import { useEffect, useRef, useCallback } from 'react';
import Graph from 'graphology';
import Sigma from 'sigma';
import FA2LayoutSupervisor from 'graphology-layout-forceatlas2/worker';
import { inferSettings } from 'graphology-layout-forceatlas2';
import { useReferralNetworkStore } from '@/store/referralNetwork';
import type { NetworkGraphData, NetworkFilters } from '@/types/referralNetwork';
import { getUserNodeColor, getUserNodeSize, getCampaignColor } from '../utils';
import { setSigmaInstance } from '../sigmaGlobals';

interface NetworkGraphProps {
  data: NetworkGraphData;
  className?: string;
}

function buildFullGraph(graphData: NetworkGraphData): Graph {
  const graph = new Graph();

  graphData.campaigns.forEach((campaign, index) => {
    graph.addNode(`campaign_${campaign.id}`, {
      label: campaign.name,
      x: Math.random() * 100,
      y: Math.random() * 100,
      size: 16,
      color: getCampaignColor(index),
      type: 'circle',
      nodeType: 'campaign',
      nodeId: campaign.id,
    });
  });

  graphData.users.forEach((user) => {
    const color = getUserNodeColor(user.direct_referrals, user.is_partner, user.campaign_id);
    const size = getUserNodeSize(user.direct_referrals);

    graph.addNode(`user_${user.id}`, {
      label: user.display_name,
      x: Math.random() * 100,
      y: Math.random() * 100,
      size,
      color,
      type: 'circle',
      nodeType: 'user',
      nodeId: user.id,
      isPartner: user.is_partner,
      directReferrals: user.direct_referrals,
      campaignId: user.campaign_id,
    });
  });

  graphData.edges.forEach((edge) => {
    if (graph.hasNode(edge.source) && graph.hasNode(edge.target)) {
      const edgeKey = `${edge.source}->${edge.target}`;
      if (!graph.hasEdge(edgeKey)) {
        graph.addEdgeWithKey(edgeKey, edge.source, edge.target, {
          color:
            edge.type === 'partner_campaign'
              ? 'rgba(255, 138, 101, 0.5)'
              : edge.type === 'campaign'
                ? 'rgba(77, 217, 192, 0.06)'
                : 'rgba(255,255,255,0.03)',
          size: edge.type === 'partner_campaign' ? 1.5 : 0.3,
          edgeType: edge.type,
        });
      }
    }
  });

  return graph;
}

function computeHiddenNodes(graph: Graph, filters: NetworkFilters): Set<string> {
  const hidden = new Set<string>();
  const filterCampaignSet = new Set(filters.campaigns);
  const hasCampaignFilter = filterCampaignSet.size > 0;

  graph.forEachNode((node, attrs) => {
    if (attrs.nodeType === 'user') {
      if (filters.partnersOnly && !attrs.isPartner) {
        hidden.add(node);
      } else if ((attrs.directReferrals ?? 0) < filters.minReferrals) {
        hidden.add(node);
      } else if (
        hasCampaignFilter &&
        attrs.campaignId !== null &&
        !filterCampaignSet.has(attrs.campaignId)
      ) {
        hidden.add(node);
      }
    } else if (attrs.nodeType === 'campaign') {
      if (hasCampaignFilter && !filterCampaignSet.has(attrs.nodeId)) {
        hidden.add(node);
      }
    }
  });

  return hidden;
}

const FA2_DURATION_MS = 3000;

function clampOutlierPositions(graph: Graph): void {
  const xs: number[] = [];
  const ys: number[] = [];

  graph.forEachNode((_, attrs) => {
    xs.push(attrs.x as number);
    ys.push(attrs.y as number);
  });

  if (xs.length < 2) return;

  const meanX = xs.reduce((a, b) => a + b, 0) / xs.length;
  const meanY = ys.reduce((a, b) => a + b, 0) / ys.length;

  const stdX = Math.sqrt(xs.reduce((sum, x) => sum + (x - meanX) ** 2, 0) / xs.length) || 1;
  const stdY = Math.sqrt(ys.reduce((sum, y) => sum + (y - meanY) ** 2, 0) / ys.length) || 1;

