'use client';

import React from 'react';

export interface WatchSegment {
  startSec: number;
  endSec: number;
  watchedAt: string;
}

interface SegmentedProgressBarProps {
  segments: WatchSegment[];
  duration: number;
  percent: number;
  className?: string;
  height?: 'sm' | 'md' | 'lg';
  showTooltip?: boolean;
  interactive?: boolean;
  onSegmentClick?: (segment: WatchSegment, position: number) => void;
}

const heightPixels = {
  sm: '4px',
  md: '8px',
  lg: '12px',
};

export function SegmentedProgressBar({
  segments,
  duration,
  percent,
  className = '',
  height = 'md',
  showTooltip = true,
  interactive = false,
  onSegmentClick,
}: SegmentedProgressBarProps) {
  const [tooltipPos, setTooltipPos] = React.useState<{ x: number; time: string } | null>(null);
  const containerRef = React.useRef<HTMLDivElement>(null);

  // Normalize segments: merge overlapping ranges
  const normalizedSegments = React.useMemo(() => {
    if (segments.length === 0) return [];

    const sorted = [...segments].sort((a, b) => a.startSec - b.startSec);
    const merged: WatchSegment[] = [];

    for (const seg of sorted) {
      if (merged.length === 0) {
        merged.push({ ...seg });
      } else {
        const last = merged[merged.length - 1];
        // Check for overlap or adjacency (within 0.5s)
        if (seg.startSec <= last.endSec + 0.5) {
          // Merge
          last.endSec = Math.max(last.endSec, seg.endSec);
        } else {
          // Gap, add new segment
          merged.push({ ...seg });
        }
      }
    }

    return merged;
  }, [segments]);

  const handleMouseMove = React.useCallback(
    (e: React.MouseEvent<HTMLDivElement>) => {
      if (!showTooltip || !containerRef.current) return;

      const rect = containerRef.current.getBoundingClientRect();
      const x = e.clientX - rect.left;
      const percentage = Math.max(0, Math.min(1, x / rect.width));
      const time = Math.round(percentage * duration);

      setTooltipPos({
        x,
        time: formatTime(time),
      });
    },
    [duration, showTooltip]
  );

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

  const handleClick = (e: React.MouseEvent<HTMLDivElement>) => {
    if (!interactive || !onSegmentClick || !containerRef.current) return;

    const rect = containerRef.current.getBoundingClientRect();
    const x = e.clientX - rect.left;
    const percentage = Math.max(0, Math.min(1, x / rect.width));
    const position = Math.round(percentage * duration);

    // Find which segment was clicked
    for (const segment of normalizedSegments) {
      if (position >= segment.startSec && position <= segment.endSec) {
        onSegmentClick(segment, position);
        break;
      }
    }
  };

  const barHeight = heightPixels[height];

  return (
    <div style={{ width: '100%', display: 'flex', flexDirection: 'column', gap: '4px' }} className={className}>
      {/* Main progress bar container */}
      <div
        ref={containerRef}
        style={{
          position: 'relative',
          width: '100%',
          height: barHeight,
          backgroundColor: '#d1d5db',
          borderRadius: '9999px',
          overflow: 'hidden',
          cursor: interactive ? 'pointer' : 'default',
        }}
        onMouseMove={handleMouseMove}
        onMouseLeave={handleMouseLeave}
        onClick={handleClick}
      >
        {/* Watched segments */}
        {normalizedSegments.map((segment, idx) => {
          const startPercent = (segment.startSec / duration) * 100;
          const endPercent = (segment.endSec / duration) * 100;
          const width = endPercent - startPercent;

          return (
            <div
              key={idx}
              style={{
                position: 'absolute',
                top: 0,
                height: '100%',
                backgroundColor: '#ff6900',
                left: `${Math.max(0, startPercent)}%`,
                width: `${Math.max(0, Math.min(100, width))}%`,
                transition: 'background-color 200ms',
              }}
              title={`${formatTime(segment.startSec)} - ${formatTime(segment.endSec)}`}
              onMouseEnter={(e) => {
                e.currentTarget.style.backgroundColor = '#2563eb';
              }}
              onMouseLeave={(e) => {
                e.currentTarget.style.backgroundColor = '#3b82f6';
              }}
            />
          );
        })}

        {/* Current progress line */}
        {percent > 0 && (
          <div
            style={{
              position: 'absolute',
              top: 0,
              bottom: 0,
              width: '2px',
              backgroundColor: '#ef4444',
              opacity: 0.8,
              pointerEvents: 'none',
              zIndex: 10,
              left: `${Math.max(0, Math.min(100, percent))}%`,
              transform: 'translateX(-50%)',
            }}
          />
        )}
      </div>

      {/* Tooltip text - only show if showTooltip is true */}
      {tooltipPos && showTooltip && (
        <div style={{ fontSize: '12px', color: '#6b7280', whiteSpace: 'nowrap' }}>
          {tooltipPos.time} / {formatTime(duration)}
        </div>
      )}
    </div>
  );
}

function formatTime(seconds: number): string {
  const h = Math.floor(seconds / 3600);
  const m = Math.floor((seconds % 3600) / 60);
  const s = Math.floor(seconds % 60);

  if (h > 0) {
    return `${h}:${String(m).padStart(2, '0')}:${String(s).padStart(2, '0')}`;
  }
  return `${m}:${String(s).padStart(2, '0')}`;
}