'use server';
import { signOut } from '@/auth';
import { db, applications, jobs, students, resumes, grades, internships } from '@workspace/db';
import { eq, and } from '@workspace/db/drizzle';
import { revalidatePath } from 'next/cache';

export async function signOutAction() {
  await signOut();
}

export async function applyForJob(jobId: number, studentId: number, resumeId: number) {
  try {
    // Check if student has already applied for this job
    const existingApplication = await db.query.applications.findFirst({
      where: and(eq(applications.jobId, jobId), eq(applications.studentId, studentId)),
    });

    if (existingApplication) {
      return { success: false, error: 'You have already applied for this job' };
    }

    // Create new application
    await db.insert(applications).values({
      jobId,
      studentId,
      resumeId,
      status: 'pending',
    });

    revalidatePath('/applications');
    return { success: true };
  } catch (error) {
    console.error('Error applying for job:', error);
    return { success: false, error: 'Failed to apply for job' };
  }
}

export async function getStudentApplications(studentId: number) {
  try {
    const studentApplications = await db.query.applications.findMany({
      where: eq(applications.studentId, studentId),
      with: {
        job: {
          with: {
            company: true,
          },
        },
        resume: true,
      },
    });

    return { success: true, applications: studentApplications };
  } catch (error) {
    console.error('Error fetching student applications:', error);
    return { success: false, error: 'Failed to fetch applications' };
  }
}

export async function getStudentProfile(studentId: number) {
  try {
    const student = await db.query.students.findFirst({
      where: eq(students.id, studentId),
      with: {
        grades: true,
        resumes: true,
        internships: true,
      },
    });

    return { success: true, student };
  } catch (error) {
    console.error('Error fetching student profile:', error);
    return { success: false, error: 'Failed to fetch student profile' };
  }
}

export async function updateStudentProfile(studentId: number, data: any) {
  try {
    const { section, ...updateData } = data;

    switch (section) {
      case 'grades':
        return await updateGrades(studentId, updateData.grades);
        
      case 'internships':
        return await updateInternships(studentId, updateData.internships);
        
      case 'resumes':
        return await updateResumes(studentId, updateData.resumes);
        
      default:
        // Update student basic information
        await db
          .update(students)
          .set({
            ...updateData,
            updatedAt: new Date(),
          })
          .where(eq(students.id, studentId));
        
        revalidatePath('/profile');
        return { success: true };
    }
  } catch (error) {
    console.error('Error updating student profile:', error);
    return { success: false, error: 'Failed to update profile' };
  }
}

async function updateGrades(studentId: number, gradesList: any[]) {
  try {
    // Delete existing grades for this student
    await db.delete(grades).where(eq(grades.studentId, studentId));
    
    // Insert new grades
    if (gradesList && gradesList.length > 0) {
      const validGrades = gradesList.filter(grade => grade.sgpi > 0); // Only save grades with SGPI > 0
      
      if (validGrades.length > 0) {
        await db.insert(grades).values(
          validGrades.map(grade => ({
            studentId,
            sem: parseInt(grade.sem),
            sgpi: parseFloat(grade.sgpi).toFixed(2),
            isKT: Boolean(grade.isKT),
            deadKT: Boolean(grade.deadKT),
          }))
        );
      }
    }
    
    revalidatePath('/profile');
    return { success: true };
  } catch (error) {
    console.error('Error updating grades:', error);
    return { success: false, error: 'Failed to update grades' };
  }
}

async function updateInternships(studentId: number, internshipsList: any[]) {
  try {
    // Delete existing internships for this student
    await db.delete(internships).where(eq(internships.studentId, studentId));
    
    // Insert new internships
    if (internshipsList && internshipsList.length > 0) {
      await db.insert(internships).values(
        internshipsList.map(internship => ({
          studentId,
          title: internship.title,
          company: internship.company,
          location: internship.location,
          description: internship.description,
          startDate: new Date(internship.startDate),
          endDate: new Date(internship.endDate),
        }))
      );
    }
    
    revalidatePath('/profile');
    return { success: true };
  } catch (error) {
    console.error('Error updating internships:', error);
    return { success: false, error: 'Failed to update internships' };
  }
}

async function updateResumes(studentId: number, resumesList: any[]) {
  try {
    // Delete existing resumes for this student
    await db.delete(resumes).where(eq(resumes.studentId, studentId));
    
    // Insert new resumes
    if (resumesList && resumesList.length > 0) {
      await db.insert(resumes).values(
        resumesList.map(resume => ({
          studentId,
          title: resume.title,
          link: resume.link,
        }))
      );
    }
    
    revalidatePath('/profile');
    return { success: true };
  } catch (error) {
    console.error('Error updating resumes:', error);
    return { success: false, error: 'Failed to update resumes' };
  }
}

export async function getAvailableJobs() {
  try {
    const availableJobs = await db.query.jobs.findMany({
      where: eq(jobs.active, true),
      with: {
        company: true,
      },
    });

    return { success: true, jobs: availableJobs };
  } catch (error) {
    console.error('Error fetching available jobs:', error);
    return { success: false, error: 'Failed to fetch jobs' };
  }
}

export async function getFeaturedCompanies() {
  try {
    const companies = await db.query.companies.findMany({
      with: {
        jobs: {
          where: eq(jobs.active, true),
        },
      },
    });

    // Filter companies with active jobs and sort by number of jobs
    const companiesWithJobs = companies
      .filter((company) => company.jobs.length > 0)
      .sort((a, b) => b.jobs.length - a.jobs.length)
      .slice(0, 6); // Top 6 companies

    return { success: true, companies: companiesWithJobs };
  } catch (error) {
    console.error('Error fetching featured companies:', error);
    return { success: false, error: 'Failed to fetch companies' };
  }
}

export async function getResumes(studentId: number) {
  try {
    const r = await db.select().from(resumes).where(eq(resumes.studentId, studentId));
    return { success: true, resumes: r };
  } catch (error) {
    console.error('Error fetching resumes for studentId:', studentId, '\n', error);
    return { success: false, error: 'Failed to fetch resumes' };
  }
}

export async function getStudentApplicationJobIds(studentId: number) {
  try {
    const studentApplications = await db.query.applications.findMany({
      where: eq(applications.studentId, studentId),
      columns: {
        jobId: true,
      },
    });

    const appliedJobIds = studentApplications.map(app => app.jobId);
    return { success: true, appliedJobIds };
  } catch (error) {
    console.error('Error fetching student applied job IDs:', error);
    return { success: false, error: 'Failed to fetch applied job IDs' };
  }
}