<script setup lang="ts">
import { computed, inject, onMounted, ref } from 'vue'
import { useRouter } from 'vue-router'
import { useAuthStore } from '@/stores/auth'
import { usersApi } from '@/api'
import { downloadFile } from '@/utils/downloadFile'
import { useLecturesStore } from '@/stores/lectures'
import { useUserStore } from '@/stores/user'
import GlassCard from '@/components/ui/GlassCard.vue'
import LectureCard from '@/components/ui/LectureCard.vue'
import ProgressBar from '@/components/ui/ProgressBar.vue'
import AchievementBadge from '@/components/ui/AchievementBadge.vue'
import EmptyState from '@/components/ui/EmptyState.vue'
import AppIcon from '@/components/ui/AppIcon.vue'
import EnrollmentLimitModal from '@/components/ui/EnrollmentLimitModal.vue'
import { formatUserName } from '@/utils/formatUserName'

const auth = useAuthStore()
const lectures = useLecturesStore()
const userStore = useUserStore()
const router = useRouter()
const enrollmentLimitModalOpen = ref(false)
const addToast = inject('addToast') as
  | ((message: string, type?: 'success' | 'error' | 'info') => void)
  | undefined

const user = computed(() => auth.user!)

const userMetaLine = computed(() => {
  const parts: string[] = []
  if (user.value.institute) parts.push(user.value.institute)
  if (user.value.direction) parts.push(user.value.direction)
  if (Number.isFinite(user.value.year) && (user.value.year as number) > 0)
    parts.push(`${user.value.year} курс`)
  return parts.join(' · ')
})
const nextLecture = computed(() => lectures.registeredLectures[0] ?? lectures.all[0])
const recommended = computed(() =>
  lectures.all.filter((l) => !lectures.registeredIds.includes(l.id)).slice(0, 3),
)
const achievements = computed(() => userStore.achievements.filter((a) => a.unlocked).slice(0, 3))
const reminders = computed(() => userStore.notifications.slice(0, 3))
const currentLevelXp = computed(() => user.value.currentLevelXp ?? 0)
const nextLevelXp = computed(() => user.value.nextLevelXp)
const userXp = computed(() => user.value.xp ?? 0)
const hasLevelProgress = computed(() => nextLevelXp.value !== undefined)
const hasNextLevel = computed(
  () => typeof nextLevelXp.value === 'number' && nextLevelXp.value > currentLevelXp.value,
)
const levelProgressMax = computed(() =>
  hasNextLevel.value ? nextLevelXp.value! - currentLevelXp.value : 1,
)
const levelProgress = computed(() => {
  if (!hasLevelProgress.value) return 0
  if (!hasNextLevel.value) return 1
  return Math.min(Math.max(userXp.value - currentLevelXp.value, 0), levelProgressMax.value)
})
const levelProgressLabel = computed(() =>
  !hasLevelProgress.value
    ? `Уровень ${user.value.level}`
    : hasNextLevel.value
      ? `Прогресс до уровня ${user.value.level + 1}`
      : 'Максимальный уровень',
)
const levelProgressText = computed(() =>
  hasNextLevel.value
    ? `${levelProgress.value} / ${levelProgressMax.value} XP`
    : `${userXp.value} XP`,
)

async function downloadLectureIcs(id: string) {
  try {
    const blob = await usersApi.downloadEnrollmentIcs(id)
    downloadFile(blob, `lecture-${id}.ics`)
    addToast?.("Файл календаря скачан", "success")
  } catch (err) {
    addToast?.(err instanceof Error ? err.message : "Не удалось скачать .ics", "error")
  }
}

onMounted(async () => {
  await Promise.all([
    lectures.all.length ? Promise.resolve() : lectures.fetchLectures(),
    userStore.fetchStudentData(),
  ])
  await lectures.fetchRegisteredForCurrentUser()
})

async function registerLecture(id: string) {
  try {
    await lectures.register(id)
    addToast?.('Вы записаны на лекцию.', 'success')
  } catch (err) {
    if (err instanceof Error && err.message.includes('Лимит записей достигнут')) {
      enrollmentLimitModalOpen.value = true
      return
    }
    addToast?.(err instanceof Error ? err.message : 'Не удалось записаться на лекцию.', 'error')
  }
}
</script>

<template>
  <div class="dashboard page-content">
    <div class="dashboard-welcome">
      <div>
        <h1 class="page-title">Добрый день, {{ formatUserName(user.name) }}!</h1>
        <p v-if="userMetaLine" class="text-secondary">{{ userMetaLine }}</p>
      </div>
      <div class="quick-actions">
        <button class="btn-primary" @click="router.push('/catalog')">Найти лекцию</button>
        <button class="btn-secondary" @click="router.push('/my-lectures')">Мои записи</button>
      </div>
    </div>

