'use client'

import { useEffect, useState, useCallback } from 'react'
import ReactFlow, {
  Node,
  Edge,
  Background,
  Controls,
  MiniMap,
  useNodesState,
  useEdgesState,
  ConnectionMode,
} from 'reactflow'
import 'reactflow/dist/style.css'

interface Cluster {
  clusterId: number
  name?: string
  noteIds: string[]
}

interface BridgeNote {
  noteId: string
  bridgeScore: number
  clustersConnected: number[]
  note?: {
    id: string
    title: string | null
    content: string
  }
}

interface ClusterVisualizationProps {
  clusters: Cluster[]
  bridgeNotes: BridgeNote[]
  onNodeClick?: (nodeId: string, type: 'note' | 'cluster') => void
}

// Generate HSL colors for clusters
function generateClusterColor(clusterId: number, totalClusters: number): string {
  const hue = (clusterId * 360 / totalClusters) % 360
  return `hsl(${hue}, 70%, 60%)`
}

export function ClusterVisualization({
  clusters,
  bridgeNotes,
  onNodeClick
}: ClusterVisualizationProps) {
  const [nodes, setNodes, onNodesChange] = useNodesState([])
  const [edges, setEdges, onEdgesChange] = useEdgesState([])
  const [selectedCluster, setSelectedCluster] = useState<number | null>(null)

  // Build graph from clusters and bridge notes
  useEffect(() => {
    if (clusters.length === 0) return

    const newNodes: Node[] = []
    const newEdges: Edge[] = []
    const noteToCluster = new Map<string, number>()

    const clusterColor = generateClusterColor

    // Create cluster nodes and position notes around them
    const clusterCenterX = 200
    const clusterCenterY = 200
    const clusterSpacing = 400

    clusters.forEach((cluster, clusterIndex) => {
      const cx = clusterCenterX + (clusterIndex % 4) * clusterSpacing
      const cy = clusterCenterY + Math.floor(clusterIndex / 4) * clusterSpacing
      const color = clusterColor(cluster.clusterId, clusters.length)

      // Add cluster label node
      newNodes.push({
        id: `cluster-${cluster.clusterId}`,
        type: 'default',
        position: { x: cx, y: cy - 150 },
        data: {
          label: (
            <div className="px-3 py-1 rounded-full text-sm font-medium" style={{ backgroundColor: color }}>
              {cluster.name || `Cluster ${cluster.clusterId}`}
              <span className="ml-2 text-xs opacity-75">({cluster.noteIds.length} notes)</span>
            </div>
          )
        },
        style: {
          background: 'transparent',
          border: 'none',
        },
        className: 'cursor-pointer'
      })

      // Add note nodes for this cluster
      const noteRadius = 120
      cluster.noteIds.forEach((noteId, noteIndex) => {
        const angle = (noteIndex / cluster.noteIds.length) * 2 * Math.PI
        const nx = cx + Math.cos(angle) * noteRadius
        const ny = cy + Math.sin(angle) * noteRadius

        noteToCluster.set(noteId, cluster.clusterId)

        // Check if this is a bridge note
        const bridge = bridgeNotes.find(b => b.noteId === noteId)
        const isBridge = !!bridge

        newNodes.push({
          id: noteId,
          type: 'default',
          position: { x: nx, y: ny },
          data: {
            label: bridge?.note?.title || noteId.slice(0, 8)
          },
          style: {
            background: isBridge ? '#FFD700' : color,
            border: isBridge ? '3px solid #B8860B' : '2px solid rgba(0,0,0,0.1)',
            borderRadius: '50%',
            width: isBridge ? 50 : 35,
            height: isBridge ? 50 : 35,
            fontSize: '10px',
            fontWeight: isBridge ? 'bold' : 'normal'
          },
          className: `cursor-pointer transition-transform hover:scale-110 ${isBridge ? 'shadow-lg' : ''}`
        })
      })
    })

    // Create edges between bridge notes and their connected clusters
    bridgeNotes.forEach(bridge => {
      const bridgeNodeId = bridge.noteId
      const bridgeNode = newNodes.find(n => n.id === bridgeNodeId)

      if (!bridgeNode) return

      bridge.clustersConnected.forEach(clusterId => {
        const clusterLabelId = `cluster-${clusterId}`
        if (clusterLabelId !== bridgeNodeId) {
          newEdges.push({
            id: `${bridgeNodeId}-${clusterId}`,
            source: bridgeNodeId,
            target: clusterLabelId,
            type: 'smoothstep',
            animated: true,
            style: {
              stroke: '#FFD700',
              strokeWidth: 2
            },
            label: 'bridge'
          })
        }
      })
    })

    setNodes(newNodes)
    setEdges(newEdges)
  }, [clusters, bridgeNotes, setNodes, setEdges])

  const onNodeClickHandler = useCallback((event: React.MouseEvent, node: Node) => {
    const id = node.id

    if (id.startsWith('cluster-')) {
      const clusterId = parseInt(id.replace('cluster-', ''))
      setSelectedCluster(clusterId === selectedCluster ? null : clusterId)
      onNodeClick?.(id, 'cluster')
    } else {
      onNodeClick?.(id, 'note')
    }
  }, [selectedCluster, onNodeClick])

  if (clusters.length === 0) {
    return (
      <div className="flex items-center justify-center h-64 text-gray-500">
        <div className="text-center">
          <svg className="w-16 h-16 mx-auto mb-4 opacity-50" fill="none" viewBox="0 0 24 24" stroke="currentColor">
            <path strokeLinecap="round" strokeLinejoin="round" strokeWidth={1} d="M19 11H5m14 0a2 2 0 012 2v6a2 2 0 01-2 2H5a2 2 0 01-2-2v-6a2 2 0 012-2m14 0V9a2 2 0 00-2-2M5 11V9a2 2 0 012-2m0 0V5a2 2 0 012-2h6a2 2 0 012 2v2M7 7h10" />
          </svg>
          <p>No clusters to display</p>
          <p className="text-sm mt-2">Create more notes to generate clusters</p>
        </div>
      </div>
    )
  }

  return (
    <div className="w-full h-[600px] border rounded-lg overflow-hidden bg-gray-50">
      <ReactFlow
        nodes={nodes}
        edges={edges}
        onNodesChange={onNodesChange}
        onEdgesChange={onEdgesChange}
        onNodeClick={onNodeClickHandler}
        connectionMode={ConnectionMode.Loose}
        fitView
      >
        <Background />
        <Controls />
        <MiniMap />
      </ReactFlow>

      {selectedCluster !== null && (
        <div className="absolute bottom-4 left-4 bg-white rounded-lg shadow-lg p-4 max-w-xs">
          <h3 className="font-semibold mb-2">
            {clusters.find(c => c.clusterId === selectedCluster)?.name || `Cluster ${selectedCluster}`}
          </h3>
          <p className="text-sm text-gray-600">
            {clusters.find(c => c.clusterId === selectedCluster)?.noteIds.length || 0} notes
          </p>
        </div>
      )}

      <div className="absolute top-4 right-4 bg-white rounded-lg shadow-lg p-3">
        <div className="flex items-center gap-4 text-sm">
          <div className="flex items-center gap-2">
            <div className="w-4 h-4 rounded-full bg-yellow-400 border-2 border-yellow-600"></div>
            <span>Bridge note</span>
          </div>
          <div className="flex items-center gap-2">
            <div className="w-4 h-4 rounded-full bg-blue-500"></div>
            <span>Regular note</span>
          </div>
        </div>
      </div>
    </div>
  )
}