import React, { useRef, useState, useMemo } from 'react';
import { AppConfig, LayoutSplits, Partition } from '../types';
// ИСПРАВЛЕНИЕ: Добавлена иконка Move в импорты
import { Grid, MousePointer2, Trash2, RotateCcw, X, Plus, Move } from 'lucide-react';

interface Props {
  config: AppConfig;
  splits: LayoutSplits;
  onChange: (splits: LayoutSplits) => void;
}

type EditMode = 'lines' | 'cells';
type Axis = 'x' | 'y';

// Тип для перетаскивания
type DragTarget = 
  | { type: 'main'; axis: Axis; index: number }
  | { type: 'partition'; cellKey: string; id: string; axis: Axis };

export const LayoutStep: React.FC<Props> = ({ config, splits, onChange }) => {
  const svgRef = useRef<SVGSVGElement>(null);
  
  const [mode, setMode] = useState<EditMode>('lines');
  
  // Мышь и состояния
  const [mousePos, setMousePos] = useState({ x: 0, y: 0 }); 
  const [isButtonHovered, setIsButtonHovered] = useState(false);
  
  // Main Grid States
  const [phantomMainAxis, setPhantomMainAxis] = useState<Axis | null>(null);
  const [hoveredMainSplit, setHoveredMainSplit] = useState<{ axis: Axis; index: number } | null>(null);

  // Partition States
  const [hoveredCell, setHoveredCell] = useState<{ i: number; j: number } | null>(null);
  const [hoveredPartition, setHoveredPartition] = useState<{ id: string; cellKey: string } | null>(null);
  const [phantomPartition, setPhantomPartition] = useState<{ axis: Axis; offset: number } | null>(null);
  
  // Selection & Dragging
  const [selectedPartitionId, setSelectedPartitionId] = useState<string | null>(null);
  const [dragging, setDragging] = useState<DragTarget | null>(null);

  // --- Safe Data Access ---
  const safeX = Array.isArray(splits?.x) ? splits.x : [];
  const safeY = Array.isArray(splits?.y) ? splits.y : [];
  const safePartitions = splits?.partitions || {};

  // --- Dimensions & Aspect Ratio ---
  const drawerW = Math.max(1, config.drawer.width || 300);
  const drawerD = Math.max(1, config.drawer.depth || 400);
  const aspectRatio = drawerD / drawerW;

  // ViewBox (internal SVG coordinates)
  const viewBoxW = 1000;
  const viewBoxH = viewBoxW * aspectRatio;

  const sortedX = useMemo(() => [0, ...safeX, 1].sort((a, b) => a - b), [safeX]);
  const sortedY = useMemo(() => [0, ...safeY, 1].sort((a, b) => a - b), [safeY]);

  // --- Helper: Get Partition Data ---
  const getSelectedPartition = () => {
      if (!selectedPartitionId) return null;
      for (const key in safePartitions) {
          const part = safePartitions[key].find(p => p.id === selectedPartitionId);
          if (part) return { key, part };
      }
      return null;
  };
  const selectedData = getSelectedPartition();

  // --- ACTIONS: MAIN GRID ---
  const removeMainSplit = (axis: Axis, index: number) => {
    const newSplits = { ...splits, x: [...safeX], y: [...safeY] };
    newSplits[axis] = newSplits[axis].filter((_, i) => i !== index);
    onChange(newSplits);
    setHoveredMainSplit(null);
    setDragging(null);
    setIsButtonHovered(false);
  };

  // --- ACTIONS: PARTITIONS ---
  const createPartition = (i: number, j: number, axis: Axis, offset: number) => {
      const key = `${i}-${j}`;
      const current = safePartitions[key] || [];
      const newPart: Partition = {
          id: Math.random().toString(36).substr(2, 9),
          axis,
          offset,
          height: config.drawer.height || 80,
          rounded: false
      };
      onChange({ ...splits, partitions: { ...safePartitions, [key]: [...current, newPart] } });
      setSelectedPartitionId(newPart.id);
  };

  const updatePartition = (key: string, id: string, updates: Partial<Partition>) => {
      const current = safePartitions[key] || [];
      const updated = current.map(p => p.id === id ? { ...p, ...updates } : p);
      onChange({ ...splits, partitions: { ...safePartitions, [key]: updated } });
  };

  const removePartition = (key: string, id: string) => {
      const current = safePartitions[key] || [];
      onChange({ ...splits, partitions: { ...safePartitions, [key]: current.filter(p => p.id !== id) } });
      if (selectedPartitionId === id) setSelectedPartitionId(null);
      setHoveredPartition(null);
  };

