'use client';

import { useState } from 'react';
import { Plus, Trash2, Save } from 'lucide-react';
import { Badge, Button } from '@nextcraft/ui';
import type { Job, Seniority } from '@nextcraft/types';
import { formatSalaryK, relativeTime, seniorityLabel } from '../../lib/format';

/* -------------------------------------------------------------------------- */
/*  Mock posting list (status + applicant count derived from the Job)        */
/* -------------------------------------------------------------------------- */

type PostingStatus = 'active' | 'draft' | 'expired';

interface PostingRow {
  job: Job;
  status: PostingStatus;
  applicants: number;
}

interface ApplicantRow {
  name: string;
  appliedAt: string;
  stage: 'Screening' | 'Interview' | 'Offer';
  matchScore: number;
}

/* Deterministically derive a posting status per job id. */
function deriveStatus(job: Job, idx: number): PostingStatus {
  if (idx < 8) return 'active';
  if (idx < 11) return 'draft';
  return 'expired';
}

function deriveApplicants(job: Job, idx: number): number {
  return 4 + ((job.matchScore + idx * 7) % 18);
}

function deriveApplicantList(job: Job): ApplicantRow[] {
  const names = [
    'Maya Okonkwo',
    'Devon Park',
    'Priya Iyer',
    'Tomás Vega',
    'Liam Chen',
    'Yuki Tanaka',
    'Sofia Marchetti',
  ];
  const stages: ApplicantRow['stage'][] = ['Screening', 'Interview', 'Offer'];
  const count = 5 + (job.matchScore % 2);
  const rows: ApplicantRow[] = [];
  for (let i = 0; i < count; i++) {
    const stage = stages[i % stages.length];
    rows.push({
      name: names[(job.matchScore + i) % names.length],
      appliedAt: new Date(Date.UTC(2026, 7, 28 - i * 2)).toISOString(),
      stage,
      matchScore: 78 + ((job.matchScore + i * 3) % 18),
    });
  }
  return rows;
}

/* -------------------------------------------------------------------------- */
/*  Status badge                                                              */
/* -------------------------------------------------------------------------- */

function StatusBadge({ status }: { status: PostingStatus }) {
  if (status === 'active') return <Badge variant="success">Active</Badge>;
  if (status === 'draft') return <Badge variant="warning">Draft</Badge>;
  return <Badge variant="default">Expired</Badge>;
}

function StageBadge({ stage }: { stage: ApplicantRow['stage'] }) {
  if (stage === 'Offer') return <Badge variant="success">Offer</Badge>;
  if (stage === 'Interview') return <Badge variant="info">Interview</Badge>;
  return <Badge variant="warning">Screening</Badge>;
}

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

export interface PostingManagerProps {
  jobs: Job[];
}

export function PostingManager({ jobs }: PostingManagerProps) {
  const postings: PostingRow[] = jobs.map((job, idx) => ({
    job,
    status: deriveStatus(job, idx),
    applicants: deriveApplicants(job, idx),
  }));

  const [selectedId, setSelectedId] = useState<string>(postings[0]?.job.id ?? '');
  const selected = postings.find((p) => p.job.id === selectedId) ?? null;

  return (
    <div className="grid grid-cols-1 gap-6 lg:grid-cols-[360px_1fr]">
      {/* Left panel — posting list */}
      <div className="flex flex-col gap-3">
        <div className="flex items-center justify-between">
          <h2 className="text-sm font-semibold uppercase tracking-wide text-slate-500 dark:text-slate-400">
            Postings
          </h2>
          <Button size="sm" variant="primary" icon={<Plus className="h-3.5 w-3.5" />} type="button">
            New
          </Button>
        </div>
        <div className="flex flex-col gap-2">
          {postings.map((p) => {
            const active = p.job.id === selectedId;
            return (
              <button
                key={p.job.id}
                type="button"
                onClick={() => setSelectedId(p.job.id)}
                className={[
                  'flex flex-col gap-1.5 rounded-lg border p-3 text-left transition-colors',
                  active
                    ? 'border-primary-500 bg-primary-50 dark:border-primary-700 dark:bg-primary-900/30'
                    : 'border-slate-200 bg-white hover:bg-slate-50 dark:border-slate-800 dark:bg-slate-900 dark:hover:bg-slate-800',
                ].join(' ')}
              >
                <div className="flex items-start justify-between gap-2">
                  <span className="text-sm font-semibold text-slate-900 dark:text-slate-100">
                    {p.job.title}
                  </span>
                  <StatusBadge status={p.status} />
                </div>
                <div className="flex flex-wrap items-center gap-x-3 gap-y-1 text-xs text-slate-500 dark:text-slate-400">
                  <span>{relativeTime(p.job.postedAt)}</span>
                  <span>·</span>
                  <span>{p.applicants} applicants</span>
                </div>
              </button>
            );
          })}
        </div>
      </div>

