import { useMemo, useState, type ReactNode } from 'react'
import { Link, useParams } from 'react-router-dom'
import { de } from '../strings/de'
import { getGerbil, updateGerbil } from '../api/gerbils'
import { listColorVarieties, listContacts, listEnclosures, listLitters } from '../api/lookups'
import { useApi, useMutation } from '../hooks/useApi'
import { formatDate, genderLabel, statusLabel } from '../format/labels'
import { fromDisplayString, genotypeToFarbschlag, toDisplayString } from '../genetics'
import FarbschlagImage from '../components/FarbschlagImage'
import Charakterbogen from '../components/Charakterbogen'
// FEAT-6 (Oscar): Tab-Inhalte + Profilfoto
import GerbilHealthTab from '../components/GerbilHealthTab'
import GerbilPhotosTab from '../components/GerbilPhotosTab'
import GerbilProfilePhoto from '../components/GerbilProfilePhoto'
import GerbilWeightTab from '../components/GerbilWeightTab'

type DetailTab = 'photos' | 'health' | 'weight'

/** Parse a stored genotype string and derive its normalized form + Farbschlag. */
function describeGenotype(genotype: string | null): { display: string; farbschlag: string } | null {
  if (!genotype || !genotype.trim()) return null
  try {
    const g = fromDisplayString(genotype)
    return { display: toDisplayString(g), farbschlag: genotypeToFarbschlag(g) }
  } catch {
    // Unparseable: show the raw value, no derived Farbschlag.
    return { display: genotype, farbschlag: de.genetics.unknownFarbschlag }
  }
}

function Row({ label, value }: { label: string; value: ReactNode }) {
  return (
    <div className="def-row">
      <dt>{label}</dt>
      <dd>{value ?? '—'}</dd>
    </div>
  )
}

export default function GerbilDetailPage() {
  const t = de.pages.gerbils
  const { id = '' } = useParams()
  const [tab, setTab] = useState<DetailTab>('photos')

  const gerbil = useApi(() => getGerbil(id), [id])
  const forSale = useMutation(() => updateGerbil(id, { status: 'ForSale' }))
  // FEAT-14: Charakterbogen (persisted on the Gerbil).
  const [charTraits, setCharTraits] = useState<string[]>([])
  const [charNote, setCharNote] = useState('')
  const [charInit, setCharInit] = useState<string | null>(null)
  const saveCharacter = useMutation(() =>
    updateGerbil(id, { characterTraits: charTraits, characterNote: charNote.trim() || null }),
  )
  const colorVarieties = useApi(() => listColorVarieties(), [])
  const enclosures = useApi(() => listEnclosures(), [])
  const contacts = useApi(() => listContacts(), [])
  const litters = useApi(() => listLitters(), [])

  const colorName = useMemo(
    () => new Map((colorVarieties.data ?? []).map((c) => [c.id, c.name])),
    [colorVarieties.data],
  )
  const enclosureName = useMemo(
    () => new Map((enclosures.data ?? []).map((e) => [e.id, e.name])),
    [enclosures.data],
  )
  const contactName = useMemo(
    () => new Map((contacts.data ?? []).map((c) => [c.id, c.name])),
    [contacts.data],
  )
  const litterName = useMemo(
    () => new Map((litters.data ?? []).map((l) => [l.id, l.name])),
    [litters.data],
  )

  if (gerbil.loading) return <p className="muted">{de.common.loading}</p>
  if (gerbil.error || !gerbil.data) {
    return (
      <section className="page">
        <p className="muted">{gerbil.error ?? t.detail.notFound}</p>
        <Link to="/rennmaeuse" className="btn">
          {t.detail.back}
        </Link>
      </section>
    )
  }

  const g = gerbil.data
  const geno = describeGenotype(g.genotype)
  const lookup = (map: Map<string, string>, key: string | null) => (key ? (map.get(key) ?? '—') : '—')
  const storedColorName = g.colorVarietyId ? (colorName.get(g.colorVarietyId) ?? null) : null

