import React, { useState, useMemo } from 'react';
import { Risk, Project } from '../../types';
import { getUserEmail } from '../../lib/formatters';
import { AlertTriangle, ShieldAlert, CheckCircle2, ChevronRight, X, Info } from 'lucide-react';
import { HelpTooltip } from './HelpTooltip';

interface RiskHeatmapMatrixProps {
  risks: Risk[];
  projects?: Project[];
  compact?: boolean;
  onSelectRisk?: (risk: Risk) => void;
  title?: string;
  subtitle?: string;
}

// Standard 5-point likelihood and impact levels
const LIKELIHOOD_LEVELS = [
  { val: 1, label: 'Rare', short: '1 - Rare' },
  { val: 2, label: 'Unlikely', short: '2 - Unlikely' },
  { val: 3, label: 'Possible', short: '3 - Possible' },
  { val: 4, label: 'Likely', short: '4 - Likely' },
  { val: 5, label: 'Almost Certain', short: '5 - Almost Certain' },
];

const IMPACT_LEVELS = [
  { val: 5, label: 'Severe', short: '5 - Severe' },
  { val: 4, label: 'Critical', short: '4 - Critical' },
  { val: 3, label: 'Major', short: '3 - Major' },
  { val: 2, label: 'Moderate', short: '2 - Moderate' },
  { val: 1, label: 'Minor', short: '1 - Minor' },
];

export const getCellSeverity = (score: number) => {
  if (score >= 15) {
    return {
      name: 'Critical',
      bgClass: 'bg-rose-950/70 border-rose-600/70 text-rose-100 hover:bg-rose-900/90',
      badgeClass: 'bg-rose-500/20 text-rose-300 border-rose-500/40',
      textColor: 'text-rose-400',
    };
  }
  if (score >= 10) {
    return {
      name: 'High',
      bgClass: 'bg-orange-950/60 border-orange-700/60 text-orange-200 hover:bg-orange-900/80',
      badgeClass: 'bg-orange-500/20 text-orange-300 border-orange-500/40',
      textColor: 'text-orange-400',
    };
  }
  if (score >= 5) {
    return {
      name: 'Moderate',
      bgClass: 'bg-amber-950/50 border-amber-800/50 text-amber-300 hover:bg-amber-900/70',
      badgeClass: 'bg-amber-500/20 text-amber-300 border-amber-500/40',
      textColor: 'text-amber-400',
    };
  }
  return {
    name: 'Low',
    bgClass: 'bg-emerald-950/40 border-emerald-800/40 text-emerald-300 hover:bg-emerald-900/60',
    badgeClass: 'bg-emerald-500/20 text-emerald-300 border-emerald-500/40',
    textColor: 'text-emerald-400',
  };
};

export const RiskHeatmapMatrix: React.FC<RiskHeatmapMatrixProps> = ({
  risks,
  projects = [],
  compact = false,
  onSelectRisk,
  title,
  subtitle,
}) => {
  const [matrixMode, setMatrixMode] = useState<'5x5' | '3x3'>('5x5');
  const [selectedCell, setSelectedCell] = useState<{
    impactLabel: string;
    likelihoodLabel: string;
    score: number;
    risks: Risk[];
  } | null>(null);

  // Map project names for easy lookup
  const projectMap = useMemo(() => {
    const map: Record<string, string> = {};
    projects.forEach((p) => {
      map[String(p.id)] = p.name;
    });
    return map;
  }, [projects]);

  // Pre-calculate risk counts by exact coordinates (1-5)
  const matrix5x5 = useMemo(() => {
    const grid: Record<string, Risk[]> = {};
    for (let imp = 1; imp <= 5; imp++) {
      for (let lik = 1; lik <= 5; lik++) {
        grid[`${imp}-${lik}`] = [];
      }
    }

    risks.forEach((r) => {
      const imp = Math.min(5, Math.max(1, Number(r.impact) || 1));
      const lik = Math.min(5, Math.max(1, Number(r.likelihood) || 1));
      grid[`${imp}-${lik}`].push(r);
    });

    return grid;
  }, [risks]);

