import { useState } from 'react'
import { Link } from 'react-router-dom'
import {
  CalendarClock,
  Check,
  Copy,
  ExternalLink,
  Globe,
  Inbox,
  Plus,
  UserPlus,
  X,
} from 'lucide-react'

import { Badge, Modal, Panel } from '../components/ui'
import { Empty, Labeled, Note, Select, btnGhost, btnPrimary, fieldCls } from '../components/form'
import { CAP, can } from '../lib/can'
import { useAuth } from '../lib/useAuth'
import { useOrgBranding } from '../lib/orgQueries'
import {
  APPLICATION_STATUSES,
  useConvertApplication,
  useCreateOffer,
  useCreatePosting,
  useInboundApplications,
  useInterviewOffers,
  usePostings,
  useReviewApplication,
  useSetPostingStatus,
  useWithdrawOffer,
  type InboundApplication,
  type PostingInput,
} from '../lib/careers'
import { useRequisitions } from '../tools/recruitmatch/requisitionQueries'

// CAREERS: what the outside world sees, and what it sends back.
//
// Three things on one screen because they are one flow: a posting goes public, applications arrive from it,
// and the ones worth pursuing get an interview. Splitting them into three screens would mean a recruiter
// checking three places to find out whether the job they published this morning worked.
//
// THE PUBLIC LINK IS THE PRODUCT HERE. A posting nobody can reach is a draft, so the address is shown, is
// copyable in one click, and is opened in a new tab from the same screen. A recruiter should be able to
// publish and then look at what a stranger sees, without asking anybody how.

export function Careers() {
  const { principal } = useAuth()
  const mayPublish = can(principal, CAP.requirementEdit)
  const mayReview = can(principal, CAP.candidateWrite)

  return (
    <div className="space-y-4">
      <PostingsPanel mayPublish={mayPublish} />
      <InboundPanel mayReview={mayReview} />
      <OffersPanel mayReview={mayReview} />
    </div>
  )
}

// publicCareersURL builds the address a stranger uses. It is derived from the current origin rather than
// configured, because the application is served from the same host as the API, and a configured base would
// be one more thing that can be wrong in staging and right in production.
function publicCareersURL(slug: string, token?: string): string {
  const base = `${window.location.origin}/careers/${encodeURIComponent(slug)}`
  return token ? `${base}/${encodeURIComponent(token)}` : base
}

function CopyLink({ url, label }: { url: string; label: string }) {
  const [copied, setCopied] = useState(false)
  return (
    <span className="flex items-center gap-1">
      <button
        type="button"
        className={btnGhost}
        onClick={() => {
          void navigator.clipboard.writeText(url)
          setCopied(true)
          window.setTimeout(() => setCopied(false), 2000)
        }}
      >
        {copied ? <Check size={12} /> : <Copy size={12} />} {copied ? 'Copied' : label}
      </button>
      <a href={url} target="_blank" rel="noreferrer" className={btnGhost} title="Open what a stranger sees">
        <ExternalLink size={12} />
      </a>
    </span>
  )
}

function PostingsPanel({ mayPublish }: { mayPublish: boolean }) {
  const branding = useOrgBranding()
  const postings = usePostings()
  const setStatus = useSetPostingStatus()
  const [newOpen, setNewOpen] = useState(false)

  const slug = branding.data?.slug ?? ''
  const list = postings.data?.postings ?? []
  const published = list.filter((p) => p.status === 'published')

  return (
    <Panel
      title="Job postings"
      hint={published.length === 1 ? '1 live' : `${published.length} live`}
    >
      {!slug && (
        <div className="mb-3">
          <Note tone="warn">
            This organization has no public handle set, so a posting has no address to publish to. An
            operator sets it when the account is provisioned.
          </Note>
        </div>
      )}
      {slug && (
        <div className="mb-3 flex flex-wrap items-center gap-2 text-[11px] text-muted">
          <Globe size={12} />
          Your careers page is at
          <code className="rounded bg-navy-950/60 px-1.5 py-0.5 text-ink">{publicCareersURL(slug)}</code>
          <CopyLink url={publicCareersURL(slug)} label="Copy" />
        </div>
      )}

