/**
 * RankingTable.jsx
 * Displays the ranked list of candidates with scores, badges, and selection status.
 * Each row is clickable to show the full detail panel.
 */
import { Trophy, ChevronRight, CheckCircle, XCircle, TrendingUp } from 'lucide-react';
import ScoreRing from './ScoreRing';

function SkillBadge({ skill, variant = 'green' }) {
  return (
    <span className={`badge-${variant} mr-1 mb-1`}>{skill}</span>
  );
}

function RankIcon({ rank }) {
  if (rank === 1) return <span className="text-lg">🥇</span>;
  if (rank === 2) return <span className="text-lg">🥈</span>;
  if (rank === 3) return <span className="text-lg">🥉</span>;
  return (
    <span className="w-6 h-6 rounded-full bg-slate-800 border border-slate-700 flex items-center justify-center text-xs text-slate-400 font-semibold">
      {rank}
    </span>
  );
}

export default function RankingTable({ candidates, selectedId, onSelectCandidate, jobTitle }) {
  if (!candidates || candidates.length === 0) return null;

  return (
    <div className="space-y-4 animate-slide-up">
      {/* Table header */}
      <div className="flex items-center justify-between">
        <div>
          <h2 className="text-xl font-bold text-white flex items-center gap-2">
            <Trophy size={20} className="text-amber-400" />
            Ranked Candidates
          </h2>
          <p className="text-slate-400 text-sm mt-0.5">
            {candidates.length} candidates screened for <span className="text-primary-300 font-medium">{jobTitle}</span>
          </p>
        </div>
        <div className="flex items-center gap-3 text-xs text-slate-500">
          <span className="flex items-center gap-1"><span className="w-2 h-2 rounded-full bg-emerald-500 inline-block" /> Selected (≥50)</span>
          <span className="flex items-center gap-1"><span className="w-2 h-2 rounded-full bg-red-500 inline-block" /> Rejected</span>
        </div>
      </div>

      {/* Desktop table */}
      <div className="card overflow-hidden">
        <div className="overflow-x-auto">
          <table className="w-full">
            <thead>
              <tr className="border-b border-slate-800 bg-slate-900/80">
                <th className="text-left px-5 py-3.5 text-xs font-semibold text-slate-500 uppercase tracking-wider w-12">Rank</th>
                <th className="text-left px-5 py-3.5 text-xs font-semibold text-slate-500 uppercase tracking-wider">Candidate</th>
                <th className="text-center px-4 py-3.5 text-xs font-semibold text-slate-500 uppercase tracking-wider">Score</th>
                <th className="text-left px-4 py-3.5 text-xs font-semibold text-slate-500 uppercase tracking-wider">Skills Match</th>
                <th className="text-center px-4 py-3.5 text-xs font-semibold text-slate-500 uppercase tracking-wider hidden md:table-cell">Exp Fit</th>
                <th className="text-center px-4 py-3.5 text-xs font-semibold text-slate-500 uppercase tracking-wider hidden lg:table-cell">Edu Fit</th>
                <th className="text-center px-4 py-3.5 text-xs font-semibold text-slate-500 uppercase tracking-wider">Status</th>
                <th className="px-4 py-3.5 w-10"></th>
              </tr>
            </thead>
            <tbody className="divide-y divide-slate-800">
              {candidates.map((c) => {
                const isSelected = selectedId === c.rank;
                const totalReq = c.matched_skills.length + c.missing_skills.length;
                const skillPct = totalReq > 0
                  ? Math.round((c.matched_skills.length / totalReq) * 100)
                  : 100;

                return (
                  <tr
                    key={c.rank}
                    id={`candidate-row-${c.rank}`}
                    onClick={() => onSelectCandidate(c)}
                    className={`cursor-pointer transition-all duration-150 ${
                      isSelected
                        ? 'bg-primary-900/20 border-l-2 border-l-primary-500'
                        : 'hover:bg-slate-800/40'
                    }`}
                  >
                    {/* Rank */}
                    <td className="px-5 py-4">
                      <div className="flex items-center justify-center">
                        <RankIcon rank={c.rank} />
                      </div>
                    </td>

                    {/* Candidate Info */}
                    <td className="px-5 py-4">
                      <div className="font-semibold text-slate-100">{c.name}</div>
                      <div className="text-xs text-slate-500 mt-0.5 truncate max-w-[180px]">{c.filename}</div>
                    </td>

                    {/* Score Ring */}
                    <td className="px-4 py-4 text-center">
                      <div className="flex flex-col items-center gap-1">
                        <ScoreRing score={c.final_score} size={52} />
                        <span className="text-xs text-slate-500">{c.match_percent}%</span>
                      </div>
                    </td>

                    {/* Skills Match */}
                    <td className="px-4 py-4">
                      <div className="flex items-center gap-2 mb-1.5">
                        <div className="flex-1 h-1.5 bg-slate-800 rounded-full overflow-hidden">
                          <div
                            className="h-full rounded-full transition-all duration-700"
                            style={{
                              width: `${skillPct}%`,
                              backgroundColor: skillPct >= 70 ? '#10b981' : skillPct >= 40 ? '#f59e0b' : '#ef4444'
                            }}
                          />
                        </div>
                        <span className="text-xs text-slate-400 w-8 text-right">{skillPct}%</span>
                      </div>
                      <div className="flex flex-wrap">
                        {c.matched_skills.slice(0, 3).map(s => (
                          <SkillBadge key={s} skill={s} variant="green" />
                        ))}
                        {c.matched_skills.length > 3 && (
                          <span className="text-xs text-slate-500 self-center">+{c.matched_skills.length - 3}</span>
                        )}
                        {c.matched_skills.length === 0 && (
                          <span className="text-xs text-slate-600 italic">None matched</span>
                        )}
                      </div>
                    </td>

                    {/* Experience Fit */}
                    <td className="px-4 py-4 text-center hidden md:table-cell">
                      <ScorePill score={c.experience_score} />
                    </td>

                    {/* Education Fit */}
                    <td className="px-4 py-4 text-center hidden lg:table-cell">
                      <div className="text-xs text-slate-400">{c.education_degree}</div>
                      <ScorePill score={c.education_score} />
                    </td>

                    {/* Status Badge */}
                    <td className="px-4 py-4 text-center">
                      {c.status === 'Selected' ? (
                        <span className="badge-green flex items-center gap-1 justify-center whitespace-nowrap">
                          <CheckCircle size={12} /> Selected
                        </span>
                      ) : (
                        <span className="badge-red flex items-center gap-1 justify-center whitespace-nowrap">
                          <XCircle size={12} /> Rejected
                        </span>
                      )}
                    </td>

                    {/* Arrow */}
                    <td className="px-4 py-4">
                      <ChevronRight size={16} className={`transition-colors ${isSelected ? 'text-primary-400' : 'text-slate-700'}`} />
                    </td>
                  </tr>
                );
              })}
            </tbody>
          </table>
        </div>
      </div>
    </div>
  );
}

function ScorePill({ score }) {
  const color = score >= 80 ? 'text-emerald-400' : score >= 50 ? 'text-amber-400' : 'text-red-400';
  return <span className={`text-sm font-semibold ${color}`}>{score.toFixed(0)}</span>;
}