// All-day row height management and animations

import { eventBus } from '../core/EventBus';
import { ALL_DAY_CONSTANTS } from '../core/CalendarConfig';
import { AllDayEventRenderer } from '../renderers/AllDayEventRenderer';
import { AllDayLayoutEngine } from '../utils/AllDayLayoutEngine';
import { ColumnDetectionUtils } from '../utils/ColumnDetectionUtils';
import { CalendarEvent } from '../types/CalendarTypes';
import {
  DragMouseEnterHeaderEventPayload,
  DragStartEventPayload,
  DragMoveEventPayload,
  DragEndEventPayload,
  DragColumnChangeEventPayload
} from '../types/EventTypes';
import { DragOffset, MousePosition } from '../types/DragDropTypes';

/**
 * AllDayManager - Handles all-day row height animations and management
 * Uses AllDayLayoutEngine for all overlap detection and layout calculation
 */
export class AllDayManager {
  private allDayEventRenderer: AllDayEventRenderer;
  private layoutEngine: AllDayLayoutEngine | null = null;
  
  // State tracking for differential updates
  private currentLayouts: Map<string, string> = new Map();
  private currentAllDayEvents: CalendarEvent[] = [];
  private currentWeekDates: string[] = [];

  constructor() {
    this.allDayEventRenderer = new AllDayEventRenderer();
    this.setupEventListeners();
  }

  /**
   * Setup event listeners for drag conversions
   */
  private setupEventListeners(): void {
    eventBus.on('drag:mouseenter-header', (event) => {
      const { targetDate, mousePosition, originalElement, cloneElement } = (event as CustomEvent<DragMouseEnterHeaderEventPayload>).detail;

      console.log('🔄 AllDayManager: Received drag:mouseenter-header', {
        targetDate,
        originalElementId: originalElement?.dataset?.eventId,
        originalElementTag: originalElement?.tagName
      });

      if (targetDate && cloneElement) {
        this.handleConvertToAllDay(targetDate, cloneElement);
      }

      this.checkAndAnimateAllDayHeight();
    });

    eventBus.on('drag:mouseleave-header', (event) => {
      const { originalElement, cloneElement } = (event as CustomEvent).detail;

      console.log('🚪 AllDayManager: Received drag:mouseleave-header', {
        originalElementId: originalElement?.dataset?.eventId
      });

      this.checkAndAnimateAllDayHeight();
    });

    // Listen for drag operations on all-day events
    eventBus.on('drag:start', (event) => {
      const { draggedElement, draggedClone, mouseOffset } = (event as CustomEvent<DragStartEventPayload>).detail;

      // Check if this is an all-day event by checking if it's in all-day container
      const isAllDayEvent = draggedElement.closest('swp-allday-container');
      if (!isAllDayEvent) return; // Not an all-day event

      const eventId = draggedElement.dataset.eventId;
      console.log('🎯 AllDayManager: Starting drag for all-day event', { eventId });
      this.handleDragStart(draggedElement, eventId || '', mouseOffset);
    });

    eventBus.on('drag:column-change', (event) => {
      const { draggedElement, draggedClone, mousePosition } = (event as CustomEvent<DragColumnChangeEventPayload>).detail;
     
      if(draggedClone == null)
        return;

      // Filter: Only handle events where clone IS an all-day event
      if (!draggedClone.hasAttribute('data-allday')) {
        return; // This is not an all-day event, let EventRendererManager handle it
      }

      console.log('🔄 AllDayManager: Handling drag:column-change for all-day event', {
        eventId : draggedElement.dataset.eventId,
        cloneId: draggedClone.dataset.eventId
      });
      
      this.handleColumnChange(draggedClone, mousePosition);
    });

    eventBus.on('drag:end', (event) => {
      const { draggedElement, mousePosition, finalPosition, target } = (event as CustomEvent<DragEndEventPayload>).detail;

      if (target != 'swp-day-header') // we are not inside the swp-day-header, so just ignore.
        return;

      const eventId = draggedElement.dataset.eventId;
      console.log('🎬 AllDayManager: Received drag:end', {
        eventId: eventId,
        finalPosition
      });
      const dragClone = document.querySelector(`swp-allday-container swp-event[data-event-id="clone-${eventId}"]`);

      console.log('🎯 AllDayManager: Ending drag for all-day event', { eventId });
      this.handleDragEnd(draggedElement, dragClone as HTMLElement, { column: finalPosition.column || '', y: 0 });
    });

