)!
	const [query, setQuery] = useState("")
	const customEmojiPacks = useCustomEmojis(client.store, room)
	const emojis = useFilteredEmojis(query, {
		frequentlyUsed: client.store.frequentlyUsedEmoji,
		customEmojiPacks,
	})
	const [previewEmoji, setPreviewEmoji] = useState<Emoji>()
	const clearQuery = useCallback(() => setQuery(""), [])
	const close = use(ModalCloseContext)
	const onSelectWrapped = (emoji?: PartialEmoji) => {
		if (!emoji) {
			return
		}
		onSelect(emoji, selected?.includes(emoji.u))
		if (emoji.c) {
			client.incrementFrequentlyUsedEmoji(emoji.u)
				.catch(err => console.error("Failed to increment frequently used emoji", err))
		}
		if (closeOnSelect) {
			close()
		}
	}
	const getEmojiFromAttrs = (elem: HTMLButtonElement) => {
		const groupIdx = elem.getAttribute("data-emoji-group-index")
		if (!groupIdx) {
			return
		}
		const idx = elem.getAttribute("data-emoji-index")
		if (!idx) {
			return
		}
		const emoji = emojis[+groupIdx]?.[+idx]
		if (!emoji) {
			return
		}
		return emoji
	}
	const onClickEmoji = useEvent((evt: React.MouseEvent<HTMLButtonElement>) =>
		onSelectWrapped(getEmojiFromAttrs(evt.currentTarget)))
	const onMouseOverEmoji = useEvent((evt: React.MouseEvent<HTMLButtonElement>) =>
		setPreviewEmoji(getEmojiFromAttrs(evt.currentTarget)))
	const onMouseOutEmoji = useCallback(() => setPreviewEmoji(undefined), [])
	const onClickFreeformReact = useEvent(() => onSelectWrapped({ u: query }))

	const renderedCats: JSX.Element[] = []
	let currentCatRender: JSX.Element[] = []
	let currentCatNum: number | string = -1
	const renderCurrentCategory = () => {
		if (!currentCatRender.length) {
			return
		}
		const categoryName = typeof currentCatNum === "number" ? categories[currentCatNum] : currentCatNum
		renderedCats.push(<div
			className="emoji-category"
			key={currentCatNum}
			id={`emoji-category-${categoryName}`}
			style={{ containIntrinsicHeight: `${1.5 + Math.ceil(currentCatRender.length / 8) * 2.5}rem` }}
		>
			<h4 className="emoji-category-name">{categoryName}</h4>
			<div className="emoji-category-list">
				{currentCatRender}
			</div>
		</div>)
		currentCatRender = []
		currentCatNum = -1
	}
	for (let catIdx = 0; catIdx < emojis.length; catIdx++) {
		const cat = emojis[catIdx]
		for (let emojiIdx = 0; emojiIdx < cat.length; emojiIdx++) {
			const emoji = cat[emojiIdx]
			if (emoji.c === 2) {
				continue
			}
			if (emoji.c !== currentCatNum) {
				renderCurrentCategory()
				currentCatNum = emoji.c
			}
			currentCatRender.push(<button
				key={`${emoji.c}-${emoji.u}`}
				className={`emoji ${selected?.includes(emoji.u) ? "selected" : ""}`}
				data-emoji-group-index={catIdx}
				data-emoji-index={emojiIdx}
				onMouseOver={onMouseOverEmoji}
				onMouseOut={onMouseOutEmoji}
				onClick={onClickEmoji}
			>{renderEmoji(emoji)}</button>)
		}
		renderCurrentCategory()
	}
	const onChangeQuery = useCallback((evt: React.ChangeEvent<HTMLInputElement>) => setQuery(evt.target.value), [])
	const onClickCategoryButton = useCallback((evt: React.MouseEvent) => {
		const categoryName = evt.currentTarget.getAttribute("title")!
		document.getElementById(`emoji-category-${categoryName}`)?.scrollIntoView({ behavior: "smooth" })
	}, [])
	return <div className="emoji-picker" style={style}>
		<div className="emoji-category-bar">
			<button
				className="emoji-category-icon"
				data-category-id={CATEGORY_FREQUENTLY_USED}
				title={CATEGORY_FREQUENTLY_USED}
				onClick={onClickCategoryButton}
			>{<RecentIcon/>}</button>
			{sortedEmojiCategories.map(cat =>
				<button
					key={cat.index}
					className="emoji-category-icon"
					data-category-id={cat.index}
					title={cat.name ?? categories[cat.index]}
					onClick={onClickCategoryButton}
				>{cat.icon}</button>,
			)}
			{customEmojiPacks.map(customPack =>
				<button
					key={customPack.id}
					className="emoji-category-icon custom-emoji"
					data-category-id={customPack.id}
					title={customPack.name}
					onClick={onClickCategoryButton}
				>
					{customPack.icon ? <img src={getMediaURL(customPack.icon)} alt="" /> : <FallbackPackIcon/>}
				</button>,
			)}
		</div>
		<div className="emoji-search">
			<input autoFocus onChange={onChangeQuery} value={query} type="search" placeholder="Search emojis"/>
			<button onClick={clearQuery} disabled={query === ""}>
				{query !== "" ? <CloseIcon/> : <SearchIcon/>}
			</button>
		</div>
		<div className="emoji-list">
			{renderedCats}
			{allowFreeform && query && <button
				className="freeform-react"
				onClick={onClickFreeformReact}
			>React with "{query}"</button>}
		</div>
		{previewEmoji ? <div className="emoji-preview">
			<div className="big-emoji">{renderEmoji(previewEmoji)}</div>
			<div className="emoji-name">{previewEmoji.t}</div>
			<div className="emoji-shortcode">:{previewEmoji.n}:</div>
		</div> : <div className="emoji-preview"/>}
	</div>
}

export default EmojiPicker