import constants from "./constants";

import Mousetrap from "mousetrap";
import { Strategy, Textcomplete, StrategyProps } from "@textcomplete/core";
import { TextareaEditor } from "@textcomplete/textarea";

import fuzzy from "fuzzy";

import { store } from "./store";

export default enableAutocomplete;

const nicksStrategy: StrategyProps = {
	id: "nicks",
	match: /(^|\s)(@([a-zA-Z_[\]\\^{}|`@][a-zA-Z0-9_[\]\\^{}|`-]*)?)$/,
	search(term: string, callback: (matches: string[] | string[][]) => void) {
		term = term.slice(1);

		if (term[0] === "@") {
			// TODO: type
			// eslint-disable-next-line @typescript-eslint/restrict-plus-operands
			callback(
				completeNicks(term.slice(1), true).map((val) => [
					"@" + val[0],
					"@" + val[1],
				])
			);
		} else {
			callback(completeNicks(term, true));
		}
	},
	template([string]: [string, string]) {
		return string;
	},
	replace([, original]: [string, string]) {
		return "$1" + replaceNick(original);
	},
	index: 2,
};

const chanStrategy: StrategyProps = {
	id: "chans",
	match: /(^|\s)((?:#|\+|&|![A-Z0-9]{5})(?:[^\s]+)?)$/,
	search(term: string, callback: (matches: string[][]) => void) {
		callback(completeChans(term));
	},
	template([string]: [string, string]) {
		return string;
	},
	replace([, original]: [string, string]) {
		return "$1" + original;
	},
	index: 2,
};

const commandStrategy: StrategyProps = {
	id: "commands",
	match: /^\/(\w*)$/,
	search(term: string, callback: (matches: string[][]) => void) {
		callback(completeCommands("/" + term));
	},
	template([string]: [string, string]) {
		return string;
	},
	replace([, original]: [string, string]) {
		return original;
	},
	index: 1,
};

const foregroundColorStrategy: StrategyProps = {
	id: "foreground-colors",
	match: /\x03(\d{0,2}|[A-Za-z ]{0,10})$/,
	search(term: string, callback: (matches: string[][]) => void) {
		term = term.toLowerCase();

		const matchingColorCodes = constants.colorCodeMap
			.filter((i) => fuzzy.test(term, i[0]) || fuzzy.test(term, i[1]))
			.map((i) => {
				if (fuzzy.test(term, i[1])) {
					return [
						i[0],
						fuzzy.match(term, i[1], {
							pre: "<b>",
							post: "</b>",
						}).rendered,
					];
				}

				return i;
			});

		callback(matchingColorCodes);
	},
	template(value: string[]) {
		return `<span class="irc-fg${parseInt(value[0], 10)}">${
			value[1]
		}</span>`;
	},
	replace(value: string) {
		return "\x03" + value[0];
	},
	index: 1,
};

const backgroundColorStrategy: StrategyProps = {
	id: "background-colors",
	match: /\x03(\d{2}),(\d{0,2}|[A-Za-z ]{0,10})$/,
	search(
		term: string,
		callback: (matchingColorCodes: string[][]) => void,
		match: string[]
	) {
		term = term.toLowerCase();
		const matchingColorCodes = constants.colorCodeMap
			.filter((i) => fuzzy.test(term, i[0]) || fuzzy.test(term, i[1]))
			.map((pair) => {
				if (fuzzy.test(term, pair[1])) {
					return [
						pair[0],
						fuzzy.match(term, pair[1], {
							pre: "<b>",
							post: "</b>",
						}).rendered,
					];
				}

				return pair;
			})
			.map((pair) => pair.concat(match[1])); // Needed to pass fg color to `template`...

		callback(matchingColorCodes);
	},
	template(value: string[]) {
		return `<span class="irc-fg${parseInt(
			value[2],
			10
		)} irc-bg irc-bg${parseInt(value[0], 10)}">${value[1]}</span>`;
	},
	replace(value: string[]) {
		return "\x03$1," + value[0];
	},
	index: 2,
};

function enableAutocomplete(input: HTMLTextAreaElement) {
	let tabCount = 0;
	let lastMatch = "";
	let currentMatches: string[] | string[][] = [];

	input.addEventListener("input", (e) => {
		if ((e as CustomEvent).detail === "autocomplete") {
			return;
		}

		tabCount = 0;
		currentMatches = [];
		lastMatch = "";
	});