      {postings.isError ? (
        <Note tone="risk">{(postings.error as Error).message}</Note>
      ) : list.length === 0 ? (
        <Empty
          title="Nothing published"
          reason="A posting is the public face of a job order. It starts as a draft, so nothing goes live until you publish it."
        />
      ) : (
        <ul className="space-y-2">
          {list.map((p) => (
            <li
              key={p.id}
              className="flex flex-wrap items-center justify-between gap-3 rounded-lg border border-line/60 bg-navy-950/30 px-3 py-2"
            >
              <div className="min-w-0">
                <div className="flex flex-wrap items-center gap-2">
                  <span className="text-sm font-semibold text-ink">{p.title}</span>
                  <Badge
                    color={
                      p.status === 'published'
                        ? 'var(--color-ok)'
                        : p.status === 'closed'
                          ? 'var(--color-faint)'
                          : 'var(--color-warn)'
                    }
                    subtle
                  >
                    {p.status}
                  </Badge>
                </div>
                <div className="text-[11px] text-faint">
                  {p.applications === 1 ? '1 application' : `${p.applications} applications`}
                  {p.published_at ? ` · live since ${new Date(p.published_at).toLocaleDateString()}` : ''}
                  {p.closes_at ? ` · closes ${new Date(p.closes_at).toLocaleDateString()}` : ''}
                </div>
              </div>
              <div className="flex flex-wrap items-center gap-2">
                {/* The link is only offered for a LIVE posting. Handing somebody a link to a draft would be
                    handing them a 404, and the server is right to answer one. */}
                {p.status === 'published' && slug && (
                  <CopyLink url={publicCareersURL(slug, p.public_token)} label="Copy the link" />
                )}
                {mayPublish && p.status === 'draft' && (
                  <button
                    type="button"
                    className={btnPrimary}
                    onClick={() => setStatus.mutate({ id: p.id, status: 'published' })}
                  >
                    Publish it
                  </button>
                )}
                {mayPublish && p.status === 'published' && (
                  <button
                    type="button"
                    className={btnGhost}
                    onClick={() => setStatus.mutate({ id: p.id, status: 'closed' })}
                  >
                    Close it
                  </button>
                )}
              </div>
            </li>
          ))}
        </ul>
      )}

      {setStatus.isError && (
        <div className="mt-2">
          <Note tone="risk">{(setStatus.error as Error).message}</Note>
        </div>
      )}

      {mayPublish && (
        <div className="mt-3 border-t border-line/40 pt-3">
          <button type="button" className={btnPrimary} onClick={() => setNewOpen(true)}>
            <Plus size={13} /> Write a posting
          </button>
        </div>
      )}

      <NewPostingModal open={newOpen} onClose={() => setNewOpen(false)} />
    </Panel>
  )
}

const emptyPosting: PostingInput = {
  requisition_id: '',
  title: '',
  summary: '',
  responsibilities: '',
  qualifications: '',
  location_text: '',
  remote_allowed: false,
  employment_type: 'contract',
  clearance_text: '',
  pay_range_text: '',
}

function NewPostingModal({ open, onClose }: { open: boolean; onClose: () => void }) {
  const create = useCreatePosting()
  const reqs = useRequisitions({ status: 'open' })
  const [v, setV] = useState<PostingInput>(emptyPosting)

  const openReqs = reqs.data?.requisitions ?? []

  return (
    <Modal open={open} onClose={onClose} title="Write a job posting">
      <form
        className="space-y-3"
        onSubmit={(e) => {
          e.preventDefault()
          if (!v.requisition_id || !v.title.trim()) return
          create.mutate(v, {
            onSuccess: () => {
              setV(emptyPosting)
              onClose()
            },
          })
        }}
      >
        <Note tone="muted">
          This becomes a public page. Everything written here is read by people outside your organization, so
          leave out anything about the client that is not yours to publish.
        </Note>

