#!/usr/bin/env node

/**
 * Front-matter enrichment utility for ObsiViewer
 * Ensures all markdown files have complete, standardized YAML front-matter
 */

import { promises as fs } from 'fs';
import path from 'path';
import matter from 'gray-matter';
import { Document, parseDocument } from 'yaml';

const TZ_OFFSET = '-04:00'; // America/Toronto

/**
 * Mutex map to prevent concurrent writes to the same file
 */
const fileLocks = new Map();

/**
 * Acquire a lock for a file path
 */
async function acquireLock(filePath) {
  while (fileLocks.has(filePath)) {
    await new Promise(resolve => setTimeout(resolve, 10));
  }
  fileLocks.set(filePath, true);
}

/**
 * Release a lock for a file path
 */
function releaseLock(filePath) {
  fileLocks.delete(filePath);
}

/**
 * Format a date to ISO 8601 with Toronto timezone offset
 * @param {Date} date - Date to format
 * @returns {string} - ISO 8601 formatted date with timezone
 */
function formatDateISO(date) {
  const year = date.getFullYear();
  const month = String(date.getMonth() + 1).padStart(2, '0');
  const day = String(date.getDate()).padStart(2, '0');
  const hours = String(date.getHours()).padStart(2, '0');
  const minutes = String(date.getMinutes()).padStart(2, '0');
  const seconds = String(date.getSeconds()).padStart(2, '0');
  
  return `${year}-${month}-${day}T${hours}:${minutes}:${seconds}${TZ_OFFSET}`;
}

/**
 * Get current timestamp in ISO 8601 format with timezone
 */
function nowISO() {
  return formatDateISO(new Date());
}

/**
 * Get file creation date (birthtime or fallback to ctime/mtime)
 */
async function getCreationDate(absPath) {
  try {
    const stats = await fs.stat(absPath);
    // Use birthtime if available (Windows, macOS), otherwise ctime
    const creationTime = stats.birthtime && stats.birthtime.getTime() > 0 
      ? stats.birthtime 
      : (stats.ctime || stats.mtime);
    return formatDateISO(creationTime);
  } catch (error) {
    console.warn(`[ensureFrontmatter] Could not get creation date for ${absPath}:`, error.message);
    return nowISO();
  }
}

/**
 * Enrich front-matter of a markdown file with required properties
 * 
 * @param {string} absPath - Absolute path to the markdown file
 * @returns {Promise<{modified: boolean, content: string}>}
 */
export async function enrichFrontmatterOnOpen(absPath) {
  await acquireLock(absPath);
  
  try {
    // Read file
    const raw = await fs.readFile(absPath, 'utf-8');
    
    // Parse front-matter and content (disable date parsing to keep strings)
    const parsed = matter(raw, { 
      language: 'yaml', 
      delimiters: '---',
      engines: {
        yaml: {
          parse: (str) => {
            // Use yaml library directly to preserve types
            const doc = parseDocument(str);
            return doc.toJSON();
          }
        }
      }
    });
    
    // Get file basename without extension
    const basename = path.basename(absPath, '.md');
    
    // Get creation date
    const creationDate = await getCreationDate(absPath);
    const modificationDate = nowISO();
    
    // Define required properties in order
    const requiredProps = [
      ['titre', basename],
      ['auteur', 'Bruno Charest'],
      ['creation_date', creationDate],
      ['modification_date', modificationDate],
      ['catégorie', ''],
      ['tags', []],
      ['aliases', []],
      ['status', 'en-cours'],
      ['publish', false],
      ['favoris', false],
      ['template', false],
      ['task', false],
      ['archive', false],
      ['draft', false],
      ['private', false],
    ];
    
    // Parse existing front-matter data
    const existingData = parsed.data || {};
    
    // Track if we inserted any new properties
    let inserted = false;
    
    // Build complete data object with defaults for missing keys
    const completeData = {};
    
    // First, add all required properties in order
    for (const [key, defaultValue] of requiredProps) {
      if (existingData.hasOwnProperty(key)) {
        // Preserve existing value
        completeData[key] = existingData[key];
      } else {
        // Add default value
        completeData[key] = defaultValue;
        inserted = true;
      }
    }
    
    // Update modification_date only if we inserted something
    if (inserted) {
      completeData['modification_date'] = modificationDate;
    }
    
    // Then add any custom properties that exist
    for (const key of Object.keys(existingData)) {
      if (!completeData.hasOwnProperty(key)) {
        completeData[key] = existingData[key];
      }
    }
    
    // Build new ordered document from complete data
    const orderedDoc = new Document();
    for (const key of Object.keys(completeData)) {
      orderedDoc.set(key, completeData[key]);
    }
    
    // Serialize YAML without blank lines
    let yamlContent = orderedDoc.toString().trim();
    
    // Remove any blank lines within the YAML
    yamlContent = yamlContent.split('\n').filter(line => line.trim() !== '').join('\n');
    
    // Reconstruct the file
    const frontmatter = `---\n${yamlContent}\n---`;
    const bodyContent = parsed.content;
    
    // Ensure proper spacing after front-matter
    const newContent = bodyContent.startsWith('\n') 
      ? `${frontmatter}${bodyContent}`
      : `${frontmatter}\n${bodyContent}`;
    
    // Check if content actually changed (compare normalized content)
    const modified = raw.trim() !== newContent.trim();
    
    if (modified) {
      // Atomic write: temp file + rename
      const tempPath = `${absPath}.tmp`;
      const backupPath = `${absPath}.bak`;
      
      try {
        // Create backup
        await fs.copyFile(absPath, backupPath);
        
        // Write to temp
        await fs.writeFile(tempPath, newContent, 'utf-8');
        
        // Atomic rename
        await fs.rename(tempPath, absPath);
        
        console.log(`[ensureFrontmatter] Enriched: ${path.basename(absPath)}`);
      } catch (writeError) {
        // Cleanup on error
        try {
          await fs.unlink(tempPath).catch(() => {});
          await fs.copyFile(backupPath, absPath).catch(() => {});
        } catch {}
        throw writeError;
      }
    }
    
    return { modified, content: newContent };
    
  } finally {
    releaseLock(absPath);
  }
}

/**
 * Extract front-matter properties from a markdown file
 * 
 * @param {string} absPath - Absolute path to the markdown file
 * @returns {Promise<object>} - Front-matter data
 */
export async function extractFrontmatter(absPath) {
  try {
    const raw = await fs.readFile(absPath, 'utf-8');
    const parsed = matter(raw, { 
      language: 'yaml', 
      delimiters: '---',
      engines: {
        yaml: {
          parse: (str) => {
            // Use yaml library directly to preserve types
            const doc = parseDocument(str);
            return doc.toJSON();
          }
        }
      }
    });
    return parsed.data || {};
  } catch (error) {
    console.warn(`[ensureFrontmatter] Could not extract front-matter from ${absPath}:`, error.message);
    return {};
  }
}