<script setup lang="ts">
import { computed, reactive, ref, watch } from 'vue'
import Select from 'primevue/select'
import { ChevronLeft, ChevronRight, Layers3, Pencil, Search, Trash2, TriangleAlert, UserPlus, Users, X } from '@lucide/vue'

import AdminPageHeader from '../../components/admin/AdminPageHeader.vue'
import AdminSeasonToolbar from '../../components/admin/AdminSeasonToolbar.vue'
import Button from '../../components/ui/Button.vue'
import Card from '../../components/ui/Card.vue'
import Modal from '../../components/ui/Modal.vue'
import { useAwardsStore } from '../../stores/awards'
import type { AdminCandidateItem } from '../../types/awards'

const store = useAwardsStore()
const saving = ref(false)
const deleting = ref(false)
const adminMessage = ref('')
const adminError = ref('')

const seasonDetail = computed(() => store.adminSeasonDetail)
const selectedSeasonId = computed(() => store.adminSelectedSeasonId)

/* ---------- Filter + Suche + Pagination ---------- */
const search = ref('')
const categoryFilter = ref<number | null>(null)
const page = ref(1)
const pageSize = 10

const categoryOptions = computed(() =>
  seasonDetail.value.categories.map((category) => ({ label: `${category.groupName} · ${category.name}`, value: category.id })),
)
const categoryFilterOptions = computed(() => [{ label: 'Alle Kategorien', value: null }, ...categoryOptions.value])
const categoryLabelMap = computed(() =>
  Object.fromEntries(seasonDetail.value.categories.map((c) => [c.id, `${c.groupName} · ${c.name}`])),
)
const duplicateCandidateKeys = computed(() => {
  const counts = new Map<string, number>()
  for (const candidate of seasonDetail.value.candidates) {
    const categoryKey = `${candidate.categoryId}`
    const nameKey = `${categoryKey}:name:${candidate.displayName.trim().toLowerCase()}`
    const slugKey = `${categoryKey}:slug:${candidate.channelSlug.trim().toLowerCase()}`
    counts.set(nameKey, (counts.get(nameKey) ?? 0) + 1)
    if (candidate.channelSlug.trim()) counts.set(slugKey, (counts.get(slugKey) ?? 0) + 1)
  }
  return counts
})
const duplicateCandidateCount = computed(() =>
  seasonDetail.value.candidates.filter((candidate) =>
    (duplicateCandidateKeys.value.get(`${candidate.categoryId}:name:${candidate.displayName.trim().toLowerCase()}`) ?? 0) > 1 ||
    (duplicateCandidateKeys.value.get(`${candidate.categoryId}:slug:${candidate.channelSlug.trim().toLowerCase()}`) ?? 0) > 1,
  ).length,
)

const filteredCandidates = computed(() => {
  const query = search.value.trim().toLowerCase()
  let list = seasonDetail.value.candidates
  if (categoryFilter.value) list = list.filter((c) => c.categoryId === categoryFilter.value)
  if (query) {
    list = list.filter((c) =>
      [c.displayName, c.channelSlug, c.platform, categoryLabelMap.value[c.categoryId] ?? '']
        .join(' ')
        .toLowerCase()
        .includes(query),
    )
  }
  return list
})

const totalPages = computed(() => Math.max(1, Math.ceil(filteredCandidates.value.length / pageSize)))
const pagedCandidates = computed(() => {
  const start = (page.value - 1) * pageSize
  return filteredCandidates.value.slice(start, start + pageSize)
})
const rangeStart = computed(() => (filteredCandidates.value.length === 0 ? 0 : (page.value - 1) * pageSize + 1))
const rangeEnd = computed(() => Math.min(page.value * pageSize, filteredCandidates.value.length))

watch([search, categoryFilter, () => seasonDetail.value.candidates.length], () => {
  page.value = 1
})
watch(totalPages, (max) => {
  if (page.value > max) page.value = max
})

function clearFilters() {
  search.value = ''
  categoryFilter.value = null
}

/* ---------- Modal: anlegen / bearbeiten ---------- */
const modalOpen = ref(false)
const editingId = ref<number | 'new' | null>(null)
const form = reactive({ categoryId: 0, displayName: '', channelSlug: '', platform: 'Twitch' })

const modalTitle = computed(() => (editingId.value === 'new' ? 'Kandidat anlegen' : 'Kandidat bearbeiten'))
const canSave = computed(() =>
  Boolean(selectedSeasonId.value && form.categoryId && form.displayName.trim() && form.channelSlug.trim()),
)