        <Labeled label="Which job order" hint="a posting is the public face of one, so it cannot stand alone">
          <Select
            value={v.requisition_id}
            choices={[
              { value: '', label: 'Choose a job order' },
              ...openReqs.map((r) => ({ value: r.id, label: r.title })),
            ]}
            onChange={(id) => {
              const r = openReqs.find((x) => x.id === id)
              // The title is seeded from the job order, because the internal name is usually the right
              // public one, and a recruiter who wants a different one can simply type over it.
              setV({ ...v, requisition_id: id, title: v.title || (r?.title ?? '') })
            }}
            className="w-full"
          />
        </Labeled>
        <Labeled label="Title">
          <input
            value={v.title}
            maxLength={200}
            onChange={(e) => setV({ ...v, title: e.target.value })}
            className={fieldCls}
          />
        </Labeled>
        <Labeled label="Summary" hint="the paragraph somebody reads before deciding to keep reading">
          <textarea
            value={v.summary}
            rows={3}
            maxLength={4000}
            onChange={(e) => setV({ ...v, summary: e.target.value })}
            className={fieldCls}
          />
        </Labeled>
        <Labeled label="What they will do">
          <textarea
            value={v.responsibilities}
            rows={4}
            maxLength={8000}
            onChange={(e) => setV({ ...v, responsibilities: e.target.value })}
            className={fieldCls}
          />
        </Labeled>
        <Labeled label="What they need">
          <textarea
            value={v.qualifications}
            rows={4}
            maxLength={8000}
            onChange={(e) => setV({ ...v, qualifications: e.target.value })}
            className={fieldCls}
          />
        </Labeled>
        <div className="grid gap-2.5 sm:grid-cols-2">
          <Labeled label="Location">
            <input
              value={v.location_text}
              maxLength={200}
              onChange={(e) => setV({ ...v, location_text: e.target.value })}
              className={fieldCls}
            />
          </Labeled>
          <Labeled label="Employment type">
            <Select
              value={v.employment_type}
              choices={[
                { value: 'contract', label: 'Contract' },
                { value: 'contract_to_hire', label: 'Contract to hire' },
                { value: 'direct_hire', label: 'Direct hire' },
              ]}
              onChange={(t) => setV({ ...v, employment_type: t })}
              className="w-full"
            />
          </Labeled>
          <Labeled
            label="Clearance"
            hint="written in your own words for the advert, and still a self reported indicator"
          >
            <input
              value={v.clearance_text}
              maxLength={200}
              placeholder="Active TS/SCI required"
              onChange={(e) => setV({ ...v, clearance_text: e.target.value })}
              className={fieldCls}
            />
          </Labeled>
          <Labeled label="Pay range" hint="what you are willing to publish, in whatever form you publish it">
            <input
              value={v.pay_range_text}
              maxLength={200}
              placeholder="150,000 to 175,000"
              onChange={(e) => setV({ ...v, pay_range_text: e.target.value })}
              className={fieldCls}
            />
          </Labeled>
        </div>
        <label className="flex items-center gap-2 text-sm text-muted">
          <input
            type="checkbox"
            checked={v.remote_allowed}
            onChange={(e) => setV({ ...v, remote_allowed: e.target.checked })}
          />
          Remote is allowed
        </label>

