/**
 * Map Obsidian-style search queries to Meilisearch format
 * Supports: tag:, path:, file: operators with free text search
 */
export function mapObsidianQueryToMeili(qRaw) {
  const tokens = String(qRaw).trim().split(/\s+/);
  const filters = [];
  const meiliQ = [];
  let restrict = null;
  let rangeStart = null;
  let rangeEnd = null;

  const parseDate = (s) => {
    if (!s) return null;
    // Accept YYYY-MM-DD
    const m = String(s).match(/^(\d{4})-(\d{2})-(\d{2})$/);
    if (!m) return null;
    const d = new Date(`${m[1]}-${m[2]}-${m[3]}T00:00:00Z`);
    if (Number.isNaN(d.getTime())) return null;
    return d;
  };

  for (const token of tokens) {
    // tag: operator - filter by exact tag match
    if (token.startsWith('tag:')) {
      const value = token.slice(4).replace(/^["']|["']$/g, '');
      if (value) {
        // Remove leading # if present
        const cleanTag = value.startsWith('#') ? value.substring(1) : value;
        filters.push(`tags = "${cleanTag}"`);
      }
    }
    // path: operator - filter by parent directory path
    // We use parentDirs array to simulate startsWith behavior
    else if (token.startsWith('path:')) {
      const value = token.slice(5).replace(/^["']|["']$/g, '');
      if (value) {
        // Normalize path separators
        const normalizedPath = value.replace(/\\/g, '/');
        filters.push(`parentDirs = "${normalizedPath}"`);
      }
    }
    // file: operator - restrict search to file field
    else if (token.startsWith('file:')) {
      const value = token.slice(5).replace(/^["']|["']$/g, '');
      if (value) {
        // Restrict search to file field only
        restrict = ['file'];
        meiliQ.push(value);
      }
    }
    // year: operator - facet filter
    else if (token.startsWith('year:')) {
      const value = token.slice(5).replace(/^["']|["']$/g, '');
      const n = Number(value);
      if (!Number.isNaN(n)) {
        filters.push(`year = ${n}`);
      }
    }
    // month: operator - facet filter (1-12)
    else if (token.startsWith('month:')) {
      const value = token.slice(6).replace(/^["']|["']$/g, '');
      const n = Number(value);
      if (!Number.isNaN(n)) {
        filters.push(`month = ${n}`);
      }
    }
    // date:YYYY-MM-DD (single day)
    else if (token.startsWith('date:')) {
      const value = token.slice(5);
      const d = parseDate(value);
      if (d) {
        const start = new Date(d); start.setUTCHours(0,0,0,0);
        const end = new Date(d); end.setUTCHours(23,59,59,999);
        const startMs = start.getTime();
        const endMs = end.getTime();
        filters.push(`((createdAt >= ${startMs} AND createdAt <= ${endMs}) OR (updatedAt >= ${startMs} AND updatedAt <= ${endMs}))`);
      }
    }
    // from:/to: YYYY-MM-DD
    else if (token.startsWith('from:')) {
      const d = parseDate(token.slice(5));
      if (d) {
        const s = new Date(d); s.setUTCHours(0,0,0,0);
        rangeStart = s.getTime();
      }
    }
    else if (token.startsWith('to:')) {
      const d = parseDate(token.slice(3));
      if (d) {
        const e = new Date(d); e.setUTCHours(23,59,59,999);
        rangeEnd = e.getTime();
      }
    }
    // Regular text token
    else if (token) {
      meiliQ.push(token);
    }
  }

  // If we captured a from/to range, add a combined date filter
  if (rangeStart !== null || rangeEnd !== null) {
    const startMs = rangeStart ?? 0;
    const endMs = rangeEnd ?? 8640000000000000; // large future
    filters.push(`((createdAt >= ${startMs} AND createdAt <= ${endMs}) OR (updatedAt >= ${startMs} AND updatedAt <= ${endMs}))`);
  }

  return {
    meiliQ: meiliQ.join(' ').trim(),
    filters,
    restrict
  };
}

/**
 * Build Meilisearch search parameters from parsed query
 */
export function buildSearchParams(parsedQuery, options = {}) {
  const {
    limit = 20,
    offset = 0,
    sort,
    highlight = true
  } = options;

  const params = {
    q: parsedQuery.meiliQ,
    limit: Number(limit),
    offset: Number(offset),
    filter: parsedQuery.filters.length ? parsedQuery.filters.join(' AND ') : undefined,
    facets: ['tags', 'parentDirs', 'year', 'month'],
    attributesToHighlight: highlight ? ['title', 'content'] : [],
    highlightPreTag: '<mark>',
    highlightPostTag: '</mark>',
    attributesToCrop: ['content'],
    cropLength: 80,
    cropMarker: '…',
    attributesToSearchOn: parsedQuery.restrict?.length ? parsedQuery.restrict : undefined,
    sort: sort ? [String(sort)] : undefined,
    showMatchesPosition: false
  };

  // Remove undefined values
  Object.keys(params).forEach(key => {
    if (params[key] === undefined) {
      delete params[key];
    }
  });

  return params;
}