'use client'

import { useEffect, useId, useState } from 'react'
import { useSearchParams, useRouter } from 'next/navigation'
import { useLocale, useTranslations } from 'next-intl'
import { Switch } from '@/components/ui/switch'
import { AttnLine } from '@/components/ui/attn-line'
import { useToast } from '@/components/ui/use-toast'
import { getErrorMessage, type ErrorLocale } from '@/lib/errors/get-error-message'
import { AgentMemoryPanel } from '@/components/settings/AgentMemoryPanel'
import { AgentSkillsPanel } from '@/components/settings/AgentSkillsPanel'
import { AgentKnowledgePanel } from '@/components/agent-knowledge/AgentKnowledgePanel'
import {
  SettingsGroup,
  SettingsRow,
  SettingsRowEnd,
  SettingsSectionHeader,
  SettingsSeg,
} from '@/components/settings/SettingsRows'

// "Assistenten": the ledger profile the agent reads before booking (Kunskap =
// "Vad din agent vet", opens on the konteringskarta and is the default view),
// what the assistant remembers about this company (Minne, editable), and the
// domain knowledge it ships with (Kompetens, read-only). The segmented control
// keeps all three one click away instead of stacked.
type View = 'knowledge' | 'memory' | 'skills'

const VIEW_ROUTE: Record<View, string> = {
  knowledge: '/settings/assistant',
  memory: '/settings/assistant?view=memory',
  skills: '/settings/assistant?view=skills',
}

const VIEW_OPTIONS: Array<{ value: View; label: string }> = [
  { value: 'knowledge', label: 'Kunskap' },
  { value: 'memory', label: 'Minne' },
  { value: 'skills', label: 'Kompetens' },
]

export function AssistantSettingsContent() {
  const tNav = useTranslations('settings_nav')
  const tIntro = useTranslations('settings_intro')
  const searchParams = useSearchParams()
  const router = useRouter()
  const raw = searchParams.get('view')
  const view: View = raw === 'skills' ? 'skills' : raw === 'memory' ? 'memory' : 'knowledge'

  function setView(next: View) {
    // 'knowledge' is the default: keep its URL clean (no query string).
    router.replace(VIEW_ROUTE[next] ?? VIEW_ROUTE.knowledge, { scroll: false })
  }

  return (
    <div>
      <SettingsSectionHeader title={tNav('assistant')} intro={tIntro('assistant')} />

      <div className="mt-6">
        <SettingsSeg value={view} onChange={setView} options={VIEW_OPTIONS} aria-label="Välj vy" />
      </div>

      {/* Only the active view mounts, so each panel's data is fetched lazily
          the first time its view is opened (same behavior as when Radix Tabs
          unmounted the inactive panels). */}
      <div className="mt-6">
        {view === 'knowledge' && <AgentKnowledgePanel />}
        {view === 'memory' && <AgentMemoryPanel />}
        {view === 'skills' && <AgentSkillsPanel />}
      </div>

      <FabVisibilityRow />
    </div>
  )
}

// Per-user toggle for the floating assistant button bottom-right. The value
// lives on user_preferences (server-rendered into the dashboard layout), so
// a successful save triggers router.refresh() to make the button react
// immediately instead of on next navigation.
function FabVisibilityRow() {
  const t = useTranslations('settings_assistant')
  const errorLocale = useLocale() as ErrorLocale
  const { toast } = useToast()
  const router = useRouter()
  // null = the value is not known: still loading, or the read failed (loadError).
  const [hideFab, setHideFab] = useState<boolean | null>(null)
  // detail === null: transient, so the line carries a retry. A detail sentence
  // means the user has to act (an expired session) and a retry cannot help.
  const [loadError, setLoadError] = useState<{ detail: string | null } | null>(null)
  const [reloadKey, setReloadKey] = useState(0)
  const [saving, setSaving] = useState(false)
  const errorId = useId()

