import { useState, useEffect, useCallback, type CSSProperties } from 'react';
import type { DerivedLegacyVessel } from '../../features/legacyDashboard/model/types';
import { VESSEL_TYPES } from '../../entities/vessel/model/meta';
import type { SortKey, SortDir } from './VesselSelectModal';

interface VesselSelectGridProps {
  vessels: DerivedLegacyVessel[];
  selectedMmsis: Set<number>;
  toggleMmsi: (mmsi: number) => void;
  setMmsis: (mmsis: Set<number>) => void;
  sortKey: SortKey | null;
  sortDir: SortDir;
  onSort: (key: SortKey) => void;
}

interface DragState {
  startIdx: number;
  endIdx: number;
  direction: 'check' | 'uncheck';
}

const STYLE_TABLE: CSSProperties = {
  width: '100%',
  borderCollapse: 'collapse',
  fontSize: 11,
};

const STYLE_TH: CSSProperties = {
  position: 'sticky',
  top: 0,
  background: 'rgba(15,23,42,0.98)',
  color: '#94a3b8',
  textAlign: 'left',
  padding: '6px 8px',
  borderBottom: '1px solid rgba(148,163,184,0.2)',
  fontWeight: 500,
  cursor: 'pointer',
  userSelect: 'none',
};

function getSortIndicator(col: SortKey, sortKey: SortKey | null, sortDir: SortDir): string {
  if (sortKey !== col) return ' –';
  return sortDir === 'asc' ? ' ▲' : ' ▼';
}

const STYLE_TH_CHECKBOX: CSSProperties = {
  ...STYLE_TH,
  width: 28,
};

function getTdStyle(isSelected: boolean): CSSProperties {
  return {
    padding: '5px 8px',
    borderBottom: '1px solid rgba(148,163,184,0.08)',
    cursor: 'pointer',
    background: isSelected ? 'rgba(59,130,246,0.12)' : undefined,
  };
}

function getStateBadgeStyle(isFishing: boolean, isTransit: boolean): CSSProperties {
  const color = isFishing ? '#22C55E' : isTransit ? '#3B82F6' : '#64748B';
  return {
    background: `${color}22`,
    color,
    borderRadius: 3,
    padding: '1px 4px',
    fontSize: 10,
  };
}

function getDotStyle(color: string): CSSProperties {
  return {
    display: 'inline-block',
    width: 8,
    height: 8,
    borderRadius: '50%',
    background: color,
    marginRight: 4,
    verticalAlign: 'middle',
  };
}

function isInDragRange(idx: number, drag: DragState): boolean {
  const min = Math.min(drag.startIdx, drag.endIdx);
  const max = Math.max(drag.startIdx, drag.endIdx);
  return idx >= min && idx <= max;
}

function getDragHighlight(direction: 'check' | 'uncheck'): string {
  return direction === 'check' ? 'rgba(59,130,246,0.18)' : 'rgba(148,163,184,0.12)';
}

export function VesselSelectGrid({ vessels, selectedMmsis, toggleMmsi, setMmsis, sortKey, sortDir, onSort }: VesselSelectGridProps) {
  const [dragState, setDragState] = useState<DragState | null>(null);

  const handleMouseDown = useCallback(
    (idx: number, e: React.MouseEvent) => {
      // 체크박스 직접 클릭은 무시 (기존 onChange 처리)
      if ((e.target as HTMLElement).tagName === 'INPUT') return;
      e.preventDefault();
      const isSelected = selectedMmsis.has(vessels[idx].mmsi);
      setDragState({ startIdx: idx, endIdx: idx, direction: isSelected ? 'uncheck' : 'check' });
    },
    [vessels, selectedMmsis],
  );

  const handleMouseEnter = useCallback(
    (idx: number) => {
      if (!dragState) return;
      setDragState((prev) => (prev ? { ...prev, endIdx: idx } : null));
    },
    [dragState],
  );