    // Listen for drag cancellation to recalculate height
    eventBus.on('drag:cancelled', (event) => {
      const { draggedElement, reason } = (event as CustomEvent).detail;

      console.log('🚫 AllDayManager: Drag cancelled', {
        eventId: draggedElement?.dataset?.eventId,
        reason
      });

      // Recalculate all-day height since clones may have been removed
      this.checkAndAnimateAllDayHeight();
    });

    // Listen for height check requests from EventRendererManager
    eventBus.on('allday:checkHeight', () => {
      console.log('📏 AllDayManager: Received allday:checkHeight request');
      this.checkAndAnimateAllDayHeight();
    });
  }

  private getAllDayContainer(): HTMLElement | null {
    return document.querySelector('swp-calendar-header swp-allday-container');
  }

  private getCalendarHeader(): HTMLElement | null {
    return document.querySelector('swp-calendar-header');
  }

  private getHeaderSpacer(): HTMLElement | null {
    return document.querySelector('swp-header-spacer');
  }

  /**
   * Calculate all-day height based on number of rows
   */
  private calculateAllDayHeight(targetRows: number): {
    targetHeight: number;
    currentHeight: number;
    heightDifference: number;
  } {
    const root = document.documentElement;
    const targetHeight = targetRows * ALL_DAY_CONSTANTS.SINGLE_ROW_HEIGHT;
    // Read CSS variable directly from style property or default to 0
    const currentHeightStr = root.style.getPropertyValue('--all-day-row-height') || '0px';
    const currentHeight = parseInt(currentHeightStr) || 0;
    const heightDifference = targetHeight - currentHeight;

    return { targetHeight, currentHeight, heightDifference };
  }

  /**
   * Collapse all-day row when no events
   */
  public collapseAllDayRow(): void {
    this.animateToRows(0);
  }

  /**
   * Check current all-day events and animate to correct height
   */
  public checkAndAnimateAllDayHeight(): void {
    const container = this.getAllDayContainer();
    if (!container) {
      this.animateToRows(0);
      return;
    }

    const allDayEvents = container.querySelectorAll('swp-event');

    // Calculate required rows - 0 if no events (will collapse)
    let maxRows = 0;

    if (allDayEvents.length > 0) {
      // Find the HIGHEST row number in use (not count of unique rows)
      let highestRow = 0;

      (Array.from(allDayEvents) as HTMLElement[]).forEach((event: HTMLElement) => {
        const gridRow = parseInt(event.style.gridRow) || 1;
        highestRow = Math.max(highestRow, gridRow);
      });

      // Max rows = highest row number (e.g. if row 3 is used, height = 3 rows)
      maxRows = highestRow;

      console.log('🔍 AllDayManager: Height calculation FIXED', {
        totalEvents: allDayEvents.length,
        highestRowFound: highestRow,
        maxRows
      });
    }

    // Animate to required rows (0 = collapse, >0 = expand)
    this.animateToRows(maxRows);
  }

  /**
   * Animate all-day container to specific number of rows
   */
  public animateToRows(targetRows: number): void {
    const { targetHeight, currentHeight, heightDifference } = this.calculateAllDayHeight(targetRows);

    if (targetHeight === currentHeight) return; // No animation needed

    console.log(`🎬 All-day height animation: ${currentHeight}px → ${targetHeight}px (${Math.ceil(currentHeight / ALL_DAY_CONSTANTS.SINGLE_ROW_HEIGHT)} → ${targetRows} rows)`);

    // Get cached elements
    const calendarHeader = this.getCalendarHeader();
    const headerSpacer = this.getHeaderSpacer();
    const allDayContainer = this.getAllDayContainer();

    if (!calendarHeader || !allDayContainer) return;