  // Seed the Charakterbogen once from the loaded gerbil (adjust-state-during-render).
  if (charInit !== g.id) {
    setCharInit(g.id)
    setCharTraits(g.characterTraits ?? [])
    setCharNote(g.characterNote ?? '')
  }

  return (
    <section className="page">
      <header className="page-head">
        <div>
          <GerbilProfilePhoto gerbilId={g.id} />
          <h2>{g.name}</h2>
          <span className={`badge badge--${g.status.toLowerCase()}`}>{statusLabel(g.status)}</span>
        </div>
        <div className="head-actions">
          <Link to={`/rennmaeuse/${g.id}/bearbeiten`} className="btn btn--primary">
            {t.detail.edit}
          </Link>
          <Link to={`/genetik?parent=${g.id}`} className="btn">
            {t.detail.testMating}
          </Link>
          {g.status !== 'ForSale' && (
            <button
              type="button"
              className="btn"
              disabled={forSale.pending}
              onClick={async () => {
                const r = await forSale.run()
                if (r.ok) gerbil.reload()
              }}
            >
              {de.pages.abgabe.markAction}
            </button>
          )}
          <Link to={`/rennmaeuse/${g.id}/stammbaum`} className="btn">
            {de.pages.stammbaum.openButton}
          </Link>
          {/* FEAT-13: Abgabe abschließen — Vertrag-Assistent mit diesem Tier vorausgewählt. */}
          {g.status !== 'Deceased' && g.status !== 'GivenAway' && (
            <Link to={`/vertraege/neu?tiere=${g.id}`} className="btn">
              {de.pages.vertraege.wizard.title}
            </Link>
          )}
          <Link to="/rennmaeuse" className="btn">
            {t.detail.back}
          </Link>
        </div>
      </header>

      <h3>{t.detail.masterData}</h3>
      <dl className="def-list">
        <Row label={t.fields.gender} value={genderLabel(g.gender)} />
        <Row label={t.fields.status} value={statusLabel(g.status)} />
        <Row label={t.fields.dateOfBirth} value={formatDate(g.dateOfBirth)} />
        {g.status === 'Deceased' && (
          <>
            <Row label={t.fields.dateOfDeath} value={formatDate(g.dateOfDeath)} />
            <Row label={t.fields.causeOfDeath} value={g.causeOfDeath} />
          </>
        )}
        {g.status === 'GivenAway' && (
          <Row label={t.fields.goHomeDate} value={formatDate(g.goHomeDate)} />
        )}
        <Row
          label={t.fields.colorVariety}
          value={
            storedColorName ? (
              <span className="farbschlag-value">
                <FarbschlagImage name={storedColorName} size={32} />
                {storedColorName}
              </span>
            ) : (
              '—'
            )
          }
        />
        <Row label={t.fields.enclosure} value={lookup(enclosureName, g.enclosureId)} />
        <Row label={t.fields.litter} value={lookup(litterName, g.litterId)} />
        <Row label={t.fields.origin} value={lookup(contactName, g.originContactId)} />
        <Row label={t.fields.receiver} value={lookup(contactName, g.receiverContactId)} />
        <Row label={t.fields.notes} value={g.notes} />
      </dl>

      <h3>{t.detail.genetics}</h3>
      {geno ? (
        <dl className="def-list">
          <Row label={t.fields.genotype} value={<code>{geno.display}</code>} />
          <Row
            label={t.detail.resolvedPrefix}
            value={
              <>
                {geno.farbschlag}
                {storedColorName &&
                  geno.farbschlag !== de.genetics.unknownFarbschlag &&
                  storedColorName !== geno.farbschlag && (
                    <small className="mismatch-hint"> ⚠ {t.detail.farbschlagMismatch}</small>
                  )}
              </>
            }
          />
        </dl>
      ) : (
        <p className="muted">{t.detail.genotypeNotSet}</p>
      )}

      <h3>{de.character.sectionTitle}</h3>
      <Charakterbogen
        traits={charTraits}
        note={charNote}
        onTraitsChange={setCharTraits}
        onNoteChange={setCharNote}
      />
      <div className="form-actions">
        <button
          type="button"
          className="btn btn--primary"
          disabled={saveCharacter.pending}
          onClick={async () => {
            const r = await saveCharacter.run()
            if (r.ok) gerbil.reload()
          }}
        >
          {saveCharacter.pending ? t.form.saving : de.character.save}
        </button>
        {saveCharacter.error && <span className="error-text">{saveCharacter.error}</span>}
      </div>

      <h3 className="visually-hidden">{t.detail.moreData}</h3>
      <div className="tabs" role="tablist">
        {(['photos', 'health', 'weight'] as const).map((key) => (
          <button
            key={key}
            type="button"
            role="tab"
            aria-selected={tab === key}
            className={tab === key ? 'tab tab--active' : 'tab'}
            onClick={() => setTab(key)}
          >
            {t.detail.tabs[key]}
          </button>
        ))}
      </div>
      <div className="tab-panel" role="tabpanel">
        {tab === 'photos' && <GerbilPhotosTab gerbilId={g.id} />}
        {tab === 'health' && <GerbilHealthTab gerbilId={g.id} />}
        {tab === 'weight' && <GerbilWeightTab gerbilId={g.id} />}
      </div>
    </section>
  )
}