import { generateRandomString } from "./utils";

const UNIQUE_CURSOR = `${generateRandomString(16)}`;
const HEADER_REGEX = `^#+\\s.*${UNIQUE_CURSOR}.*$`;
const UNORDERED_LIST_REGEX = `^\\s*(-|\\*)\\s.*${UNIQUE_CURSOR}.*$`;
const TASK_LIST_REGEX = `^\\s*(-|[0-9]+\\.) +\\[.\\]\\s.*${UNIQUE_CURSOR}.*$`;
const BLOCK_QUOTES_REGEX = `^\\s*>.*${UNIQUE_CURSOR}.*$`;
const NUMBERED_LIST_REGEX = `^\\s*\\d+\\.\\s.*${UNIQUE_CURSOR}.*$`
const MATH_BLOCK_REGEX = /\$\$[\s\S]*?\$\$/g;
const INLINE_MATH_BLOCK_REGEX = /\$[\s\S]*?\$/g;
const CODE_BLOCK_REGEX = /```[\s\S]*?```/g;
const INLINE_CODE_BLOCK_REGEX = /`.*`/g;

enum Context {
	Text = "Text",
	Heading = "Heading",
	BlockQuotes = "BlockQuotes",
	UnorderedList = "UnorderedList",
	NumberedList = "NumberedList",
	CodeBlock = "CodeBlock",
	MathBlock = "MathBlock",
	TaskList = "TaskList",
}

// eslint-disable-next-line @typescript-eslint/no-namespace
namespace Context {
	export function values(): Array<Context> {
		return Object.values(Context).filter(
			(value) => typeof value === "string"
		) as Array<Context>;
	}

	export function getContext(prefix: string, suffix: string): Context {
		if (new RegExp(HEADER_REGEX, "gm").test(prefix + UNIQUE_CURSOR + suffix)) {
			return Context.Heading;
		}
		if (new RegExp(BLOCK_QUOTES_REGEX, "gm").test(prefix + UNIQUE_CURSOR + suffix)) {
			return Context.BlockQuotes;
		}

		if (new RegExp(TASK_LIST_REGEX, "gm").test(prefix + UNIQUE_CURSOR + suffix)) {
			return Context.TaskList;
		}

		if (
			isCursorInRegexBlock(prefix, suffix, MATH_BLOCK_REGEX) ||
			isCursorInRegexBlock(prefix, suffix, INLINE_MATH_BLOCK_REGEX)
		) {
			return Context.MathBlock;
		}

		if (isCursorInRegexBlock(prefix, suffix, CODE_BLOCK_REGEX) || isCursorInRegexBlock(prefix, suffix, INLINE_CODE_BLOCK_REGEX)) {
			return Context.CodeBlock;
		}
		if (new RegExp(NUMBERED_LIST_REGEX, "gm").test(prefix + UNIQUE_CURSOR + suffix)) {
			return Context.NumberedList;
		}
		if (new RegExp(UNORDERED_LIST_REGEX, "gm").test(prefix + UNIQUE_CURSOR + suffix)) {
			return Context.UnorderedList;
		}

		return Context.Text;
	}

	export function get(value: string) {
		for (const context of Context.values()) {
			if (value === context) {
				return context;
			}
		}
		return undefined;
	}
}

function isCursorInRegexBlock(
	prefix: string,
	suffix: string,
	regex: RegExp
): boolean {
	const text = prefix + UNIQUE_CURSOR + suffix;
	const codeBlocks = extractBlocks(text, regex);
	for (const block of codeBlocks) {
		if (block.includes(UNIQUE_CURSOR)) {
			return true;
		}
	}
	return false;
}

function extractBlocks(text: string, regex: RegExp) {
	const codeBlocks = text.match(regex);
	return codeBlocks ? codeBlocks.map((block) => block.trim()) : [];
}

export default Context;