    // Get current parent height for animation
    const currentParentHeight = parseFloat(getComputedStyle(calendarHeader).height);
    const targetParentHeight = currentParentHeight + heightDifference;

    const animations = [
      calendarHeader.animate([
        { height: `${currentParentHeight}px` },
        { height: `${targetParentHeight}px` }
      ], {
        duration: 150,
        easing: 'ease-out',
        fill: 'forwards'
      })
    ];

    // Add spacer animation if spacer exists, but don't use fill: 'forwards'
    if (headerSpacer) {
      const root = document.documentElement;
      const headerHeightStr = root.style.getPropertyValue('--header-height');
      const headerHeight = parseInt(headerHeightStr);
      const currentSpacerHeight = headerHeight + currentHeight;
      const targetSpacerHeight = headerHeight + targetHeight;

      animations.push(
        headerSpacer.animate([
          { height: `${currentSpacerHeight}px` },
          { height: `${targetSpacerHeight}px` }
        ], {
          duration: 150,
          easing: 'ease-out'
          // No fill: 'forwards' - let CSS calc() take over after animation
        })
      );
    }

    // Update CSS variable after animation
    Promise.all(animations.map(anim => anim.finished)).then(() => {
      const root = document.documentElement;
      root.style.setProperty('--all-day-row-height', `${targetHeight}px`);
      eventBus.emit('header:height-changed');
    });
  }

  /**
   * Store current layouts from DOM for comparison
   */
  private storeCurrentLayouts(): void {
    this.currentLayouts.clear();
    const container = this.getAllDayContainer();
    if (!container) return;
    
    container.querySelectorAll('swp-event').forEach(element => {
      const htmlElement = element as HTMLElement;
      const eventId = htmlElement.dataset.eventId;
      const gridArea = htmlElement.style.gridArea;
      if (eventId && gridArea) {
        this.currentLayouts.set(eventId, gridArea);
      }
    });
    
    console.log('📋 AllDayManager: Stored current layouts', {
      count: this.currentLayouts.size,
      layouts: Array.from(this.currentLayouts.entries())
    });
  }

  /**
   * Set current events and week dates (called by EventRendererManager)
   */
  public setCurrentEvents(events: CalendarEvent[], weekDates: string[]): void {
    this.currentAllDayEvents = events;
    this.currentWeekDates = weekDates;
    
    console.log('📝 AllDayManager: Set current events', {
      eventCount: events.length,
      weekDatesCount: weekDates.length
    });
  }

  /**
   * Calculate layout for ALL all-day events using AllDayLayoutEngine
   * This is the correct method that processes all events together for proper overlap detection
   */
  public calculateAllDayEventsLayout(events: CalendarEvent[], weekDates: string[]): Map<string, {
    startColumn: number;
    endColumn: number;
    row: number;
    columnSpan: number;
    gridArea: string;
  }> {
    console.log('🔍 AllDayManager: calculateAllDayEventsLayout - Processing all events together', {
      eventCount: events.length,
      events: events.map(e => ({ id: e.id, title: e.title, start: e.start.toISOString().split('T')[0], end: e.end.toISOString().split('T')[0] })),
      weekDates
    });
    
    // Store current state
    this.currentAllDayEvents = events;
    this.currentWeekDates = weekDates;
    
    // Initialize layout engine with provided week dates
    this.layoutEngine = new AllDayLayoutEngine(weekDates);
    
    // Calculate layout for all events together - AllDayLayoutEngine handles CalendarEvents directly
    const layouts = this.layoutEngine.calculateLayout(events);
    