  // document-level mouseup: 드래그 종료
  useEffect(() => {
    if (!dragState) return;

    const handleMouseUp = () => {
      const { startIdx, endIdx, direction } = dragState;
      if (startIdx === endIdx) {
        // 단일 클릭
        toggleMmsi(vessels[startIdx].mmsi);
      } else {
        // 범위 선택
        const min = Math.min(startIdx, endIdx);
        const max = Math.max(startIdx, endIdx);
        const newSet = new Set(selectedMmsis);
        for (let i = min; i <= max; i++) {
          const mmsi = vessels[i].mmsi;
          if (direction === 'check') newSet.add(mmsi);
          else newSet.delete(mmsi);
        }
        setMmsis(newSet);
      }
      setDragState(null);
    };

    document.addEventListener('mouseup', handleMouseUp);
    return () => document.removeEventListener('mouseup', handleMouseUp);
  }, [dragState, vessels, selectedMmsis, toggleMmsi, setMmsis]);

  return (
    <table style={{ ...STYLE_TABLE, userSelect: dragState ? 'none' : undefined }}>
      <thead>
        <tr>
          <th style={STYLE_TH_CHECKBOX} />
          <th style={STYLE_TH} onClick={() => onSort('shipCode')}>업종{getSortIndicator('shipCode', sortKey, sortDir)}</th>
          <th style={STYLE_TH} onClick={() => onSort('permitNo')}>등록번호{getSortIndicator('permitNo', sortKey, sortDir)}</th>
          <th style={STYLE_TH} onClick={() => onSort('name')}>선명{getSortIndicator('name', sortKey, sortDir)}</th>
          <th style={STYLE_TH} onClick={() => onSort('mmsi')}>MMSI{getSortIndicator('mmsi', sortKey, sortDir)}</th>
          <th style={STYLE_TH} onClick={() => onSort('sog')}>속력{getSortIndicator('sog', sortKey, sortDir)}</th>
          <th style={STYLE_TH} onClick={() => onSort('state')}>상태{getSortIndicator('state', sortKey, sortDir)}</th>
        </tr>
      </thead>
      <tbody>
        {vessels.map((v, idx) => {
          const isSelected = selectedMmsis.has(v.mmsi);
          const meta = VESSEL_TYPES[v.shipCode];
          const inRange = dragState ? isInDragRange(idx, dragState) : false;

          // 드래그 중 범위 내 행 → 예상 상태 미리보기
          let rowBg: string | undefined;
          if (inRange && dragState) {
            rowBg = getDragHighlight(dragState.direction);
          } else if (isSelected) {
            rowBg = 'rgba(59,130,246,0.12)';
          }

          const tdStyle = getTdStyle(false); // 배경은 tr에서 관리
          const stateBadgeStyle = getStateBadgeStyle(v.state.isFishing, v.state.isTransit);
          const mmsiDisplay = String(v.mmsi);
          const sogDisplay = v.sog !== null ? `${v.sog.toFixed(1)} kt` : '–';

          // 드래그 중 범위 내 체크 상태 미리보기
          const previewChecked = inRange && dragState
            ? dragState.direction === 'check'
            : isSelected;

          return (
            <tr
              key={v.mmsi}
              style={{ cursor: 'pointer', background: rowBg }}
              onMouseDown={(e) => handleMouseDown(idx, e)}
              onMouseEnter={() => handleMouseEnter(idx)}
            >
              <td style={tdStyle}>
                <input
                  type="checkbox"
                  title="선택"
                  checked={previewChecked}
                  onChange={() => toggleMmsi(v.mmsi)}
                  onClick={(e) => e.stopPropagation()}
                  style={{ cursor: 'pointer' }}
                />
              </td>
              <td style={tdStyle}>
                <span style={getDotStyle(meta.color)} />
                {v.shipCode}
              </td>
              <td style={tdStyle}>{v.permitNo}</td>
              <td style={tdStyle}>{v.name}</td>
              <td style={tdStyle}>{mmsiDisplay}</td>
              <td style={tdStyle}>{sogDisplay}</td>
              <td style={tdStyle}>
                <span style={stateBadgeStyle}>{v.state.label}</span>
              </td>
            </tr>
          );
        })}
      </tbody>
    </table>
  );
}