<template>
  <div>
    <!-- Loading State -->
    <div v-if="loading" class="flex justify-center py-12">
      <q-spinner color="primary" size="64px" />
    </div>

    <!-- Error State -->
    <div v-else-if="error" class="bg-white rounded-xl shadow-sm p-12 text-center">
      <q-icon name="error_outline" size="64px" color="negative" />
      <p class="text-gray-500 mt-4">{{ error }}</p>
      <q-btn color="primary" label="กลับ" class="mt-4" @click="router.back()" />
    </div>

    <!-- Course Detail -->
    <div v-else-if="course">
      <!-- Header with Actions -->
      <div class="flex flex-col md:flex-row md:justify-between md:items-start gap-4 mb-6">
        <div>
          <q-btn flat icon="arrow_back" label="กลับ" @click="router.back()" class="mb-2" />
          <h1 class="text-2xl font-bold text-gray-900">{{ course.title.th }}</h1>
          <p class="text-gray-500">{{ course.title.en }}</p>
        </div>
        <div class="flex gap-2">
          <q-btn
            color="positive"
            label="อนุมัติคอร์ส"
            icon="check_circle"
            @click="confirmApprove"
          />
          <q-btn
            color="negative"
            label="ปฏิเสธ"
            icon="cancel"
            outline
            @click="showRejectModal = true"
          />
        </div>
      </div>

      <!-- Course Info Cards -->
      <div class="grid grid-cols-1 lg:grid-cols-3 gap-6 mb-6">
        <!-- Main Info -->
        <div class="lg:col-span-2 bg-white rounded-xl shadow-sm overflow-hidden">
          <!-- Thumbnail -->
          <div class="h-48 bg-gray-100 flex items-center justify-center">
            <img
              v-if="course.thumbnail_url"
              :src="course.thumbnail_url"
              :alt="course.title.th"
              class="w-full h-full object-cover"
            />
            <q-icon v-else name="school" size="80px" color="grey-4" />
          </div>

          <div class="p-6">
            <div class="flex flex-wrap gap-2 mb-4">
              <q-badge :color="getStatusColor(course.status)" :label="getStatusLabel(course.status)" />
              <q-badge color="grey" :label="course.category.name.th" />
              <q-badge v-if="course.is_free" color="green" label="ฟรี" />
              <q-badge v-else color="blue" :label="`฿${course.price.toLocaleString()}`" />
              <q-badge v-if="course.have_certificate" color="purple" label="มีใบประกาศนียบัตร" />
            </div>

            <h3 class="font-semibold text-gray-700 mb-2">รายละเอียด</h3>
            <p class="text-gray-600 whitespace-pre-line">{{ course.description.th }}</p>
            
            <div class="border-t mt-4 pt-4">
              <p class="text-sm text-gray-500">{{ course.description.en }}</p>
            </div>
          </div>
        </div>

        <!-- Side Info -->
        <div class="space-y-4">
          <!-- Stats -->
          <div class="bg-white rounded-xl shadow-sm p-6">
            <h3 class="font-semibold text-gray-700 mb-4">สถิติ</h3>
            <div class="space-y-3">
              <div class="flex justify-between">
                <span class="text-gray-500">จำนวนบท</span>
                <span class="font-medium">{{ course.chapters.length }}</span>
              </div>
              <div class="flex justify-between">
                <span class="text-gray-500">จำนวนบทเรียน</span>
                <span class="font-medium">{{ totalLessons }}</span>
              </div>
              <div class="flex justify-between">
                <span class="text-gray-500">วิดีโอ</span>
                <span class="font-medium">{{ videoCount }}</span>
              </div>
              <div class="flex justify-between">
                <span class="text-gray-500">แบบทดสอบ</span>
                <span class="font-medium">{{ quizCount }}</span>
              </div>
            </div>
          </div>

          <!-- Instructors -->
          <div class="bg-white rounded-xl shadow-sm p-6">
            <h3 class="font-semibold text-gray-700 mb-4">ผู้สอน</h3>
            <div class="space-y-3">
              <div
                v-for="instructor in course.instructors"
                :key="instructor.user_id"
                class="flex items-center gap-3"
              >
                <div class="w-10 h-10 bg-primary-100 rounded-full flex items-center justify-center">
                  <q-icon name="person" color="primary" />
                </div>
                <div>
                  <div class="font-medium">{{ instructor.user.username }}</div>
                  <div class="text-sm text-gray-500">{{ instructor.user.email }}</div>
                  <q-badge v-if="instructor.is_primary" color="primary" label="หลัก" size="sm" class="mt-1" />
                </div>
              </div>
            </div>
          </div>