    // Convert to expected return format
    const result = new Map<string, {
      startColumn: number;
      endColumn: number;
      row: number;
      columnSpan: number;
      gridArea: string;
    }>();
    
    layouts.forEach((layout, eventId) => {
      result.set(eventId, {
        startColumn: layout.startColumn,
        endColumn: layout.endColumn,
        row: layout.row,
        columnSpan: layout.columnSpan,
        gridArea: layout.gridArea
      });
      
      console.log('✅ AllDayManager: Calculated layout for event', {
        eventId,
        title: events.find(e => e.id === eventId)?.title,
        gridArea: layout.gridArea,
        layout: layout
      });
    });
    
    return result;
  }


  /**
   * Handle conversion of timed event to all-day event - SIMPLIFIED
   * During drag: Place in row 1 only, calculate column from targetDate
   */
  private handleConvertToAllDay(targetDate: string, cloneElement: HTMLElement): void {
    console.log('🔄 AllDayManager: Converting to all-day (row 1 only during drag)', {
      eventId: cloneElement.dataset.eventId,
      targetDate
    });

    // Get all-day container, request creation if needed
    let allDayContainer = this.getAllDayContainer();

    // Calculate target column from targetDate using ColumnDetectionUtils
    const targetColumn = ColumnDetectionUtils.getColumnIndexFromDate(targetDate);

    cloneElement.removeAttribute('style');
    cloneElement.classList.add('all-day-style');
    cloneElement.style.gridRow = '1';
    cloneElement.style.gridColumn = targetColumn.toString();
    cloneElement.dataset.allday = 'true'; // Set the all-day attribute for filtering

    // Add to container
    allDayContainer?.appendChild(cloneElement);

    console.log('✅ AllDayManager: Converted to all-day style (simple row 1)', {
      eventId: cloneElement.dataset.eventId,
      gridColumn: targetColumn,
      gridRow: 1
    });
  }


  /**
   * Handle drag start for all-day events
   */
  private handleDragStart(originalElement: HTMLElement, eventId: string, mouseOffset: DragOffset): void {
    // Create clone
    const clone = originalElement.cloneNode(true) as HTMLElement;
    clone.dataset.eventId = `clone-${eventId}`;

    // Get container
    const container = this.getAllDayContainer();
    if (!container) return;

    // Add clone to container
    container.appendChild(clone);

    // Copy positioning from original
    clone.style.gridColumn = originalElement.style.gridColumn;
    clone.style.gridRow = originalElement.style.gridRow;

    // Add dragging style
    clone.classList.add('dragging');
    clone.style.zIndex = '1000';
    clone.style.cursor = 'grabbing';

    // Make original semi-transparent
    originalElement.style.opacity = '0.3';

    console.log('✅ AllDayManager: Created drag clone for all-day event', {
      eventId,
      cloneId: clone.dataset.eventId,
      gridColumn: clone.style.gridColumn,
      gridRow: clone.style.gridRow
    });
  }

  /**
   * Handle drag move for all-day events - SPECIALIZED FOR ALL-DAY CONTAINER
   */
  private handleColumnChange(dragClone: HTMLElement, mousePosition: MousePosition): void {
    // Get the all-day container to understand its grid structure
    const allDayContainer = this.getAllDayContainer();
    if (!allDayContainer) return;

    // Calculate target column using ColumnDetectionUtils
    const targetColumn = ColumnDetectionUtils.getColumnIndexFromX(mousePosition.x);

    // Update clone position - ALWAYS keep in row 1 during drag
    // Use simple grid positioning that matches all-day container structure
    dragClone.style.gridColumn = targetColumn.toString();
    dragClone.style.gridRow = '1'; // Force row 1 during drag
    dragClone.style.gridArea = `1 / ${targetColumn} / 2 / ${targetColumn + 1}`;

    console.log('🔄 AllDayManager: Updated all-day drag clone position', {
      eventId: dragClone.dataset.eventId,
      targetColumn,
      gridRow: 1,
      gridArea: dragClone.style.gridArea,
      mouseX: mousePosition.x
    });
  }

  /**
   * Handle drag end for all-day events - WITH DIFFERENTIAL UPDATES
   */
  private handleDragEnd(originalElement: HTMLElement, dragClone: HTMLElement, finalPosition: { column: string; y: number }): void {
    console.log('🎯 AllDayManager: Starting drag end with differential updates', {
      eventId: dragClone.dataset.eventId,
      finalColumn: finalPosition.column
    });