  // Pre-calculate 3x3 summary matrix
  const matrix3x3 = useMemo(() => {
    const buckets: Record<string, Risk[]> = {
      'high-low': [],
      'high-med': [],
      'high-high': [],
      'med-low': [],
      'med-med': [],
      'med-high': [],
      'low-low': [],
      'low-med': [],
      'low-high': [],
    };

    risks.forEach((r) => {
      const imp = Number(r.impact) || 1;
      const lik = Number(r.likelihood) || 1;

      const impKey = imp >= 4 ? 'high' : imp === 3 ? 'med' : 'low';
      const likKey = lik >= 4 ? 'high' : lik === 3 ? 'med' : 'low';

      buckets[`${impKey}-${likKey}`].push(r);
    });

    return buckets;
  }, [risks]);

  // Overall severity summary counters
  const summaryCounters = useMemo(() => {
    let low = 0;
    let moderate = 0;
    let high = 0;
    let critical = 0;

    risks.forEach((r) => {
      const score = (Number(r.impact) || 1) * (Number(r.likelihood) || 1);
      if (score >= 15) critical++;
      else if (score >= 10) high++;
      else if (score >= 5) moderate++;
      else low++;
    });

    return { low, moderate, high, critical };
  }, [risks]);

  const handleCellClick = (impactLabel: string, likelihoodLabel: string, score: number, cellRisks: Risk[]) => {
    if (cellRisks.length === 0) {
      if (selectedCell) setSelectedCell(null);
      return;
    }
    setSelectedCell({
      impactLabel,
      likelihoodLabel,
      score,
      risks: cellRisks,
    });
  };

  return (
    <div className="space-y-4">
      {/* Header & Controls */}
      <div className="flex flex-col sm:flex-row sm:items-center justify-between gap-3">
        <div>
          <div className="flex items-center gap-2">
            {title && <h3 className="text-sm font-semibold text-white">{title}</h3>}
            <HelpTooltip
              title="Risk Heatmap Guidance"
              content="Visualizes project risk exposure based on ISO 31000 standards. Severity score = Likelihood (1–5) × Impact (1–5). Click any populated cell to drill into registered risks."
              size="sm"
              placement="bottom"
            />
          </div>
          {subtitle && <p className="text-xs text-slate-400 mt-0.5">{subtitle}</p>}
        </div>

        <div className="flex items-center gap-2 self-end sm:self-auto">
          {/* Mode Switcher */}
          <div className="flex items-center bg-slate-900/90 p-0.5 rounded-lg border border-slate-700/80 text-[11px]">
            <button
              type="button"
              onClick={() => {
                setMatrixMode('5x5');
                setSelectedCell(null);
              }}
              className={`px-2.5 py-1 rounded-md font-medium transition cursor-pointer ${
                matrixMode === '5x5' ? 'bg-blue-600 text-white shadow-xs' : 'text-slate-400 hover:text-white'
              }`}
            >
              5×5 Exact Matrix
            </button>
            <button
              type="button"
              onClick={() => {
                setMatrixMode('3x3');
                setSelectedCell(null);
              }}
              className={`px-2.5 py-1 rounded-md font-medium transition cursor-pointer ${
                matrixMode === '3x3' ? 'bg-blue-600 text-white shadow-xs' : 'text-slate-400 hover:text-white'
              }`}
            >
              3×3 Summary
            </button>
          </div>
          <HelpTooltip
            title="Matrix Resolution Switcher"
            content="Toggle between 5×5 detailed granular risk distribution and 3×3 executive aggregated categories (Low, Medium, High)."
            size="sm"
            placement="left"
          />
        </div>
      </div>

      {/* Summary Score Badges */}
      <div className="grid grid-cols-4 gap-2">
        <div className="bg-rose-500/10 border border-rose-500/30 p-2 rounded-xl text-center">
          <span className="text-[10px] text-rose-400 font-semibold block uppercase">Critical (15–25)</span>
          <span className="text-base font-bold text-rose-200">{summaryCounters.critical}</span>
        </div>
        <div className="bg-orange-500/10 border border-orange-500/30 p-2 rounded-xl text-center">
          <span className="text-[10px] text-orange-400 font-semibold block uppercase">High (10–14)</span>
          <span className="text-base font-bold text-orange-200">{summaryCounters.high}</span>
        </div>
        <div className="bg-amber-500/10 border border-amber-500/30 p-2 rounded-xl text-center">
          <span className="text-[10px] text-amber-400 font-semibold block uppercase">Moderate (5–9)</span>
          <span className="text-base font-bold text-amber-200">{summaryCounters.moderate}</span>
        </div>
        <div className="bg-emerald-500/10 border border-emerald-500/30 p-2 rounded-xl text-center">
          <span className="text-[10px] text-emerald-400 font-semibold block uppercase">Low (1–4)</span>
          <span className="text-base font-bold text-emerald-200">{summaryCounters.low}</span>
        </div>
      </div>