  // --- MOUSE HANDLER ---
  const handleMouseMove = (e: React.MouseEvent) => {
    if (!svgRef.current) return;
    const rect = svgRef.current.getBoundingClientRect();
    if (rect.width === 0) return;

    // Normalize coordinates (0 to 1)
    const nx = Math.max(0, Math.min(1, (e.clientX - rect.left) / rect.width));
    const ny = Math.max(0, Math.min(1, (e.clientY - rect.top) / rect.height));
    setMousePos({ x: nx, y: ny });

    // --- DRAGGING LOGIC ---
    if (dragging) {
        if (dragging.type === 'main') {
            const newSplits = { ...splits, x: [...safeX], y: [...safeY] };
            const val = dragging.axis === 'x' ? nx : ny;
            newSplits[dragging.axis][dragging.index] = val;
            onChange(newSplits);
        } else {
            // Dragging Partition
            const pDrag = dragging as { type: 'partition'; cellKey: string; id: string; axis: Axis };
            const [iStr, jStr] = pDrag.cellKey.split('-');
            const i = parseInt(iStr); const j = parseInt(jStr);
            
            const cellX1 = sortedX[i]; const cellX2 = sortedX[i+1];
            const cellY1 = sortedY[j]; const cellY2 = sortedY[j+1];
            
            let newOffset = 0;
            if (pDrag.axis === 'x') {
                newOffset = (nx - cellX1) / (cellX2 - cellX1);
            } else {
                newOffset = (ny - cellY1) / (cellY2 - cellY1);
            }
            newOffset = Math.max(0.05, Math.min(0.95, newOffset));
            updatePartition(pDrag.cellKey, pDrag.id, { offset: newOffset });
        }
        return;
    }

    if (isButtonHovered) return;

    // --- HOVER LOGIC: MAIN LINES ---
    if (mode === 'lines') {
        setHoveredMainSplit(null);
        const SNAP = 0.015; 
        
        // Phantom Line
        if (nx > SNAP && nx < 1-SNAP && ny > SNAP && ny < 1-SNAP) {
             const closeToX = safeX.some(val => Math.abs(nx - val) < SNAP);
             const closeToY = safeY.some(val => Math.abs(ny - val) < SNAP);
             if (!closeToX && !closeToY) {
                 const distRight = 1 - nx; const distBottom = 1 - ny;
                 setPhantomMainAxis(Math.min(nx, distRight) < Math.min(ny, distBottom) ? 'y' : 'x');
             } else { setPhantomMainAxis(null); }
        }
    } 
    
    // --- HOVER LOGIC: PARTITIONS ---
    else if (mode === 'cells') {
        setHoveredPartition(null);
        setPhantomPartition(null);
        setHoveredCell(null);

        // 1. Find which cell we are in
        let cellIndex = null;
        for(let i=0; i<sortedX.length-1; i++) {
            if (nx >= sortedX[i] && nx <= sortedX[i+1]) {
                for(let j=0; j<sortedY.length-1; j++) {
                    if (ny >= sortedY[j] && ny <= sortedY[j+1]) {
                        cellIndex = { i, j };
                        break;
                    }
                }
            }
        }

        if (cellIndex) {
            setHoveredCell(cellIndex);
            const key = `${cellIndex.i}-${cellIndex.j}`;
            const parts = safePartitions[key] || [];
            
            const cx1 = sortedX[cellIndex.i]; const cx2 = sortedX[cellIndex.i+1];
            const cy1 = sortedY[cellIndex.j]; const cy2 = sortedY[cellIndex.j+1];
            const cw = cx2 - cx1; const ch = cy2 - cy1;