        {create.isError && <Note tone="risk">{(create.error as Error).message}</Note>}

        <button
          type="submit"
          disabled={!v.requisition_id || !v.title.trim() || create.isPending}
          className={btnPrimary}
        >
          {create.isPending ? 'Saving' : 'Save it as a draft'}
        </button>
        <p className="text-[11px] text-faint">
          It saves as a draft. Nothing is public until you publish it from the list.
        </p>
      </form>
    </Modal>
  )
}

function InboundPanel({ mayReview }: { mayReview: boolean }) {
  const apps = useInboundApplications()
  const [offerFor, setOfferFor] = useState<InboundApplication | null>(null)

  const list = apps.data?.applications ?? []
  const fresh = list.filter((a) => a.status === 'new')

  return (
    <Panel title="Applications" hint={fresh.length === 1 ? '1 new' : `${fresh.length} new`}>
      {apps.isError ? (
        <Note tone="risk">{(apps.error as Error).message}</Note>
      ) : list.length === 0 ? (
        <Empty
          title="Nothing has come in"
          reason="Applications from your published postings land here. Nothing arrives until a posting is live."
        />
      ) : (
        <ul className="space-y-2">
          {list.map((a) => (
            <ApplicationRow key={a.id} app={a} mayReview={mayReview} onOffer={() => setOfferFor(a)} />
          ))}
        </ul>
      )}
      <NewOfferModal app={offerFor} onClose={() => setOfferFor(null)} />
    </Panel>
  )
}

function ApplicationRow({
  app,
  mayReview,
  onOffer,
}: {
  app: InboundApplication
  mayReview: boolean
  onOffer: () => void
}) {
  const review = useReviewApplication()
  const convert = useConvertApplication()
  const [open, setOpen] = useState(false)
  const [reason, setReason] = useState('')

  const status = APPLICATION_STATUSES.find((s) => s.value === app.status)

  return (
    <li className="rounded-lg border border-line/60 bg-navy-950/30 px-3 py-2">
      <div className="flex flex-wrap items-start justify-between gap-3">
        <div className="min-w-0">
          <div className="flex flex-wrap items-center gap-2">
            <button
              type="button"
              onClick={() => setOpen(!open)}
              className="text-sm font-semibold text-ink hover:underline"
            >
              {app.full_name}
            </button>
            <Badge color={app.status === 'new' ? 'var(--color-warn)' : 'var(--color-blue)'} subtle>
              {status?.label ?? app.status}
            </Badge>
            {app.has_resume && <span className="text-[11px] text-faint">resume attached</span>}
          </div>
          <div className="text-[11px] text-faint">
            {app.posting_title} · {app.email}
            {app.location_text ? ` · ${app.location_text}` : ''} ·{' '}
            {new Date(app.created_at).toLocaleDateString()}
          </div>
        </div>
        <div className="flex flex-wrap items-center gap-2">
          {/* An application that BECAME a candidate links to the record rather than offering convert again.
              Converting twice would create the duplicate this product has a whole screen for removing. */}
          {app.candidate_id ? (
            <Link to={`/bench/candidate/${app.candidate_id}`} className={btnGhost}>
              Open the record
            </Link>
          ) : (
            mayReview && (
              <>
                <button
                  type="button"
                  className={btnPrimary}
                  disabled={convert.isPending}
                  onClick={() => convert.mutate(app.id)}
                >
                  <UserPlus size={13} /> {convert.isPending ? 'Adding' : 'Add to the bench'}
                </button>
                <button type="button" className={btnGhost} onClick={() => setOpen(!open)}>
                  Review it
                </button>
              </>
            )
          )}
          {app.candidate_id && mayReview && (
            <button type="button" className={btnGhost} onClick={onOffer}>
              <CalendarClock size={13} /> Offer times
            </button>
          )}
        </div>
      </div>

      {open && (
        <div className="mt-2 space-y-2 border-t border-line/40 pt-2">
          {app.cover_note && (
            <p className="whitespace-pre-wrap text-[11px] leading-relaxed text-muted">{app.cover_note}</p>
          )}
          <div className="flex flex-wrap gap-3 text-[11px] text-faint">
            {app.phone && <span>{app.phone}</span>}
            {app.clearance_self_reported && <span>clearance stated as {app.clearance_self_reported}</span>}
            <span>came from {app.source}</span>
            {/* Consent is shown because it is the legal basis for holding this person's details at all, and
                an application without one is a fact somebody needs to see rather than a missing field. */}
            {app.consented_at ? (
              <span>consented {new Date(app.consented_at).toLocaleDateString()}</span>
            ) : (
              <span className="text-warn">no consent recorded</span>
            )}
          </div>
          {app.status_reason && <Note tone="muted">Recorded reason: {app.status_reason}</Note>}