function openCreate() {
  adminMessage.value = ''
  adminError.value = ''
  editingId.value = 'new'
  form.categoryId = categoryFilter.value ?? seasonDetail.value.categories[0]?.id ?? 0
  form.displayName = ''
  form.channelSlug = ''
  form.platform = 'Twitch'
  modalOpen.value = true
}

function openEdit(candidate: AdminCandidateItem) {
  adminMessage.value = ''
  adminError.value = ''
  editingId.value = candidate.id
  form.categoryId = candidate.categoryId
  form.displayName = candidate.displayName
  form.channelSlug = candidate.channelSlug
  form.platform = candidate.platform
  modalOpen.value = true
}

async function saveModal() {
  if (!canSave.value || !selectedSeasonId.value) return
  saving.value = true
  adminError.value = ''
  try {
    if (editingId.value === 'new') {
      await store.createAdminCandidate(selectedSeasonId.value, { ...form })
      adminMessage.value = `„${form.displayName}" wurde angelegt.`
    } else if (typeof editingId.value === 'number') {
      await store.updateAdminCandidate(editingId.value, selectedSeasonId.value, { ...form })
      adminMessage.value = `„${form.displayName}" wurde gespeichert.`
    }
    modalOpen.value = false
  } catch (error) {
    adminError.value = error instanceof Error ? error.message : 'Speichern fehlgeschlagen.'
  } finally {
    saving.value = false
  }
}

/* ---------- Löschen mit Bestätigung ---------- */
const candidateToDelete = ref<AdminCandidateItem | null>(null)

async function confirmDelete() {
  if (!candidateToDelete.value || !selectedSeasonId.value) return
  deleting.value = true
  adminError.value = ''
  try {
    await store.deleteAdminCandidate(candidateToDelete.value.id, selectedSeasonId.value)
    adminMessage.value = `„${candidateToDelete.value.displayName}" wurde gelöscht.`
    candidateToDelete.value = null
  } catch (error) {
    adminError.value = error instanceof Error ? error.message : 'Löschen fehlgeschlagen.'
  } finally {
    deleting.value = false
  }
}
</script>

<template>
  <div class="space-y-6">
    <AdminPageHeader
      eyebrow="Kandidaten"
      title="Kandidaten verwalten"
      description="Suchen, filtern, anlegen, bearbeiten und löschen – auch bei vielen Nominierten bleibt die Liste übersichtlich."
      :icon="Users"
    />

    <AdminSeasonToolbar />

    <section class="grid gap-4 md:grid-cols-3">
      <Card class="p-5">
        <div class="flex items-start justify-between gap-4">
          <div>
            <p class="text-xs font-semibold uppercase tracking-[0.18em] text-violet-500">Kandidaten</p>
            <strong class="mt-3 block text-3xl text-violet-900">{{ seasonDetail.candidates.length }}</strong>
          </div>
          <Users class="h-6 w-6 text-violet-500" />
        </div>
      </Card>
      <Card class="p-5">
        <div class="flex items-start justify-between gap-4">
          <div>
            <p class="text-xs font-semibold uppercase tracking-[0.18em] text-violet-500">Kategorien</p>
            <strong class="mt-3 block text-3xl text-violet-900">{{ seasonDetail.categories.length }}</strong>
          </div>
          <UserPlus class="h-6 w-6 text-violet-500" />
        </div>
      </Card>
      <Card class="p-5" :class="duplicateCandidateCount > 0 ? 'border-amber-200 bg-amber-50/60' : ''">
        <div class="flex items-start justify-between gap-4">
          <div>
            <p class="text-xs font-semibold uppercase tracking-[0.18em]" :class="duplicateCandidateCount > 0 ? 'text-amber-600' : 'text-violet-500'">Mögliche Duplikate</p>
            <strong class="mt-3 block text-3xl" :class="duplicateCandidateCount > 0 ? 'text-amber-700' : 'text-violet-900'">{{ duplicateCandidateCount }}</strong>
          </div>
          <Layers3 class="h-6 w-6" :class="duplicateCandidateCount > 0 ? 'text-amber-500' : 'text-violet-500'" />
        </div>
      </Card>
    </section>

