import { useState, useRef, useEffect } from 'react'
import type { Layer } from '../../../data/layerDatabase'

const PRESET_COLORS = [
  '#ef4444','#f97316','#eab308','#22c55e','#06b6d4',
  '#3b82f6','#8b5cf6','#a855f7','#ec4899','#f43f5e',
  '#64748b','#ffffff',
]

interface LayerTreeProps {
  layers: (Layer & { children?: Layer[] })[]
  enabledLayers: Set<string>
  onToggleLayer: (layerId: string, enabled: boolean) => void
  layerColors?: Record<string, string>
  onColorChange?: (layerId: string, color: string) => void
}

export function LayerTree({ layers, enabledLayers, onToggleLayer, layerColors = {}, onColorChange }: LayerTreeProps) {
  const allLeafIds = getAllLeafIds(layers)
  const allEnabled = allLeafIds.length > 0 && allLeafIds.every(id => enabledLayers.has(id))

  const handleToggleAll = () => {
    const newState = !allEnabled
    getAllNodeIds(layers).forEach(id => onToggleLayer(id, newState))
  }

  return (
    <div style={{ padding: '0 4px' }}>
      <div style={{
        display: 'flex', alignItems: 'center', justifyContent: 'space-between',
        padding: '4px 8px 8px', marginBottom: '4px',
        borderBottom: '1px solid var(--bd)',
      }}>
        <span style={{ fontSize: '10px', fontWeight: 600, color: 'var(--t3)', fontFamily: 'var(--fK)' }}>
          전체 레이어
        </span>
        <div
          className={`lyr-sw ${allEnabled ? 'on' : ''}`}
          onClick={handleToggleAll}
          style={{ cursor: 'pointer' }}
        />
      </div>

      {layers.map(layer => (
        <LayerNode
          key={layer.id}
          layer={layer}
          enabledLayers={enabledLayers}
          onToggleLayer={onToggleLayer}
          layerColors={layerColors}
          onColorChange={onColorChange}
          depth={0}
        />
      ))}
    </div>
  )
}

function getAllLeafIds(layers: (Layer & { children?: Layer[] })[]): string[] {
  const ids: string[] = []
  for (const l of layers) {
    if (l.children && l.children.length > 0) {
      ids.push(...getAllLeafIds(l.children))
    } else {
      ids.push(l.id)
    }
  }
  return ids
}

function getAllNodeIds(layers: (Layer & { children?: Layer[] })[]): string[] {
  const ids: string[] = []
  for (const l of layers) {
    ids.push(l.id)
    if (l.children && l.children.length > 0) {
      ids.push(...getAllNodeIds(l.children))
    }
  }
  return ids
}

interface LayerNodeProps {
  layer: Layer & { children?: Layer[] }
  enabledLayers: Set<string>
  onToggleLayer: (layerId: string, enabled: boolean) => void
  layerColors: Record<string, string>
  onColorChange?: (layerId: string, color: string) => void
  depth: number
}

function LayerNode({ layer, enabledLayers, onToggleLayer, layerColors, onColorChange, depth }: LayerNodeProps) {
  const [expanded, setExpanded] = useState(depth < 1)
  const hasChildren = layer.children && layer.children.length > 0
  const isEnabled = enabledLayers.has(layer.id)

  const getAllDescendantIds = (node: Layer & { children?: Layer[] }): string[] => {
    const ids: string[] = []
    if (node.children) {
      for (const child of node.children) {
        ids.push(child.id)
        ids.push(...getAllDescendantIds(child))
      }
    }
    return ids
  }

  const handleSwitchClick = (e: React.MouseEvent) => {
    e.stopPropagation()
    const newState = !isEnabled
    onToggleLayer(layer.id, newState)
    if (hasChildren) {
      getAllDescendantIds(layer).forEach(id => onToggleLayer(id, newState))
    }
  }

  const handleHeaderClick = () => {
    if (hasChildren) setExpanded(!expanded)
  }

  // depth 0 — 대분류 (lyr-g1 / lyr-h1)
  if (depth === 0) {
    return (
      <div className="lyr-g1">
        <div className="lyr-h1" onClick={handleHeaderClick}>
          {hasChildren ? (
            <span className={`lyr-arr ${expanded ? 'open' : ''}`}>▶</span>
          ) : (
            <span className="lyr-arr" style={{ visibility: 'hidden' }}>▶</span>
          )}
          <div className={`lyr-sw ${isEnabled ? 'on' : ''}`} onClick={handleSwitchClick} />
          {layer.icon && <span>{layer.icon}</span>}
          {layer.name}
          {layer.count !== undefined && (
            <span className="lyr-h1-cnt">{layer.count.toLocaleString()}</span>
          )}
        </div>
        {hasChildren && (
          <div className={`lyr-c1 ${expanded ? '' : 'collapsed'}`} style={{ maxHeight: expanded ? '800px' : '0' }}>
            {layer.children!.map(child => (
              <LayerNode key={child.id} layer={child} enabledLayers={enabledLayers} onToggleLayer={onToggleLayer} layerColors={layerColors} onColorChange={onColorChange} depth={depth + 1} />
            ))}
          </div>
        )}
      </div>
    )
  }