            // Local coords in cell (0..1)
            const lx = (nx - cx1) / cw;
            const ly = (ny - cy1) / ch;

            // Check existing partitions
            let foundPart = null;
            const PART_SNAP = 0.05; 

            for (const p of parts) {
                if (p.axis === 'x') {
                    if (Math.abs(lx - p.offset) < PART_SNAP * (aspectRatio > 1 ? 1 : aspectRatio)) foundPart = p;
                } else {
                    if (Math.abs(ly - p.offset) < PART_SNAP * (aspectRatio < 1 ? 1 : 1/aspectRatio)) foundPart = p;
                }
            }

            if (foundPart) {
                setHoveredPartition({ id: foundPart.id, cellKey: key });
            } else {
                // Show Phantom Partition
                const distLeft = lx; const distRight = 1 - lx;
                const distTop = ly; const distBottom = 1 - ly;
                const minX = Math.min(distLeft, distRight);
                const minY = Math.min(distTop, distBottom);
                
                const axis = minX < minY ? 'y' : 'x'; 
                
                if (lx > 0.05 && lx < 0.95 && ly > 0.05 && ly < 0.95) {
                    setPhantomPartition({ axis, offset: axis === 'x' ? lx : ly });
                }
            }
        }
    }
  };

  const handleMouseDown = (e: React.MouseEvent) => {
    if (isButtonHovered) return;

    if (mode === 'lines') {
        if (hoveredMainSplit) {
            if (e.button === 0) setDragging({ type: 'main', ...hoveredMainSplit });
            else if (e.button === 2) removeMainSplit(hoveredMainSplit.axis, hoveredMainSplit.index);
        } else if (phantomMainAxis) {
            const val = phantomMainAxis === 'x' ? mousePos.x : mousePos.y;
            const newSplits = { ...splits, x: [...safeX], y: [...safeY] };
            newSplits[phantomMainAxis] = [...newSplits[phantomMainAxis], val];
            onChange(newSplits);
            setDragging({ type: 'main', axis: phantomMainAxis, index: newSplits[phantomMainAxis].length - 1 });
        }
    } 
    else if (mode === 'cells') {
        if (hoveredPartition) {
            const key = hoveredPartition.cellKey;
            const parts = safePartitions[key] || [];
            const part = parts.find(p => p.id === hoveredPartition.id);
            if (part) {
                if (e.button === 0) {
                    setDragging({ type: 'partition', cellKey: key, id: part.id, axis: part.axis });
                    setSelectedPartitionId(part.id);
                } else if (e.button === 2) {
                    removePartition(key, part.id);
                }
            }
        } else if (hoveredCell && phantomPartition) {
            if (e.button === 0) {
                createPartition(hoveredCell.i, hoveredCell.j, phantomPartition.axis, phantomPartition.offset);
            }
        } else {
            setSelectedPartitionId(null);
        }
    }
  };

  const handleMainSplitHover = (e: React.MouseEvent, axis: Axis, index: number) => {
      if (mode !== 'lines' || dragging) return;
      e.stopPropagation();
      setHoveredMainSplit({ axis, index });
      setPhantomMainAxis(null);
  };

  return (
    <div className="bg-slate-900 p-4 rounded-xl shadow-lg border border-slate-800 h-full flex flex-col relative overflow-hidden">
      
      {/* HEADER */}
      <div className="flex justify-between items-center mb-2 z-20 shrink-0">
        <h2 className="text-lg font-bold flex items-center gap-2 text-primary">
          <Grid size={20} /> 2. Редактор макета
        </h2>
        
        <div className="flex bg-slate-800 p-1 rounded-lg border border-slate-700">
            <button onClick={() => { setMode('lines'); setSelectedPartitionId(null); }} 
                className={`flex items-center gap-2 px-3 py-1.5 rounded-md text-xs font-bold transition-all ${mode === 'lines' ? 'bg-primary text-white shadow' : 'text-gray-400 hover:text-gray-200'}`}>
               <Move size={14}/> Границы
            </button>
            <button onClick={() => setMode('cells')} 
                className={`flex items-center gap-2 px-3 py-1.5 rounded-md text-xs font-bold transition-all ${mode === 'cells' ? 'bg-primary text-white shadow' : 'text-gray-400 hover:text-gray-200'}`}>
               <Grid size={14}/> Внутри ячеек
            </button>
        </div>

