/**
 * TimeBlockCalendarOverlay - Renders time block overlays on the scheduler calendar
 *
 * Shows blocked time periods with visual styling:
 * - Hard blocks: Red with diagonal stripes, 50% opacity
 * - Soft blocks: Yellow with dotted border, 30% opacity
 * - Business blocks: Full-width across the lane
 * - Resource blocks: Only on matching resource lane
 */

import React, { useMemo, useState } from 'react';
import { BlockedDate, BlockType, BlockPurpose } from '../../types';

interface TimeBlockCalendarOverlayProps {
  blockedDates: BlockedDate[];
  resourceId: string;
  viewDate: Date;
  zoomLevel: number;
  pixelsPerMinute: number;
  startHour: number;
  dayWidth: number;
  laneHeight: number;
  days: Date[];
  onDayClick?: (day: Date) => void;
}

interface TimeBlockTooltipProps {
  block: BlockedDate;
  position: { x: number; y: number };
}

const TimeBlockTooltip: React.FC<TimeBlockTooltipProps> = ({ block, position }) => {
  return (
    <div
      className="fixed z-[100] px-3 py-2 bg-gray-900 text-white text-sm rounded-lg shadow-lg max-w-xs pointer-events-none"
      style={{
        left: position.x + 10,
        top: position.y - 40,
      }}
    >
      <div className="font-semibold">{block.title}</div>
      <div className="text-xs text-gray-300 mt-1">
        {block.block_type === 'HARD' ? 'Hard Block' : 'Soft Block'}
        {block.all_day ? ' (All Day)' : ` (${block.start_time} - ${block.end_time})`}
      </div>
    </div>
  );
};

const TimeBlockCalendarOverlay: React.FC<TimeBlockCalendarOverlayProps> = ({
  blockedDates,
  resourceId,
  viewDate,
  zoomLevel,
  pixelsPerMinute,
  startHour,
  dayWidth,
  laneHeight,
  days,
  onDayClick,
}) => {
  const [hoveredBlock, setHoveredBlock] = useState<{ block: BlockedDate; position: { x: number; y: number } } | null>(null);

  // Filter blocks for this resource (includes business-level blocks where resource_id is null)
  const relevantBlocks = useMemo(() => {
    return blockedDates.filter(
      (block) => block.resource_id === null || block.resource_id === resourceId
    );
  }, [blockedDates, resourceId]);

  // Calculate block positions for each day
  const blockOverlays = useMemo(() => {
    const overlays: Array<{
      block: BlockedDate;
      left: number;
      width: number;
      dayIndex: number;
    }> = [];

    relevantBlocks.forEach((block) => {
      // Parse date string as local date, not UTC
      // "2025-12-06" should be Dec 6 in local timezone, not UTC
      const [year, month, dayNum] = block.date.split('-').map(Number);
      const blockDate = new Date(year, month - 1, dayNum);
      blockDate.setHours(0, 0, 0, 0);

      // Find which day this block falls on
      days.forEach((day, dayIndex) => {
        const dayStart = new Date(day);
        dayStart.setHours(0, 0, 0, 0);

        if (blockDate.getTime() === dayStart.getTime()) {
          let left: number;
          let width: number;

          if (block.all_day) {
            // Full day block
            left = dayIndex * dayWidth;
            width = dayWidth;
          } else if (block.start_time && block.end_time) {
            // Partial day block
            const [startHours, startMins] = block.start_time.split(':').map(Number);
            const [endHours, endMins] = block.end_time.split(':').map(Number);

            const startMinutes = (startHours - startHour) * 60 + startMins;
            const endMinutes = (endHours - startHour) * 60 + endMins;

            left = dayIndex * dayWidth + startMinutes * pixelsPerMinute * zoomLevel;
            width = (endMinutes - startMinutes) * pixelsPerMinute * zoomLevel;
          } else {
            // Default to full day if no times specified
            left = dayIndex * dayWidth;
            width = dayWidth;
          }

          overlays.push({
            block,
            left,
            width,
            dayIndex,
          });
        }
      });
    });

    return overlays;
  }, [relevantBlocks, days, dayWidth, pixelsPerMinute, zoomLevel, startHour]);

  const getBlockStyle = (blockType: BlockType, purpose: BlockPurpose, isBusinessLevel: boolean): React.CSSProperties => {
    const baseStyle: React.CSSProperties = {
      position: 'absolute',
      top: 0,
      height: '100%',
      pointerEvents: 'auto',
      cursor: 'default',
      zIndex: 5, // Ensure overlays are visible above grid lines
    };

    // Business-level blocks (including business hours): Simple gray background
    // No fancy styling - just indicates "not available for booking"
    if (isBusinessLevel) {
      return {
        ...baseStyle,
        background: 'rgba(107, 114, 128, 0.25)', // Gray-500 at 25% opacity (more visible)
      };
    }

    // Resource-level blocks: Purple (hard) / Cyan (soft)
    if (blockType === 'HARD') {
      return {
        ...baseStyle,
        background: `repeating-linear-gradient(
          -45deg,
          rgba(147, 51, 234, 0.25),
          rgba(147, 51, 234, 0.25) 5px,
          rgba(147, 51, 234, 0.4) 5px,
          rgba(147, 51, 234, 0.4) 10px
        )`,
        borderTop: '2px solid rgba(147, 51, 234, 0.7)',
        borderBottom: '2px solid rgba(147, 51, 234, 0.7)',
      };
    } else {
      return {
        ...baseStyle,
        background: 'rgba(6, 182, 212, 0.15)',
        borderTop: '2px dashed rgba(6, 182, 212, 0.7)',
        borderBottom: '2px dashed rgba(6, 182, 212, 0.7)',
      };
    }
  };

  const handleMouseEnter = (e: React.MouseEvent, block: BlockedDate) => {
    setHoveredBlock({
      block,
      position: { x: e.clientX, y: e.clientY },
    });
  };

  const handleMouseMove = (e: React.MouseEvent) => {
    if (hoveredBlock) {
      setHoveredBlock({
        ...hoveredBlock,
        position: { x: e.clientX, y: e.clientY },
      });
    }
  };

  const handleMouseLeave = () => {
    setHoveredBlock(null);
  };

  return (
    <>
      {blockOverlays.map((overlay, index) => {
        const isBusinessLevel = overlay.block.resource_id === null;
        const style = getBlockStyle(overlay.block.block_type, overlay.block.purpose, isBusinessLevel);

        return (
          <div
            key={`${overlay.block.time_block_id}-${overlay.dayIndex}-${index}`}
            style={{
              ...style,
              left: overlay.left,
              width: overlay.width,
              cursor: onDayClick ? 'pointer' : 'default',
            }}
            onMouseEnter={(e) => handleMouseEnter(e, overlay.block)}
            onMouseMove={handleMouseMove}
            onMouseLeave={handleMouseLeave}
            onClick={() => onDayClick?.(days[overlay.dayIndex])}
          >
            {/* Only show badge for resource-level blocks */}
            {!isBusinessLevel && (
              <div className="absolute top-1 left-1 px-1.5 py-0.5 text-white text-[10px] font-bold rounded shadow-sm uppercase tracking-wide bg-purple-600">
                R
              </div>
            )}
          </div>
        );
      })}

      {/* Tooltip */}
      {hoveredBlock && (
        <TimeBlockTooltip block={hoveredBlock.block} position={hoveredBlock.position} />
      )}
    </>
  );
};

export default TimeBlockCalendarOverlay;