  // depth 1 — 중분류 (lyr-g2 / lyr-h2) 또는 leaf
  if (depth === 1) {
    // 자식 없는 depth 1 → leaf로 렌더링 (해양관측·기상 하위 등)
    if (!hasChildren) {
      return (
        <div className="lyr-t" onClick={(e) => { if (!(e.target as HTMLElement).closest('.lyr-csw, .lyr-cpop')) handleSwitchClick(e) }}>
          <div className={`lyr-sw ${isEnabled ? 'on' : ''}`} />
          {layer.icon && <span>{layer.icon}</span>}
          <span style={{ flex: 1 }}>{layer.name}</span>
          {layer.count !== undefined && <span className="lyr-cnt">{layer.count.toLocaleString()}</span>}
          {onColorChange && (
            <ColorSwatch color={layerColors[layer.id]} onChange={(c) => onColorChange(layer.id, c)} />
          )}
        </div>
      )
    }

    return (
      <div className="lyr-g2">
        <div className="lyr-h2" onClick={handleHeaderClick}>
          {hasChildren ? (
            <span className={`lyr-arr ${expanded ? 'open' : ''}`}>▶</span>
          ) : (
            <span className="lyr-arr" style={{ visibility: 'hidden' }}>▶</span>
          )}
          <div className={`lyr-sw ${isEnabled ? 'on' : ''}`} onClick={handleSwitchClick} />
          {layer.icon && <span>{layer.icon}</span>}
          {layer.name}
          {layer.count !== undefined && (
            <span className="lyr-h2-cnt">{layer.count.toLocaleString()}</span>
          )}
        </div>
        <div className={`lyr-c2 ${expanded ? '' : 'collapsed'}`} style={{ maxHeight: expanded ? '600px' : '0' }}>
          {layer.children!.map(child => (
            <LayerNode key={child.id} layer={child} enabledLayers={enabledLayers} onToggleLayer={onToggleLayer} layerColors={layerColors} onColorChange={onColorChange} depth={depth + 1} />
          ))}
        </div>
      </div>
    )
  }

  // depth 2+ leaf — 색상 스와치 포함
  if (!hasChildren) {
    return (
      <div className="lyr-t" onClick={(e) => { if (!(e.target as HTMLElement).closest('.lyr-csw, .lyr-cpop')) handleSwitchClick(e) }}>
        <div className={`lyr-sw ${isEnabled ? 'on' : ''}`} />
        {layer.icon && <span>{layer.icon}</span>}
        <span style={{ flex: 1 }}>{layer.name}</span>
        {layer.count !== undefined && <span className="lyr-cnt">{layer.count.toLocaleString()}</span>}
        {onColorChange && (
          <ColorSwatch color={layerColors[layer.id]} onChange={(c) => onColorChange(layer.id, c)} />
        )}
      </div>
    )
  }

  // depth 2+ with children
  return (
    <div>
      <div className="lyr-t" style={{ gap: '6px' }}>
        <span className={`lyr-arr ${expanded ? 'open' : ''}`} onClick={handleHeaderClick} style={{ cursor: 'pointer', fontSize: '7px', width: '10px', textAlign: 'center' }}>▶</span>
        <div className={`lyr-sw ${isEnabled ? 'on' : ''}`} onClick={handleSwitchClick} />
        {layer.icon && <span>{layer.icon}</span>}
        <span onClick={handleHeaderClick} style={{ cursor: 'pointer', flex: 1 }}>{layer.name}</span>
        {layer.count !== undefined && <span className="lyr-cnt">{layer.count.toLocaleString()}</span>}
      </div>
      {expanded && (
        <div style={{ paddingLeft: '16px' }}>
          {layer.children!.map(child => (
            <LayerNode key={child.id} layer={child} enabledLayers={enabledLayers} onToggleLayer={onToggleLayer} layerColors={layerColors} onColorChange={onColorChange} depth={depth + 1} />
          ))}
        </div>
      )}
    </div>
  )
}

// 색상 스와치 + 피커
function ColorSwatch({ color, onChange }: { color?: string; onChange: (c: string) => void }) {
  const [open, setOpen] = useState(false)
  const ref = useRef<HTMLDivElement>(null)

  useEffect(() => {
    if (!open) return
    const handler = (e: MouseEvent) => {
      if (ref.current && !ref.current.contains(e.target as Node)) setOpen(false)
    }
    document.addEventListener('mousedown', handler)
    return () => document.removeEventListener('mousedown', handler)
  }, [open])

  return (
    <div ref={ref} style={{ position: 'relative', flexShrink: 0 }}>
      <div
        className={`lyr-csw ${color ? 'has-color' : ''}`}
        style={color ? { borderColor: color, background: color } : {}}
        onClick={(e) => { e.stopPropagation(); setOpen(!open) }}
      />
      {open && (
        <div className="lyr-cpop show" onClick={(e) => e.stopPropagation()}>
          <div className="lyr-cpr">
            {PRESET_COLORS.map(pc => (
              <div
                key={pc}
                className={`lyr-cpr-i ${color === pc ? 'sel' : ''}`}
                style={{ background: pc }}
                onClick={() => { onChange(pc); setOpen(false) }}
              />
            ))}
          </div>
          <div className="lyr-ccustom">
            <label>커스텀</label>
            <input
              type="color"
              value={color || '#06b6d4'}
              onChange={(e) => { onChange(e.target.value); setOpen(false) }}
            />
          </div>
        </div>
      )}
    </div>
  )
}