/**
 * Utility for positioning floating menus relative to editor selections or cursor positions
 */
export class MenuPositioner {
  /**
   * Position a menu element relative to a text selection or cursor position
   * @param {HTMLElement} menuElement - The menu element to position
   * @param {Editor} editorInstance - The TipTap editor instance
   * @param {Object|null} clientRect - Optional custom client rect for positioning
   */
  static positionMenu(menuElement, editorInstance, clientRect = null) {
    const { view } = editorInstance;
    const { selection } = editorInstance.state;

    let start, end;
    if (clientRect) {
      // Ensure clientRect has all required properties
      start = {
        left: clientRect.left || 0,
        right: clientRect.right || clientRect.left || 0,
        top: clientRect.top || 0,
        bottom: clientRect.bottom || clientRect.top || 0,
      };
      end = start;
    } else {
      try {
        start = view.coordsAtPos(selection.from);
        end = view.coordsAtPos(selection.to);
      } catch (error) {
        console.warn('Failed to get coordinates from editor selection:', error);
        // Fallback to a default position
        start = { left: 10, top: 10, right: 20, bottom: 20 };
        end = start;
      }
    }

    // Validate coordinates
    if (!start || typeof start.left !== 'number' || typeof start.top !== 'number') {
      console.warn('Invalid start coordinates, using fallback:', start);
      start = { left: 10, top: 10, right: 20, bottom: 20 };
    }
    if (!end || typeof end.left !== 'number' || typeof end.top !== 'number') {
      console.warn('Invalid end coordinates, using start coordinates:', end);
      end = start;
    }

    // Calculate the center of the selection
    let left = (start.left + end.left) / 2;
    
    // Get menu dimensions - ensure menu is visible to get accurate measurements
    const wasHidden = menuElement.style.display === 'none';
    if (wasHidden) {
      menuElement.style.visibility = 'hidden';
      menuElement.style.display = 'block';
    }
    
    const menuWidth = menuElement.offsetWidth || 200; // fallback width
    const menuHeight = menuElement.offsetHeight || 100; // fallback height
    
    if (wasHidden) {
      menuElement.style.display = 'none';
      menuElement.style.visibility = '';
    }
    
    // Start by trying to position above the selection
    let top = start.top - menuHeight - 10; // 10px above selection
    let placement = 'above';

    // If the calculated top is negative or too close to viewport top, position below
    if (top < 10) {
      top = (end.bottom || end.top || start.top) + 10; // 10px below selection
      placement = 'below';
    }

    // Adjust horizontal position if it goes out of viewport
    const viewportWidth = window.innerWidth;
    
    // Check if menu would overflow on the right
    if (left + menuWidth / 2 > viewportWidth - 10) {
      left = viewportWidth - menuWidth - 10; // Align to right edge with padding
    }
    // Check if menu would overflow on the left
    else if (left - menuWidth / 2 < 10) {
      left = 10; // Align to left edge with padding
    }
    // Center the menu horizontally on the selection
    else {
      left = left - menuWidth / 2;
    }

    // Final validation
    if (isNaN(left) || isNaN(top)) {
      console.warn('NaN detected in basic positioning, using fallback values:', { left, top });
      left = isNaN(left) ? 10 : left;
      top = isNaN(top) ? 10 : top;
    }

    // Apply positioning
    menuElement.style.left = `${left}px`;
    menuElement.style.top = `${top}px`;
    
    // Add a data attribute to indicate placement for potential styling
    menuElement.setAttribute('data-placement', placement);
    
    console.log(`Menu positioned ${placement} selection at: left=${left}px, top=${top}px`);
    
    return { left, top, placement };
  }

  /**
   * Position a menu element with enhanced viewport awareness
   * Includes additional checks for viewport boundaries and scroll position
   * @param {HTMLElement} menuElement - The menu element to position
   * @param {Editor} editorInstance - The TipTap editor instance
   * @param {Object|null} clientRect - Optional custom client rect for positioning
   */
  static positionMenuAdvanced(menuElement, editorInstance, clientRect = null) {
    const { view } = editorInstance;
    const { selection } = editorInstance.state;