          <!-- Timeline -->
          <div class="bg-white rounded-xl shadow-sm p-6">
            <h3 class="font-semibold text-gray-700 mb-4">ไทม์ไลน์</h3>
            <div class="space-y-3 text-sm">
              <div class="flex justify-between">
                <span class="text-gray-500">สร้างเมื่อ</span>
                <span>{{ formatDate(course.created_at) }}</span>
              </div>
              <div class="flex justify-between">
                <span class="text-gray-500">อัพเดทล่าสุด</span>
                <span>{{ formatDate(course.updated_at) }}</span>
              </div>
            </div>
          </div>
        </div>
      </div>

      <!-- Course Structure -->
      <div class="bg-white rounded-xl shadow-sm p-6 mb-6">
        <h3 class="font-semibold text-gray-700 mb-4">โครงสร้างหลักสูตร</h3>
        
        <div class="space-y-4">
          <q-expansion-item
            v-for="(chapter, index) in course.chapters"
            :key="chapter.id"
            :label="`บทที่ ${index + 1}: ${chapter.title.th}`"
            :caption="`${chapter.lessons.length} บทเรียน`"
            header-class="bg-gray-50 rounded-lg"
            expand-icon-class="text-primary"
          >
            <div class="pl-4 pt-2">
              <div
                v-for="(lesson, lessonIndex) in chapter.lessons"
                :key="lesson.id"
                class="flex items-center gap-3 py-2 border-b last:border-b-0"
              >
                <q-icon
                  :name="getLessonIcon(lesson.type)"
                  :color="lesson.is_published ? 'primary' : 'grey'"
                  size="24px"
                />
                <div class="flex-1">
                  <span class="text-gray-600">{{ lessonIndex + 1 }}. {{ lesson.title.th }}</span>
                  <q-badge
                    v-if="!lesson.is_published"
                    color="grey"
                    label="Draft"
                    size="sm"
                    class="ml-2"
                  />
                </div>
                <q-badge :color="getLessonTypeColor(lesson.type)" :label="lesson.type" size="sm" />
              </div>
            </div>
          </q-expansion-item>
        </div>
      </div>

      <!-- Approval History -->
      <div class="bg-white rounded-xl shadow-sm p-6">
        <h3 class="font-semibold text-gray-700 mb-4">ประวัติการอนุมัติ</h3>
        
        <q-timeline color="primary">
          <q-timeline-entry
            v-for="history in course.approval_history"
            :key="history.id"
            :title="getActionLabel(history.action)"
            :subtitle="formatDateTime(history.created_at)"
            :icon="getActionIcon(history.action)"
            :color="getActionColor(history.action)"
          >
            <div class="text-sm text-gray-600">
              <p>โดย: {{ history.submitter.username }}</p>
              <p v-if="history.reviewer">ผู้ตรวจสอบ: {{ history.reviewer.username }}</p>
              <p v-if="history.comment" class="mt-2 p-2 bg-gray-50 rounded">{{ history.comment }}</p>
            </div>
          </q-timeline-entry>
        </q-timeline>
      </div>
    </div>

    <!-- Reject Dialog -->
    <q-dialog v-model="showRejectModal" persistent>
      <q-card style="min-width: 400px">
        <q-card-section class="row items-center q-pb-none">
          <div class="text-h6">ปฏิเสธคอร์ส</div>
          <q-space />
          <q-btn icon="close" flat round dense @click="showRejectModal = false" />
        </q-card-section>

        <q-card-section>
          <p class="text-gray-600 mb-4">
            กรุณาระบุเหตุผลในการปฏิเสธคอร์ส "{{ course?.title.th }}"
          </p>
          <q-input
            v-model="rejectReason"
            type="textarea"
            outlined
            rows="4"
            label="เหตุผล *"
            :rules="[val => !!val || 'กรุณาระบุเหตุผล']"
            hide-bottom-space
            lazy-rules="ondemand"
          />
        </q-card-section>

        <q-card-actions align="right" class="q-pa-md">
          <q-btn flat label="ยกเลิก" color="grey-7" @click="showRejectModal = false" />
          <q-btn
            label="ยืนยันการปฏิเสธ"
            color="negative"
            :loading="actionLoading"
            :disable="!rejectReason.trim()"
            @click="confirmReject"
          />
        </q-card-actions>
      </q-card>
    </q-dialog>
  </div>
</template>

<script setup lang="ts">
import { useQuasar } from 'quasar';
import { adminService, type CourseDetailForReview } from '~/services/admin.service';

definePageMeta({
  layout: 'admin',
  middleware: ['auth', 'admin']
});

const $q = useQuasar();
const router = useRouter();
const route = useRoute();

// Data
const course = ref<CourseDetailForReview | null>(null);
const loading = ref(true);
const error = ref('');
const actionLoading = ref(false);
const showRejectModal = ref(false);
const rejectReason = ref('');

