'use client';

import { useMemo, useState } from 'react';
import { Search, Filter, FileCode, ShieldCheck, Target } from 'lucide-react';
import { Avatar, Badge } from '@nextcraft/ui';
import type { Candidate } from '@nextcraft/types';
import { matchBadgeClasses } from '../../lib/format';

/* -------------------------------------------------------------------------- */
/*  Filter config                                                             */
/* -------------------------------------------------------------------------- */

const STACK_OPTIONS = [
  { value: 'all', label: 'All stacks' },
  { value: 'stack-orchestration', label: 'AI Orchestration' },
  { value: 'stack-safety', label: 'AI Safety' },
  { value: 'stack-designer', label: 'Product Design' },
  { value: 'stack-operator', label: 'Field Operator' },
  { value: 'stack-science', label: 'Comp Sciences' },
];

const DEFENSE_OPTIONS = [
  { value: 0, label: 'Any defense score' },
  { value: 70, label: 'Defense 70+' },
  { value: 80, label: 'Defense 80+' },
  { value: 90, label: 'Defense 90+' },
];

const ARTIFACT_OPTIONS = [
  { value: 0, label: 'Any artifacts' },
  { value: 1, label: '1+ artifacts' },
  { value: 3, label: '3+ artifacts' },
  { value: 5, label: '5+ artifacts' },
  { value: 10, label: '10+ artifacts' },
];

/** Derive 3 short microcredential badges from a candidate's stack + count. */
function microcredentialBadges(cand: Candidate): string[] {
  const stackMap: Record<string, string[]> = {
    'stack-orchestration': ['Agent Arch', 'Tool Use', 'RAG', 'Eval', 'Routing'],
    'stack-safety': ['Red Team', 'Model Cards', 'Bias Audit', 'Policy', 'Interp'],
    'stack-designer': ['Agentic UX', 'Conv UX', 'Transparency', 'Trust', 'Persona'],
    'stack-operator': ['Robotics', 'Vision', 'Calibration', 'AR', 'Field Data'],
    'stack-science': ['Sci Python', 'HPC', 'PINNs', 'Active Learn', 'Bioinformatics'],
  };
  const pool = stackMap[cand.competencyStackId] ?? ['MC-1', 'MC-2', 'MC-3'];
  // Spread selection deterministically based on id suffix.
  const offset = Number(cand.id.replace(/\D/g, '')) % pool.length;
  return [pool[offset % pool.length], pool[(offset + 1) % pool.length], pool[(offset + 2) % pool.length]];
}

/* -------------------------------------------------------------------------- */
/*  Component                                                                 */
/* -------------------------------------------------------------------------- */

export interface TalentSearchProps {
  candidates: Candidate[];
}

export function TalentSearch({ candidates }: TalentSearchProps) {
  const [query, setQuery] = useState('');
  const [stack, setStack] = useState('all');
  const [minDefense, setMinDefense] = useState(0);
  const [minArtifacts, setMinArtifacts] = useState(0);

  const filtered = useMemo(() => {
    const q = query.trim().toLowerCase();
    return candidates.filter((c) => {
      if (q) {
        const hay = `${c.name} ${c.headline}`.toLowerCase();
        if (!hay.includes(q)) return false;
      }
      if (stack !== 'all' && c.competencyStackId !== stack) return false;
      if (c.defenseScore < minDefense) return false;
      if (c.artifactCount < minArtifacts) return false;
      return true;
    });
  }, [candidates, query, stack, minDefense, minArtifacts]);

  const selectClass =
    'h-9 rounded-md border border-slate-300 bg-white px-2.5 text-sm text-slate-900 focus:border-primary-500 focus:ring-2 focus:ring-primary-500/30 focus:outline-none dark:border-slate-700 dark:bg-slate-800 dark:text-slate-100';