          {mayReview && !app.candidate_id && (
            <div className="flex flex-wrap items-end gap-2">
              <input
                value={reason}
                maxLength={240}
                placeholder="Why, in a sentence"
                onChange={(e) => setReason(e.target.value)}
                className={`${fieldCls} max-w-sm`}
              />
              {APPLICATION_STATUSES.filter((s) => s.value !== 'new' && s.value !== 'accepted').map((s) => (
                <button
                  key={s.value}
                  type="button"
                  className={btnGhost}
                  title={s.hint}
                  onClick={() => review.mutate({ id: app.id, status: s.value, reason: reason.trim() })}
                >
                  {s.label}
                </button>
              ))}
            </div>
          )}
          {review.isError && <Note tone="risk">{(review.error as Error).message}</Note>}
          {convert.isError && <Note tone="risk">{(convert.error as Error).message}</Note>}
        </div>
      )}
    </li>
  )
}

function OffersPanel({ mayReview }: { mayReview: boolean }) {
  const offers = useInterviewOffers()
  const withdraw = useWithdrawOffer()
  const branding = useOrgBranding()
  const slug = branding.data?.slug ?? ''

  const list = offers.data?.offers ?? []
  const open = list.filter((o) => o.status === 'open')

  return (
    <Panel title="Interview scheduling" hint={open.length === 1 ? '1 waiting' : `${open.length} waiting`}>
      <p className="pb-2 text-[11px] leading-relaxed text-faint">
        Offer somebody a few times and send them the link. They pick one, and the interview is created when
        they do, so nobody spends a morning trading messages about Thursday.
      </p>
      {offers.isError ? (
        <Note tone="risk">{(offers.error as Error).message}</Note>
      ) : list.length === 0 ? (
        <Empty
          title="Nothing scheduled"
          reason="Offer times from an application once it is on the bench, and the link appears here."
        />
      ) : (
        <ul className="space-y-2">
          {list.map((o) => (
            <li
              key={o.id}
              className="flex flex-wrap items-center justify-between gap-3 rounded-lg border border-line/60 bg-navy-950/30 px-3 py-2"
            >
              <div className="min-w-0">
                <div className="flex flex-wrap items-center gap-2 text-sm">
                  <span className="font-semibold text-ink">{o.candidate_name}</span>
                  <span className="text-faint">for {o.role}</span>
                  <Badge color={o.status === 'open' ? 'var(--color-warn)' : 'var(--color-ok)'} subtle>
                    {o.status}
                  </Badge>
                </div>
                <div className="text-[11px] text-faint">
                  {o.kind} ·{' '}
                  {o.times_available === 1 ? '1 time left' : `${o.times_available} times left`} · expires{' '}
                  {new Date(o.expires_at).toLocaleDateString()}
                </div>
              </div>
              <div className="flex flex-wrap items-center gap-2">
                {o.status === 'open' && slug && (
                  <CopyLink
                    url={`${window.location.origin}/careers/${encodeURIComponent(slug)}/schedule/${encodeURIComponent(o.public_token)}`}
                    label="Copy the link"
                  />
                )}
                {mayReview && o.status === 'open' && (
                  <button type="button" className={btnGhost} onClick={() => withdraw.mutate(o.id)}>
                    <X size={12} /> Withdraw
                  </button>
                )}
              </div>
            </li>
          ))}
        </ul>
      )}
      {withdraw.isError && (
        <div className="mt-2">
          <Note tone="risk">{(withdraw.error as Error).message}</Note>
        </div>
      )}
    </Panel>
  )
}