      {/* Right panel — detail */}
      <div>
        {selected ? (
          <PostingDetail posting={selected} />
        ) : (
          <div className="flex h-64 items-center justify-center rounded-lg border border-dashed border-slate-300 text-slate-500 dark:border-slate-700 dark:text-slate-400">
            Select a posting to view details
          </div>
        )}
      </div>
    </div>
  );
}

function PostingDetail({ posting }: { posting: PostingRow }) {
  const { job, applicants } = posting;
  const applicantList = deriveApplicantList(job);
  const seniorityOptions: Seniority[] = ['entry', 'mid', 'senior', 'staff', 'principal'];

  const inputClass =
    'h-10 w-full rounded-md border border-slate-300 bg-white px-3 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">
      {/* Posting form */}
      <div className="rounded-lg border border-slate-200 bg-white p-5 dark:border-slate-800 dark:bg-slate-900">
        <div className="mb-4 flex items-center justify-between">
          <h2 className="text-lg font-semibold text-slate-900 dark:text-slate-100">
            Edit Posting
          </h2>
          <StatusBadge status={posting.status} />
        </div>

        <div className="flex flex-col gap-4">
          <div className="flex flex-col gap-1.5">
            <label className="text-sm font-medium text-slate-700 dark:text-slate-200">Title</label>
            <input className={inputClass} defaultValue={job.title} aria-label="Posting title" />
          </div>

          <div className="flex flex-col gap-1.5">
            <label className="text-sm font-medium text-slate-700 dark:text-slate-200">Description</label>
            <textarea
              className="min-h-24 w-full rounded-md border border-slate-300 bg-white p-3 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"
              defaultValue={job.description}
              aria-label="Posting description"
            />
          </div>

          <div className="flex flex-col gap-1.5">
            <label className="text-sm font-medium text-slate-700 dark:text-slate-200">
              Required Competencies
            </label>
            <div className="flex flex-wrap gap-2">
              {job.requiredCompetencies.map((c) => (
                <span
                  key={c}
                  className="inline-flex items-center gap-1 rounded-full bg-primary-100 px-2.5 py-1 text-xs font-medium text-primary-700 dark:bg-primary-900/40 dark:text-primary-300"
                >
                  {c}
                </span>
              ))}
            </div>
          </div>

          <div className="grid grid-cols-1 gap-4 sm:grid-cols-2">
            <div className="flex flex-col gap-1.5">
              <label className="text-sm font-medium text-slate-700 dark:text-slate-200">Seniority</label>
              <select className={inputClass} defaultValue={job.seniority} aria-label="Seniority">
                {seniorityOptions.map((s) => (
                  <option key={s} value={s}>
                    {seniorityLabel(s)}
                  </option>
                ))}
              </select>
            </div>
            <div className="flex flex-col gap-1.5">
              <label className="text-sm font-medium text-slate-700 dark:text-slate-200">Location</label>
              <input className={inputClass} defaultValue={job.location} aria-label="Location" />
            </div>
          </div>

