// Copyright (c) The Move Contributors
// SPDX-License-Identifier: Apache-2.0

import { Node } from '..';
import { treeFn } from '../printer';
import { AstPath, Doc } from 'prettier';

/**
 * Creates a callback function to print commments and comment-related nodes.
 *
 * @param path
 * @returns
 */
export default function (path: AstPath<Node>): treeFn | null {
    switch (path.node.type) {
        case Formatting.LineComment:
            return printLineComment;
        case Formatting.BlockComment:
            return printBlockComment;
        case Formatting.EmptyLine:
            return printEmptyLine;
        case Formatting.Newline:
            return printNewline;
        default:
            return null;
    }
}

export enum Formatting {
    LineComment = 'line_comment',
    BlockComment = 'block_comment',
    /**
     * Token that doesn't exist in the grammar but we insert it in
     * the `Tree` representation of CST to represent an empty line.
     */
    EmptyLine = 'empty_line',
    /**
     * Special node to insert a newline before the next node.
     * We use it to make a call to hardline or not.
     */
    Newline = 'newline',
}

export function startsOnNewLine(path: AstPath<Node>): boolean {
    return path.previous?.type == Formatting.EmptyLine;
}

export function shouldNewLine(path: AstPath<Node>): boolean {
    return path.node.nextNamedSibling?.type == Formatting.Newline;
}

/**
 * Test if a node is a formatting node.
 *
 * @param node
 * @returns
 */
export function isFormatting(node: Node): boolean {
    return [
        Formatting.LineComment,
        Formatting.BlockComment,
        Formatting.EmptyLine,
        Formatting.Newline,
    ].includes(node.type as Formatting);
}

export function isComment(node: Node | null): boolean {
    return [Formatting.LineComment, Formatting.BlockComment].includes(node?.type as Formatting);
}

export function isEmptyLine(node: Node | null): boolean {
    return Formatting.EmptyLine == node?.type;
}

export function isNewline(node: Node | null): boolean {
    return Formatting.Newline == node?.type;
}

/**
 * Print `line_comment` node.
 * Comments are handled via the `addLeadingComments` function.
 */
export function printLineComment(path: AstPath<Node>): Doc {
    return path.node.text;
}

/**
 * Print `block_comment` node.
 */
export function printBlockComment(path: AstPath<Node>): Doc {
    return path.node.text;
}

export function printEmptyLine(path: AstPath<Node>): Doc {
    return ''; // should not be printed directly, used in `join(hardline)` to act as an extra newline
}

export function printNewline(path: AstPath<Node>): Doc {
    return ''; // should not be printed, ever
}