<template>
  <div>
    <!-- Loading -->
    <div v-if="loading" class="flex justify-center py-20">
      <q-spinner-dots size="50px" color="primary" />
    </div>

    <template v-else-if="course">
      <!-- Course Header -->
      <div class="bg-white rounded-xl shadow-sm p-6 mb-6">
        <div class="flex flex-col md:flex-row gap-6">
          <!-- Thumbnail -->
          <div
            class="bg-gray-100 rounded-lg flex items-center justify-center flex-shrink-0 relative group cursor-pointer overflow-hidden border border-gray-200"
            style="width: 192px; height: 128px;"
            @click="triggerThumbnailUpload"
          >
            <img
              v-if="course.thumbnail_url"
              :src="course.thumbnail_url"
              :alt="course.title.th"
              class="w-full h-full object-cover"
            />
            <div v-else class="flex flex-col items-center">
              <q-icon name="image" size="30px" color="grey-5" />
              <span class="text-grey-6 text-xs mt-1">อัพโหลดรูป</span>
            </div>

            <!-- Overlay -->
            <div class="absolute inset-0 bg-black/40 opacity-0 group-hover:opacity-100 transition-opacity flex flex-col items-center justify-center">
              <q-icon name="photo_camera" color="white" size="24px" />
              <span class="text-white text-xs mt-1">เปลี่ยนรูป</span>
            </div>

            <!-- Loading -->
            <div v-if="uploadingThumbnail" class="absolute inset-0 bg-white/80 flex items-center justify-center">
              <q-spinner color="primary" size="2em" />
            </div>

            <!-- Hidden Input -->
            <input
              ref="thumbnailInputRef"
              type="file"
              accept="image/*"
              class="hidden"
              @click.stop
              @change="handleThumbnailUpload"
            />
          </div>

          <!-- Info -->
          <div class="flex-1">
            <div class="flex items-start justify-between">
              <div>
                <h1 class="text-2xl font-bold text-gray-900">{{ course.title.th }}</h1>
                <p class="text-gray-600 mt-1">{{ course.description.th }}</p>
              </div>

              <!-- Status Badges -->
              <div class="flex gap-2">
                <q-badge v-if="course.is_free" color="purple">ฟรี</q-badge>
                <q-badge v-else color="purple">เสียเงิน</q-badge>
                <q-badge :color="getStatusColor(course.status)">
                  {{ getStatusLabel(course.status) }}
                </q-badge>
              </div>
            </div>

            <!-- Stats -->
            <div class="flex items-center gap-6 mt-4 text-gray-600">
              <div class="flex items-center gap-1">
                <q-icon name="menu_book" size="20px" />
                <span>{{ totalLessons }} บทเรียน</span>
              </div>
              <div class="flex items-center gap-1">
                <q-icon name="people" size="20px" />
                <span>{{ totalStudentsCount }} ผู้เรียน</span>
              </div>
            </div>
          </div>

          <!-- Actions -->
          <div class="flex flex-col gap-2">
            <q-btn
              outline
              color="primary"
              label="แก้ไข"
              icon="edit"
              @click="navigateTo(`/instructor/courses/${course.id}/edit`)"
            />
            <q-btn
              v-if="course.status === 'DRAFT'"
              color="primary"
              label="ขออนุมัติหลักสูตร"
              @click="requestApproval"
            />
          </div>
        </div>
      </div>

      <!-- Tabs -->
      <q-tabs
        v-model="activeTab"
        class="bg-white rounded-t-xl shadow-sm text-primary-600"
        active-color="primary"
        indicator-color="primary"
        align="left"
      >
        <q-tab name="structure" icon="list" label="โครงสร้าง" />
        <q-tab name="students" icon="people" label="ผู้เรียน" />
        <q-tab name="instructors" icon="manage_accounts" label="ผู้สอน" />
        <q-tab name="quiz" icon="quiz" label="ผลการทดสอบ" />
        <q-tab name="announcements" icon="campaign" label="ประกาศ" />
      </q-tabs>

