// Codex dossier — a single spirit's occult record at /codex/:id.
// Fetches GET /api/codex/:id; 404s render a themed "not reached" state.

import { useEffect, useState, type CSSProperties } from 'react'
import { Link, useParams } from 'react-router-dom'
import { useTranslation } from 'react-i18next'
import { PUBLIC_ORIGIN, usePageMeta } from '../lib/pageMeta'
import type { CodexEntityDetail } from '../lib/types'
import './CodexEntityPage.css'

type DetailState =
  | { status: 'loading' }
  | { status: 'error' }
  | { status: 'notfound' }
  | { status: 'ready'; entity: CodexEntityDetail }

function formatDate(iso: string, locale: string): string {
  const date = new Date(iso)
  if (Number.isNaN(date.getTime())) return iso
  return new Intl.DateTimeFormat(locale, {
    year: 'numeric',
    month: 'long',
    day: 'numeric',
  }).format(date)
}

/** Voice profiles are loose records — render whatever the veil preserved. */
function formatVoiceValue(value: unknown): string {
  if (value === null || value === undefined) return '—'
  if (typeof value === 'number') {
    return Number.isInteger(value) ? String(value) : value.toFixed(2)
  }
  if (typeof value === 'object') return JSON.stringify(value)
  return String(value)
}

export function CodexEntityPage() {
  const { t, i18n } = useTranslation()
  const { id } = useParams<{ id: string }>()
  const [state, setState] = useState<DetailState>({ status: 'loading' })

  // Every spirit is a distinct, unique page — give each one its own title,
  // description and canonical URL so they rank individually instead of all
  // sharing the app's single static title. The persona doubles as the
  // description: it is the actual unique prose a searcher would be looking
  // for. Marked up as a fictional Person so previews and rich results can
  // never imply this is a record of a real dead human.
  const detail = state.status === 'ready' ? state.entity : null
  usePageMeta({
    title: detail ? `${detail.name} — ${detail.epithet}` : undefined,
    description: detail?.persona,
    path: id ? `/codex/${id}` : undefined,
    structuredData: detail
      ? {
          '@context': 'https://schema.org',
          '@type': 'Person',
          name: detail.name,
          alternateName: detail.epithet,
          description: detail.persona,
          additionalType: 'https://schema.org/FictionalCharacter',
          url: `${PUBLIC_ORIGIN}/codex/${id}`,
        }
      : undefined,
  })

  useEffect(() => {
    if (!id) {
      setState({ status: 'notfound' })
      return
    }
    const controller = new AbortController()
    setState({ status: 'loading' })

    fetch(`/api/codex/${encodeURIComponent(id)}`, {
      credentials: 'include',
      signal: controller.signal,
    })
      .then(async (res) => {
        if (res.status === 404) {
          setState({ status: 'notfound' })
          return
        }
        if (!res.ok) throw new Error(`the registry answered ${res.status}`)
        const entity = (await res.json()) as CodexEntityDetail
        setState({ status: 'ready', entity })
      })
      .catch(() => {
        if (!controller.signal.aborted) setState({ status: 'error' })
      })

    return () => controller.abort()
  }, [id])

  return (
    <div className="codex-detail-page">
      <div className="codex-detail-overlay" aria-hidden="true" />

      <nav className="codex-detail-nav">
        <Link to="/codex" className="codex-detail-back">
          {t('codex.back')}
        </Link>
      </nav>

      {state.status === 'loading' && (
        <p className="codex-detail-state">
          {t('codex.detail.loading', 'summoning the dossier…')}
        </p>
      )}

      {state.status === 'error' && (
        <p className="codex-detail-state codex-detail-state-error" role="alert">
          {t('common.error')}
        </p>
      )}

      {state.status === 'notfound' && (
        <div className="codex-detail-missing">
          <div className="codex-detail-missing-sigil" aria-hidden="true" />
          <h1 className="codex-detail-missing-title">
            {t('codex.detail.notReached', 'this spirit has not been reached')}
          </h1>
          <Link to="/codex" className="codex-detail-cta codex-detail-cta-ghost">
            {t('codex.back')}
          </Link>
        </div>
      )}

      {state.status === 'ready' && (
        <Dossier entity={state.entity} locale={i18n.language} />
      )}
    </div>
  )
}

function Dossier({ entity, locale }: { entity: CodexEntityDetail; locale: string }) {
  const { t } = useTranslation()
  const discoverer = entity.discovered_by ?? t('codex.detail.unknownMedium', 'unknown medium')

  const stats: Array<{ label: string; value: string }> = [
    {
      label: t('codex.detail.stats.sightings', 'sightings'),
      value: String(entity.sightings),
    },
    {
      label: t('codex.detail.stats.contacts', 'contacts'),
      value: String(entity.contact_count),
    },
    {
      label: t('codex.detail.stats.discoveredBy', 'discovered by'),
      value: discoverer,
    },
    {
      label: t('codex.detail.stats.discoveredAt', 'entered the registry'),
      value: formatDate(entity.discovered_at, locale),
    },
  ]

  return (
    <article className="codex-dossier" data-rarity={entity.rarity}>
      <header className="codex-dossier-header">
        <div
          className="codex-dossier-glyph"
          style={{ '--glyph-hue': entity.visual.hue } as CSSProperties}
          aria-hidden="true"
        />
        <span className="codex-dossier-form">
          {t(`codex.form.${entity.visual.form}`, entity.visual.form)}
        </span>
        <h1 className="codex-dossier-name">{entity.name}</h1>
        <p className="codex-dossier-epithet">{entity.epithet}</p>
        <span className="codex-dossier-rarity" data-rarity={entity.rarity}>
          {t(`codex.rarity.${entity.rarity}`)}
        </span>
      </header>

      <section className="codex-dossier-section">
        <h2 className="codex-dossier-heading">{t('codex.persona')}</h2>
        <p className="codex-dossier-persona">{entity.persona}</p>
      </section>

      <section className="codex-dossier-section">
        <h2 className="codex-dossier-heading">
          {t('codex.detail.utterances', 'known utterances')}
        </h2>
        {entity.quotes.length > 0 ? (
          <ul className="codex-dossier-quotes">
            {entity.quotes.map((quote, i) => (
              <li key={i} className="codex-dossier-quote">
                “{quote}”
              </li>
            ))}
          </ul>
        ) : (
          <p className="codex-dossier-none">
            {t('codex.detail.noUtterances', 'no utterances recorded yet')}
          </p>
        )}
      </section>

      <section className="codex-dossier-section">
        <dl className="codex-dossier-stats">
          {stats.map((stat) => (
            <div key={stat.label} className="codex-dossier-stat">
              <dt>{stat.label}</dt>
              <dd>{stat.value}</dd>
            </div>
          ))}
        </dl>
      </section>

      <section className="codex-dossier-section">
        <h2 className="codex-dossier-heading">
          {t('codex.detail.voiceSignature', 'voice signature')}
        </h2>
        <table className="codex-dossier-voice">
          <tbody>
            {Object.entries(entity.voice).map(([key, value]) => (
              <tr key={key}>
                <th scope="row">{key.replace(/_/g, ' ')}</th>
                <td>{formatVoiceValue(value)}</td>
              </tr>
            ))}
          </tbody>
        </table>
      </section>

      <footer className="codex-dossier-footer">
        <Link to="/seance" className="codex-detail-cta">
          {t('codex.detail.attemptContact', 'attempt contact')}
        </Link>
      </footer>
    </article>
  )
}