// 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, EventLayout } from '../utils/AllDayLayoutEngine';
import { ColumnBounds, 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: EventLayout[] = [];
  private currentAllDayEvents: CalendarEvent[] = [];
  private currentWeekDates: string[] = [];
  private newLayouts: EventLayout[] = [];

  // Expand/collapse state
  private isExpanded: boolean = false;
  private actualRowCount: number = 0;
  private readonly MAX_COLLAPSED_ROWS = 4; // Show 4 rows when collapsed (3 events + 1 indicator row)


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

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

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

      this.handleConvertToAllDay(payload);
      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 { originalElement: 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) => {
      let draggedElement: DragEndEventPayload = (event as CustomEvent<DragEndEventPayload>).detail;

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

      this.handleDragEnd(draggedElement);
    });

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

    if (this.currentLayouts.length > 0) {
      // Find the HIGHEST row number in use from currentLayouts
      let highestRow = 0;

      this.currentLayouts.forEach((layout) => {
        highestRow = Math.max(highestRow, layout.row);
      });

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

      console.log('🔍 AllDayManager: Height calculation using currentLayouts', {
        totalLayouts: this.currentLayouts.length,
        highestRowFound: highestRow,
        maxRows
      });
    }

    // Store actual row count
    this.actualRowCount = maxRows;

    // Determine what to display
    let displayRows = maxRows;

    if (maxRows > this.MAX_COLLAPSED_ROWS) {
      // Show chevron button
      this.updateChevronButton(true);

      // Show 4 rows when collapsed (3 events + indicators)
      if (!this.isExpanded) {

        displayRows = this.MAX_COLLAPSED_ROWS;
        this.updateOverflowIndicators();

      } else {

        this.clearOverflowIndicators();

      }
    } else {
      
      // Hide chevron - not needed
      this.updateChevronButton(false);
      this.clearOverflowIndicators();
    }

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

  /**
   * 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');
    });
  }


  /**
   * 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[]): EventLayout[] {

    // Store current state
    this.currentAllDayEvents = events;
    this.currentWeekDates = weekDates;

    // Initialize layout engine with provided week dates
    var layoutEngine = new AllDayLayoutEngine(weekDates);

    // Calculate layout for all events together - AllDayLayoutEngine handles CalendarEvents directly
    return layoutEngine.calculateLayout(events);

  }


  /**
   * Handle conversion of timed event to all-day event - SIMPLIFIED
   * During drag: Place in row 1 only, calculate column from targetDate
   */
  private handleConvertToAllDay(payload: DragMouseEnterHeaderEventPayload): void {

    if (payload.draggedClone?.dataset == null)
      console.error("payload.cloneElement.dataset.eventId is null");


    console.log('🔄 AllDayManager: Converting to all-day (row 1 only during drag)', {
      eventId: payload.draggedClone.dataset.eventId,
      targetDate: payload.targetColumn
    });

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


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

    // Add to container
    allDayContainer?.appendChild(payload.draggedClone);

    ColumnDetectionUtils.updateColumnBoundsCache();

  }


  /**
   * 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.getColumnBounds(mousePosition);

    if (targetColumn == null)
      return;

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

  }

  /**
   * Handle drag end for all-day events - WITH DIFFERENTIAL UPDATES
   */
  private handleDragEnd(dragEndEvent: DragEndEventPayload): void {

    if (dragEndEvent.draggedClone == null)
      return;


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

    // 3. Create temporary array with existing events + the dropped event
    let eventId = dragEndEvent.draggedClone.dataset.eventId;
    let eventDate = dragEndEvent.finalPosition.column?.date;
    let eventType = dragEndEvent.draggedClone.dataset.type;

    if (eventDate == null || eventId == null || eventType == null)
      return;


    const droppedEvent: CalendarEvent = {
      id: eventId,
      title: dragEndEvent.draggedClone.dataset.title || dragEndEvent.draggedClone.textContent || '',
      start: new Date(eventDate),
      end: new Date(eventDate),
      type: eventType,
      allDay: true,
      syncStatus: 'synced'
    };