    <Card class="overflow-hidden">
      <!-- Toolbar -->
      <div class="flex flex-col gap-4 border-b border-violet-100 p-5 lg:flex-row lg:items-center">
        <label class="relative block flex-1">
          <Search class="pointer-events-none absolute left-4 top-1/2 h-4 w-4 -translate-y-1/2 text-violet-400" />
          <input
            v-model="search"
            type="text"
            class="h-11 w-full rounded-2xl border border-violet-200 bg-white pl-11 pr-4 text-sm outline-none transition focus:border-violet-400 focus:ring-4 focus:ring-violet-100"
            placeholder="Name, Handle oder Plattform suchen …"
          />
        </label>
        <Select
          v-model="categoryFilter"
          :options="categoryFilterOptions"
          option-label="label"
          option-value="value"
          class="w-full lg:w-72"
        />
        <Button v-if="search || categoryFilter" variant="ghost" class="gap-1" @click="clearFilters">
          <X class="h-4 w-4" /> Filter
        </Button>
        <Button class="gap-2" @click="openCreate">
          <UserPlus class="h-4 w-4" /> Kandidat anlegen
        </Button>
      </div>

      <p v-if="adminMessage" class="border-b border-emerald-100 bg-emerald-50 px-5 py-3 text-sm text-emerald-700">{{ adminMessage }}</p>
      <p v-if="adminError" class="border-b border-rose-100 bg-rose-50 px-5 py-3 text-sm text-rose-700">{{ adminError }}</p>

      <!-- Tabellenkopf (Desktop) -->
      <div class="hidden grid-cols-[minmax(0,1.6fr)_minmax(0,1.2fr)_120px_96px] gap-4 border-b border-violet-100 bg-violet-50/40 px-6 py-3 text-[11px] font-semibold uppercase tracking-[0.16em] text-violet-500 lg:grid">
        <span>Kandidat</span>
        <span>Kategorie</span>
        <span>Plattform</span>
        <span class="text-right">Aktionen</span>
      </div>

      <!-- Zeilen -->
      <div class="divide-y divide-violet-50">
        <div
          v-for="candidate in pagedCandidates"
          :key="candidate.id"
          class="grid grid-cols-1 gap-3 px-6 py-4 transition hover:bg-violet-50/40 lg:grid-cols-[minmax(0,1.6fr)_minmax(0,1.2fr)_120px_96px] lg:items-center lg:gap-4"
        >
          <div class="flex min-w-0 items-center gap-3">
            <span class="grid h-10 w-10 shrink-0 place-items-center rounded-full bg-[linear-gradient(135deg,#c4b5fd,#f5a9d6)] text-sm font-semibold text-white">
              {{ candidate.displayName.charAt(0) }}
            </span>
            <div class="min-w-0">
              <p class="truncate font-semibold text-slate-800">{{ candidate.displayName }}</p>
              <p class="truncate text-xs text-slate-500">{{ candidate.channelSlug }}</p>
              <p
                v-if="(duplicateCandidateKeys.get(`${candidate.categoryId}:name:${candidate.displayName.trim().toLowerCase()}`) ?? 0) > 1 || (duplicateCandidateKeys.get(`${candidate.categoryId}:slug:${candidate.channelSlug.trim().toLowerCase()}`) ?? 0) > 1"
                class="mt-1 text-xs font-semibold text-amber-700"
              >
                Mögliches Duplikat in dieser Kategorie
              </p>
            </div>
          </div>
          <div class="min-w-0">
            <span class="inline-block max-w-full truncate rounded-full border border-violet-100 bg-violet-50/70 px-3 py-1 text-xs font-semibold text-violet-700">
              {{ categoryLabelMap[candidate.categoryId] || 'Ohne Kategorie' }}
            </span>
          </div>
          <div>
            <span class="rounded-full border border-amber-200 bg-amber-50 px-3 py-1 text-xs font-semibold text-amber-700">{{ candidate.platform }}</span>
          </div>
          <div class="flex gap-2 lg:justify-end">
            <button
              class="grid h-9 w-9 place-items-center rounded-full border border-violet-200 text-violet-600 transition hover:bg-violet-50"
              title="Bearbeiten"
              @click="openEdit(candidate)"
            >
              <Pencil class="h-4 w-4" />
            </button>
            <button
              class="grid h-9 w-9 place-items-center rounded-full border border-rose-200 text-rose-500 transition hover:bg-rose-50"
              title="Löschen"
              @click="candidateToDelete = candidate"
            >
              <Trash2 class="h-4 w-4" />
            </button>
          </div>
        </div>

        <div v-if="filteredCandidates.length === 0" class="px-6 py-12 text-center">
          <p class="text-sm text-slate-500">
            {{ seasonDetail.candidates.length === 0 ? 'Noch keine Kandidaten in diesem Jahr.' : 'Keine Treffer für den aktuellen Filter.' }}
          </p>
          <Button class="mt-4 gap-2" @click="openCreate"><UserPlus class="h-4 w-4" /> Ersten Kandidaten anlegen</Button>
        </div>
      </div>