    // 1. Store current layouts BEFORE any changes
    this.storeCurrentLayouts();

    // 2. Normalize clone ID
    const cloneId = dragClone.dataset.eventId;
    if (cloneId?.startsWith('clone-')) {
      dragClone.dataset.eventId = cloneId.replace('clone-', '');
    }

    // 3. Create temporary array with existing events + the dropped event
    const droppedEventId = dragClone.dataset.eventId || '';
    const droppedEventDate = dragClone.dataset.allDayDate || finalPosition.column;
    
    const droppedEvent: CalendarEvent = {
      id: droppedEventId,
      title: dragClone.dataset.title || dragClone.textContent || '',
      start: new Date(droppedEventDate),
      end: new Date(droppedEventDate),
      type: 'work',
      allDay: true,
      syncStatus: 'synced'
    };

    // Use current events + dropped event for calculation
    const tempEvents = [...this.currentAllDayEvents, droppedEvent];

    // 4. Calculate new layouts for ALL events
    const newLayouts = this.calculateAllDayEventsLayout(tempEvents, this.currentWeekDates);

    // 5. Apply differential updates - only update events that changed
    let changedCount = 0;
    newLayouts.forEach((layout, eventId) => {
      const oldGridArea = this.currentLayouts.get(eventId);
      const newGridArea = layout.gridArea;

      if (oldGridArea !== newGridArea) {
        changedCount++;
        const element = document.querySelector(`[data-event-id="${eventId}"]`) as HTMLElement;
        if (element) {
          console.log('🔄 AllDayManager: Updating event position', {
            eventId,
            oldGridArea,
            newGridArea
          });

          // Add transition class for smooth animation
          element.classList.add('transitioning');
          element.style.gridArea = newGridArea;
          element.style.gridRow = layout.row.toString();
          element.style.gridColumn = `${layout.startColumn} / ${layout.endColumn + 1}`;

          // Remove transition class after animation
          setTimeout(() => element.classList.remove('transitioning'), 200);
        }
      }
    });

    // 6. Clean up drag styles from the dropped clone
    dragClone.classList.remove('dragging');
    dragClone.style.zIndex = '';
    dragClone.style.cursor = '';
    dragClone.style.opacity = '';

    // 7. Restore original element opacity
    originalElement.style.opacity = '';

    // 8. Check if height adjustment is needed
    this.checkAndAnimateAllDayHeight();

    console.log('✅ AllDayManager: Completed differential drag end', {
      eventId: droppedEventId,
      totalEvents: newLayouts.size,
      changedEvents: changedCount,
      finalGridArea: newLayouts.get(droppedEventId)?.gridArea
    });
  }

  /**
   * Get existing all-day events from DOM
   * Since we don't have direct access to EventManager, we'll get events from the current DOM
   */
  private getExistingAllDayEvents(): CalendarEvent[] {
    const allDayContainer = this.getAllDayContainer();
    if (!allDayContainer) {
      return [];
    }

    const existingElements = allDayContainer.querySelectorAll('swp-event');
    const events: CalendarEvent[] = [];

    existingElements.forEach(element => {
      const htmlElement = element as HTMLElement;
      const eventId = htmlElement.dataset.eventId;
      const title = htmlElement.dataset.title || htmlElement.textContent || '';
      const allDayDate = htmlElement.dataset.allDayDate;

      if (eventId && allDayDate) {
        events.push({
          id: eventId,
          title: title,
          start: new Date(allDayDate),
          end: new Date(allDayDate),
          type: 'work',
          allDay: true,
          syncStatus: 'synced'
        });
      }
    });

    return events;
  }

  private getVisibleDatesFromDOM(): string[] {
    const dayHeaders = document.querySelectorAll('swp-calendar-header swp-day-header');
        const weekDates: string[] = [];
        
        dayHeaders.forEach(header => {
            const dateAttr = header.getAttribute('data-date');
            if (dateAttr) {
                weekDates.push(dateAttr);
            }
        });
    
    return weekDates;
  }

}