/**
 * @fileoverview Rule to prevent spaces around emphasis markers in Markdown.
 * @author Pixel998
 */
//-----------------------------------------------------------------------------
// Type Definitions
//-----------------------------------------------------------------------------
/**
 * @import { SourceRange } from "@eslint/core";
 * @import { Heading, Paragraph, TableCell, Text } from "mdast";
 * @import { MarkdownRuleDefinition } from "../types.js";
 * @typedef {"spaceInEmphasis"} NoSpaceInEmphasisMessageIds
 * @typedef {[{ checkStrikethrough?: boolean }]} NoSpaceInEmphasisOptions
 * @typedef {MarkdownRuleDefinition<{ RuleOptions: NoSpaceInEmphasisOptions, MessageIds: NoSpaceInEmphasisMessageIds }>} NoSpaceInEmphasisRuleDefinition
 */
//-----------------------------------------------------------------------------
// Helpers
//-----------------------------------------------------------------------------
const whitespacePattern = /[ \t]/u;
/**
 * Creates a marker pattern based on whether strikethrough should be included.
 * @param {boolean} checkStrikethrough Whether to include strikethrough markers.
 * @returns {RegExp} The marker pattern.
 */
function createMarkerPattern(checkStrikethrough) {
    return checkStrikethrough
        ? /(?<=(?<!\\)(?:\\{2})*)(?:\*\*\*|\*\*|\*|___|__|_|~~|~)/gu
        : /(?<=(?<!\\)(?:\\{2})*)(?:\*\*\*|\*\*|\*|___|__|_)/gu;
}
//-----------------------------------------------------------------------------
// Rule Definition
//-----------------------------------------------------------------------------
export default /** @satisfies {NoSpaceInEmphasisRuleDefinition} */ ({
    meta: {
        type: "problem",
        docs: {
            recommended: true,
            description: "Disallow spaces around emphasis markers",
            url: "https://github.com/eslint/markdown/blob/main/docs/rules/no-space-in-emphasis.md",
        },
        fixable: "whitespace",
        messages: {
            spaceInEmphasis: "Unexpected space around emphasis marker.",
        },
        schema: [
            {
                type: "object",
                properties: {
                    checkStrikethrough: {
                        type: "boolean",
                    },
                },
                additionalProperties: false,
            },
        ],
        defaultOptions: [
            {
                checkStrikethrough: false,
            },
        ],
    },
    create(context) {
        const { sourceCode } = context;
        const [{ checkStrikethrough }] = context.options;
        const markerPattern = createMarkerPattern(checkStrikethrough);
        /** @type {string[]} */
        let buffer;
        /**
         * Reports a surrounding-space violation if present.
         * @param {number} checkIndex Character index to test for whitespace.
         * @param {number} highlightStartIndex Start index for highlighting.
         * @param {number} highlightEndIndex End index for highlighting.
         * @returns {void}
         */
        function reportWhitespace(checkIndex, highlightStartIndex, highlightEndIndex) {
            if (whitespacePattern.test(sourceCode.text[checkIndex])) {
                context.report({
                    loc: {
                        start: sourceCode.getLocFromIndex(highlightStartIndex),
                        end: sourceCode.getLocFromIndex(highlightEndIndex),
                    },
                    messageId: "spaceInEmphasis",
                    fix(fixer) {
                        return fixer.removeRange([checkIndex, checkIndex + 1]);
                    },
                });
            }
        }
        return {
            "heading, paragraph, tableCell"(
            /** @type {Heading | Paragraph | TableCell} */ node) {
                const [startOffset, endOffset] = sourceCode.getRange(node);
                // Initialize `buffer` with a whitespace-masked character array.
                buffer = new Array(endOffset - startOffset).fill(" ");
            },
            ":matches(heading, paragraph, tableCell) > text"(
            /** @type {Text} */ node) {
                const [startOffset, endOffset] = sourceCode.getRange(node);
                const parentNodeStartOffset = // Parent node can be `Heading`, `Paragraph`, or `TableCell`.
                 sourceCode.getParent(node).position.start.offset;
                // Add the content of a `Text` node into the current buffer at the correct offsets.
                for (let i = startOffset; i < endOffset; i++) {
                    buffer[i - parentNodeStartOffset] = sourceCode.text[i];
                }
            },
            ":matches(heading, paragraph, tableCell):exit"(
            /** @type {Heading | Paragraph | TableCell} */ node) {
                const maskedText = buffer.join("");
                /** @type {Map<string, SourceRange[]>} */
                const markerGroups = new Map();
                /** @type {RegExpExecArray | null} */
                let match;
                while ((match = markerPattern.exec(maskedText)) !== null) {
                    const marker = match[0];
                    const startOffset = // Adjust `markerPattern` match index to the full source code.
                     match.index + node.position.start.offset;
                    const endOffset = startOffset + marker.length;
                    if (!markerGroups.has(marker)) {
                        markerGroups.set(marker, []);
                    }
                    markerGroups.get(marker).push([startOffset, endOffset]);
                }
                for (const group of markerGroups.values()) {
                    for (let i = 0; i < group.length - 1; i += 2) {
                        const startMarker = group[i];
                        reportWhitespace(startMarker[1], startMarker[0], startMarker[1] + 2);
                        const endMarker = group[i + 1];
                        reportWhitespace(endMarker[0] - 1, endMarker[0] - 2, endMarker[1]);
                    }
                }
            },
        };
    },
});