Calendar/src/utils/ColumnDetectionUtils.ts

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

import { MousePosition } from "../types/DragDropTypes";


export interface ColumnBounds {
    date: string;
    left: number;
    right: number;
    boundingClientRect: DOMRect,
    element : HTMLElement,
    index: 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');
        let index = 1;
        // Cache hver kolonnes x-grænser
        columns.forEach(column => {
            const rect = column.getBoundingClientRect();
            const date = (column as HTMLElement).dataset.date;

            if (date) {
                this.columnBoundsCache.push({
                    boundingClientRect : rect,
                    element: column as HTMLElement,
                    date,
                    left: rect.left,
                    right: rect.right, 
                    index: index++
                });
            }
        });

        // 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 getColumnBounds(position: MousePosition): ColumnBounds | null{
        if (this.columnBoundsCache.length === 0) {
            this.updateColumnBoundsCache();
        }

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

        return null;
    }

    /**
     * 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];
    }
}