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

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

    // 5. Apply differential updates - only update events that changed
    let changedCount = 0;
    this.newLayouts.forEach((layout) => {
      // Find current layout for this event
      var currentLayout = this.currentLayouts.find(old => old.calenderEvent.id === layout.calenderEvent.id);
      var currentGridArea = currentLayout?.gridArea;
      var newGridArea = layout.gridArea;

      if (currentGridArea !== newGridArea) {
        changedCount++;
        const element = dragEndEvent.draggedClone;
        if (element) {
          // 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);
        }
      }
    });

    if (changedCount > 0)
      this.currentLayouts = this.newLayouts;

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

    // 7. Restore original element opacity
    dragEndEvent.originalElement.remove(); //TODO: this should be an event that only fade and remove if confirmed dragdrop

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

  }

  /**
   * Update chevron button visibility and state
   */
  private updateChevronButton(show: boolean): void {
    const headerSpacer = this.getHeaderSpacer();
    if (!headerSpacer) return;

    let chevron = headerSpacer.querySelector('.allday-chevron') as HTMLElement;

    if (show && !chevron) {
      // Create chevron button
      chevron = document.createElement('button');
      chevron.className = 'allday-chevron collapsed';
      chevron.innerHTML = `
        <svg width="12" height="8" viewBox="0 0 12 8">
          <path d="M1 1.5L6 6.5L11 1.5" stroke="currentColor" stroke-width="2" fill="none"/>
        </svg>
      `;
      chevron.onclick = () => this.toggleExpanded();
      headerSpacer.appendChild(chevron);
    } else if (!show && chevron) {
      // Remove chevron button
      chevron.remove();
    } else if (chevron) {
      // Update chevron state
      chevron.classList.toggle('collapsed', !this.isExpanded);
      chevron.classList.toggle('expanded', this.isExpanded);
    }
  }

  /**
   * Toggle between expanded and collapsed state
   */
  private toggleExpanded(): void {
    this.isExpanded = !this.isExpanded;
    this.checkAndAnimateAllDayHeight();
  }

  /**
   * Update overflow indicators for collapsed state
   */
  private updateOverflowIndicators(): void {
    const container = this.getAllDayContainer();
    if (!container) return;

    container.querySelectorAll('swp-event').forEach((element) => {
      const event = element as HTMLElement;
      const gridRow = parseInt(event.style.gridRow) || 1;

      if (gridRow === 4) {
        // Store original content before converting to indicator
        if (!event.dataset.originalTitle) {
          event.dataset.originalTitle = event.dataset.title || event.innerHTML;
        }

        // Convert row 4 events to indicators
        const overflowCount = this.actualRowCount - 3; // Total overflow rows
        event.classList.add('max-event-overflow');
        event.innerHTML = `<span>+${overflowCount} more</span>`;
        event.onclick = (e) => {
          e.stopPropagation();
          this.toggleExpanded();
        };
      } else if (gridRow > 4) {
        // Hide events beyond row 4
        event.style.display = 'none';
      }
    });
  }

  /**
   * Clear overflow indicators and restore normal state
   */
  private clearOverflowIndicators(): void {
    const container = this.getAllDayContainer();
    if (!container) return;

    container.querySelectorAll('.max-event-overflow').forEach((event) => {
      const htmlEvent = event as HTMLElement;
      htmlEvent.classList.remove('max-event-overflow');
      htmlEvent.onclick = null;

      // Restore original title from data-title
      if (htmlEvent.dataset.title) {
        htmlEvent.innerHTML = htmlEvent.dataset.title;
      } else if (htmlEvent.dataset.originalTitle) {
        htmlEvent.innerHTML = htmlEvent.dataset.originalTitle;
      }
    });

    // Show all hidden events
    container.querySelectorAll('swp-event[style*="display: none"]').forEach((event) => {
      (event as HTMLElement).style.display = '';
    });
  }

}