      <!-- Tab Panels -->
      <q-tab-panels v-model="activeTab" class="bg-white rounded-b-xl shadow-sm">
        <!-- Structure Tab -->
        <q-tab-panel name="structure" class="p-6">
          <CourseStructureTab :course-id="course.id" :chapters="course.chapters" />
        </q-tab-panel>

        <!-- Students Tab -->
        <q-tab-panel name="students" class="p-6">
          <CourseStudentsTab :course-id="course.id" />
        </q-tab-panel>

        <!-- Instructors Tab -->
        <q-tab-panel name="instructors" class="p-6">
          <CourseInstructorsTab :course-id="course.id" />
        </q-tab-panel>

        <!-- Quiz Results Tab -->
        <q-tab-panel name="quiz" class="p-6">
          <CourseQuizResultsTab :course-id="course.id" :chapters="course.chapters" />
        </q-tab-panel>

        <!-- Announcements Tab -->
        <q-tab-panel name="announcements" class="p-6">
          <CourseAnnouncementsTab :course-id="course.id" />
        </q-tab-panel>
      </q-tab-panels>
    </template>
  </div>
</template>

<script setup lang="ts">
import { useQuasar } from 'quasar';
import {
  instructorService,
  type CourseDetailResponse
} from '~/services/instructor.service';



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

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

// State
const loading = ref(true);
const course = ref<CourseDetailResponse | null>(null);
const activeTab = ref('structure');
const uploadingThumbnail = ref(false);
const thumbnailInputRef = ref<HTMLInputElement | null>(null);
const totalStudentsCount = ref(0);

// Computed
const totalLessons = computed(() => {
  if (!course.value) return 0;
  return course.value.chapters.reduce((sum, ch) => sum + ch.lessons.length, 0);
});

// Methods
const fetchCourse = async () => {
  loading.value = true;
  try {
    const courseId = parseInt(route.params.id as string);
    const [courseData, studentsData] = await Promise.all([
      instructorService.getCourseById(courseId),
      instructorService.getEnrolledStudents(courseId, 1, 1)
    ]);
    
    course.value = courseData;
    totalStudentsCount.value = studentsData.total;
  } catch (error) {
    console.error('Failed to fetch course:', error);
    $q.notify({ type: 'negative', message: 'ไม่สามารถโหลดข้อมูลหลักสูตรได้', position: 'top' });
  } finally {
    loading.value = false;
  }
};


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

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

const triggerThumbnailUpload = () => {
  thumbnailInputRef.value?.click();
};

const handleThumbnailUpload = async (event: Event) => {
  const input = event.target as HTMLInputElement;
  const files = input.files;
  if (!files || files.length === 0 || !course.value) return;

  uploadingThumbnail.value = true;
  try {
    const response = await instructorService.uploadCourseThumbnail(course.value.id, files[0]);
    if (response.data?.thumbnail_url) {
      course.value.thumbnail_url = response.data.thumbnail_url;
    }
    $q.notify({ type: 'positive', message: response.message, position: 'top' });
    input.value = '';
  } catch (error: any) {
    $q.notify({
      type: 'negative',
      message: error.data?.error?.message || error.data?.message || 'เกิดข้อผิดพลาดในการอัพโหลดรูปภาพ',
      position: 'top'
    });
  } finally {
    uploadingThumbnail.value = false;
  }
};

const requestApproval = async () => {
  if (!course.value) return;
  try {
    const response = await instructorService.submitCourseForApproval(course.value.id);
    $q.notify({ type: 'positive', message: response.message || 'ส่งขออนุมัติสำเร็จ', position: 'top' });
    fetchCourse();
  } catch (error: any) {
    $q.notify({ 
      type: 'negative', 
      message: error.data?.message || 'ไม่สามารถส่งขออนุมัติได้', 
      position: 'top' 
    });
  }
};

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