      {/* 5x5 Matrix Mode */}
      {matrixMode === '5x5' && (
        <div className="bg-[#090d16]/80 p-3 rounded-2xl border border-slate-800/90 overflow-x-auto">
          <div className="min-w-[480px]">
            {/* Top axis label: Likelihood */}
            <div className="text-center text-[10px] font-bold text-slate-400 uppercase tracking-wider mb-2 pl-24">
              Likelihood / Probability &rarr;
            </div>

            <div className="flex">
              {/* Left Y-Axis Label: Impact */}
              <div className="w-6 flex items-center justify-center -mr-2">
                <span className="text-[10px] font-bold text-slate-400 uppercase tracking-widest -rotate-90 whitespace-nowrap">
                  &uarr; Impact / Severity
                </span>
              </div>

              {/* Grid with Row Headers */}
              <div className="flex-1">
                {/* Column Headers */}
                <div className="grid grid-cols-6 gap-1.5 mb-1.5 text-center">
                  <div className="text-[10px] font-semibold text-slate-500 flex items-center justify-end pr-2">
                    Impact \ Lik.
                  </div>
                  {LIKELIHOOD_LEVELS.map((lik) => (
                    <div key={lik.val} className="text-[10px] font-semibold text-slate-400 bg-slate-900/60 py-1 rounded-md">
                      {lik.short}
                    </div>
                  ))}
                </div>

                {/* Rows (Impact 5 down to 1) */}
                <div className="space-y-1.5">
                  {IMPACT_LEVELS.map((imp) => (
                    <div key={imp.val} className="grid grid-cols-6 gap-1.5">
                      {/* Row Header */}
                      <div className="text-[10px] font-semibold text-slate-400 bg-slate-900/60 rounded-md flex items-center justify-end pr-2">
                        {imp.short}
                      </div>

                      {/* 5 Cells */}
                      {LIKELIHOOD_LEVELS.map((lik) => {
                        const cellRisks = matrix5x5[`${imp.val}-${lik.val}`] || [];
                        const score = imp.val * lik.val;
                        const sev = getCellSeverity(score);
                        const hasRisks = cellRisks.length > 0;
                        const isSelected =
                          selectedCell?.impactLabel === imp.label && selectedCell?.likelihoodLabel === lik.label;

                        return (
                          <button
                            key={lik.val}
                            type="button"
                            onClick={() => handleCellClick(imp.label, lik.label, score, cellRisks)}
                            className={`relative rounded-xl border p-2 text-center transition-all cursor-pointer ${
                              sev.bgClass
                            } ${isSelected ? 'ring-2 ring-blue-400 scale-[1.03] z-10 shadow-lg' : ''} ${
                              hasRisks ? 'shadow-xs font-bold' : 'opacity-70 hover:opacity-100'
                            }`}
                            title={`Impact: ${imp.label} (${imp.val}) × Likelihood: ${lik.label} (${lik.val}) = Score ${score} (${sev.name})`}
                          >
                            {/* Score small indicator */}
                            <span className="text-[9px] block text-slate-400/80 font-mono">
                              {score}
                            </span>

                            {/* Risk count or empty dash */}
                            {hasRisks ? (
                              <div className="mt-0.5 flex items-center justify-center gap-1">
                                <span className="h-1.5 w-1.5 rounded-full bg-white animate-pulse"></span>
                                <span className="text-xs font-extrabold text-white px-1.5 py-0.2 rounded-full bg-black/40 border border-white/20">
                                  {cellRisks.length} {cellRisks.length === 1 ? 'Risk' : 'Risks'}
                                </span>
                              </div>
                            ) : (
                              <span className="text-xs text-slate-600 block mt-0.5">&mdash;</span>
                            )}
                          </button>
                        );
                      })}
                    </div>
                  ))}
                </div>
              </div>
            </div>
          </div>
        </div>
      )}

