const fs = require('fs');
const path = require('path');

//
//#region Tools ...
/**
 * Extracts Doxygen-style documentation from MQL5 files and generates Markdown.
 * @param {string} filePath - Path to the .mq5 or .mqh file
 * @param {string} outputPath - Path to save the generated .md file
 */
function extractMQL5Documentation(filePath, outputPath) {
    //
    if (!fs.existsSync(filePath)) {
        console.error(`Error: File not found at ${filePath}`);
        return;
    }

    //
    const content = fs.readFileSync(filePath, 'utf8');
    const lines = content.split('\n');
    const extractedDocs = [];

    //
    let currentCommentBlock = [];
    let isInsideBlockComment = false;

    //
    // State machine to parse comments and map them to the next line of code
    for (let i = 0; i < lines.length; i++) {
        //
        const line = lines[i];
        const trimmedLine = line.trim();

        //
        // 1. Handle Block Comments (/* ... */)
        if (trimmedLine.startsWith('/*') || trimmedLine.startsWith('/**')) {
            //
            isInsideBlockComment = true;
            currentCommentBlock.push(trimmedLine);
            if (trimmedLine.endsWith('*/')) {
                isInsideBlockComment = false;
            }
            continue;
        }

        //
        if (isInsideBlockComment) {
            //
            currentCommentBlock.push(trimmedLine);
            if (trimmedLine.endsWith('*/')) {
                isInsideBlockComment = false;
            }
            continue;
        }

        //
        // 2. Handle Line Comments (/// or //)
        if (trimmedLine.startsWith('///') || trimmedLine.startsWith('//')) {
            //
            currentCommentBlock.push(trimmedLine);
            continue;
        }

        //
        // 3. Handle Empty Lines (Keep them to preserve spacing before code)
        if (trimmedLine === '') {
            //
            if (currentCommentBlock.length > 0) {
                currentCommentBlock.push('');
            }
            continue;
        }

        //
        // 4. We hit actual code. If we have a comment block, map it.
        if (currentCommentBlock.length > 0) {
            //
            // Clean up trailing empty lines in the comment block
            while (currentCommentBlock.length > 0 &&
                currentCommentBlock[currentCommentBlock.length - 1].trim() === ''
            ) {
                currentCommentBlock.pop();
            }

            //
            if (currentCommentBlock.length > 0) {
                //
                extractedDocs.push({
                    comment: currentCommentBlock.join('\n'),
                    code: trimmedLine
                });
            }

            //
            currentCommentBlock = [];
        }
    }

    //
    // Generate Markdown Output
    generateMarkdown(filePath, extractedDocs, outputPath);
}

/**
 * Formats the extracted data into a clean Markdown document.
 */
function generateMarkdown(filePath, docs, outputPath) {
    //
    const fileName = path.basename(filePath);
    let md = `# Documentation for \`${fileName}\`\n\n`;
    md += `*Extracted on: ${new Date().toLocaleDateString()}*\n\n---\n\n`;

    //
    let fileHeaderFound = false;

    //
    docs.forEach((doc, index) => {
        //
        // Check if this is the file-level header (usually the very first block)
        if (index === 0 &&
            (doc.code.startsWith('#property') || doc.code.startsWith('//+--'))) {
            //
            md += `## File Overview\n`;
            md += formatComment(doc.comment) + '\n\n';
            fileHeaderFound = true;
            return;
        }

        //
        // Only document actual functions, classes, structs, or important variables
        const isDocumentableCode = /^(void|int|double|bool|string|long|ulong|uint|class|struct|enum|input)\s+/.test(doc.code)
            || doc.code.includes('class ')
            || doc.code.includes('struct ');

        if (isDocumentableCode) {
            //
            md += `### \`${extractSignature(doc.code)}\`\n\n`;
            md += `**Declaration:**\n\`\`\`cpp\n${doc.code}\n\`\`\`\n\n`;
            md += `**Documentation:**\n${formatComment(doc.comment)}\n\n---\n\n`;
        }
    });

    //
    fs.writeFileSync(outputPath, md, 'utf8');
    console.log(`✅ Successfully extracted documentation to: ${outputPath}`);
}

/**
 * Cleans up Doxygen tags for better Markdown readability.
 */
function formatComment(comment) {
    return comment
        .replace(/\/\*\*?|\*\//g, '') // Remove block comment markers
        .replace(/^\s*\*\s?/gm, '')   // Remove leading asterisks
        .replace(/^\/\/\/?\s?/gm, '') // Remove line comment markers
        .replace(/@param\s+(\w+)\s*/g, '**Param `$1`:** ')
        .replace(/@return\s*/g, '**Returns:** ')
        .replace(/@brief\s*/g, '**Summary:** ')
        .replace(/@note\s*/g, '*Note:* ')
        .replace(/@warning\s*/g, '> **Warning:** ')
        .trim();
}

/**
 * Extracts a clean function/class signature from the code line.
 */
function extractSignature(codeLine) {
    //
    // Basic extraction, stops at the first opening parenthesis or brace
    const match = codeLine.match(/^(.*?)[\({]/);
    return match ? match[1].trim() : codeLine;
}
//#endregion

//
//#region Module Exports ...
module.exports = {
    formatComment,
    generateMarkdown,
    extractSignature,
    extractMQL5Documentation,
}
//#endregion