function NewOfferModal({ app, onClose }: { app: InboundApplication | null; onClose: () => void }) {
  const create = useCreateOffer()
  const [kind, setKind] = useState('phone')
  const [duration, setDuration] = useState(30)
  const [interviewer, setInterviewer] = useState('')
  const [location, setLocation] = useState('')
  const [message, setMessage] = useState('')
  const [slots, setSlots] = useState<string[]>([''])

  if (!app) return null
  const usable = slots.map((s) => s.trim()).filter(Boolean)

  return (
    <Modal open={!!app} onClose={onClose} title={`Offer times to ${app.full_name}`}>
      <form
        className="space-y-3"
        onSubmit={(e) => {
          e.preventDefault()
          if (usable.length === 0) return
          create.mutate(
            {
              application_id: app.id,
              kind,
              round: 1,
              duration_mins: duration,
              location_text: location,
              interviewer,
              message,
              expires_in_days: 7,
              // The browser gives a local time with no zone. Converting to an instant here means the
              // candidate is offered the moment that was meant rather than the same clock reading in
              // whatever zone they happen to be in.
              slots: usable.map((s) => new Date(s).toISOString()),
            },
            {
              onSuccess: () => {
                setSlots([''])
                setMessage('')
                onClose()
              },
            },
          )
        }}
      >
        <div className="grid gap-2.5 sm:grid-cols-2">
          <Labeled label="Kind">
            <Select
              value={kind}
              choices={[
                { value: 'phone', label: 'Phone' },
                { value: 'video', label: 'Video' },
                { value: 'onsite', label: 'On site' },
              ]}
              onChange={setKind}
              className="w-full"
            />
          </Labeled>
          <Labeled label="How long">
            <Select
              value={String(duration)}
              choices={[
                { value: '15', label: '15 minutes' },
                { value: '30', label: '30 minutes' },
                { value: '45', label: '45 minutes' },
                { value: '60', label: '1 hour' },
              ]}
              onChange={(v) => setDuration(Number(v))}
              className="w-full"
            />
          </Labeled>
          <Labeled label="Who is interviewing">
            <input
              value={interviewer}
              maxLength={200}
              onChange={(e) => setInterviewer(e.target.value)}
              className={fieldCls}
            />
          </Labeled>
          <Labeled label="Where" hint="a dial in number, a link, or an address">
            <input
              value={location}
              maxLength={400}
              onChange={(e) => setLocation(e.target.value)}
              className={fieldCls}
            />
          </Labeled>
        </div>

        <Labeled label="A note to them" hint="this is read by the candidate on the scheduling page">
          <textarea
            value={message}
            rows={3}
            maxLength={2000}
            onChange={(e) => setMessage(e.target.value)}
            className={fieldCls}
          />
        </Labeled>

        <fieldset className="space-y-2">
          <legend className="text-[11px] font-bold uppercase tracking-wider text-muted">
            Times to offer
          </legend>
          {slots.map((s, i) => (
            <div key={i} className="flex gap-2">
              <input
                type="datetime-local"
                value={s}
                onChange={(e) => setSlots(slots.map((v, j) => (j === i ? e.target.value : v)))}
                className={fieldCls}
              />
              {slots.length > 1 && (
                <button
                  type="button"
                  className={btnGhost}
                  onClick={() => setSlots(slots.filter((_, j) => j !== i))}
                >
                  <X size={12} />
                </button>
              )}
            </div>
          ))}
          <button type="button" className={btnGhost} onClick={() => setSlots([...slots, ''])}>
            <Plus size={12} /> Another time
          </button>
          <p className="text-[11px] text-faint">
            Times are in your own time zone here, and are shown to the candidate in theirs.
          </p>
        </fieldset>

        {create.isError && <Note tone="risk">{(create.error as Error).message}</Note>}

        <button type="submit" disabled={usable.length === 0 || create.isPending} className={btnPrimary}>
          <Inbox size={13} /> {create.isPending ? 'Creating' : 'Create the link'}
        </button>
        <p className="text-[11px] text-faint">
          Nothing is sent for you. The link appears in the list above for you to send.
        </p>
      </form>
    </Modal>
  )
}