  return (
    <div className="flex flex-col gap-6">
      {/* Filter bar */}
      <div className="flex flex-col gap-3 rounded-lg border border-slate-200 bg-white p-4 dark:border-slate-800 dark:bg-slate-900">
        <div className="relative flex items-center">
          <Search className="pointer-events-none absolute left-3 h-4 w-4 text-slate-400" />
          <input
            type="text"
            value={query}
            onChange={(e) => setQuery(e.target.value)}
            placeholder="Search candidates by name or headline..."
            aria-label="Search candidates"
            className="h-10 w-full rounded-md border border-slate-300 bg-white pl-9 pr-3 text-sm text-slate-900 placeholder:text-slate-400 focus:border-primary-500 focus:ring-2 focus:ring-primary-500/30 focus:outline-none dark:border-slate-700 dark:bg-slate-800 dark:text-slate-100 dark:placeholder:text-slate-500"
          />
        </div>
        <div className="flex flex-wrap items-center gap-3">
          <span className="inline-flex items-center gap-1.5 text-xs font-medium text-slate-500 dark:text-slate-400">
            <Filter className="h-3.5 w-3.5" /> Filters:
          </span>
          <select
            aria-label="Competency stack"
            value={stack}
            onChange={(e) => setStack(e.target.value)}
            className={selectClass}
          >
            {STACK_OPTIONS.map((o) => (
              <option key={o.value} value={o.value}>
                {o.label}
              </option>
            ))}
          </select>
          <select
            aria-label="Minimum defense score"
            value={minDefense}
            onChange={(e) => setMinDefense(Number(e.target.value))}
            className={selectClass}
          >
            {DEFENSE_OPTIONS.map((o) => (
              <option key={o.value} value={o.value}>
                {o.label}
              </option>
            ))}
          </select>
          <select
            aria-label="Minimum artifact count"
            value={minArtifacts}
            onChange={(e) => setMinArtifacts(Number(e.target.value))}
            className={selectClass}
          >
            {ARTIFACT_OPTIONS.map((o) => (
              <option key={o.value} value={o.value}>
                {o.label}
              </option>
            ))}
          </select>
          <span className="ml-auto text-sm text-slate-500 dark:text-slate-400">
            Showing <span className="font-semibold text-slate-700 dark:text-slate-200">{filtered.length}</span> of{' '}
            {candidates.length}
          </span>
        </div>
      </div>

      {/* Candidate grid */}
      {filtered.length === 0 ? (
        <div className="rounded-lg border border-dashed border-slate-300 p-12 text-center text-slate-500 dark:border-slate-700 dark:text-slate-400">
          No candidates match your filters.
        </div>
      ) : (
        <div className="grid grid-cols-1 gap-4 md:grid-cols-2 xl:grid-cols-3">
          {filtered.map((cand) => (
            <CandidateCard key={cand.id} cand={cand} />
          ))}
        </div>
      )}
    </div>
  );
}

function CandidateCard({ cand }: { cand: Candidate }) {
  const badges = microcredentialBadges(cand);
  return (
    <article className="flex flex-col gap-3 rounded-lg border border-slate-200 bg-white p-5 shadow-sm transition-shadow hover:shadow-md dark:border-slate-800 dark:bg-slate-900">
      <div className="flex items-start gap-3">
        <Avatar name={cand.name} src={cand.avatar} size="md" />
        <div className="flex min-w-0 flex-1 flex-col">
          <h3 className="truncate text-base font-semibold text-slate-900 dark:text-slate-100">
            {cand.name}
          </h3>
          <p className="truncate text-sm text-slate-600 dark:text-slate-400">{cand.headline}</p>
        </div>
        <span
          className={`inline-flex h-9 w-12 shrink-0 items-center justify-center rounded-full text-xs font-bold ring-2 ${matchBadgeClasses(
            cand.matchScore,
          )}`}
          title="AI match score"
        >
          {cand.matchScore}%
        </span>
      </div>

      <div className="flex flex-wrap gap-1.5">
        {badges.map((b) => (
          <Badge key={b} variant="info">
            {b}
          </Badge>
        ))}
      </div>

      <div className="flex flex-wrap items-center gap-x-3 gap-y-1 text-xs text-slate-600 dark:text-slate-400">
        <span className="inline-flex items-center gap-1">
          <FileCode className="h-3.5 w-3.5" /> {cand.artifactCount} artifacts
        </span>
        <span className="inline-flex items-center gap-1">
          <ShieldCheck className="h-3.5 w-3.5" /> Defense: {cand.defenseScore}
        </span>
        <span className="inline-flex items-center gap-1">
          <Target className="h-3.5 w-3.5" /> Match: {cand.matchScore}%
        </span>
      </div>

      <a
        href={`/employer/talent/${cand.id}`}
        className="mt-auto inline-flex h-9 w-full items-center justify-center rounded-md border border-slate-300 bg-transparent text-sm font-medium text-slate-800 transition-colors hover:bg-slate-50 dark:border-slate-700 dark:text-slate-100 dark:hover:bg-slate-800"
      >
        View Profile
      </a>
    </article>
  );
}

// Re-export icon used in card stats so the import is not tree-shaken away.