        <button onClick={() => onChange({ x: [], y: [], partitions: {} })} className="px-3 py-1.5 text-xs text-red-400 border border-slate-700 rounded hover:bg-slate-800 transition-colors flex items-center gap-1">
            <RotateCcw size={14} /> Сброс
        </button>
      </div>

      {/* --- INSTRUCTIONS --- */}
      <div className="bg-slate-800/50 rounded-lg px-3 py-2 mb-2 flex items-center gap-3 text-[11px] text-gray-300 border border-slate-700/50 shrink-0">
          <MousePointer2 size={14} className="text-primary" />
          {mode === 'lines' ? (
              <div className="flex gap-3">
                  <span><b className="text-blue-400">ЛКМ:</b> Создать/Тянуть линию</span>
                  <span><b className="text-red-400">ПКМ:</b> Удалить</span>
              </div>
          ) : (
              <div className="flex gap-3">
                  <span><b className="text-green-400">ЛКМ в ячейке:</b> Создать стенку</span>
                  <span><b className="text-purple-400">Драг:</b> Двигать</span>
                  <span><b className="text-red-400">2xЛКМ:</b> Удалить</span>
              </div>
          )}
      </div>

      {/* --- CANVAS --- */}
      <div className="flex-1 bg-slate-800/30 rounded-lg flex flex-col items-center justify-center relative overflow-hidden border border-slate-700/50 min-h-0 w-full">
            <div className="relative w-full h-full flex items-center justify-center p-4">
                <div 
                    className="relative shadow-2xl bg-[#1e293b] border border-slate-600 rounded-sm overflow-hidden"
                    style={{ 
                        width: aspectRatio > 1 ? 'auto' : '100%',
                        height: aspectRatio > 1 ? '100%' : 'auto',
                        aspectRatio: `${1/aspectRatio}`,
                        maxHeight: '100%', maxWidth: '100%',
                        cursor: mode === 'lines' ? (dragging ? 'grabbing' : hoveredMainSplit ? 'col-resize' : 'crosshair') 
                               : (dragging ? 'grabbing' : hoveredPartition ? 'grab' : hoveredCell ? 'crosshair' : 'default'),
                    }}
                >   
                   <svg 
                      ref={svgRef} 
                      viewBox={`0 0 ${viewBoxW} ${viewBoxH}`} 
                      className="w-full h-full touch-none block"
                      preserveAspectRatio="none"
                      onMouseMove={handleMouseMove} 
                      onMouseDown={handleMouseDown} 
                      onMouseUp={() => setDragging(null)} 
                      onMouseLeave={() => setDragging(null)} 
                      onContextMenu={(e) => e.preventDefault()}
                   >
                      <defs>
                          <pattern id="grid" width="50" height="50" patternUnits="userSpaceOnUse">
                              <path d="M 50 0 L 0 0 0 50" fill="none" stroke="rgba(255,255,255,0.03)" strokeWidth="1"/>
                          </pattern>
                      </defs>
                      <rect width="100%" height="100%" fill="url(#grid)" />

                      {/* --- CELLS & PARTITIONS --- */}
                      {sortedX.slice(0, -1).map((x1, i) => {
                          const x2 = sortedX[i + 1];
                          return sortedY.slice(0, -1).map((y1, j) => {
                              const y2 = sortedY[j + 1];
                              const cellX = x1 * viewBoxW; const cellY = y1 * viewBoxH;
                              const cellW = (x2 - x1) * viewBoxW; const cellH = (y2 - y1) * viewBoxH;
                              
                              const key = `${i}-${j}`;
                              const parts = safePartitions[key] || [];
                              const isHovered = hoveredCell?.i === i && hoveredCell?.j === j && mode === 'cells';
                              const isAnyPartSelected = parts.some(p => p.id === selectedPartitionId);