      {/* 3x3 Summary Mode */}
      {matrixMode === '3x3' && (
        <div className="bg-[#090d16]/80 p-3 rounded-2xl border border-slate-800/90 overflow-x-auto">
          <div className="min-w-[440px]">
            {/* Top axis label: Likelihood */}
            <div className="text-center text-[10px] font-bold text-slate-400 uppercase tracking-wider mb-2 pl-24">
              Likelihood / Probability &rarr;
            </div>

            <div className="flex">
              {/* Left Y-Axis Label: Impact */}
              <div className="w-6 flex items-center justify-center -mr-2">
                <span className="text-[10px] font-bold text-slate-400 uppercase tracking-widest -rotate-90 whitespace-nowrap">
                  &uarr; Impact / Severity
                </span>
              </div>

              {/* 3x3 Table */}
              <div className="flex-1">
                {/* Column Headers */}
                <div className="grid grid-cols-4 gap-2 mb-2 text-center">
                  <div className="text-[10px] font-semibold text-slate-500 flex items-center justify-end pr-2">
                    Impact \ Lik.
                  </div>
                  <div className="text-[10px] font-semibold text-slate-300 bg-slate-900/60 py-1.5 rounded-lg">
                    Low (1&ndash;2 Rare/Unlikely)
                  </div>
                  <div className="text-[10px] font-semibold text-slate-300 bg-slate-900/60 py-1.5 rounded-lg">
                    Medium (3 Possible)
                  </div>
                  <div className="text-[10px] font-semibold text-slate-300 bg-slate-900/60 py-1.5 rounded-lg">
                    High (4&ndash;5 Likely/Certain)
                  </div>
                </div>

                {/* Row 1: High Impact (4-5) */}
                <div className="grid grid-cols-4 gap-2 mb-2">
                  <div className="text-[10px] font-semibold text-slate-300 bg-slate-900/60 rounded-lg flex items-center justify-end pr-2">
                    High (4&ndash;5 Major/Crit.)
                  </div>

                  {/* High Imp - Low Lik */}
                  {(() => {
                    const cRisks = matrix3x3['high-low'];
                    return (
                      <button
                        type="button"
                        onClick={() => handleCellClick('High (4-5)', 'Low (1-2)', 8, cRisks)}
                        className="bg-amber-950/50 border border-amber-800/60 p-3 rounded-xl text-center hover:bg-amber-900/70 transition cursor-pointer"
                      >
                        <span className="text-[10px] font-semibold text-amber-400 block">Moderate Severity</span>
                        <span className="text-xs font-bold text-white mt-1 block">
                          {cRisks.length} {cRisks.length === 1 ? 'Risk' : 'Risks'}
                        </span>
                      </button>
                    );
                  })()}

                  {/* High Imp - Med Lik */}
                  {(() => {
                    const cRisks = matrix3x3['high-med'];
                    return (
                      <button
                        type="button"
                        onClick={() => handleCellClick('High (4-5)', 'Medium (3)', 12, cRisks)}
                        className="bg-orange-950/60 border border-orange-700/60 p-3 rounded-xl text-center hover:bg-orange-900/80 transition cursor-pointer"
                      >
                        <span className="text-[10px] font-semibold text-orange-400 block">High Severity</span>
                        <span className="text-xs font-bold text-white mt-1 block">
                          {cRisks.length} {cRisks.length === 1 ? 'Risk' : 'Risks'}
                        </span>
                      </button>
                    );
                  })()}

                  {/* High Imp - High Lik */}
                  {(() => {
                    const cRisks = matrix3x3['high-high'];
                    return (
                      <button
                        type="button"
                        onClick={() => handleCellClick('High (4-5)', 'High (4-5)', 20, cRisks)}
                        className="bg-rose-950/80 border border-rose-600 p-3 rounded-xl text-center hover:bg-rose-900 transition cursor-pointer shadow-md"
                      >
                        <span className="text-[10px] font-bold text-rose-300 block">Critical Severity</span>
                        <span className="text-xs font-extrabold text-white mt-1 block">
                          {cRisks.length} {cRisks.length === 1 ? 'Risk' : 'Risks'}
                        </span>
                      </button>
                    );
                  })()}
                </div>

