import { defineStore } from 'pinia';
import { instructorService } from '~/services/instructor.service';

interface Course {
    id: number;
    title: string;
    students: number;
    lessons: number;
    icon: string;
    thumbnail: string | null;
}

interface DashboardStats {
    totalCourses: number;
    totalStudents: number;
    completedStudents: number;
}

interface CourseStatusCounts {
    approved: number;
    pending: number;
    draft: number;
    rejected: number;
}

export const useInstructorStore = defineStore('instructor', {
    state: () => ({
        stats: {
            totalCourses: 0,
            totalStudents: 0,
            completedStudents: 0
        } as DashboardStats,

        courseStatusCounts: {
            approved: 0,
            pending: 0,
            draft: 0,
            rejected: 0
        } as CourseStatusCounts,

        recentCourses: [] as Course[],
        loading: false
    }),

    getters: {
        getDashboardStats: (state) => state.stats,
        getRecentCourses: (state) => state.recentCourses
    },

    actions: {
        async fetchDashboardData() {
            this.loading = true;
            try {
                // Fetch real courses from API
                const courses = await instructorService.getCourses();

                // Fetch student counts for each course
                let totalStudents = 0;
                let completedStudents = 0;
                const courseDetails: Course[] = [];

                for (const course of courses.slice(0, 5)) {
                    try {
                        // Get student counts
                        const studentsResponse = await instructorService.getEnrolledStudents(course.id, 1, 1);
                        const courseStudents = studentsResponse.total || 0;
                        totalStudents += courseStudents;

                        // Get completed count from full list (if small) or estimate
                        if (courseStudents > 0 && courseStudents <= 100) {
                            const allStudents = await instructorService.getEnrolledStudents(course.id, 1, 100);
                            completedStudents += allStudents.data.filter(s => s.status === 'COMPLETED').length;
                        }

                        // Get lesson count from course detail
                        const courseDetail = await instructorService.getCourseById(course.id);
                        const lessonCount = courseDetail.chapters.reduce((sum, ch) => sum + ch.lessons.length, 0);

                        courseDetails.push({
                            id: course.id,
                            title: course.title.th,
                            students: courseStudents,
                            lessons: lessonCount,
                            icon: 'book',
                            thumbnail: course.thumbnail_url || null
                        });
                    } catch (e) {
                        // Course might not have students endpoint
                        courseDetails.push({
                            id: course.id,
                            title: course.title.th,
                            students: 0,
                            lessons: 0,
                            icon: 'book',
                            thumbnail: course.thumbnail_url || null
                        });
                    }
                }

                // Update stats
                this.stats.totalCourses = courses.length;
                this.stats.totalStudents = totalStudents;
                this.stats.completedStudents = completedStudents;

                // Update course status counts
                this.courseStatusCounts = {
                    approved: courses.filter(c => c.status === 'APPROVED').length,
                    pending: courses.filter(c => c.status === 'PENDING').length,
                    draft: courses.filter(c => c.status === 'DRAFT').length,
                    rejected: courses.filter(c => c.status === 'REJECTED').length
                };

                // Update recent courses (first 3)
                this.recentCourses = courseDetails.slice(0, 3);
            } catch (error) {
                console.error('Failed to fetch dashboard data:', error);
            } finally {
                this.loading = false;
            }
        }
    }
});