/**
 * ColumnDetectionUtils - Shared utility for column detection and caching
 * Used by both DragDropManager and AllDayManager for consistent column detection
 */

export interface ColumnBounds {
  date: string;
  left: number;
  right: number;
}

export class ColumnDetectionUtils {
  private static columnBoundsCache: ColumnBounds[] = [];

  /**
   * Update column bounds cache for coordinate-based column detection
   */
  public static updateColumnBoundsCache(): void {
    // Reset cache
    this.columnBoundsCache = [];

    // Find alle kolonner
    const columns = document.querySelectorAll('swp-day-column');

    // Cache hver kolonnes x-grænser
    columns.forEach(column => {
      const rect = column.getBoundingClientRect();
      const date = (column as HTMLElement).dataset.date;

      if (date) {
        this.columnBoundsCache.push({
          date,
          left: rect.left,
          right: rect.right
        });
      }
    });

    // Sorter efter x-position (fra venstre til højre)
    this.columnBoundsCache.sort((a, b) => a.left - b.left);
  }

  /**
   * Get column date from X coordinate using cached bounds
   */
  public static getColumnDateFromX(x: number): string | null {
    // Opdater cache hvis tom
    if (this.columnBoundsCache.length === 0) {
      this.updateColumnBoundsCache();
    }

    // Find den kolonne hvor x-koordinaten er indenfor grænserne
    const column = this.columnBoundsCache.find(col =>
      x >= col.left && x <= col.right
    );

    return column ? column.date : null;
  }

  /**
   * Get column index (1-based) from date
   */
  public static getColumnIndexFromDate(date: string): number {
    // Opdater cache hvis tom
    if (this.columnBoundsCache.length === 0) {
      this.updateColumnBoundsCache();
    }

    const columnIndex = this.columnBoundsCache.findIndex(col => col.date === date);
    return columnIndex >= 0 ? columnIndex + 1 : 1; // 1-based index
  }

  /**
   * Get column index from X coordinate
   */
  public static getColumnIndexFromX(x: number): number {
    const date = this.getColumnDateFromX(x);
    return date ? this.getColumnIndexFromDate(date) : 1;
  }

  /**
   * Clear cache (useful for testing or when DOM structure changes)
   */
  public static clearCache(): void {
    this.columnBoundsCache = [];
  }

  /**
   * Get current cache for debugging
   */
  public static getCache(): ColumnBounds[] {
    return [...this.columnBoundsCache];
  }
}