    <GlassCard v-if="nextLecture">
      <div class="next-lecture">
        <div>
          <div class="section-title">Ближайшая лекция</div>
          <div class="next-title">{{ nextLecture.title }}</div>
          <div class="next-meta">
            <span class="meta-line">
              <AppIcon class="meta-icon" icon="calendar" :size="14" />
              Завтра, {{ nextLecture.time }}
            </span>
            <span class="meta-line">
              <AppIcon class="meta-icon" icon="building" :size="14" />
              {{ nextLecture.building }}, ауд. {{ nextLecture.room ?? 'онлайн' }}
            </span>
            <span class="meta-line">
              <AppIcon class="meta-icon" icon="user" :size="14" />
              {{ nextLecture.teacher }}
            </span>
          </div>
        </div>
        <div class="next-actions">
          <button class="btn-primary" @click="router.push(`/lecture/${nextLecture.id}`)">
            Открыть
          </button>
          <button class="btn-secondary" @click="downloadLectureIcs(nextLecture.id)">Скачать .ics</button>
        </div>
      </div>
    </GlassCard>
    <EmptyState
      v-else-if="!lectures.loading"
      title="Пока нет лекций"
      subtitle="Каталог пуст или данные ещё не синхронизированы."
    />

    <GlassCard>
      <div class="xp-section">
        <div class="xp-header">
          <span class="xp-label">{{ levelProgressLabel }}</span>
          <span class="xp-val">{{ levelProgressText }}</span>
        </div>
        <ProgressBar :value="levelProgress" :max="levelProgressMax" :text="levelProgressText" />
      </div>
    </GlassCard>

    <section>
      <div class="section-header">
        <h2 class="section-title">
          <span class="title-with-icon">
            <AppIcon class="title-icon" icon="sparkles" :size="18" />
            Ближайшие лекции
          </span>
        </h2>
        <button class="link-btn" @click="router.push('/catalog')">Все лекции →</button>
      </div>
      <EmptyState
        v-if="lectures.loading"
        title="Загружаем рекомендации"
        subtitle="Получаем данные с backend."
      />
      <div v-else class="cards-grid">
        <LectureCard
          v-for="l in recommended"
          :key="l.id"
          :lecture="l"
          :registered="lectures.registeredIds.includes(l.id)"
          @register="registerLecture"
        />
      </div>
    </section>

    <section class="two-column">
      <GlassCard>
        <div class="section-title">
          <span class="title-with-icon">
            <AppIcon class="title-icon" icon="trophy" :size="18" />
            Достижения
          </span>
        </div>
        <div class="achievements">
          <AchievementBadge
            v-for="a in achievements"
            :key="a.id"
            :icon="a.icon"
            :title="a.title"
            :description="a.description"
            :unlocked="a.unlocked"
            :unlockedAt="a.unlockedAt"
            :coins="a.coins"
          />
        </div>
      </GlassCard>
      <GlassCard>
        <div class="section-title">
          <span class="title-with-icon">
            <AppIcon class="title-icon" icon="bell" :size="18" />
            Увидомления
          </span>
        </div>
        <div class="reminders">
          <div class="reminder-item" v-for="n in reminders" :key="n.id">
            <div class="reminder-title">{{ n.title }}</div>
            <div class="reminder-body">{{ n.body }}</div>
            <div class="reminder-date">{{ new Date(n.createdAt).toLocaleDateString('ru-RU') }}</div>
          </div>
        </div>
      </GlassCard>
    </section>

    <EnrollmentLimitModal v-model="enrollmentLimitModalOpen" />
  </div>
</template>

<style scoped>
.dashboard {
  display: flex;
  flex-direction: column;
  gap: 24px;
}
.dashboard-welcome {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 16px;
  flex-wrap: wrap;
}
.quick-actions {
  display: flex;
  gap: 10px;
  flex-wrap: wrap;
}
.next-lecture {
  display: flex;
  justify-content: space-between;
  gap: 16px;
  flex-wrap: wrap;
}
.next-title {
  font-size: 18px;
  font-weight: 700;
  margin: 6px 0;
}
.next-meta {
  display: flex;
  flex-direction: column;
  gap: 4px;
  color: var(--color-text-secondary);
  font-size: 13px;
}
.meta-line {
  display: inline-flex;
  align-items: center;
  gap: 6px;
}
.meta-icon {
  color: var(--color-text-secondary);
}
.next-actions {
  display: flex;
  gap: 10px;
  align-items: flex-start;
}
.xp-section {
  display: flex;
  flex-direction: column;
  gap: 10px;
}
.xp-header {
  display: flex;
  justify-content: space-between;
  font-size: 13px;
  font-weight: 600;
}
.xp-val {
  color: var(--color-text-secondary);
}
.section-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
}
.title-with-icon {
  display: inline-flex;
  align-items: center;
  gap: 8px;
}
.title-icon {
  color: var(--color-text);
}
.cards-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 16px;
  margin-top: 12px;
}
.link-btn {
  background: none;
  border: none;
  color: var(--color-primary-dark);
  font-weight: 600;
  font-size: 14px;
  cursor: pointer;
}
.two-column {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
  gap: 16px;
}
.achievements {
  display: flex;
  flex-direction: column;
  gap: 12px;
  margin-top: 10px;
}
.reminders {
  display: flex;
  flex-direction: column;
  gap: 12px;
  margin-top: 10px;
}
.reminder-item {
  border-bottom: 1px solid var(--color-border-glass);
  padding-bottom: 10px;
}
.reminder-item:last-child {
  border-bottom: none;
  padding-bottom: 0;
}
.reminder-title {
  font-weight: 700;
  margin-bottom: 4px;
}
.reminder-body {
  font-size: 13px;
  color: var(--color-text-secondary);
}
.reminder-date {
  font-size: 11px;
  color: var(--color-text-secondary);
  margin-top: 4px;
}
</style>