          <div className="grid grid-cols-2 gap-4">
            <div className="flex flex-col gap-1.5">
              <label className="text-sm font-medium text-slate-700 dark:text-slate-200">
                Salary Min
              </label>
              <input
                className={inputClass}
                defaultValue={formatSalaryK(job.salaryMin)}
                aria-label="Salary minimum"
              />
            </div>
            <div className="flex flex-col gap-1.5">
              <label className="text-sm font-medium text-slate-700 dark:text-slate-200">
                Salary Max
              </label>
              <input
                className={inputClass}
                defaultValue={formatSalaryK(job.salaryMax)}
                aria-label="Salary maximum"
              />
            </div>
          </div>

          <label className="flex cursor-pointer items-center justify-between gap-2 text-sm text-slate-700 dark:text-slate-200">
            <span>Remote eligible</span>
            <button
              type="button"
              role="switch"
              aria-checked={job.remote}
              className={[
                'relative h-6 w-11 rounded-full transition-colors',
                job.remote ? 'bg-primary-600' : 'bg-slate-300 dark:bg-slate-700',
              ].join(' ')}
            >
              <span
                className={[
                  'absolute top-0.5 h-5 w-5 rounded-full bg-white shadow transition-transform',
                  job.remote ? 'translate-x-5' : 'translate-x-0.5',
                ].join(' ')}
              />
            </button>
          </label>

          <div className="flex flex-wrap gap-2 pt-2">
            <Button variant="primary" size="md" icon={<Save className="h-4 w-4" />} type="button">
              Save Changes
            </Button>
            <Button variant="destructive" size="md" icon={<Trash2 className="h-4 w-4" />} type="button">
              Delete Posting
            </Button>
          </div>
        </div>
      </div>

      {/* Applicant list */}
      <div className="rounded-lg border border-slate-200 bg-white p-5 dark:border-slate-800 dark:bg-slate-900">
        <div className="mb-4 flex items-center justify-between">
          <h2 className="text-lg font-semibold text-slate-900 dark:text-slate-100">
            Applicants
          </h2>
          <span className="text-sm text-slate-500 dark:text-slate-400">
            {applicants} total · {applicantList.length} shown
          </span>
        </div>

        {/* Table on desktop, cards on mobile */}
        <div className="overflow-x-auto">
          <table className="hidden w-full md:table">
            <thead>
              <tr className="border-b border-slate-200 text-left text-xs uppercase tracking-wide text-slate-500 dark:border-slate-800 dark:text-slate-400">
                <th className="pb-2 pr-4 font-medium">Applicant</th>
                <th className="pb-2 pr-4 font-medium">Applied</th>
                <th className="pb-2 pr-4 font-medium">Stage</th>
                <th className="pb-2 pr-4 font-medium text-right">Match</th>
              </tr>
            </thead>
            <tbody>
              {applicantList.map((a, i) => (
                <tr key={i} className="border-b border-slate-100 last:border-0 dark:border-slate-800/60">
                  <td className="py-2.5 pr-4 text-sm font-medium text-slate-900 dark:text-slate-100">
                    {a.name}
                  </td>
                  <td className="py-2.5 pr-4 text-sm text-slate-600 dark:text-slate-400">
                    {relativeTime(a.appliedAt)}
                  </td>
                  <td className="py-2.5 pr-4"><StageBadge stage={a.stage} /></td>
                  <td className="py-2.5 pr-4 text-right text-sm font-semibold text-slate-700 dark:text-slate-200">
                    {a.matchScore}%
                  </td>
                </tr>
              ))}
            </tbody>
          </table>

          {/* Mobile cards */}
          <div className="flex flex-col gap-2 md:hidden">
            {applicantList.map((a, i) => (
              <div
                key={i}
                className="flex items-center justify-between rounded-md border border-slate-200 p-3 dark:border-slate-800"
              >
                <div className="flex flex-col">
                  <span className="text-sm font-medium text-slate-900 dark:text-slate-100">{a.name}</span>
                  <span className="text-xs text-slate-500 dark:text-slate-400">
                    {relativeTime(a.appliedAt)}
                  </span>
                </div>
                <div className="flex items-center gap-2">
                  <StageBadge stage={a.stage} />
                  <span className="text-sm font-semibold text-slate-700 dark:text-slate-200">
                    {a.matchScore}%
                  </span>
                </div>
              </div>
            ))}
          </div>
        </div>
      </div>
    </div>
  );
}