  // A settings row that cannot read its own value must not render one.
  // Defaulting to false on a failed GET drew a loaded-looking, interactive
  // switch in the "assistant button visible" position whatever the stored
  // preference was, and here that claim is contradicted on screen: the button
  // is server-rendered from the same column in the dashboard layout, so an
  // empty corner sat next to a switch insisting it was on.
  //
  // So the unknown value stays unknown: the switch keeps its disabled state and
  // one line says the value could not be read. 401/403 is the only case where
  // the reason changes what the user must do, so that message (from the same
  // status map the save path uses) replaces the retry instead of sitting next
  // to it; everything else is transient and the retry is the whole answer.
  useEffect(() => {
    let cancelled = false

    async function load() {
      setLoadError(null)
      try {
        const res = await fetch('/api/user/preferences')
        if (!res.ok) {
          // Not-JSON bodies (an HTML error page, an empty 502) leave null, and
          // getErrorMessage falls back to the status map.
          const body = await res.json().catch(() => null)
          if (cancelled) return
          const sessionGone = res.status === 401 || res.status === 403
          setHideFab(null)
          setLoadError({
            detail: sessionGone
              ? getErrorMessage(body, { statusCode: res.status, locale: errorLocale })
              : null,
          })
          return
        }
        // A 200 whose body will not parse is a failed read too: let it land in
        // the catch below rather than become a fabricated `false`.
        const body = await res.json()
        if (!cancelled) setHideFab(Boolean(body?.data?.hide_assistant_fab))
      } catch {
        if (!cancelled) {
          setHideFab(null)
          setLoadError({ detail: null })
        }
      }
    }

    void load()
    return () => {
      cancelled = true
    }
  }, [reloadKey, errorLocale])

  // Rolling the switch back is necessary but not sufficient: a switch that
  // flips and flips again reads as a broken control, not as a refused save, so
  // the user retries the same click instead of signing in again (401 on an
  // expired session is by far the likeliest refusal here, and the status map
  // says exactly that). One toast per failed click, never two: TOAST_LIMIT is
  // 1 (components/ui/use-toast.tsx) and a second would evict the first.
  //
  // Only the fetch sits inside the try. A router.refresh() that threw must not
  // roll the switch back and claim the save failed, because by then the write
  // has landed.
  async function handleToggle(showFab: boolean) {
    const nextHide = !showFab
    const previous = hideFab
    setHideFab(nextHide)
    setSaving(true)
    try {
      const res = await fetch('/api/user/preferences', {
        method: 'PATCH',
        headers: { 'Content-Type': 'application/json' },
        body: JSON.stringify({ hide_assistant_fab: nextHide }),
      })
      if (!res.ok) {
        // Not-JSON bodies (an HTML error page, an empty 502) leave null, and
        // getErrorMessage falls back to the status map.
        const body = await res.json().catch(() => null)
        setHideFab(previous)
        toast({
          title: t('fab_save_failed'),
          description: getErrorMessage(body, {
            statusCode: res.status,
            locale: errorLocale,
          }),
          variant: 'destructive',
        })
        return
      }
    } catch (err) {
      setHideFab(previous)
      toast({
        title: t('fab_save_failed'),
        description: getErrorMessage(err, { locale: errorLocale }),
        variant: 'destructive',
      })
      return
    } finally {
      setSaving(false)
    }
    router.refresh()
  }

  return (
    <SettingsGroup>
      <SettingsRow label={t('fab_title')} help={t('fab_description')}>
        {/* Live region always mounted so the failure is announced when it
            appears, not merely inserted. */}
        <div id={errorId} role="status" aria-live="polite" className="min-w-0">
          {loadError && (
            <AttnLine
              action={
                loadError.detail
                  ? undefined
                  : { label: t('fab_load_retry'), onClick: () => setReloadKey((k) => k + 1) }
              }
            >
              {loadError.detail
                ? `${t('fab_load_failed')} ${loadError.detail}`
                : t('fab_load_failed')}
            </AttnLine>
          )}
        </div>
        <SettingsRowEnd>
          <Switch
            checked={hideFab === null ? true : !hideFab}
            onCheckedChange={handleToggle}
            disabled={hideFab === null || saving}
            aria-label={t('fab_title')}
            aria-describedby={loadError ? errorId : undefined}
          />
        </SettingsRowEnd>
      </SettingsRow>
    </SettingsGroup>
  )
}