// Computed
const totalLessons = computed(() => 
  course.value?.chapters.reduce((sum, ch) => sum + ch.lessons.length, 0) || 0
);

const videoCount = computed(() => 
  course.value?.chapters.reduce((sum, ch) => 
    sum + ch.lessons.filter(l => l.type === 'VIDEO').length, 0
  ) || 0
);

const quizCount = computed(() => 
  course.value?.chapters.reduce((sum, ch) => 
    sum + ch.lessons.filter(l => l.type === 'QUIZ').length, 0
  ) || 0
);

// Methods
const fetchCourse = async () => {
  loading.value = true;
  error.value = '';
  
  try {
    const courseId = Number(route.params.id);
    course.value = await adminService.getCourseForReview(courseId);
  } catch (err) {
    error.value = (err as any).data?.message || 'ไม่สามารถโหลดข้อมูลคอร์สได้';
  } finally {
    loading.value = false;
  }
};

const getStatusColor = (status: string) => {
  const colors: Record<string, string> = {
    DRAFT: 'grey',
    PENDING: 'orange',
    APPROVED: 'positive',
    REJECTED: 'negative'
  };
  return colors[status] || 'grey';
};

const getStatusLabel = (status: string) => {
  const labels: Record<string, string> = {
    DRAFT: 'ฉบับร่าง',
    PENDING: 'รอตรวจสอบ',
    APPROVED: 'อนุมัติแล้ว',
    REJECTED: 'ถูกปฏิเสธ'
  };
  return labels[status] || status;
};

const getLessonIcon = (type: string) => {
  const icons: Record<string, string> = {
    VIDEO: 'play_circle',
    QUIZ: 'quiz',
    DOCUMENT: 'description'
  };
  return icons[type] || 'article';
};

const getLessonTypeColor = (type: string) => {
  const colors: Record<string, string> = {
    VIDEO: 'blue',
    QUIZ: 'purple',
    DOCUMENT: 'teal'
  };
  return colors[type] || 'grey';
};

const getActionLabel = (action: string) => {
  const labels: Record<string, string> = {
    SUBMITTED: 'ส่งเพื่อตรวจสอบ',
    APPROVED: 'อนุมัติ',
    REJECTED: 'ปฏิเสธ',
    RESUBMITTED: 'ส่งใหม่'
  };
  return labels[action] || action;
};

const getActionIcon = (action: string) => {
  const icons: Record<string, string> = {
    SUBMITTED: 'send',
    APPROVED: 'check_circle',
    REJECTED: 'cancel',
    RESUBMITTED: 'replay'
  };
  return icons[action] || 'info';
};

const getActionColor = (action: string) => {
  const colors: Record<string, string> = {
    SUBMITTED: 'primary',
    APPROVED: 'positive',
    REJECTED: 'negative',
    RESUBMITTED: 'orange'
  };
  return colors[action] || 'grey';
};

const formatDate = (date: string) => {
  return new Date(date).toLocaleDateString('th-TH', {
    day: 'numeric',
    month: 'short',
    year: '2-digit'
  });
};

const formatDateTime = (date: string) => {
  return new Date(date).toLocaleDateString('th-TH', {
    day: 'numeric',
    month: 'short',
    year: '2-digit',
    hour: '2-digit',
    minute: '2-digit'
  });
};

const confirmApprove = () => {
  if (!course.value) return;
  
  $q.dialog({
    title: 'ยืนยันการอนุมัติ',
    message: `คุณต้องการอนุมัติคอร์ส "${course.value.title.th}" หรือไม่?`,
    persistent: true,
    ok: {
      label: 'อนุมัติ',
      color: 'positive'
    },
    cancel: {
      label: 'ยกเลิก',
      flat: true
    }
  }).onOk(async () => {
    actionLoading.value = true;
    try {
      const response = await adminService.approveCourse(course.value!.id);
      $q.notify({
        type: 'positive',
        message: response.message || 'อนุมัติคอร์สสำเร็จ',
        position: 'top'
      });
      router.push('/admin/courses/pending');
    } catch (err: any) {
      $q.notify({
        type: 'negative',
        message: err.data?.message || 'เกิดข้อผิดพลาดในการอนุมัติคอร์ส',
        position: 'top'
      });
    } finally {
      actionLoading.value = false;
    }
  });
};

const confirmReject = async () => {
  if (!course.value || !rejectReason.value.trim()) return;
  
  actionLoading.value = true;
  try {
    const response = await adminService.rejectCourse(course.value.id, rejectReason.value);
    $q.notify({
      type: 'positive',
      message: response.message || 'ปฏิเสธคอร์สสำเร็จ',
      position: 'top'
    });
    showRejectModal.value = false;
    router.push('/admin/courses/pending');
  } catch (err: any) {
    $q.notify({
      type: 'negative',
      message: err.data?.message || 'เกิดข้อผิดพลาดในการปฏิเสธคอร์ส',
      position: 'top'
    });
  } finally {
    actionLoading.value = false;
  }
};

// Lifecycle
onMounted(() => {
  fetchCourse();
});
</script>