  const MAX_STD = 3;
  const minX = meanX - MAX_STD * stdX;
  const maxX = meanX + MAX_STD * stdX;
  const minY = meanY - MAX_STD * stdY;
  const maxY = meanY + MAX_STD * stdY;

  graph.forEachNode((node, attrs) => {
    const x = attrs.x as number;
    const y = attrs.y as number;
    const clampedX = Math.max(minX, Math.min(maxX, x));
    const clampedY = Math.max(minY, Math.min(maxY, y));

    if (clampedX !== x || clampedY !== y) {
      graph.setNodeAttribute(node, 'x', clampedX);
      graph.setNodeAttribute(node, 'y', clampedY);
    }
  });
}

export function NetworkGraph({ data, className }: NetworkGraphProps) {
  const containerRef = useRef<HTMLDivElement>(null);
  const sigmaRef = useRef<Sigma | null>(null);
  const graphRef = useRef<Graph | null>(null);
  const hiddenNodesRef = useRef<Set<string>>(new Set());
  const fa2Ref = useRef<FA2LayoutSupervisor | null>(null);
  const fa2TimerRef = useRef<ReturnType<typeof setTimeout> | null>(null);

  const setSelectedNode = useReferralNetworkStore((s) => s.setSelectedNode);
  const setHoveredNode = useReferralNetworkStore((s) => s.setHoveredNode);
  const setHighlightedNodes = useReferralNetworkStore((s) => s.setHighlightedNodes);
  const hoveredNodeId = useReferralNetworkStore((s) => s.hoveredNodeId);
  const highlightedNodes = useReferralNetworkStore((s) => s.highlightedNodes);
  const filters = useReferralNetworkStore((s) => s.filters);

  const killFA2 = useCallback(() => {
    if (fa2TimerRef.current !== null) {
      clearTimeout(fa2TimerRef.current);
      fa2TimerRef.current = null;
    }
    if (fa2Ref.current) {
      fa2Ref.current.kill();
      fa2Ref.current = null;
    }
  }, []);

  useEffect(() => {
    if (!containerRef.current || !data) return;

    const container = containerRef.current;
    let rafId: number;
    let cancelled = false;

    function tryInit() {
      if (cancelled || !container.isConnected) return;
      if (container.offsetWidth === 0 || container.offsetHeight === 0) {
        rafId = requestAnimationFrame(tryInit);
        return;
      }

      killFA2();
      if (sigmaRef.current) {
        sigmaRef.current.kill();
        sigmaRef.current = null;
      }

      const graph = buildFullGraph(data);
      graphRef.current = graph;

      const initialFilters = useReferralNetworkStore.getState().filters;
      hiddenNodesRef.current = computeHiddenNodes(graph, initialFilters);

      const sigma = new Sigma(graph, container, {
        renderEdgeLabels: false,
        labelDensity: 0.12,
        labelRenderedSizeThreshold: 14,
        zIndex: true,
        defaultEdgeColor: '#ffffff06',
        defaultNodeColor: '#6b7280',
        labelColor: { color: '#e8e6f0' },
        labelFont: 'Inter, system-ui, sans-serif',
        labelSize: 11,
        stagePadding: 40,
        nodeReducer: (node, attrs) => {
          const res = { ...attrs };

          if (hiddenNodesRef.current.has(node)) {
            res.hidden = true;
            return res;
          }

          const store = useReferralNetworkStore.getState();
          const hovered = store.hoveredNodeId;
          const highlighted = store.highlightedNodes;

          if (highlighted.size > 0) {
            if (highlighted.has(node)) {
              res.highlighted = true;
              res.zIndex = 2;
            } else {
              res.color = `${attrs.color}33`;
              res.label = '';
              res.zIndex = 0;
            }
          }

          if (hovered) {
            if (node === hovered) {
              res.highlighted = true;
              res.zIndex = 2;
            } else if (graph.hasNode(hovered) && graph.areNeighbors(node, hovered)) {
              res.highlighted = true;
              res.zIndex = 1;
            } else if (!highlighted.has(node)) {
              res.color = `${attrs.color}33`;
              res.label = '';
              res.zIndex = 0;
            }
          }