                {/* Row 2: Medium Impact (3) */}
                <div className="grid grid-cols-4 gap-2 mb-2">
                  <div className="text-[10px] font-semibold text-slate-300 bg-slate-900/60 rounded-lg flex items-center justify-end pr-2">
                    Medium (3 Moderate)
                  </div>

                  {/* Med Imp - Low Lik */}
                  {(() => {
                    const cRisks = matrix3x3['med-low'];
                    return (
                      <button
                        type="button"
                        onClick={() => handleCellClick('Medium (3)', 'Low (1-2)', 3, cRisks)}
                        className="bg-emerald-950/40 border border-emerald-800/40 p-3 rounded-xl text-center hover:bg-emerald-900/60 transition cursor-pointer"
                      >
                        <span className="text-[10px] font-semibold text-emerald-400 block">Low Severity</span>
                        <span className="text-xs font-bold text-white mt-1 block">
                          {cRisks.length} {cRisks.length === 1 ? 'Risk' : 'Risks'}
                        </span>
                      </button>
                    );
                  })()}

                  {/* Med Imp - Med Lik */}
                  {(() => {
                    const cRisks = matrix3x3['med-med'];
                    return (
                      <button
                        type="button"
                        onClick={() => handleCellClick('Medium (3)', 'Medium (3)', 9, cRisks)}
                        className="bg-amber-950/50 border border-amber-800/50 p-3 rounded-xl text-center hover:bg-amber-900/70 transition cursor-pointer"
                      >
                        <span className="text-[10px] font-semibold text-amber-400 block">Moderate Severity</span>
                        <span className="text-xs font-bold text-white mt-1 block">
                          {cRisks.length} {cRisks.length === 1 ? 'Risk' : 'Risks'}
                        </span>
                      </button>
                    );
                  })()}

                  {/* Med Imp - High Lik */}
                  {(() => {
                    const cRisks = matrix3x3['med-high'];
                    return (
                      <button
                        type="button"
                        onClick={() => handleCellClick('Medium (3)', 'High (4-5)', 12, cRisks)}
                        className="bg-orange-950/60 border border-orange-700/60 p-3 rounded-xl text-center hover:bg-orange-900/80 transition cursor-pointer"
                      >
                        <span className="text-[10px] font-semibold text-orange-400 block">High Severity</span>
                        <span className="text-xs font-bold text-white mt-1 block">
                          {cRisks.length} {cRisks.length === 1 ? 'Risk' : 'Risks'}
                        </span>
                      </button>
                    );
                  })()}
                </div>

                {/* Row 3: Low Impact (1-2) */}
                <div className="grid grid-cols-4 gap-2">
                  <div className="text-[10px] font-semibold text-slate-300 bg-slate-900/60 rounded-lg flex items-center justify-end pr-2">
                    Low (1&ndash;2 Minor)
                  </div>

                  {/* Low Imp - Low Lik */}
                  {(() => {
                    const cRisks = matrix3x3['low-low'];
                    return (
                      <button
                        type="button"
                        onClick={() => handleCellClick('Low (1-2)', 'Low (1-2)', 1, cRisks)}
                        className="bg-slate-900/80 border border-slate-800 p-3 rounded-xl text-center hover:bg-slate-800/80 transition cursor-pointer"
                      >
                        <span className="text-[10px] font-semibold text-slate-400 block">Trivial Severity</span>
                        <span className="text-xs font-bold text-slate-300 mt-1 block">
                          {cRisks.length} {cRisks.length === 1 ? 'Risk' : 'Risks'}
                        </span>
                      </button>
                    );
                  })()}