                              return (
                                  <g key={`cell-${key}`}>
                                      {/* Highlight Cell */}
                                      {isHovered && <rect x={cellX} y={cellY} width={cellW} height={cellH} fill="rgba(16, 185, 129, 0.05)" stroke="#10b981" strokeWidth="2" strokeDasharray="4,4" className="pointer-events-none"/>}
                                      {isAnyPartSelected && mode === 'cells' && <rect x={cellX} y={cellY} width={cellW} height={cellH} fill="transparent" stroke="#a855f7" strokeWidth="2" className="pointer-events-none opacity-50"/>}
                                      
                                      {/* Existing Partitions */}
                                      {parts.map(p => {
                                          const isSelected = selectedPartitionId === p.id;
                                          const isHoveredPart = hoveredPartition?.id === p.id;
                                          let lx1, ly1, lx2, ly2;
                                          if (p.axis === 'x') { const px = cellX + (cellW * p.offset); lx1 = px; ly1 = cellY; lx2 = px; ly2 = cellY + cellH; } 
                                          else { const py = cellY + (cellH * p.offset); lx1 = cellX; ly1 = py; lx2 = cellX + cellW; ly2 = py; }

                                          return (
                                              <g key={p.id} onDoubleClick={(e) => { e.stopPropagation(); removePartition(key, p.id); }}>
                                                  <line x1={lx1} y1={ly1} x2={lx2} y2={ly2} stroke="transparent" strokeWidth="30" />
                                                  <line x1={lx1} y1={ly1} x2={lx2} y2={ly2} stroke={isSelected ? "#a855f7" : (isHoveredPart ? "#d8b4fe" : "#7e22ce")} strokeWidth={isSelected ? 6 : 4} strokeLinecap="round" />
                                              </g>
                                          );
                                      })}

                                      {/* Phantom Partition */}
                                      {isHovered && phantomPartition && !hoveredPartition && !dragging && (
                                          <g className="pointer-events-none opacity-60">
                                              {phantomPartition.axis === 'x' ? 
                                                  <line x1={cellX + (cellW * phantomPartition.offset)} y1={cellY} x2={cellX + (cellW * phantomPartition.offset)} y2={cellY + cellH} stroke="#34d399" strokeWidth="3" strokeDasharray="6,6"/> : 
                                                  <line x1={cellX} y1={cellY + (cellH * phantomPartition.offset)} x2={cellX + cellW} y2={cellY + (cellH * phantomPartition.offset)} stroke="#34d399" strokeWidth="3" strokeDasharray="6,6"/>
                                              }
                                          </g>
                                      )}
                                  </g>
                              );
                          });
                      })}

                      {/* --- MAIN GRID X --- */}
                      {safeX.map((x, i) => {
                          const isHovered = hoveredMainSplit?.axis === 'x' && hoveredMainSplit.index === i;
                          return (
                            <g key={`x-${i}`} 
                               onMouseMove={(e) => { if(mode === 'lines' && !dragging) { e.stopPropagation(); setHoveredMainSplit({axis: 'x', index: i}); setPhantomMainAxis(null); }}}
                               onDoubleClick={(e) => { e.stopPropagation(); removeMainSplit('x', i); }}
                            >
                                <line x1={x * viewBoxW} y1="0" x2={x * viewBoxW} y2="100%" stroke="transparent" strokeWidth="40" className={mode === 'lines' ? "cursor-col-resize" : ""} />
                                <line x1={x * viewBoxW} y1="0" x2={x * viewBoxW} y2="100%" stroke={isHovered ? "#f59e0b" : "#64748b"} strokeWidth={isHovered ? 6 : 4} className="pointer-events-none" />
                            </g>
                          );
                      })}

