/**
 * dashaFormatter handles the transformation of raw JHora Dasha text
 * into structured Markdown with hierarchical headings.
 * It uses a date-aware parsing strategy to ensure complex dasha names 
 * (like in Kalachakra) are preserved correctly.
 */

const PLANET_NAMES = ['Sun', 'Moon', 'Mars', 'Rah', 'Jup', 'Sat', 'Merc', 'Ket', 'Ven'];
const RASI_NAMES = ['Ar', 'Ta', 'Ge', 'Cn', 'Le', 'Vi', 'Li', 'Sc', 'Sg', 'Cp', 'Aq', 'Pi'];

/**
 * Transforms JHora Dasha plaintext into Markdown.
 */
export function formatDasha(text: string): string {
  if (!text || !text.trim()) return '';

  const lines = text.split('\n');
  const result: string[] = [];
  let currentMD = '';

  for (let line of lines) {
    const trimmed = line.trim();
    if (!trimmed) {
      if (result.length > 0 && result[result.length - 1] !== '') {
        result.push('');
      }
      continue;
    }

    // 1. Detect Section Headers: e.g., "Vimsottari Dasa (paramayush 120yr):"
    const headerMatch = line.match(/^([A-Za-z0-9\-/\s]+ Dasa)\s*(?:\([^)]*\))?:/);
    if (headerMatch) {
      result.push(`### ${headerMatch[1]}:`);
      result.push('');
      currentMD = '';
      continue;
    }

    // 2. Identify if this line starts a new Mahadasha (MD)
    const leadingSpaces = line.match(/^\s*/)?.[0].length || 0;
    const isNewMDLine = leadingSpaces < 3 && trimmed.length > 0;
    
    const tokens = trimmed.split(/\s+/);
    let startIndex = 0;

    if (isNewMDLine) {
      const potentialMD = tokens[0];
      const isKnownName = [...PLANET_NAMES, ...RASI_NAMES].some(name => 
        potentialMD.toLowerCase().startsWith(name.toLowerCase())
      );
      
      // For Kalachakra, MD might be "Vi (Push2)" - group the first two tokens if they look like a pair
      if (isKnownName || tokens.length >= 3) {
        let mdName = tokens[0];
        // If next token is in parentheses, it's part of the MD name
        if (tokens[1] && tokens[1].startsWith('(')) {
          mdName += ` ${tokens[1]}`;
          startIndex = 2;
        } else {
          startIndex = 1;
        }
        
        currentMD = mdName;
        result.push(`#### ${currentMD}:`);
      }
    }

    // 3. Process remaining tokens using Date-Aware Grouping
    // A Dasa Item is [Name tokens...] + [Date token (optional at start)]
    const items: string[] = [];
    let currentItemParts: string[] = [];

    for (let i = startIndex; i < tokens.length; i++) {
        const token = tokens[i];
        const isDate = /^\d{4}-\d{2}-\d{2}$/.test(token);

        if (isDate) {
            // Group current parts with this date
            const itemName = currentItemParts.join(' ');
            items.push(`${itemName} ${token}`.trim());
            currentItemParts = [];
        } else {
            currentItemParts.push(token);
        }
    }
    
    // Any remaining tokens without a date (could be the final dangling item or labels)
    if (currentItemParts.length > 0) {
        items.push(currentItemParts.join(' '));
    }

    // 4. Output items in a compact horizontal grid (3 items per line)
    for (let i = 0; i < items.length; i += 3) {
        const chunk = items.slice(i, i + 3);
        result.push(chunk.join('  '));
    }
  }

  return result.join('\n').replace(/\n{3,}/g, '\n\n').trim();
}