    console.log('positionMenuAdvanced called with:', { clientRect, selection: selection.from + '-' + selection.to });

    let start, end;
    if (clientRect) {
      console.log('Using clientRect:', clientRect);
      // Ensure clientRect has all required properties
      start = {
        left: clientRect.left || 0,
        right: clientRect.right || clientRect.left || 0,
        top: clientRect.top || 0,
        bottom: clientRect.bottom || clientRect.top || 0,
      };
      end = start;
    } else {
      try {
        start = view.coordsAtPos(selection.from);
        end = view.coordsAtPos(selection.to);
        console.log('Using editor coordinates:', { start, end });
      } catch (error) {
        console.warn('Failed to get coordinates from editor selection, falling back to basic positioning:', error);
        return MenuPositioner.positionMenu(menuElement, editorInstance, clientRect);
      }
    }

    // Validate coordinates - be more strict about what we consider valid
    if (!start || typeof start.left !== 'number' || isNaN(start.left) || 
        typeof start.top !== 'number' || isNaN(start.top) ||
        start.left === 0 && start.top === 0) {
      console.warn('Invalid or zero coordinates detected, using editor selection instead:', { start, end });
      
      // Try to get coordinates from current editor selection
      try {
        start = view.coordsAtPos(selection.from);
        end = view.coordsAtPos(selection.to);
        console.log('Fallback to editor coordinates worked:', { start, end });
      } catch (error) {
        console.warn('Editor coordinates also failed, using basic positioning');
        return MenuPositioner.positionMenu(menuElement, editorInstance, null);
      }
    }

    // Get viewport dimensions and scroll position
    const viewportWidth = window.innerWidth;
    const viewportHeight = window.innerHeight;
    const scrollY = window.scrollY;
    
    // Get menu dimensions - ensure menu is visible to get accurate measurements
    const wasHidden = menuElement.style.display === 'none';
    if (wasHidden) {
      menuElement.style.visibility = 'hidden';
      menuElement.style.display = 'block';
    }
    
    const menuWidth = menuElement.offsetWidth || 200; // fallback width
    const menuHeight = menuElement.offsetHeight || 100; // fallback height
    
    if (wasHidden) {
      menuElement.style.display = 'none';
      menuElement.style.visibility = '';
    }
    
    // Calculate initial center position
    let left = (start.left + end.left) / 2;
    let top, placement;
    
    // Determine vertical placement based on available space
    const spaceAbove = start.top - scrollY;
    const spaceBelow = viewportHeight - (end.bottom - scrollY);
    
    if (spaceAbove >= menuHeight + 20 && spaceAbove > spaceBelow) {
      // Position above if there's enough space and it's the better option
      top = start.top - menuHeight - 10;
      placement = 'above';
    } else if (spaceBelow >= menuHeight + 20) {
      // Position below if there's enough space
      top = end.bottom + 10;
      placement = 'below';
    } else {
      // Choose the side with more space
      if (spaceAbove > spaceBelow) {
        top = Math.max(scrollY + 10, start.top - menuHeight - 10);
        placement = 'above-constrained';
      } else {
        top = Math.min(scrollY + viewportHeight - menuHeight - 10, end.bottom + 10);
        placement = 'below-constrained';
      }
    }
    
    // Adjust horizontal position
    const idealLeft = left - menuWidth / 2;
    
    if (idealLeft < 10) {
      left = 10;
    } else if (idealLeft + menuWidth > viewportWidth - 10) {
      left = viewportWidth - menuWidth - 10;
    } else {
      left = idealLeft;
    }

    // Final validation
    if (isNaN(left) || isNaN(top)) {
      console.warn('NaN detected in positioning calculation, using fallback values:', { left, top, start, end });
      left = isNaN(left) ? 10 : left;
      top = isNaN(top) ? 10 : top;
    }

    // Apply positioning
    menuElement.style.left = `${left}px`;
    menuElement.style.top = `${top}px`;
    menuElement.setAttribute('data-placement', placement);
    
    console.log(`Menu positioned ${placement} at: left=${left}px, top=${top}px (viewport: ${viewportWidth}x${viewportHeight}, scroll: ${scrollY})`);
    
    return { left, top, placement };
  }
}