                  {/* Low Imp - Med Lik */}
                  {(() => {
                    const cRisks = matrix3x3['low-med'];
                    return (
                      <button
                        type="button"
                        onClick={() => handleCellClick('Low (1-2)', 'Medium (3)', 3, cRisks)}
                        className="bg-emerald-950/40 border border-emerald-800/40 p-3 rounded-xl text-center hover:bg-emerald-900/60 transition cursor-pointer"
                      >
                        <span className="text-[10px] font-semibold text-emerald-400 block">Low Severity</span>
                        <span className="text-xs font-bold text-white mt-1 block">
                          {cRisks.length} {cRisks.length === 1 ? 'Risk' : 'Risks'}
                        </span>
                      </button>
                    );
                  })()}

                  {/* Low Imp - High Lik */}
                  {(() => {
                    const cRisks = matrix3x3['low-high'];
                    return (
                      <button
                        type="button"
                        onClick={() => handleCellClick('Low (1-2)', 'High (4-5)', 8, cRisks)}
                        className="bg-amber-950/50 border border-amber-800/50 p-3 rounded-xl text-center hover:bg-amber-900/70 transition cursor-pointer"
                      >
                        <span className="text-[10px] font-semibold text-amber-400 block">Moderate Severity</span>
                        <span className="text-xs font-bold text-white mt-1 block">
                          {cRisks.length} {cRisks.length === 1 ? 'Risk' : 'Risks'}
                        </span>
                      </button>
                    );
                  })()}
                </div>
              </div>
            </div>
          </div>
        </div>
      )}

      {/* Selected Cell Inspector (Drill-down) */}
      {selectedCell && selectedCell.risks.length > 0 && (
        <div className="bg-[#0f1523] border border-blue-500/40 p-4 rounded-2xl shadow-xl animate-in fade-in slide-in-from-top-2 duration-200">
          <div className="flex items-center justify-between pb-3 border-b border-slate-800">
            <div className="flex items-center gap-2">
              <div className="p-1 rounded-md bg-blue-500/20 text-blue-400">
                <Info className="w-4 h-4" />
              </div>
              <div>
                <h4 className="text-xs font-bold text-white">
                  Risks in Box: Impact [{selectedCell.impactLabel}] &times; Likelihood [{selectedCell.likelihoodLabel}]
                </h4>
                <p className="text-[10px] text-slate-400">
                  Residual Score: <strong className="text-blue-300">{selectedCell.score} / 25</strong> &bull; Total Items: {selectedCell.risks.length}
                </p>
              </div>
            </div>
            <button
              type="button"
              onClick={() => setSelectedCell(null)}
              className="p-1 text-slate-400 hover:text-white hover:bg-slate-800 rounded-lg transition"
            >
              <X className="w-4 h-4" />
            </button>
          </div>

          <div className="mt-3 space-y-2 max-h-56 overflow-y-auto pr-1 divide-y divide-slate-800/60">
            {selectedCell.risks.map((rk) => (
              <div
                key={rk.id}
                onClick={() => onSelectRisk && onSelectRisk(rk)}
                className={`pt-2 first:pt-0 ${onSelectRisk ? 'cursor-pointer hover:bg-slate-800/30 p-2 rounded-xl transition' : ''}`}
              >
                <div className="flex items-center justify-between gap-2">
                  <span className="font-semibold text-xs text-white line-clamp-1">{rk.name}</span>
                  <span className="text-[10px] font-mono text-slate-400 shrink-0">
                    Project #{rk.projectId} {projectMap[String(rk.projectId)] ? `(${projectMap[String(rk.projectId)]})` : ''}
                  </span>
                </div>
                {rk.description && (
                  <p className="text-[11px] text-slate-400 line-clamp-2 mt-0.5">{rk.description}</p>
                )}
                <div className="flex items-center gap-3 mt-1 text-[10px] text-slate-400">
                  <span>Likelihood: <strong className="text-slate-200">{rk.likelihood}</strong></span>
                  <span>Impact: <strong className="text-slate-200">{rk.impact}</strong></span>
                  <span>Owner: <strong className="text-slate-300">{getUserEmail(rk.owner)}</strong></span>
                </div>
                {rk.mitigationAction && (
                  <div className="mt-1 text-[10px] bg-slate-900/80 p-1.5 rounded-lg text-slate-300 border border-slate-800">
                    <strong className="text-blue-400">Mitigation: </strong>{rk.mitigationAction}
                  </div>
                )}
              </div>
            ))}
          </div>
        </div>
      )}
    </div>
  );
};