          return res;
        },
        edgeReducer: (edge, attrs) => {
          const res = { ...attrs };

          const [source, target] = graph.extremities(edge);
          if (hiddenNodesRef.current.has(source) || hiddenNodesRef.current.has(target)) {
            res.hidden = true;
            return res;
          }

          const store = useReferralNetworkStore.getState();
          const hovered = store.hoveredNodeId;
          const highlighted = store.highlightedNodes;

          if (hovered && graph.hasNode(hovered)) {
            if (!graph.hasExtremity(edge, hovered)) {
              res.hidden = true;
            } else {
              res.color = '#ffffff30';
              res.size = 1;
            }
          } else if (highlighted.size > 0) {
            if (!highlighted.has(source) && !highlighted.has(target)) {
              res.hidden = true;
            }
          }

          return res;
        },
      });

      sigmaRef.current = sigma;
      setSigmaInstance(sigma);

      if (graph.order > 0) {
        const inferred = inferSettings(graph);
        const supervisor = new FA2LayoutSupervisor(graph, {
          settings: {
            ...inferred,
            linLogMode: true,
            adjustSizes: true,
            barnesHutOptimize: graph.order > 100,
            gravity: 1,
            slowDown: 2,
          },
        });
        fa2Ref.current = supervisor;
        supervisor.start();

        fa2TimerRef.current = setTimeout(() => {
          if (fa2Ref.current === supervisor) {
            supervisor.kill();
            fa2Ref.current = null;
          }
          fa2TimerRef.current = null;

          if (graphRef.current) {
            clampOutlierPositions(graphRef.current);
          }

          if (sigmaRef.current) {
            sigmaRef.current.resize();
            sigmaRef.current.getCamera().animatedReset({ duration: 400 });
          }
        }, FA2_DURATION_MS);
      }

      sigma.on('clickNode', ({ node }) => {
        const attrs = graph.getNodeAttributes(node);
        const nodeType = attrs.nodeType;
        const nodeId = attrs.nodeId;

        if (typeof nodeId !== 'number') return;

        if (nodeType === 'user') {
          setSelectedNode({ type: 'user', id: nodeId });
        } else if (nodeType === 'campaign') {
          setSelectedNode({ type: 'campaign', id: nodeId });
        }
      });

      sigma.on('clickStage', () => {
        setSelectedNode(null);
      });

      sigma.on('enterNode', ({ node }) => {
        setHoveredNode(node);
        if (containerRef.current) {
          containerRef.current.style.cursor = 'pointer';
        }
      });

      sigma.on('leaveNode', () => {
        setHoveredNode(null);
        if (containerRef.current) {
          containerRef.current.style.cursor = 'default';
        }
      });
    }

    rafId = requestAnimationFrame(tryInit);

    return () => {
      cancelled = true;
      cancelAnimationFrame(rafId);
      killFA2();
      if (sigmaRef.current) {
        sigmaRef.current.kill();
        sigmaRef.current = null;
      }
      graphRef.current = null;
      setSigmaInstance(null);

      setHoveredNode(null);
      setHighlightedNodes(new Set());
    };
  }, [data, setSelectedNode, setHoveredNode, setHighlightedNodes, killFA2]);

  useEffect(() => {
    const container = containerRef.current;
    if (!container) return;

    const observer = new ResizeObserver(() => {
      if (sigmaRef.current) {
        sigmaRef.current.resize();
      }
    });

    observer.observe(container);
    return () => observer.disconnect();
  }, []);

  useEffect(() => {
    if (!graphRef.current || !sigmaRef.current) return;
    hiddenNodesRef.current = computeHiddenNodes(graphRef.current, filters);
    sigmaRef.current.refresh();
  }, [filters]);

  useEffect(() => {
    if (sigmaRef.current) {
      sigmaRef.current.refresh();
    }
  }, [hoveredNodeId, highlightedNodes]);

  return <div ref={containerRef} className={`bg-[#0a0a0f] ${className ?? ''}`} />;
}