      <!-- Pagination -->
      <div v-if="filteredCandidates.length > 0" class="flex items-center justify-between gap-4 border-t border-violet-100 px-6 py-4 text-sm text-slate-500">
        <span><strong class="text-violet-800">{{ rangeStart }}–{{ rangeEnd }}</strong> von {{ filteredCandidates.length }}</span>
        <div class="flex items-center gap-2">
          <button
            class="grid h-9 w-9 place-items-center rounded-full border border-violet-200 text-violet-600 transition hover:bg-violet-50 disabled:opacity-40 disabled:hover:bg-transparent"
            :disabled="page <= 1"
            @click="page--"
          >
            <ChevronLeft class="h-4 w-4" />
          </button>
          <span class="min-w-[72px] text-center font-semibold text-slate-700">Seite {{ page }}/{{ totalPages }}</span>
          <button
            class="grid h-9 w-9 place-items-center rounded-full border border-violet-200 text-violet-600 transition hover:bg-violet-50 disabled:opacity-40 disabled:hover:bg-transparent"
            :disabled="page >= totalPages"
            @click="page++"
          >
            <ChevronRight class="h-4 w-4" />
          </button>
        </div>
      </div>
    </Card>

    <!-- Modal: anlegen / bearbeiten -->
    <Modal :open="modalOpen" :title="modalTitle" subtitle="Anzeigename und Handle sind Pflicht." @close="modalOpen = false">
      <div class="space-y-4">
        <label class="block space-y-2">
          <span class="text-xs font-semibold uppercase tracking-[0.18em] text-slate-500">Kategorie</span>
          <Select v-model="form.categoryId" :options="categoryOptions" option-label="label" option-value="value" class="w-full" />
        </label>
        <label class="block space-y-2">
          <span class="text-xs font-semibold uppercase tracking-[0.18em] text-slate-500">Anzeigename</span>
          <input v-model="form.displayName" type="text" class="h-11 w-full rounded-2xl border border-violet-200 px-4 text-sm outline-none transition focus:border-violet-400 focus:ring-4 focus:ring-violet-100" placeholder="z. B. Jayuhime" />
        </label>
        <div class="grid gap-4 sm:grid-cols-2">
          <label class="block space-y-2">
            <span class="text-xs font-semibold uppercase tracking-[0.18em] text-slate-500">Handle</span>
            <input v-model="form.channelSlug" type="text" class="h-11 w-full rounded-2xl border border-violet-200 px-4 text-sm outline-none transition focus:border-violet-400 focus:ring-4 focus:ring-violet-100" placeholder="@channel" />
          </label>
          <label class="block space-y-2">
            <span class="text-xs font-semibold uppercase tracking-[0.18em] text-slate-500">Plattform</span>
            <input v-model="form.platform" type="text" class="h-11 w-full rounded-2xl border border-violet-200 px-4 text-sm outline-none transition focus:border-violet-400 focus:ring-4 focus:ring-violet-100" placeholder="Twitch, YouTube …" />
          </label>
        </div>
      </div>
      <template #footer>
        <Button variant="ghost" @click="modalOpen = false">Abbrechen</Button>
        <Button :disabled="saving || !canSave" @click="saveModal">{{ saving ? 'Speichert …' : 'Speichern' }}</Button>
      </template>
    </Modal>

    <!-- Modal: löschen bestätigen -->
    <Modal :open="!!candidateToDelete" title="Kandidat löschen?" @close="candidateToDelete = null">
      <div class="flex items-start gap-4">
        <span class="grid h-12 w-12 shrink-0 place-items-center rounded-full bg-rose-50 text-rose-500">
          <TriangleAlert class="h-6 w-6" />
        </span>
        <p class="text-sm leading-7 text-slate-600">
          „<strong class="text-slate-800">{{ candidateToDelete?.displayName }}</strong>" wird endgültig aus diesem Award-Jahr entfernt.
          Das lässt sich nicht rückgängig machen.
        </p>
      </div>
      <template #footer>
        <Button variant="ghost" @click="candidateToDelete = null">Abbrechen</Button>
        <Button class="!bg-rose-600 hover:!bg-rose-500" :disabled="deleting" @click="confirmDelete">
          {{ deleting ? 'Löscht …' : 'Endgültig löschen' }}
        </Button>
      </template>
    </Modal>
  </div>
</template>