	Mousetrap(input).bind(
		"tab",
		(e) => {
			if (store.state.isAutoCompleting) {
				return;
			}

			e.preventDefault();

			const text = input.value;

			if (tabCount === 0) {
				lastMatch =
					text.substring(0, input.selectionStart).split(/\s/).pop() ||
					"";

				if (lastMatch.length === 0) {
					return;
				}

				currentMatches = completeNicks(lastMatch, false);

				if (currentMatches.length === 0) {
					return;
				}
			}

			const position = input.selectionStart - lastMatch.length;
			const newMatch = replaceNick(
				// TODO: type this properly
				String(currentMatches[tabCount % currentMatches.length]),
				position
			);
			const remainder = text.substring(input.selectionStart);

			input.value = text.substr(0, position) + newMatch + remainder;

			input.selectionStart -= remainder.length;
			input.selectionEnd = input.selectionStart;

			// Propagate change to Vue model
			input.dispatchEvent(
				new CustomEvent("input", {
					detail: "autocomplete",
				})
			);

			lastMatch = newMatch;
			tabCount++;
		},
		"keydown"
	);

	const strategies = [
		nicksStrategy,
		chanStrategy,
		commandStrategy,
		foregroundColorStrategy,
		backgroundColorStrategy,
	];

	const editor = new TextareaEditor(input);
	const textcomplete = new Textcomplete(editor, strategies, {
		dropdown: {
			className: "textcomplete-menu",
			placement: "top",
		},
	});

	textcomplete.on("show", () => {
		store.commit("isAutoCompleting", true);
	});

	textcomplete.on("hidden", () => {
		store.commit("isAutoCompleting", false);
	});

	return {
		hide() {
			textcomplete.hide();
		},
		destroy() {
			textcomplete.destroy();
			store.commit("isAutoCompleting", false);
		},
	};
}

function replaceNick(original: string, position = 1) {
	// If no postfix specified, return autocompleted nick as-is
	if (!store.state.settings.nickPostfix) {
		return original;
	}

	// If there is whitespace in the input already, append space to nick
	if (
		position > 0 &&
		/\s/.test(store.state.activeChannel?.channel.pendingMessage || "")
	) {
		return original + " ";
	}

	// If nick is first in the input, append specified postfix
	return original + store.state.settings.nickPostfix;
}

function fuzzyGrep<T>(term: string, array: Array<T>) {
	const results = fuzzy.filter(term, array, {
		pre: "<b>",
		post: "</b>",
	});
	return results.map((el) => [el.string, el.original]);
}

function rawNicks() {
	if (!store.state.activeChannel) {
		return [];
	}

	if (store.state.activeChannel.channel.users.length > 0) {
		const users = store.state.activeChannel.channel.users.slice();

		return users
			.sort((a, b) => b.lastMessage - a.lastMessage)
			.map((u) => u.nick);
	}

	const me = store.state.activeChannel.network.nick;
	const otherUser = store.state.activeChannel.channel.name;

	// If this is a query, add their name to autocomplete
	if (
		me !== otherUser &&
		store.state.activeChannel.channel.type === "query"
	) {
		return [otherUser, me];
	}

	// Return our own name by default for anything that isn't a channel or query
	return [me];
}

function completeNicks(word: string, isFuzzy: boolean) {
	const users = rawNicks();
	word = word.toLowerCase();

	if (isFuzzy) {
		return fuzzyGrep(word, users);
	}

	return users.filter((w) => !w.toLowerCase().indexOf(word));
}

function getCommands() {
	let cmds = constants.commands.slice();

	if (!store.state.settings.searchEnabled) {
		cmds = cmds.filter((c) => c !== "/search");
	}

	return cmds;
}

function completeCommands(word: string) {
	const commands = getCommands();
	return fuzzyGrep(word, commands);
}

function completeChans(word: string) {
	const words: string[] = [];

	if (store.state.activeChannel) {
		for (const channel of store.state.activeChannel.network.channels) {
			// Push all channels that start with the same CHANTYPE
			if (channel.type === "channel" && channel.name[0] === word[0]) {
				words.push(channel.name);
			}
		}
	}

	return fuzzyGrep(word, words);
}