                      {/* --- MAIN GRID Y --- */}
                      {safeY.map((y, i) => {
                          const isHovered = hoveredMainSplit?.axis === 'y' && hoveredMainSplit.index === i;
                          return (
                            <g key={`y-${i}`} 
                               onMouseMove={(e) => { if(mode === 'lines' && !dragging) { e.stopPropagation(); setHoveredMainSplit({axis: 'y', index: i}); setPhantomMainAxis(null); }}}
                               onDoubleClick={(e) => { e.stopPropagation(); removeMainSplit('y', i); }}
                            >
                                <line x1="0" y1={y * viewBoxH} x2="100%" y2={y * viewBoxH} stroke="transparent" strokeWidth="40" className={mode === 'lines' ? "cursor-row-resize" : ""} />
                                <line x1="0" y1={y * viewBoxH} x2="100%" y2={y * viewBoxH} stroke={isHovered ? "#f59e0b" : "#64748b"} strokeWidth={isHovered ? 6 : 4} className="pointer-events-none" />
                            </g>
                          );
                      })}

                      {/* PHANTOMS */}
                      {mode === 'lines' && !hoveredMainSplit && !dragging && phantomMainAxis === 'x' && <line x1={mousePos.x * viewBoxW} y1="0" x2={mousePos.x * viewBoxW} y2="100%" stroke="#3b82f6" strokeWidth="4" strokeDasharray="8,8" className="pointer-events-none opacity-50"/>}
                      {mode === 'lines' && !hoveredMainSplit && !dragging && phantomMainAxis === 'y' && <line x1="0" y1={mousePos.y * viewBoxH} x2="100%" y2={mousePos.y * viewBoxH} stroke="#3b82f6" strokeWidth="4" strokeDasharray="8,8" className="pointer-events-none opacity-50"/>}
                   </svg>
                </div>
            </div>

            {/* --- SIDEBAR --- */}
            {mode === 'cells' && selectedData && (
                <div className="absolute top-0 right-0 bottom-0 w-72 bg-slate-900 border-l border-slate-700 p-4 shadow-2xl flex flex-col z-30 animate-in slide-in-from-right duration-200">
                    <div className="flex justify-between items-center mb-6">
                        <h3 className="text-sm font-bold text-white flex items-center gap-2">
                            <Grid size={16} className="text-purple-400"/> Настройки стенки
                        </h3>
                        <button onClick={() => setSelectedPartitionId(null)} className="text-gray-400 hover:text-white"><X size={20}/></button>
                    </div>

                    <div className="bg-slate-800 p-4 rounded border border-slate-700 space-y-6">
                        <div>
                            <div className="flex justify-between text-xs text-gray-300 mb-2">
                                <span>Высота</span> <span className="font-mono bg-slate-900 px-1.5 py-0.5 rounded text-xs">{selectedData.part.height} мм</span>
                            </div>
                            <input type="range" min="5" max={config.drawer.height || 100} step="1" value={selectedData.part.height}
                                onChange={(e) => updatePartition(selectedData.key, selectedData.part.id, { height: parseFloat(e.target.value) })}
                                className="w-full h-1 bg-slate-600 rounded-lg appearance-none cursor-pointer accent-purple-500"
                            />
                        </div>
                        <div className="flex items-center justify-between">
                            <label htmlFor="rounded-check" className="text-xs text-gray-300 cursor-pointer select-none">Скруглить края</label>
                            <input type="checkbox" id="rounded-check" checked={selectedData.part.rounded}
                                onChange={(e) => updatePartition(selectedData.key, selectedData.part.id, { rounded: e.target.checked })}
                                className="w-4 h-4 rounded bg-slate-700 border-slate-600 text-purple-500 focus:ring-0 cursor-pointer"
                            />
                        </div>
                        <button onClick={() => removePartition(selectedData.key, selectedData.part.id)} className="w-full py-2 bg-red-500/10 hover:bg-red-500/20 text-red-400 border border-red-500/30 rounded text-xs flex items-center justify-center gap-2 transition-colors mt-4">
                            <Trash2 size={14}/> Удалить
                        </button>
                    </div>
                    <div className="mt-auto text-[10px] text-gray-500 text-center leading-relaxed">
                        Выделите стенку для настройки.<br/>Двойной клик удаляет её.
                    </div>
                </div>
            )}
        </div>
      </div>
    </div>
  );
};